sin d>' \ v. sin d>.
—TT-—— 5rr-, from the circumstance that V=~= • ^-
A, A A » sin
Now 8l = acos(ex + edx +fy +/8y + ct') — a cos (e x +fy + ct)
= — I (1 — cosedx+f8 y) — a sin (ea;+/y + ct) sin (e§x+fdy)
--
& € uX
and in the same way the other increments are easily determined.
VOL. XV. PART I.
42 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
Let us abbreviate eSx+fdy by ki, e8x-fdy by kr, e,8x+f8y by k,e, and
e' 8 x +/8y by k' o ; then we have the following values of 8 1, &c.
* T O T • 9 ^ Z 1 rf I .
o I = — 2 1 sm2 — H --- sm k z
2
« T . 0 T, . 0 k i 1 d I' .
o I'= — 21'sin2 — + -- smkt
2 e rfz
X E> o r> • 9 ^ r 1 a? R .* ,
oR=— 2Rsm2 — H --- smkr
2 e dx
d R'= -2 R'sin2 — + - — sin k r
2 e dx
%T> n /-i — mtx ..% \ 1 afR, — mS* . ,»
oR/=— R7(l — e cosfoy) + - — ^e smfoy
2 e' afa;
— "», 5* f S \.1'*1/ — »», J X • ,. 5>
cos/dy) + -— -ie ' sin/Oy
f ay
By substituting these results in the increments of equations (1) and (2), we
shall obtain
d a = — 2 I sin d> sin2 — + 2 R sin d> sin2 — H --- sin d> sin k i
2 2 e dx
1 d R . i . , n /i — »» S * j- % \ d R 1 — m Jr.
— —
. i . , n /i — »» * j- % \ — m Jr. .. «
--- -— sm
2 2 edx e dx
». ki n-n, . .k r I dl' . 1 rfR' .
5'y=-2rsin2— + 2R'sm!— -+- -— smki --- — s
2 2 e dx edx
8 at=— 2T,sin(£/ cos 6 sin2 -^- + 2 T' sin <£' sin & sin2 _ + -- sin (p/ cos 6 sin k, e
1 rf T' . /i, • m /i — »», S« ..Jx L di. — m, > x . .. s>
' '-- ' -~— sm/Oy
§ f$t= — 2 T cos (f), cos 0 sin2 -^- + 2 T' cos (r) represents the force which one particle exerts
on another at the distance r ; x, y, z are the co-ordinates of the particle under
consideration ; x + 8x, y+Sy, z+8 z, those of another particle without the crystal ;
x + d xf, y + $/, 2 + d z', those of a particle within the crystal : r the distance between
the particle under consideration and another particle in the upper medium, r' the
corresponding distance for a particle in the lower medium ; all taken when the
system is in a state of rest : /• + p the value which r acquires at the end of the
time t ; / + g' the corresponding value of r' ; (a,), (/?,), (7,) are the displacements of
a particle within the medium at the time t. Thus, by the usual process (See Me-
moir on Dispersion in Trans. Camb. Philos. Soc., vol. vi. p. 158), we have, for the
force on the particle resolved parallel to the axis of x,
v (
=Il<
^
But (a,) = a, + 8 a, ; therefore the force parallel to the axis of x is ~ =
t* t
(5.)
It may be remarked that we have, in deducing the last equation from the
preceding one, suffered ourselves to imagine that a, has a value when the particle
is without the medium. Although it can hardly be doubted that the value of (a,)
so obtained is quite correct, we do not purpose to insist on it, but shall obviate
the objection at once by restricting our discussion to the particles situated at the
common surface of the two media. The values of 2 are the same on both sides
of the surface, each extending over half an infinite space, the one upwards, the
other downwards.
In order to find the value of the force, or of -^ , all that remains to be done
Ct f
is to substitute in equation (5) the values of 8 a, 8/3, &c. from equation (4).
44 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
The result is
e dx
+&c. (6.)
«y j
This equation, although apparently long and complicated, can, by reason of
its symmetry, be reduced to a very simple form.
The reduction is effected by transforming the co-ordinates of each particular
part in such a way, that whilst the axis of z always remains unchanged, the other
axes shall vary in such a manner that one of them shall be in the direction in
which that elementary motion to which it is due is transmitted. Thus all the
portions which Involve § a, 5/3, 8 7 will be reduced by changing the co-ordinates
to others, one of which is in the direction 10 of incidence, and the other perpendi-
cular to it, in the plane of incidence. Again, all the portions which involve d T will
be reduced by changing the co-ordinates to others, one of which is in the direction
TO of transmission of this vibration, and the other perpendicular to it, and so on.
The effects of this transformation will be twofold ; 1°, A considerable portion of
the expression will vanish altogether by virtue of the symbol 2 ; 2°, Those parts
which remain will, by virtue of the hypothesis that all the vibrations occupy the
same time, be reduced to known forms ; or at least the major part of them.
For incident vibrations, let i and p stand for the co-ordinates reckoned in
and perpendicular to the direction of incidence : then
dx=i cos (f)+p sm+p cosff).
Now, the principle on which the reduction is carried on is this ; after the co-
ordinates have been transformed, the values of the expressions are determined by
means of the law that in a complete medium extending both above and below the
d3 a
point under consideration, the ratio of -T-J- to a is — e2.
But this ratio is evidently the double of the integral —22 ( r + >— p*~) sin 2 -^ . (7.)
2 Y 2i
But further, since r^p2 + # + »2, it follows that ^ = 2 2 (0 r + ^ ^) sin 2 y ; and
also, if Ave suppose the law of force to be that of Newton, a supposition which has
been made by me, and I think established on good grounds in several preceding
memoirs, we shall have the following relations :
2
k i i*-p* ki
T = S2— ,-sm* -
REFLECTED AT THE SURFACE OF A CRYSTAL. 45
+ 2ip sin (f) cos 0 +)? sin2 0) 1 2 sin2 — *
= 2 (0 r + ^*2cos20+jo2sin2 0) 2 sin2 y ,
'?• /fe i
because 2 — «psin*-2-=:0, from the cu-cumstance that every value of i has two
equal values of p with opposite signs.
Hence 20r + ^5a;22sin2=2>-cos2^) + sin2 + 2-^z2cos2+;u2sm2). 2 sin2
= 2 (0 r + ^jo2)2sin2 ^ sin2 0 + 2(0 r + ^-i2) 2sin* y cos*0
*2) 2 sin2 cos2 (p.
But 2(r + -22sin2 = S2 - - 2 sin2
2
-C2 (8).
Hence, finally, 2(0r + ^5r02sin2^=^(sin20-
T 2i 2
Similarly, 2 (0 r + 2-^-<5 a;2) 2 sin2 ^ = ^ (sin2 0-2 cos2 0)
/* mm
Again, ^((pr + — d a?} sin A j = 2 ( r + — p2) sin Ae sin2 0
rf>'r
+ 2 (0 r + J— »») sin ** cos2
and 2 ((j)r + y-r f) sin A »= -22 (0 r + ^/>2) sin A *
as equation (8) shews.
d)'r
Denote this quantity 2 (sin0, 8y—rsm ;
and for the wave T'
8 xf = o cos (f)+j> sin (p, § y'=—o sin (f)-rpcos(p.
Hence, referring to equations (4) for the value of d /3, we get
2 — d zdy d /3= — 2 --- | i cos cos 0 ( — 2 R sin2 —-\ --- — sin kr) \ cos (b
2 e dx )
M /rfl ' - 2 cos2 ') - D, T,. (c.)
£ f f .1
The value of D, is 2 (0 / + ^ 5 *">) (1 - *—»<»-' cos/5/) ;
and the values of M, and M' respectively
(b' r'
2 (/ + !-—- e2) sin A; e, and 2 (0 >•' + *-^- o2) sin A o.
d)'/
In the same way we can write down the value of 2 -^7- §tf dy' 8/3, from that
Of
Thus 2 £-£ 5 a:' 8y' d /9,= 3 sin <£, cos 0, | - ~ T cos 0, cos 6
+ —' -T— cos d),cos6 } +3 sin d)' cos (f)' I TJ- T' cos '-2 cos2 0' + 3 cos2 <£') - D; Ty
M' dT'\
— —
-- -
and (e) is Q^.^-a).
48 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
Hence the sum of the quantities, or the value of —rj is reduced to the fol-
lowing very simple expression,
Or Cl (r ( /T 1_x . , , _, . , .* _ . . . /i, "I iM / d I d rv\
-:— =—-?:{ (I— R)sm0 + Tsm0/cosa— T'sm0'smo > +— (— |sui0
dP 2 I J e \dx dx)
' sin0, cos 0-- sin 0' sin tf-DI^-D/r,* Q,,(a,-o) (9).
€
d2 a
This value of -j-g- is now in its simplest form involving only the vibrations and
their differential coefficients with respect to x.
To find the value of .
By interchanging y and x, y1 and a/, ft and a, ft and a! in equation (5), we
have the folio whig expression as the first value.
NOW
+ 2 (0 r + r2 sin2 0 + jo2 cos2 0) 5 R
cos
^i2) sin2 0 5 I cos 0 + 2 ((pr + ^p2) cos2 (p S I cos (J> + Sic.
We have not deemed it requisite to work out this result at full ; a glance
will serve to shew that it is right, when AVC add that, by the first of equations (7)
2l((hr + (^p^ Sin2 ^= J and by the last 2 2 (0 r + ^L *») sin2 ^f=-~ ; and like re-
T & 2t T £i &
suits obtain for 2 (0 r + ±-^-p*) sin * i and 2 (0 r + J— a'2) sin Az.
Again, 2 5— SxdySa differs from (b) in having 5 a in place of S /3, or, which
is the same thing, (I - R) sin 0 in place of (I + R) cos $ ; and in having a term con-
taining R, .'. by (b) we obtain,
e \dx ax
REFLECTED AT THE SURFACE OF A CRYSTAL. 49
But 18
r
since the first part vanishes.
Denote i&-8x8y e-^^smfdy hy F ;
M-rfldRA F dR,
then J*
The next term 2 (0 ^ +2^- r+^8^) we can give
d2 CL
the value of -r- at once.
, («-«,)- Qx, («,_«) .... (14)
similarly = + Qf (p-fa-Q,,(J3,-8) .... (15)
Thus we have obtained the six equations of motion. Let us now obtain from
these equations the results to which they give rise.
In the first place d-^-'^L=-(Q +Q*<) («-«/) ' but from the values of a
d t d t
and a,, we have
-«* («-«,)= ..... (17)
hence either Qx + Qx, = c2 or a-a,=0.
NOW
i a
+Sm2— _\ +22
z I, — - — _
a quantity essentially different from zero.
We have therefore a-a,=0; and, by (17), ^-f-^|i=0» as it ought.
d t d t
In the same way it may be shewn that
/3-/?,=0, and 7-^=0.
In the second place, by doubling equation (9), we obtain 2 j-^-, or
52 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
= -c"{(I-R) sin 0 + T sin 0, cos 0-T' sin 0' sin &} + — (^-- sin 0
e \dx ax
= -c8 {(I-R) sin 0 + R,+ T, + T sin 0,cos 0-T'sin 0' sin &}
by equations (1) and (2).
Hence, by subtraction, we find that
2r> -2T 2M/rfI dR\ 2M, rfT
H ( h -: — I cos 0
dtaf e \d x d x ]
nntz d\' cin /•)' J i .'
/ dy-
2¥ dR, f 2HA,dT\ / 2M'rfT'\
• -^- -j— — I c2 T i -j— ) cos 0, cos 0 + ( c2T' — I cos 0 sin
/ dy \ e, dx) \ ef dxl
d? B d2 8
But •J^+.-jJi=i-«*, cos 6 — — -r- sin <*' sin tf = 0 .... (IV)
e \dx dx) r e, dx e' dx
and (c«-2D)R, + (c«-2D/)T,=0 ... ... (VII)
We can obtain one further reduction of the equations in the following man-
ner:
M, MM' ,M
Let -2=-p— ——p'—;
e, ^ e' e' e
_2 V COS (f) _2 IT COS ,_ 2lT COS , \' \sin0'
if we substitute these values in (IV) and divide by sm(fy+ct), retaining the
notation of (3'), we obtain
, ,s • , sin (p. cos 6 cos d>. sin d> sin <6' sin & cos d)' sin (b _
(a + 6) sin © cos (b— p c — -^ - ; -- fi - L + n'd — J- - -. — -—!- - -*-=0,
sin 9, sin (f)'
or (a + 6) cos 9 — p c cos 9, cos 6 + p' c' cos 9' sin 0'= 0.
Also equation (II) gives, by dividing out cos (fy + c t),
(a + 6) cos . sin d> , cos O'cosch'sin d> n
(a' + 6f) cos d> — p c - - r— V - J-—p'd- —i—Jn -- -*-=0 . . (VI)
sin (p, sin ,
'S0' = 0 (VI")
sin sin (>, sin (£>'
together with (eB-2D)R, + (c9-2D,)T,=0 ..... (VII)
or (see previous Memoir) R,+T,=0 ....... (VII')
SECTION II. APPLICATION TO ORDINARY REFRACTION.
The first application we propose to make of our formulae is the determination
of the intensity of light reflected and refracted at the surface of a non-crystallized
medium. This problem differs from that which we solved in the memoir on
FRESNEL'S formulae, in this respect, that in that case the incident light was sup-
posed to be light polarized in two planes at right angles to each other. We now
suppose common light to be composed of light whose plane of polarization conti-
nually shifts its position.
Our equations at once answer this hypothesis by making ', and .-. />=/>'.
Now equation (IV") is, in this case,
(1-p) (T cos 6- T' sin <9') cos ,=<).
Either, therefore, 1-^=0, or T cos 6= T sin &.
If the latter be the case, equations (I), (II), and (V"), that is, all the equations de-
pending on the plane of incidence are independent of T and T', or of the trans-
mitted ray. But this can never be conceived to exist, except perhaps in metals ;
we must, therefore, adopt the other solution 1— p=Q.
Also «=1 ; /. our equations become
T/ . • (1)
. . . (2)
(3)
-- .T. (4)
sin
By combining (1, 4) and (2) we get
2 I = T cos 6 - + -T sin cos (p sin ') = — T (cos 0 cot u cos <£ - 0' + sin 0) . (10).
Again, if the reflected light be polarized in a plane, making the angle a with
that of incidence R'=£> cos a, R=p sin a,
2R'=-2Rcota,
and
or (T cos 6 - T' sin &) cos (/> + 0' cot a = (T sin 6 + T' cos 0'),
or T(-cos0cos + 'cota + sin0)=— T'{sin0'cos' cota + cos #} . . (11).
56 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
Multiplying this equation by the former, we have
(cos & — sin & cot « cos (f) — 0') (cos 6 cos 0 + — 0' + sin 6) (sin & cos (p + (f)' cot a + cos &)
or cos 6 cos & cos 0 + 0' cot a + sin Q sin & cos — 0' cot w=
— cos 0cos # cos0 — (f)' cot u— sin 0sin #cos0 + 0'cot a, . . . (12)
or (cos 6 cos & + sin 0 sin &) (cos 0 + 0' + cos 0 — 0' tan a cot «).
7T
The first factor gives 6=& + -~ which shews that the two planes of vibration coin-
cide when ta is given. This result is interpreted by saying, that if the incident
light is polarized, the refracted light is polarized also. The other factor will be
zero when the light incident is common light, that is when *> is indeterminate ;
and, further, it is evident that both its terms will be separately zero or tana=0,
and cos (0 + 0')=0. Of these the former shews that the plane of polarization coin-
cides with that of incidence ; and the latter, that the value of the polarizing angle
is determined from the circumstance that the angles of incidence and refraction
are complementary to one another, which is the well-known law obtained by expe-
riment.
If we suppose, as FRESNEL does, that the transmitted light consists of vibra-
tions polarized in two planes at right angles to each other, we have 6 = #=0,
sin0 + 0' cos0- 0' _„ _, sin 0-0' cos 0 + 0'
\. — J. . -r~, "T . £ XV ^Z — X ; -7— -7 •,
sin 0 cos (p sin 0 cos ' cos ft + <
' cos (> — (
= _ j tan 0-0' ^ (FRESNEL'S result.)
tan 0 + 0'
2 sin 0' cos 0
sin 0 + 0' cos 0 — 0"
,-„.
Do.)
T'=
sin 0
Thus all FRESNEL'S four results are contained in our equations as particular
cases.
REFLECTED AT THE SURFACE OF A CRYSTAL. 57
Lastly, let us suppose the incident light to be polarized ; then « is no longer
indeterminate, and equation (12) gives
— -
cos(p — <
which coincides with the value of the inclination of the plane of polarization to
that of incidence given by FRESNEL'S Theory. (See AIKY'S Tracts, p. 301.)
SECTION III. MR M'CULLAGH'S HYPOTHESIS RELATIVE TO THE NATURE OF
CRYSTALLINE REFLECTION ON COMMON LIGHT. '
In this section we propose to determine the polarizing angle, and the planes
of polarization, by means of the hypothesis that each ray within the crystal is
produced by a portion of the incident light polarized in a certain plane. Let us
take the extraordinary wave, and, in discussing it, let us suppose no other to
exist. Let I, R, I', R/ be the incident and reflected vibrations in, and perpen-
dicular to, the plane of incidence. T the transmitted vibration in a plane which,
by FRESNEL'S Theory, passes through the axis of the crystal. Let this plane
make the angle 6 with that of incidence. Then all our equations of motion ap-
ply, if we omit T'.
By equation (IV.) we get p^l.
Also, we know that F= — M tan ..>;.(!)
(I -f R) cos 0 = T cos (/>, cos 6 ....... (2;
F-R'=Tsin0 ..'.... ", ....... (3)
R,+ T,=0 . . ...... . (4)
o j^ i
T,*tan0 . (5)
I' + R'=Ttan0cot0,sin0 ...... (6).
Adding (1) sin $ to (5) cos <£, we get
I-R = T^-£cos0-T,(*-l)sin0 ($)
sin cp,
T , D T- cos , a
I + K = T — 2_ cos 6
cosip
2 1'= T (tan (/> cot $, + 1) sin 6
2 R' = T (tan cot ,-!) sin 6
sinc/>
— -
\ cos
VOL. XV. PART I.
$, sinc/>\ ,.
'— — : — 7- 1 cos a+T, (s— l)sm \ a T , ,, .
I - if- T-% ) cos 6 + -^ («-l) sin 0
\cos sm sin
= cos rf> + (>,) cot 0 - •=' v - — y —- ^
•= - r — , . —a- •
T sin (0 — pj sin 6
Now * varies as the mass of ether put in motion by the ray compared with
the same mass without the crystal. Also, it is such as to equal 1 when the ray
coincides with the wave ; and we can easily find the ratio of the masses in the
following manner.
The mass outside the crystal has a common base at the surface of the crystal
with the mass inside. Also the slant heights corresponding with portions moved
during the same time, are in proportion to the velocities v, v0 of the wave with-
out and of the ray within the crystal.
Lastly, the angles made by those slant heights with the common base are
the complements of 0, which the wave and ray make respectively with
the normal.
Hence we have the ratio of the volumes in motion within the crystal to that
without = l^r-
v cos 0TTo=£.
But v0—-^— where vt is the velocity of the reave within the crystal,
COS 6
v. cos rf> sin rf> . cos rf>
the ratio of the volumes moved =
Now, by Spherical Trigonometry, it is evident that
cos (f>0 = cos $>, cos e + sin fy, sin e cos 6,
therefore the ratio of the volume in motion due to the ray within the crystal, to
that in motion due to the wave without, is
e— ~j! -- (c°s 0, c°s e + sin (b, sin e cos 6).
\ nf\c m ftf\c £ ^ ' '
sin (f> cos (/> cos e
Let A represent the ratio of the densities : then the ratio of the masses is
rin^coB^ + Bin^cosetane (gee M
But the value of s, when the ray coincides with the wave, is a multiple of
REFLECTED AT THE SURFACE OF A CRYSTAL. 5ft
S1Pt and s-l is the difference between the value of this quantity for the
sm , cos 6 tan e
-
If we suppose, with Mr M'CULLAGH and Mr NEUMANN, that A=l, our for-
mula will coincide with that of the former, by supposing that T, the transmitted
vibration, is the resolved part (in its proper direction) of the lost vibratory mo-
tion T, . This supposition amounts to conceiving that all the motion communi-
cated to the interior medium, is due to the motion at first given in a direction per-
pendicular to the surface.
The equation which we have obtained agrees well with experiment. Mr
M'CULLAGH has given the application of this equation so fully in his memoir, that
I do not think myself justified in discussing it in this place.
To obtain the result corresponding to the ordinary ray, we have only to
write 0' for $„ 90 + 6' for 6, and 1 for s, and we get
tan a= — cos (<£ + $') tan &.
This equation gives the value of the deviation or shifting of the plane of po-
larization. It is precisely the same as that obtained by M. NEUMANN and Mr
M'CULLAGH, and agrees closely with experiment.
Equating the two values of tan a, we have the following equation for deter-
mining the value of the polarizing angle :
a, j. \ ^ a T . A sin3 rf> . cos 6 tan e
cos (') tan 6 ' + cos (d> + <*,) cot 6 -- ^- . . /' — ,. . >>— 0.
1 sin (
/cos0-T'sin0'sin0' + T/ , , . (1)
(I + R)cos(/)=Tcos^/cos0-T'cos^)'sin0' ..... (2)
I'- R'= T sin 6 + T' cos & ' _ . ,* »s . - •. 4 ,/,« * • (3)
-/ /Q (4)
sui
sin ,
add together (1) and (4), and
I-RTcos0 Tsinfr
sin' *' V1' 4
By this equation and (2) we get
Put (*-l)T,sin0 = wTcos0 ..... (8)
then 21=Tcos
-
sm (p, cos 0 / sin }.
By multiplying these equations together we get
(2 sin 6 + m cot u -f m' cota) (2cos# cotfi— ncot a cot (f) + n' cot a cot 0)
= (—2 cosfl' + wcotw + w' cota) (—2 sin 6 cot0y— wzcot «cot0 + »z' cota cot ).
But when the incident light is common light, this expression will give rise to
two, of which one is the coefficient of cot u, and the other that part of the expres-
sion which does not contain ».
These are respectively,
m (2 cos & cot 0' + n' cot a cot 0) — »cot (2sin0 + »i' cota)
= n (—2 sin 6 cot, + m' cota cot) ;
REFLECTED ON THE SURFACE OF A CRYSTAL. 61
or 2cota{mn' cot(b — m' n cot (b}=2nsin6 cot (b — 2 n sin 6 cot $,
— 2m cos # cot (b' + 2 wz cos & cot <£
and 2 cot a{m' cos 0' cot ,— 4 sin 0 cos 6' cot ^>'
or cot a cot (j) (mri — m'n) — nsin 6 (cot 0 — cot <£,) + »w cos ^ (cot (f) — cot ,— cot<£') (B)
Eliminating cot a between these two equations, there results
2 sin 6 cos & (cot 0, — cot (b') cot 0 (mri — m! n) =
(m' cos & cot 0 + cot (br 4- w' sin 0 cot 0 + cot 0,) x
(M sin 6 cot (b — cot , + m cos #" cot 0 — cot (b'} . . (11)
This is the equation which determines the polarizing angle.
We can reduce it to a much more simple form by expunging one of the fac-
tors : thus,
L j. i. w./ sind).— — cot ,— $' is a small quantity, depending on the differences of the squares of the
refractive indices : call it of the first order.
n n ( sin d> — d>' cos (b + d)'
n'-m' n = COS 6 sin & sin cOS in ^ sin - sin (f) + fr cos $=fc-u si
sin d) + (b' cos (b —
_ sin — cos(b + <'sin (b + ()
n -L r sin (b — d). M cos 0 cos ^ sjn ^
(j cos PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
Now 0_0'— 0_0/+0 _0' = 0_0/ + D suppose
0 + 0'= 0 + 0,_ 0,_ (f)'= fy + 0,_ D
sin 0 — 0' = sin 0 — 0, + cos 0 — 0, . D
sin 0 + 0' = sin 0 + 0, — cos 0 -t- 0, D
sin 0 — 0' sin 0 — 0,
sinT^T^O =sin (0 + 0,) + C ' L
But this quantity has to be multiplied into cos 0 + 0' , which is itself of the first
order
v sin 0 — 0' sin 0 — 0,
cos 0T0' =^ £ - = ~— ^=£ cos 0 + 0'
sin 0 + 0 sin 0 + 0,
omitting quantities of the second order.
Hence, dividing by S1 -L~=J', we get
" sm0 + 0/
a, -i — -T-, ^ a w cos 0 sin 0, cos 6
tan 0' cos 0 + 0' + cot 6 cos (0 + 0,)— - -^— =° •
sin 0 — 0,8m 6*
which is of the/orm given by Mr M'CULLAGII, and is precisely the same as that
obtained by the process in Section III. The value of u too is the same as that
given by the formula there employed, which shews that we are correct in assum-
ing that u depends only on the diiference between the ray and the wave.
If it seem difficult to leave the quantity T, as part of the undetermined quan-
tity, we may easily get rid of the difficulty. In fact, our only reason for adopting
this mode of proceeding was, that, since it is requisite to have some one indeter-
minate quantity, we may as well have that quantity a compound one as a simple
one, provided it simplifies our operations. Let us therefore combine with our
former equations, the equation (VII'.), R, + T,=0.
Then if we multiply equation (1) by 1+*, and equation (4) by 2, and add
them, we have
/T T>N l^ - • J. 2 COS2 0\ f ,. N . , 2 COS2 0, 1 rp /)
(I — R) (l + #sm0 + — — ,r ) = { (l + *)sm0/+ — . ,r/ > Tcosfl
' \ sin 0 / sin 0, )
{,, , . , . 2 COS2 0' 1 T>/ • Or
(1 + *;• sm 0 + - E. \ T' sm U ,
sin 0'
or if 1 + s=2 + 2 1 where t is very small,
(I-R) -_ + ;sin0 =Tcos0(-r + ifsin0/\ -T' sin & __
\sin0 V \sin0, T/ \sin0'
sn
,,/COS0. Sin 0 Sin0-^-iy-r . ., , \
2 I = T cos 6 { —&• + -r— £ - * -^t- sin2 0 - smj 0, )
\ cos 0 sin 0, sin (p/ )
T' ' ft' /cos $*' s^n ^ / s'n "^ ~ a"/h r~a~
\cos0 sin 0' sin0'
REFLECTED ON THE SURFACE OF A CRYSTAL. 63
(sin 0 + 0, cos 0 — 0, sin 0 . „ , . „ , \ „ „ /j
2- — 2^-: — i — r.'_/_- - . sin2 0 — sin- 0 . 1 cos 0
cos 0 sin 0X sin (p; /
sin
cos<£sm(p' sm
^^_
' ^
/sin d> — sin 0, sin ^), r7
/sin &-<$>' cos 04-0' sin <£ -.— =-,- - T-^-T \ • a,
«'= ( — -L — ^s— -. — XT — r — t -. — -j-jsuro)— sur q>' I sin (7
V cos ' /sin 0-0, cos 0 + 0, sin 0 \
• - "~ — • - JT/ jl * IL ~~" * "• - H" alii lit — bill \u . I
sin — d)' cos ' sin 0 . . - . \
+ - - - ' L-''sm2 ^-sm » =
sin (p, \ cos 0 sin
tan & / \
' "fh fh' ( ^'n 0 — ^' ^"^ ^ "^ *?' — ^ ^^ *P ^® 0 sin2 0 — sin2 0' I
cot
_ \
esin(t) cos0siny 0 — sin- 0,1 =0
, /tan ^' (sin2 A -sin2 A') cot^rsin^-sin2*,^
The part which multiplies f IB sm0Cos0 (- -W^^^ ^(f+^ ~)
J
___
sin 0 cos 0 sin (0 +
_ A sin2 0X cos 0 tan 6
~~2 ' sin cos '
,. ,ir>. . A (sin20— sin2 A.) sin2rf>. tanc
.-. the subtractive part of equation (13) is - . ^- ysin (^ /^ sin g'
Our equation is therefore
sin (0-0') cos (0 + 0')_L *fl sin ¥-¥' cos ^±S A (sin2 0 - sin8 0,) sin2 0, tan f _ n
~ ~2 sin + sin a"
O jo
If we adopt the nota'lon of Mr M'CULLAGH, and put tan e= — g— sin u cos u,
where JS2=='
smj 0
((r — b2} sin w cos u sin2 rf)
tanf = ^ . 2 , r
sm2 0,
the above equation becomes
,, sin • — d>' cos a> + d)' , /, sin . cos + d>,
^^^ sin^ + 00 sin (0 + 0)
A (a*— I-} (sin2 0 — sin2 4 J sin2 * sin CD c"s u
2 ' sin (^J + 0,) sin 0
This coincides very nearly with M. NEUMANN'S formula.
64 PROFESSOR KELLAND ON THE POLARIZATION OF LIGHT
To find the value of the deviation, we have recourse to equation (A).
By substituting for m, mf, &c. their values in the first side of this equation,
and omitting quantities of the second order, this is reduced to
2 cos 6 sin & ,
cot a . —Y—.-—rr sin (d>,— d> ') cos (,)
sm ') cos (9, + 9')
sin 9, sin 9' cos (9 + 9')
By equating these we have
tana=— cos (0 + 0') tan 0" . . . (16)
On this result it is unnecessary to offer any remark.
. SECTION V. BIAXAL CRYSTALS.
We shall be very brief in our exposition of the method of proceeding which
must be applied to Biaxal Crystals. In fact, we have little else to do than to
repeat our previous formulae, making the slight difference in them which consists
in supposing a quantity s for each ray in both cases different from unity. Thus
for the one ray, we shall have
. a T, . sin3d>. cos 6 tan e
tan a = cos (9 + 9,) cot 6 - =-' A . // ,, --*
T sin (<£ — 9,) sm 0
and for the other,
A, T' sin3*' sin & tan V
tan a = cos (<£ + 9') tan & — ^ A -— *- -- --- w
1 sin (9 — . sin2 d> cos <9sin ''w - aO sin i-J/(«2— c2) r2
and .-. cos0 + 4>,cot0- ^A — E ... '. ., 9 y
sin (<£ — 0,) sm 0 2
i. — XT , a, T.' . sin d)' sin2 (b sin 6' sin (a + w.) sin i •\L (a2 — c2) r.2
= cos0 + ^'tan0'--7if A- -—_« ^^ - ^-^ •
sm 9 — 9 cos D •
See M'CULLAGH (Note to p. 37).
It is to be noticed that a, a, are the angles Avhich the direction of transmission
of one (and therefore approximately of both) of the waves makes with the optic
axes, and 4/ the angle between the plane passing through these directions and the
optic axes. The same kind of proceeding may be applied to the other method.
We do not think it necessary to work out the equations for biaxal crystals at full
length. Should experiments be made on this branch of optics, requiring a refe-
rence to their results, a very little additional labour will enable us to reduce our
iormulse to a shape fitted for numerical computation. A c the present time, to
REFLECTED ON THE SURFACE OF A CRYSTAL. ()5
enter farther on this subject, would be to swell the bulk of the present memoir
to little purpose.
By making the equations slightly more general, and omitting the terms which
correspond to the transmitted rays, retaining only those which correspond to
the lost vibration, denoted by T, in the memoir, we obtain the formulae for
metallic reflexion. There is no difficulty whatever in deducing from such for-
mulae the following results: — 1. That if light be reflected at the surface of
a metal, both the vibrations in the plane and perpendicular to the plane of re-
flexion, will suffer retardation. 2. That the retardation of the vibration, perpen-
dicular to the plane of reflexion, will be independent of the angle of incidence.
3. That vibrations in the plane of reflexion, will suffer retardation depending on
the angle of incidence. 4. That the intensity of the reflected vibrations perpendi-
cular to the plane of reflexion is equal to that of the incident ones. 5. That the
intensity of the vibrations in the plane of reflexion depends on the angle of inci-
dence. The interpretation of these results would be, 1. That polarized incident
light would suffer a change of polarization from plane to elliptical, from elliptical
to more or less elliptical. 2. That the tendency of a very great number of re-
flexions would be to change light polarized in any plane to light polarized in the
plane of incidence. 3. That the effect on common light would be twofold ; first,
to produce in it an excess of vibrations perpendicular to the plane of reflexion :
and, secondly, to change the phases of the two parts in, and perpendicular to, the
plane of reflexion relative to one another. The former change is analogous to
that which transparent media produce on light, the latter it is difficult to interpret.
All that would appear to result from it is the following : — " That if a continual
succession of such retardations were to take pla,ce, the parts of the ray would be
totally disjoined from each other, and the result would be a ray consisting of two
perfectly polarized pencils, one in, and the other perpendicular to, the plane of
reflexion, travelling together ; the intensity of the former being much greater
than that of the latter. I regret that my limits do not permit me to produce any
equations.
VOL. XV. PART I.
IV. On certain Physiological Inferences which may be drawn from the Study of the.
Nerves of the Eyeball. By W. P. ALISON, M.D., Professor of the Theory of
Medicine.
(Read 7th December 1840.)
IT has been justly observed that the great discovery of the appropriation of
the different portions of the Nervous System to the exercise of different functions,
would never have been clearly established, but for the fortunate circumstance
that, in certain parts of the body, especially on the face, the nerves of sense and
of voluntary motion are distinct throughout their whole course. And this consi-
deration may instruct us that, when we have an organ supplied with a variety of
nerves, known to be of perfectly different endowments, the study of the peculi-
arities of these nerves may give us an insight into the purpose or use of some
of those pieces of structure in all parts of the Nervous System, in which we must
still admit that we see much contrivance, without understanding its intention. *
In the case of the Eyeball, it is generally allowed that we see, separated for
us by Nature, almost every kind of nerve which the physiology of any part of
the body includes ; we have the nerve of the special sensation, and that of com-
mon sensation ; we have the nerves which excite motion in obedience to the will,
and those which excite motion over which the will has no control ; we can point
out the incident nerve and the efferent nerve, concerned in two distinct examples
of the reflex function of the spinal cord; and we can specify the nerve by
which the nutrition of the whole organ, and more than one secretion contained
in it, are liable to be influenced and controlled. And when we attend to the
peculiarities of these nerves, and to facts which have been observed in regard
to then* action, I think we have sufficient data for certain inferences appli-
cable to other parts of the Nervous System, which have not yet been distinctly
pointed out, and which are steps in the progress of that most difficult, but like-
wise most interesting department of Physiology, where our object is to detect
the laws by which mental acts are connected with the physical changes of living
beings ; and where, accordingly, the intimations of our own consciousness must
be admitted as part of the foundation of our inferences.
I. The first peculiarity in the nerves of the eyeball to which I wish to direct
attention is this, that those supplying the muscles by which the eyeball is instinc-
VOL. XV. PART I. T
68 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
tively or voluntarily moved are, if not wholly (as SCARPA and others have main-
tained), at least almost entirely devoid of any of those filaments which we now
regard as the organs of common sensation ; the straight and oblique muscles hav-
ing their nerves from the 3d, 4th, and 6th, to the almost complete exclusion of
the ophthalmic branch of the 5th.*
I think we cannot doubt that the reason of this peculiarity, by which the
muscles of the eyeball are distinguished — perhaps from every other muscle in the
body, viz. the absence of purely sensitive filaments in then* composition — is that
already assigned by VAN DEEN,| viz. that these muscles are intended to be regu-
lated and guided in their contractions, not by sensations excited in their own
substance, or in parts directly in contact with them, but by the sensations of the
Retina ; and I think farther, that to this peculiarity we are to ascribe, both the
positive fact, that the movements of these muscles are naturally consentient in the
two eyes, so as to preserve the parallelism of the optic axes ; and likewise the
negative fact, that we have hardly any power to insulate an act of the will on one
of these muscles, so as to move the one eyeball in a different direction from the
otljer ; i. e. the left eye, for example, turns inwards when the right eye turns out-
wards, because both are habitually guided by the sensations of the retina, which
are similarly affected by these movements of the two eyes ; and we have little
power of moving either eye independently of the other, because we have hardly
any sensations, consequent on the movement of the one eye and not of the other,
whereby to guide the efforts of the will for this purpose.^ And this consideration
suggests some important reflections on the office of sensitive nerves and of sensa-
tions in regard to all movements of voluntary muscles.
It appears to me, notwithstanding some difficulties recently raised, that the
essential peculiarity of all strictly Animal motion is, that it is motion dependent
* " Cerium et inconcussum ut," says SCARPA, " quinti nervorum cerebri ramum ophtlialmicum, or-
bitaui transgradientem, ne minimum quidem filamentum valde conspicuis cscteroquin nervis oculum mo-
ventibus addere." (De Gangliis, &c. Isis, 1832.)
t Do Differentia et Nexu inter Nervos vitee animalis et vitae organic®; p. 162.
J It has been stated by Sir CHARLES BELL, that he believes the 3d nerve to be sensitive as well as
motor, because it has an origin from behind as well as from before the grey matter of the crus cerebri ;
and although the examples of the portio dura and the spinal accessory nerves (which appear to be purely
motor, although originating in part from the posterior portion of the cord) render that inference doubtful,
yet I am bound to admit that, according to the statement of VALENTIN,* there is experimental evidence
of sensations being felt on irritation of the 3d nerve. But this author is equally confident, from experi-
ment, that there is no sensibility in the 6th nerve ;t and it should be remembered that movements are
often performed by the 3d nerve, — such as rolling the eyes inwards, and raising the eyelid, — which are not
prompted by the sensations of the retina;, and for the regulation of which sensations in the moving parts
themselves may therefore be required.
* De Functionibus Nervorum Cerebralium, &c. p. 1C. t Ibid. p. 30.
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 69
more or less directly on Sensation ; that if we are certain of any movement in
an organized body being altogether independent of sensation, and affording no
indication of any mental act, we should refer it to the same class as movements
in vegetables ; and that in designating such movement as Organic, but not Animal,
we express a distinction of essential importance in physiology.
It has indeed been lately maintained by several eminent physiologists, who
have studied the indications' of what is now called the Reflex Function of the
Spinal Cord, that many living actions, such as respiration, deglutition, coughing,
sneezing, and vomiting, the evacuation of the bowels and bladder, and even the
movements by which irritations of the surface are avoided or repelled, — certainly
attended in the natural state by sensations, and usually thought to indicate sen-
sation, and therefore to belong to the department of animal life, — are independent
of sensation, and ought, therefore, according to the principle above stated, to be
referred to that of organic life. But although it is well ascertained that move-
ments may be excited in perfectly paralytic limbs, by irritations applied to the sur-
face, which must be carried back to the sensitive, and cross from thence to the
motor portions of the spinal cord connected with those limbs ; and therefore that
the whole series of nervous actions which takes place when any of these reflex or
sympathetic actions are excited, may be in some degree imitated by mechanical
irritation of the nervous matter, independently of sensation ; yet when it is in-
ferred from this fact that, in the entire and healthy body, Sensation does not inter-
vene, as a part of the sequence of cause and effect on which such actions depend,
this theory overlooks so much of what has been formerly ascertained and pointed
out in regard to them, that I do not think we can expect it long to hold its ground
in physiology.
The movements which are excited by irritation of the sensitive nerves, in
the undoubted absence of sensation (which of course can only be known in the
human body in the state of disease), are general and irregular, and have not the
character of selection and adaptation to particular purposes, which is essential to
the useful application of any such actions in the living body. And when it is sup-
posed that such movements as respiration, coughing, or deglutition, are equally
independent of sensation, we not only overlook this, their essential character, of
selection of individual nerves and adaptation to particular ends, but disregard the
following facts, long ago stated in evidence, that sensations intervene in the pro-
cess by which they are excited.
1. In various cases, impressions on the sensitive nerves of different parts
of the body excite the same sensation, and then the same reflex or sympathetic
action follows, — as when intense nausea results from changes whether in the
brain, fauces, stomach, bowels, liver, or kidneys, and is in each case followed by
the same act of retching, — or when a full inspiration follows the dashing of cold
water on the face, breast, abdomen, or extremities.
70 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
2. Conversely, in various instances, different impressions made on the same
parts of the body, and therefore on the same sensitive nerve, exert different sen-
sations, in which case they are not followed by the same reflex actions. Thus
certain impressions on the nostrils and face, followed by the sensation of cold or
of tickling, excite the act of inspiration, but other impressions on the same parts,
fully as strongly felt, but exciting different sensations, as in cutting or bruising,
have no such effect ; and the same is remarkably observed as to different im-
pressions on the fauces and on the stomach, some of which excite nausea and
then retching, while many others have no such effect. These facts plainly in-
dicate that, in the natural state, the reflex actions, characterized as above stated,
follow not the impressions on particular nerves, but the excitement of particular
sensations. And it is easy to shew that many phenomena seen during sleep, or
in decapitated animals (when the medulla oblongata has been left in connexion
with the cord), and which have been thought indications even of well regulated
reflex movements, independent of sensation, may be reconciled to the same doc-
trine, if we remember that sensations may be quite distinct, but momentary, and
so leave no trace on the recollection.
Then it is to be remembered, that several of these reflex actions are abso-
lutely identical with those which are excited by emotions and passions, i. e. by
changes which are peculiar to the mental part of our constitution, as in the cases
of sighing, Aveeping, laughing, even retching and vomiting ; and again, that they
are observed to be remarkably obedient to well known laws of mind. Thus they
are, like the strictly voluntary actions, obedient to the law of habit, which, as
applied to the mental changes preceding muscular contractions, is merely the law
of association of ideas ; and they are so effectually controlled by the occurrence
of any very engrossing mental act, — sensation, emotion, or voluntary effort, — as
plainly to imply, that they are not only attended by the consciousness, but mo-
dified by the agency, of the mental part of our constitution.
I stated and illustrated these facts, chiefly by commenting on the writings of
WHYTT and MONRO, before the offices of the brain and the cerebellum, in animal
motion, had been clearly distinguished from those of the spinal cord ;* and it does
not appear to me that their force is in the least impaired by the facts which have
been since ascertained, touching the portions of the nervous matter with which
sensation, or recollection, or any other mental act, is especially connected.'
The case now before us, however, is one in which we see exemplified, not
merely the power of sensations, directly, or through the intervention of other
mental acts resulting from them, to excite muscular motion, but more especially
their office in guiding and regulating those muscular actions Avhich are excited
through the nerves. The difference between the muscles of the eyeball and other
* See Edinburgh Medico-Chirurgical Trans, vol. ii.
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 71
muscles of the body in the respect above stated, illustrates perfectly the import-
ance of the sensitive nerves of muscles, whether these are bound up with their
motor nerves, as in most parts of the body, or separated from them, as in the
face ; and the importance of those muscular sensations, excited by the contraction
of muscles, on the efficacy of which, as a means of acquiring knowledge, the late
Dr BROWN dwelt with so much earnestness and ability, but perhaps with some-
what exaggerated ideas.
The office of the sensitive nerves of the voluntary muscles in general, and of
the retina and the optic nerve in the eye, in regulating the animal motions, is
obviously to furnish the sensations by which the mind is guided, in selecting the
muscles and portions of muscles, and in determining the degree of contraction
which is requisite for the attainment of any object. And of the necessity of such
a regulator in the case of the eye, we have an instructive example when one eye
is affected with anaurosis, the effect of which is to prevent that insensible eye
from following accurately the movements of the sound eye, when turned in differ-
ent directions, and thus to cause occasional and temporary distortion. In fixing on
the muscles, or portions of muscles, on which it must act, when it feels certain sen-
sations, in order to attain certain objects, the mind sometimes merely yields to that
mysterious impulse, independent both of experience and of reasoning, to which
we give the name of Instinct ; but in the greater number of cases, in our species, it
is guided by experience and education. The sensations which result from any
particular muscular action are recollected ; and it is the anticipation, or rather I
believe we should say the commencing recurrence, of these sensations, which deter-
mines the repetition of the action. Thus the faculty of memory is essential to all
strictly voluntary, as distinguished from instinctive, movements ; and the experi-
ments of FLOURENS and of HERTWIG instruct us, that it is the cerebellum, not the
brain proper, Avhich furnishes the physical conditions requisite for this recollection
of muscular sensations.
Although there appears at first some difficulty in understanding how sensa-
tions which are only anticipated, or the beginning of which only is felt, can
guide the contractions on which their perfect recurrence is to depend, we shall
have no difficulty in conceiving this, if we recollect that it must necessarily be
precisely in the same manner that a musician is enabled to go over any piece of
music from recollection ; — the anticipated sensation is throughout that operation
the guide to the motion by which its own recurrence is to be secured.
In the performance of any such complex successions of muscular movements,
we must allow that it is difficult to conceive, that there is not only a continual
transmission donmtvards, perhaps to different parts of the body, of certain definite
nervous actions resulting from efforts of the will, — by motor nerves, — but likewise
at least as many transmissions upwards by the sensitive filaments, of changes
VOL. XV. PART I. U
72 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
produced by the movements excited, — sensations thereby felt, — and mental deter-
minations consequent on these, by which the successive volitions are guided. But
it is admitted that, in all sciences, " Reason can sometimes go farther than Ima-
gination can venture to follow ;" and in no department of science can we more
reasonably expect to meet with such examples than in tracing the actions of that
exquisite mechanism, by which the sensations and powers of living animals are
placed in connection with the world which is given them to inhabit.
But we may go a step farther, and understand more distinctly the mode in
which sensations continually regulate and guide muscular actions, if we reflect
on the phenomena to which MULLER has very properly directed the attention of
physiologists under the name of Consentient motions, and of which the study of the
eye furnishes us with some of the most instructive examples.
I need hardly say that this term is applied in cases where different nerves,
and thereby muscles, are excited to action simultaneously, and where it is difficult
or impossible to separate the combination. Such cases occur very frequently,
both as to the strictly voluntary and the sympathetic or reflex movements, but
especially as to the latter ; and the following are the facts most important to be
observed in regard to them.
1. The strictly voluntary motions thus simultaneously performed, are chiefly
where the action that is willed requires considerable exertion, and is performed
with difficulty. " Thus when we wish to contract the muscles of the external
ear, we induce contraction of the occipito-frontalis muscle at the same time, with-
out wishing it. During the most violent muscular action, many muscles act by
association, although their action serves no apparent purpose. Thus a man mak-
ing much exertion moves the muscles of his face, as if they aided him in lifting a
load," &c.
2. In regard to most of the cerebral motor nerves, and nerves moving the
trunk of the body, particularly when these act in obedience to sensation or emo-
tion, the most important fact regarding their consentient action is, that this
tendency is observed especially in the opposite nerves of the same pairs. Thus
in the latter description of movements performed by the irides of the eyes, by the
muscles of the face, by the pharynx, diaphragm, intercostal muscles, abdominal,
lumbar, and perineal muscles, — in the actions of winking from bright light, of
deglutition, breathing, coughing, sneezing, vomiting, laughing, sighing, weeping,
— straining for evacuation of any of the viscera of the abdomen or pelvis, — it is
certain, and is essential to the due performance of each action, that the corre-
sponding portions of the nerves of the same pair, on each side of the body, should
be affected, and should act on the muscles, exactly alike ; and this is observed,
even when the sensation exciting the movement is felt only through one nerve,
and on one side of the body ; as in the contraction of both pupils from bright
light acting on one eye, or in the simultaneous and successive contractions of all
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 73
the muscles of respiration, in consequence of a sensation excited in one of the
nostrils, or one of the bronchise.
3. Another fact as to these consentient movements, is satisfactorily observed
only in the eye, but is no doubt extensively applicable in many parts, viz. that the
stimulus of this consentient movement of voluntary muscles passes through the
ganglia, and thereby aifects muscles of strictly involuntary motion ; the iris being
distinctly observed to contract whenever the eyeball is voluntarily and forcibly
rolled inwards by the action of the third nerve. And MULLER relates experiments
in his own person, distinctly shewing that this effect takes place even on the pu-
pil of the right eye, in consequence of forcible voluntary exertions made through
the third nerve of the left eye, and when the right eyeball is not moved.
I think it impossible to doubt that MULLER is so far right in ascribing these
phenomena to what he calls " the conducting power of the cerebral substance at
the origin of the nervous fibres, whereby those which are contiguous to each other
are liable to be affected simultaneously, and the influence of the will (or of any
mental act) is with difficulty confined or insulated on individual fibres," or some-
thing is required to insulate it ; and that these observations put us in possession
of an important fact regarding the influence, either of volition or of sensation, or
of the changes in the nervous matter attending these mental acts, in exciting mus-
cular action, viz. that this influence naturally extends to some distance in the larger
masses of the nervous matter, and requires the action of some additional cause,
to insulate it on individual muscles, or portions of muscles. And in so far as the
motor influence dependent on sensation is concerned, this is strictly in accordance
with what is observed as to the imitation of that influence, in experiments on
the reflex function in paralyzed or decapitated animals.
I think MULLER is also certainly right in supposing that the tendency to con-
sentient movement in the similar or corresponding portions of any pair of nerves,
is the reason why the third nerve is not employed to give the movement outward
to the eyeball ; two other nerves (the fourth and sixth) being employed to give
this movement, because it is a movement which must always be consentient with
that excited in a dissimilar part, and therefore through dissimilar nerves, on the
other side of the body. And although this tendency to consentient motion is
much less seen in the nerves of the same pair going to the extremities, yet MUL-
LER justly observes, that the extreme difficulty always felt in rotating one arm in
one direction, and the other in the opposite at the same moment, must be ascribed
to the violation implied in that effort, of this tendency to consentient action in the
corresponding portions of the same pairs of nerves.
But I think it also certain, particularly from what we see in the eye, that
this observation goes but very little way in explaining the general phenomenon
of Consentience. The tendency to consentient action in the nerves of the same
pair in any part of the extremities, is so slight as to shew, that the conducting
74 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
power at the origins of these nerves cannot he very strong, and, therefore, that
proximity of origin can afford hut a very imperfect explanation of the very
strong tendency to consentience remarked in almost all the motions of the trunk
of the body. Consciousness informs us that, although it is very difficult to act
at the same moment on dissimilar portions of the same pair of nerves, yet there
is in general no difficulty in refraining from acting at the same moment on the cor-
responding portions ; and in no case any difficulty in acting, at the same mo-
ment, on dissimilar and distant nerves. And there are facts observed in the eye,
which have quite the value of the experimentum crucis, as shewing, that the chief
cause of consentience of movement in our muscular organs is very different from
the connection of nerves, at their roots or in their course. These facts are, that
while those corresponding portions of the 3d nerve, which elevate and depress the
eyeball, i. e. those which go to the superior and inferior recti, always act simul-
taneously ; those which go the rectus internus and inferior oblique do not usually
act together in the two eyes. Again, the 4th and 6th nerves never act together on
the two sides of the body, but each is uniformly combined in its movement with
a portion of the 3d on the other side. The reason obviously is, that the Sensations
which result from the action of the 4th and 6th nerves of the one eye, cannot be
identified with those which result from the action of the nerves of the same pair
in the other eye, and cannot be separated from those which result from the action
of that portion < f the 3d pair in the other eye. There is no other circumstance,
but the identity of the resulting and guiding sensation, which can be pointed out
as existing where the consentience is observed, and not existing where it is not
observed.
From these facts, therefore, we learn that the main cause of Consentience of
muscular movement is simply Identity of the Guiding Sensations. Whether it is
by an original instinct, or by repeated trials and acquired experience, that the
acts of volition are directed to the nerves in each eye, which so turn the eyeballs
as to keep the optic axes parallel, and so produce the single sensations, is a dif-
ferent question ; but what has been stated seems to me quite enough to shew, that
it is because the single sensations result, that these nerves are consentient.
I have no doubt that this principle, deduced from the movements of the eye-
ball, is strictly applicable to all the cases of consentient movement excited by
the nerves of the same pairs on the face, fauces, thorax, abdomen, and pelvis, in
the different actions which have been already mentioned. The movements which
these nerves excite, are always followed by certain sensations, generally grateful,
influenced by the degree in which the actions are performed ; and by these sen-
sations, the extent to which the actions are carried, and the energy with which
they are performed, are felt to be habitually regulated. These resulting and guid-
ing sensations are felt to be affected exactly alike by the movement which is
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 78
excited on both sides of the body ; and hence we instinctively carry the move*
ment to the same extent in both.
It was a speculation of DARWIN, that the actions of inspiration and expira-
tion are originally determined by the uneasy sensation of anxiety in the chest
of the new-born child leading to irregular and convulsive movements, out of which
those are quickly selected, which are found by rapid experience to be effectual in
appeasing that uneasy feeling ; and although I do not agree to this statement, as
expressing the order of events at that early period of life, and can assign no cause
but Instinct for the original selection of the proper nerves and muscles for this
purpose, yet I believe that, at all periods of life, it is the sensation felt to result
from the action of inspiration already in progress, which determines the energy
Avith which it shall be performed, the extent to which it shall go, and even the
number of muscles that shall be excited to partake in it.
And that this is the true account of the matter, we have farther and satisfac-
tory proof in the fact, that in various cases of disease, particularly in cases of Em-
pyema, the contractions of the muscles of inspiration on one side of the chest be^
come ineffectual for inflating the lungs, and for appeasing the sense of anxiety in
the breast ; in which case their nerves are no longer excited, and those muscles
cease to act ; they remain flaccid, and even, according to the observation of Dr
STOKES, they gradually become paralytic from inaction ; a phenomenon, as I con-
ceive, almost exactly similar to the loss of power in some of the muscles of the
eyeball in cases of amaurosis affecting one eye.
II. Again, another important application of the information acquired by
study of the nerves of the eyeball, is to explain the use of the Plexuses or ana-
logous contrivances, through which all the nerves, sensitive and motor, pass both
to the upper and lower extremities, very generally in the animal kingdom.
In regard to the use of this very remarkable piece of structure, found in those
nerves, by which the most forcible and the most nicely regulated muscular move-
ments are effected, there have been various opinions. Several authors, among
others Sir CHARLES BELL, have supposed it to be intended to facilitate the com-
binations of different muscles for particular actions, proceeding on the plausible
supposition that, when the will acts simultaneously on several muscles, its influ-
ence proceeds from a single point, and is diffused from thence to those different
muscles.
" The principal cause of the irregularity and seeming intricacy in the dis-
tribution of nerves, is the necessity of arranging and combining a great many
muscles in the different offices. Wherever we trace nerves of motion, we find
that before entering the muscles they interchange branches, and form an intricate
leash of nerves, or what is called a plexus. This plexus is intricate in propor-
tion to the number of muscles to be moved, and the variety of oombinations into
VOL. XV. PART L X
76 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL
which the muscles enter ; while the filaments of nerves which go to the skin re-
gularly diverge to their destination. From the fin of a fish to the arm of a man,
the plexus increases in complexity in proportion to the variety or extent of mo-
tions to be pea-formed by the extremity. By the interchange of filaments, the
combination among the muscles is formed ; not only are the classes of extensors
and flexors constituted in the plexus, but all the varieties of combinations are there
formed, and the curious relations established which exist between opposing muscles,
or rather between the contractions of one class and the relaxation of another." In
short, it appears to be his idea, that a plexus is necessary to enable a single effort
of the mind to throw into action a combination of muscular contractions, and a
succession of efforts to excite such a succession of these combinations as exists
in every complex movement.
But the case of the muscles of the eyeball seems quite sufficient to set aside
this opinion. None of these nerves on the opposite sides of the body are con-
nected by plexuses, yet no nerves can combine their actions more perfectly or
more surely. There is no more perfect consentience in the living body than that
between the 6th nerve of the right eye, and the inner portion of the 3d of the left,
and both are often exerted in varied combinations with many other nerves and
muscles ; but no nerves in the body can have less connection, so far as anatomy
informs us, either at their origin or in their course.
In fact, when we reflect on what passes within us when we throw into ac-
tion any two muscles at the same moment, we shall see that when such a vo-
luntary effort is made, it is just as easy for us to excite simultaneously the most
widely distant or the most closely contiguous muscles ; and again, when we at-
tend to the necessary selection of so many different and distant muscles, in any of
the requisite combinations which are apparently under the influence of Sensation,
as in coughing, sneezing, vomiting, &c. we shall perceive that, in the entire state
of our faculties, any intense sensation may be said to have at its command all
the muscles of the body ; and although, as I have stated, I believe all mental acts
to be guided by sensations in the selections which they make, yet I think it quite
plain that neither proximity of origin, nor connection in their course, can be as-
signed as the cause of any of these selections.
I believe that Dr MONRO made a nearer approach to the true statement of
the use of a plexus, and put it in a simpler view, when he said, that " the chief
intention of Nature in this very solicitous intermixture of the nervous fibrils, is to
lessen the danger by which accidents or diseases affecting the trunks of the nerves
would, without these contrivances, have been attended. Thus let us suppose, that
two nerves are sufficient to supply the flexors and extensors of the forearm, it is
evidently better for us that the one-half of each nerve should go to the flexors, and
the other half of each to the extensors, than the whole of the first nerve should have
gone to the flexors, and the whole of the second to the extensors. For if by accident
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL, 77
or disease one of these nerves should be cut across, or lose its powers, we should,
on the first supposition, preserve one-half of the powers, both of flexion and exten-
sion, which would surely be preferable to our possessing fully the power of flexion
without any power of extension. And thus, in the arm, where five trunks are
found, there would on this supposition, as to the use of a plexus, be only one-fifth
of the power lost, of performing any motion, by division of any one of these
nerves." — (Obs. p. 45.)
That this is really the effect of this arrangement in regard to the effects of
injury, appears to be siifficiently established by the experiments by PANIZZA on
frogs, in which animals the plexus supplying the inferior extremities is much less
intricate than in the mammalia. " If," he says, " one anterior root of the three last
spinal muscles be cut, the motions of the corresponding extremity are as perfect as
if the motiferous nervous system of the part had not been injured. Even if two
roots be divided, although for a moment the motions are not so energetic as at first,
yet they are speedily renewed, and the frog springs as if it had suffered no injury.
Yet by this operation, more than two-thirds of the nervous matter which presides
over the motion of the extremity is destroyed ; and if the third filament is divided,
all motion immediately ceases in the limb." " Whence, if I am not mistaken,
appears the use of the nervous plexuses, which, by the intermixture of the filaments
of different roots having a common function, establish among them, as it were,
such a concentrated force, that each is adequate to preserve the integrity of the
function, when, by means of any harm, the continuity of the other filaments js
interrupted." (Edin. Med. and Surg. Journal, No. 126, p. 89.)
I am aware of experiments by CRONENBERG and by MULLER, who found that
by cutting one of the nerves entering the crural plexus in the frog, they could
paralyze or greatly enfeeble certain movements of a limb, and leave others unim-
paired ; and of the elaborate investigations of MULLER and others in Germany,
which lead to this conclusion, that every nervous fibril, whether passing through
a plexus or not, remains perfectly distinct from its origin to its termination.
Notwithstanding these observations, it is distinctly admitted by MULLER, that
" plexuses convey to each muscle of a limb fibres from different parts of the
brain and spinal cord."
It seems to me, however, hardly possible to suppose, that this very carefully
adjusted piece of structure is intended merely as a guard against injury, and
therefore is of no use in any person or animal on whom such an injury as the
section of one of the nerves of an extremity has never been inflicted. But if we
advert to what has been said already of the evidence that any voluntary effort,
which excites a muscle to contraction, extends its influence over a considerable
portion of the cerebro-spinal axis, and at the same time to the evidence, in the
experiments above quoted, that every muscle supplied from a plexus, has part of
its motor nerves, and may be excited to contraction, from each of the nerves en-
78 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
tering that plexus, we can hardly miss the conclusion, that this contrivance not
merely provides against injury, but multiplies the power which acts on each of these
muscles, and enables the mind to vary the degree of energy which it can expend
on each, in a degree much greater than in any case where it can act on a muscle
only from a single point of the spinal cord.
Then, if we remember farther, that by means of the plexus, each sensitive
nerve which supplies any muscle of the extremities, consists of fibrils coming
from different points of the cord, we can easily perceive that, by this arrangement,
the sensations resulting from each portion of the muscle may be more distinct, and
more easily discriminated from each other, than those which are excited by ner-
vous fibrils bound in the same sheath throughout their course, and originating
beside each other in the cord.
Thus the effect and use of a plexus will be, to make the muscular sensations
more precise and distinct, and to make the power which the will can exert over
the muscles greater, and capable of greater increase at pleasure, than where such
arrangement does not exist ; and therefore, to increase the force and precision
with which the efforts of volition may be directed and insulated on the muscles
which are thus supplied with nerves. And I think that any one who attends to
the subject may observe that he is actually conscious of these differences, when
he compares the effects of his voluntary exertions in his extremities with the
motions of his head and trunk.
I think, therefore, that Sir CHARLES BELL was right in asserting that the
plexus enables the acts of the will to form combinations of muscular motions for
definite ends, in greater variety and with greater precision than they otherwise
could : but I apprehend the reason to be, not that each combination is eifected by
an impulse emanating from a single point, nor that the different combinations are
formed in the plexus, but that the plexus, rendering the muscular sensations more
distinct, and the acts of the will more energetic, enables the mind to act on all
the muscles thus supplied with more power and precision, and to recollect and
resume the action at any subsequent time with more certainty and uniformity,
and thus facilitates combinations.
III. Let us next attend to the information given by the study of the nerves
of the eye, as to the influence and use of the Ganglia of the Sympathetic nerve, of
which it is generally admitted that the ciliary ganglion, furnishing the ciliary
nerves, and through which the iris is moved, is a specimen and representative.
On this subject there has been much discussion at different times, which may
be set aside as irrelevant or hypothetical, because proceeding on the supposition,
that part of the office of the sympathetic, as of other nerves, is to give the vital
power or energy to the muscles it supplies. It has always seemed to me ex-
tremely improbable, that any one of the solid textures of the living body should
.PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 79
have for its office to give to any other, the power of taking on any vital action ;
and that the only doctrine on this subject which involves no hypothesis, is that of
HALLEE, who regarded every part of the body which is endowed with irritability,
as possessing that property in itself, but subject to excitement and to control, of one
kind or another, from the nervous system ; and the nervous system as exercising
that control chiefly, and in the natural and healthy state probably only, in so
far as it is the seat and the instrument of mental act's.
This doctrine, excluding the larger masses of the nervous system from all
share in bestowing the property of irritability or vital energy on muscles, has
received, as it seems to me, the only confirmation of which, in the present state
of our knowledge, it stood in need, from the experiments of Dr REID, which were
laid before the British Association in 1834, and have since been repeated on warm-
blooded as well as cold-blooded animals. These experiments prove, that after the
irritability of muscles has been, as nearly as possible, extinguished by irritation,
it is perfectly recovered by rest, notwithstanding that all their connections with
the brain and spinal cord have been cut.
There is, however, nothing hypothetical or visionary in the assertion as to
the nerves, that " Soli in corpore, Mentis sunt ministri;" and, therefore, when
we observe that all the great organs of involuntary motion, and among others the
iris, have nerves which have passed through ganglia, and when we remember
that all those organs are beyond the power of the will, but are peculiarly liable
to control from certain involuntary acts of Mind, particularly from Sensations
and Emotions, our business is to inquire whether there is any thing in the struc-
ture of those parts of the nervous system which can be supposed to unfit them
for the one of those offices, and fit them for the other. And if we keep steadily
in mind this precise object of our inquiries, we shall find the subject less obscure
and intricate than it has often been thought.
When it is stated that the nerves which pass through the Ciliary Ganglion sup-
ply the only muscle in the eyeball, the actions of which are truly involuntary, —
that all the truly involuntary muscles of the body have in like manner nerves
which pass through ganglia, — and, farther, that all these ganglia appear, from the
most recent and careful examination, to be, like the ciliary ganglion, formed of
filaments both from motor and sensitive nerves, it is impossible to doubt, that
much of what can be ascertained as to the office of this ganglion in the eye,
must be truly applicable to the other ganglia supplying involuntary muscles in
the body.
If we were to assert, however, that all nerves which excite involuntary move-
ments in the body, in obedience to sensation or emotion, are ganglionic nerves,
or that it is through ganglia only, that these involuntary acts of mind affect the
body, we shall be immediately met by various examples of sensations (or the ner-
VOL. XV. PART I. Y
g() PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
vous actions which attend sensations) certainly exciting movements through
motor nerves destitute of ganglia. Of this, the portio dura and phrenic nerve
furnish sufficient examples.
But setting aside the supposition that the ganglia are necessary to enable
the involuntary affections of mind to act on the muscles, let us inquire how far
the opinion long ago stated by Dr JOHNSTON and others is correct, — that the
ganglia intercept the influence of the Will, — prevent the voluntary acts of mind
from acting on the muscles which have their nerves only through them.
A decided opinion is given against this supposition, both by MULLER, and by
liis very intelligent translator Dr BALY. The reason given by MULLER is this,
that as we know from the experiment formerly mentioned of forcibly acting on
the muscles of the eyeball, and thereby causing contraction of the iris, that a mo-
tor influence can traverse the ciliary ganglion, there is no reason to suppose that
a voluntary motor infmence should be arrested in it, if really brought to it. He
considers it, therefore, more probable, that the fibres of the " sympathetic, at
their origin in the spinal cord and brain, are not in communication with the
source of the voluntary influence ;" i. e. that they are not set on the fibres by
which the will acts downwards from the source of voluntary power ; to which
Dr BALY adds, that to suppose the admixture of other fibres in the sympathetic
to have the effect of removing the motor cerebro-spinal nerves from the action of
the will, is in opposition to one of the fundamental principles in physiology, that
of the course and influence of nerves in their " peripheral part," i. e. at a distance
from the brain and spinal cord, being insulated, — i. e. admitting of no admixture
or transference of power from one filament to another. These authors, therefore,
regard the ciliary nerves as beyond the influence of the will, by reason of the
mode of their origin, not of their passing through the ciliary ganglion.
But, on the other hand, if we attend to the experiment insisted on by MULLER,
we shall see that its result is not correctly stated by his expression, that it shews
that a motor influence can be transmitted through a ganglion, and therefore gives
us reason to presume that an effort of volition could traverse the ganglion also,
if really carried to it. When the 3d nerve transmits an effort of volition to the
muscles of the eyeball, and at the same time causes contraction of the pupil, it is
plain that the influence which affects the iris has originated in the " source of vo-
luntary influence" in the brain, — that it is not only a motor influence, but one
consequent on a voluntary effort, which has traversed the ciliary ganglion. The
ganglion has not prevented the influence of volition from acting on the nerves
and muscular fibres which it supplies, although the will has no power of regulat-
ing the movement of these fibres ; and this being so, I do not see how it can be
denied that it has modified, in one way or other, the endowments of the nerves
entering it; rendering them incapable, not of transmitting the influence of the vo-
lition, but of obeying any specific efforts of the will.
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 81
In fact, if it were in consequence of their roots having no connection with
the motor portion of the brain and spinal cord, that the ganglionic nerves in the
eye or elsewhere are not obedient to the will, and if the nerves underwent no
change of endowment in the ganglia, we do not see why the motor nerves of the
involuntary muscles (e. g. the motor filaments of the ciliary nerves) should pass
through ganglia at all ; they would be fitted for their function merely by their
mode of origin.
Nor does it seem to me difficult to define a little more precisely the modes in
which, in this as in other instances, by the connection established in every one of
the ganglia of the sympathetic between motor filaments from the anterior, and
sensitive filaments from the posterior, column of the spinal cord, the involuntary
muscles, although we believe them to be supplied with motor nerves through the
ganglia, are withdrawn from the power of the will.
1. Even if we implicitly rely on the experiments of VALENTIN and others in
Germany, tending to correct the previous statements of HALLER, BICHAT, WIL-
SON PHILIP, MAYO, and many others, and to shew that all the involuntary
muscles may, under certain circumstances, be excited by physical irritations
applied to their nerves,* — yet I think it cannot be doubted (from the negative
result of so many experiments made previously by so many experienced physi-
ologists) that the power of the motor nerves to excite muscular contraction is
greatly diminished by passing through ganglia. The contractions, so excited in
involuntary muscles in these experiments, have followed irritation above the gan-
glia, or even in the central masses, much more surely than in the nerves below the
ganglia ; and their force, and the certainty with which they can be produced,
are certainly much inferior to those of the contractions excited by similar means
through nerves not ganglionic, i. e. voluntary muscles.
2. The vital agency of the sensitive nerves passing through the ganglia seems
also to be much modified ; they certainly do not shew on irritation, when in the
natural state, nearly as much sensibility as other nerves ; and their grand pecu-
liarity seems to be, that although supplying the muscular fibres, they are in-
capable of transmitting those muscular sensations by which, in the case of the
voluntary muscles, we are continually informed of the contractions we excite.
Although the study of the eye teaches us that the influence of volition can tra-
verse a ganglion, yet in no one instance in the body is this influence felt to be ex-
erted on muscles placed beyond ganglia. And when we reflect on what has been
said of the importance of the resulting and guiding sensations, in insulating and
directing the efforts of the will, we shall easily perceive that the want of any such
sensations in the present case, is sufficient to explain the inefficiency of voluntarv
efforts over those muscles. These seem to be results of the degree of intermixture
* See Valentin Do Functionibus Nervorum, &c, p. 62.
82 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
of the motor and sensitive filaments (with the interposition of grey matter),
which takes place in the ganglia, instead of taking place at the extremities of the
nervous filaments in the muscular fibres themselves.
It is very well worthy of notice that there is one action of the eye, in which
the ciliary nerves are essentially concerned, and in which there is a distinct re-
sulting sensation consequent on their action, and that in that action the ciliary
nerves and the iris may be said to act in obedience to the will : I mean that still
mysterious effort, whereby the eye increases its own refracting power, and so en-
ables the rays from an object brought gradually nearer it, to form a distinct image
on the retina and excite a distinct sensation in the mind ; which effort is uniformly
coincident with a gradual contraction of the pupil. Here an effort of volition is
made in the direction of the eye, and the continued gratification of the sense, re-
sulting from that effort, in so far as it affects the refractive power, seems to act
the same part there, as the gratification of the sensations in the chest, in regulat-
ing the contractions of the muscles of respiration.
However, I am aware that objections may be stated to these speculations;
and probably it is wiser to rest at present on the general inference, deducible from
a comparison of the ganglionic nerves of the eye and of other parts, that when the
sensitive and motor filaments which connect a muscle with the spinal cord, meet
in a ganglion before reaching the cord, their endowments are so far modified
that the sensations thence resulting are rendered less precise ; that the efforts of
the Avill cannot be insulated on such a muscle, and, therefore, although capable
of being influenced by the will, it is truly involuntary.
But it is obviously part of the design of Nature, in the construction of the gangli-
onic nerves, not only that they should withdraw the muscles they supply from the
dominion of the will, but likewise that they should facilitate and increase upon them
the power of what I have elsewhere called Sensorial Influence, i. e. the influence
attending or resulting from Sensations and Emotions of mind, which we know to
originate or to be excited exclusively in the larger masses of the nervous system, and
to act with peculiar power on muscles and other organs which have their nerves
through the ganglia. Here also the study of the eye gives us important information.
The ordinary action of the iris, in obedience to the stimulus of light, is cer-
tainly effected by a reflex action, in which the optic nerve, the corpora quadrige-
mina, and the 3d nerve are concerned, and which has been fully illustrated by the
experiments of MAYO, FLOURENS, VALENTIN, and others. That the peculiar sen-
sation of light, excited by the impression on the corpora quadrigemina, not only
attends the action but regulates its degree, is at least highly probable ; although
it is right to admit, that the action occurs occasionally in cases of amaurosis,
where the patient expresses himself as conscious of no sensation ; and I do not
think that there is so good evidence of the necessary interposition of mental
changes in this action, performed by an involuntary muscle, as in the cases where
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. gjj
selected and regulated contractions of voluntary muscles are excited by the reflex
function of the cord, as, e. g. in the contraction of the orbicularis oculi and of this
muscle only, effected through the 7th nerve, on the same sensation being felt.
As the 3d nerve appears to have roots in the posterior as well as anterior
portion of the crus cerebri, it is certainly quite possible that those of its fila-
ments which enter the lenticular ganglion are set on sensitive, not on motor por-
tions of the cerebro-spinal axis ; but if so, the observations already made shew
that they are capable of being excited by an influence acting downwards from the
strictly motor portions.
The indirect and probably modified influence, resulting from volition, and
transmitted through the ganglia to the involuntary muscles, and of which we have
this unequivocal example in the eye, is in itself in all probability an important part
of the design of Nature in the construction of the sympathetic nerve and its gan-
glia. I perfectly agree with MULLER, that it is in this way only, that the effect
of muscular exercise on the action of the heart, and much of the beneficial
strengthening effect of exercise, is to be explained ; and this indirect influence of
voluntary muscular exertion on the heart is obviously important, as keeping its
actions in unison with any occasionally required increase of voluntary muscular
exertion ; and so enabling us to keep up exertions which must otherwise have
failed. And a slighter degree of the same indirect influence of exercise is seen in
the movements of the stomach and intestines, which become to a certain degree
torpid from inactivity of the voluntary muscles. For this slighter agency of vo-
luntary exertion on the moving organs supplied by the splanchnic nerves, there is
probably provision made, in these nerves passing through a greater number of
ganglia, before they reach the moving fibres, than the nerves of the heart, and
therefore having the indirect influence of the voluntary efforts transmitted through
them in a less degree of intensity.
But it is very important, in reference to the use of the ganglionic nerves, to
observe, that the movement of the iris is capable of being affected, not only
through the 3d nerve, but likewise through the 5th nerve and the sympathetic,
i. e. by all the filaments which form part of the composition of the ciliary gan-
glion. I shall not enter on the observations which have been made on the differ-
ences observed in different muscles in this respect ; nor on the speculations of
some German physiologists as to the mode of action, particularly of the sympa-
thetic, on the iris ; but only observe that the effect chiefly observed from the section
of both these nerves on the iris, is a gradual and permanent contraction of the
pupil. The influence of both these nerves on the iris is therefore strictly analo-
gous to the kind of influence observed in experiments on animals, from injury of
different parts of the nervous system, or the sympathetic nerve, on other involun-
tary muscles, consisting, as MULLER states, " either in enduring contractions, or in
a long-continued modification of the ordinary rhythmic action of the organ ;" a
VOL. XV. PART I. Z
g4 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
change, e. g. in the number and rapidity of the beats of the heart, or of the peri-
staltic movements of the intestines ; in short, as HALLER long ago expressed it, a
change of the property of irritability itself, as resident in these muscular organs.
Now, when we apply these observations generally, to the living actions of
those muscles which have their nerves from the sympathetic, I think we can be
at no loss as to the use of great part, at least, of the structure of this part of the
nervous system. These nerves place the organs which they supply in connexion
with the whole extent of the cerebro-spinal axis ; we know, from the observations
now stated as to the iris, that an influence may be transmitted to these organs
through any of the nerves entering any one of the ganglia ; we know, from such
experiments as those of LE GALLOIS and Dr WILSON PHILIP, as well as from the
effects of injuries on the human body, that injuries acting on any large portions
of the brain or spinal cord, affect the heart at least,. if not other of these organs,
nearly alike ; we know that, in the natural state, all these organs are peculiarly
under the control of what I have called sensorial influence, i. e. an influence re-
sulting from those changes in the nervous system which attend intense sensations
and emotions of mind; we know, from various facts, some of which I have elsewhere
collected,* that this sensorial influence, although often originating from an impres-
sion made on a single point, extends itself rapidly in different directions through
the nervous matter, and that it can cross from the sensitive portions of the nervous
matter to the motor portions, probably at any part of the spinal cord. The effect of
any arrangement which brings a particular muscle into communication with many
points of the cord, must be still more decided in regard to this sensorial influence,
than as to the influence of volition as affected by a plexus. The purpose of the
multiplied origins of the spinal accessory nerve, which appears, from the experi-
ments of VALENTIN and others, to transmit an influence to a greater number of
nerves, connected with the cervical plexus, than had been formerly suspected,
and therefore to be essentially concerned in many complex actions consequent on
sensation and emotion, is thus easily understood. Some observations already
published by Dr REID, shew more precisely that in the case of the heart, just as
in the case of the iris, the sensorial influence, or one exactly similar to it, affecting
the contractile power of the muscle, may be transmitted through different nerves
entering the ganglia, and so passing to the muscles ; for he found that a violent
blow on the head influenced the actions of the heart much less, when the sym-
pathetic and par vagum were cut in the neck, than when these nerves were en-
tire, shewing that a part of that influence passes through these nerves ; and on
the other hand, he found that when an animal in which these nerves had been
cut was under the impression of fear, its heart's actions were quickened nearly in
the usual way ; shewing that another part of that influence must pass through
* Outlines of Physiology, p. 398.
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 85
other nerves. It seems impossible to miss the conclusion, that the arrangements
and the communications of those ganglionic nerves are designed and adapted,
according to the laws of nervous action, — while they intercept the direct influence
of the Will, — to multiply and concentrate, on all the organs they supply, that
equally certain, equally important, and more varied and extended influence which
results from Sensations and Emotions of mind. And I think it appears clearly,
from what has been said, that these are objects which the arrangements of this
part of the nervous system must necessarily be so disposed as to secure.
IV. The last question which I shall here consider as elucidated by what we
observe in the eye, relates to the mode of transmission of that Sensorial influence,
resulting, in the natural state, from mental sensations and emotions, which affects
the organic functions of Nutrition and Secretion, and, in all probability, the vital
properties and composition of the blood itself, in all parts of the body.
It has been long known that the lacrymal gland is supplied so completely
by the fifth nerve, that it must be through a branch of this nerve, almost exclu-
sively, that the passions of the mind, or the sensation of pain excited in other
parts of the body, must produce their effects on the flow of tears ; and the expe-
riments of MAGENDIE, in which inflammation and ulceration of the conjunctiva
and cornea, and ultimate collapse of the eye, followed section of this nerve,
and some cases presenting the same series of phenomena in the human body
(of which I have myself seen two), have shewn that the nutrition of the whole
eyeball, and especially the secretion of mucus on the conjunctiva, are under the
control bf this nerve. It is hardly necessary to say, that the common expres-
sion of this nerve " presiding over these functions," is vague and unsatisfac-
tory; but that it is the nerve destined to affect these functions, in the way
in which nature intends them to be affected by changes in the nervous sys-
tem, is sufficiently obvious ; and is another general principle derived from obser-
vations on the eye, and manifestly applicable to the nerves of common sensation
all over the body. I have formerly stated a conjecture, which I still think the
most probable explanation of the inflammation excited by disease or section of
this nerve, viz. that the sensitive nerve, which Sir C. BELL has well denominated
the " guard of the organ," having thus lost its power, the irritations which, in
the natural state, are applied to the mucous membrane, and by an action there,
attended with sensation, determine a sufficient flow of the natural protecting
mucus, now lose their effect, and the membrane is reduced nearly to the condi-
tion of a serous membrane, and inflames (as all serous membranes do), merely
from the contact of the air.
This influence of sensitive nerves and of sensations, and this consequence of
the want of such influence, I take to be an important point in the physiology of
other mucous membranes as well as this ; but we are moreimmediately concern ed
86 PROFESSOR ALISON ON THE NERVES OF THE EYEBALL.
with the question, in what manner the fifth nerve is qualified for transmitting
downwards the effect which sensations, even in distant parts of the body, and
emotions or passions of the mind, have on the circulation through the eye, and
on all its secretions.
The instance of the lacrymal gland, and of the mamma, (which, according to
the dissections of MULLER, has its nerves merely from the intercostals, to the ex-
clusion of the sympathetic,) are enough to shew, that the most intense agency of
mental emotion may take place through the nerves of common sensation.
I think Dr MARSHALL HALL has good reason for the opinion which he has
stated, that as the nerves which supply most of the internal organs of secretion,
and of organic life in general, are ganglionic, and as the circulation in the
eye itself is liable to influence from section of the sympathetic nerve as well
as of the 5th, it is probable that the Gasserian ganglion, and the ganglia on
the sensitive roots of the spinal nerves generally, must be designed for the in-
fluence of these nerves on secretion and nutrition, not for their functions in
regard to sensation ; but it seems to me much more doubtful, whether MULLER
is right in his conjecture, that the grey matter of the ganglia, and the grey fibres
passing from them along the nerves, are the parts of the nervous system designed
exclusively to affect the organic functions of secretion and nutrition. There are
no experiments to shew any such peculiar power in the grey matter of the ner-
vous system ; and I can state one fact which shews unequivocally that if it is, as
MULLER supposes, through the grey matter in the Gasserian ganglion, and of the
branches of the sympathetic which communicate, beyond that ganglion, Avith the
fifth nerve, that any emotions or sensations affect the secretions of the eye, that
grey matter must itself be acted on by the substance of the fifth nerve behind
the ganglion. For in one of the cases of palsy, affecting the fifth nerve on
one side, which was long under observation in the clinical ward, it was quite
obvious that neither emotions of mind, nor sensations excited in the sound nostril,
or in other parts of the body, affected the eye of the palsied side, which, although
inflamed, remained always dry when the other was suffused on such occasions.
Now, in this case it was ultimately ascertained by dissection, that the diseased
(and ultimately wasted) portion of the nerve was behind the Gasserian ganglion,
between it and the origin on the crus cerebelli ; from which it appears quite cer-
tain, that the influence of mental sensation and emotion must pass downwards
through this portion of the nerve (which I believe hardly contains any grey fibres)
on its way from the sensorium commune to the eyeball.
Whatever may be the use of the grey matter in the ganglia, or in other parts
of the nervous system, I think we cannot doubt that there is here a grand excep-
tion to the principle which has been laid doAvn by several authors, that the same
nerve is never employed to convey impressions upwards to the sensorium and
downwards to the extremities of the nerves. At least, if there be a set of nerves
PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 87
destined solely to convey the influence of sensation and emotion downwards to the
organs of organic life, these nerves are every where bound up in the same sheath
with the nerves of common sensation, by which impressions are carried upwards
to the brain.
Thus the study of the nerves of the eyeball enables us, I think, to give a de-
cided opinion as to the following points : —
1. That all strictly animal muscular movement is not only excited, directly
or indirectly, by Sensations producing it, but is continually guided and regulated
by sensations which succeed and result from it.
2. That it is the province of these resulting sensations, commencing or anti-
cipated, to determine on individual muscles the influence of the Will ; and where
distinct annual movements are always consentient, it is because the sensations
thus guiding them are the same.
3. That neither the connections of nerves at their roots (so far as anatomy
has detected them), nor the Plexuses which they form in their course, can be
assigned as the cause of consentience of their movements, or of any combinations
of their actions ; but that the plexuses of nerves, placing both the sentient and
motor nerves of the muscles of the extremities in connection with a large surface
of the spinal cord, seem to be designed and fitted to render the muscular sensations
more distinct, and the acts of the will more energetic than they otherwise would
have been, and thereby to give power, facility, and precision to the combinations
and successions of muscular contractions in all movements of the limbs.
4. That the action in nervous matter which is excited by an act of the will,
can traverse a Ganglion, but is never felt to be exercised, and therefore cannot be
applied to any specific object, beyond it, apparently because of a modification of
the endowments, both of sensitive and motor filaments of nerves, where they are
subdivided and intermixed with the grey matter of a ganglion.
5. That the motor filaments of nerves which have passed through ganglia
may be affected by changes in the sensitive as well as the motor filaments which
enter the ganglia ; and that in this way, probably, the influence of sensations and
emotions of mind (which must be transmitted through the ganglia, because it
affects especially muscles which have only ganglionic nerves) is conveyed from
many parts of the spinal cord, and concentrated on the muscles of organic life.
6. That the influence of changes in the nervous system, and especially of
such as accompany sensations and emotions of mind, on the capillary circulation,
on the functions of nutrition and secretion, and on the properties of the blood,
may be transmitted downwards by the nerves of common sensation, and that it
is probably with a view to this influence that the ganglia are formed on the roots
of those nerves.
VOL. XV. PART I. A a
V. — Notice of the Fossil Fishes found in the Old Red-Sandstone formation of
Orkney, particularly of an undescribed species, Diplopterus Agassis. By
Dr T. S. TRAILL, F. R. S.E.
(Read 21st December 1840.)
It is well known to those who have paid attention to the progress of Fossil
Ichthyology that, until the publication of M. AGASSIZ, the distinctive characters
of the orders, genera, and species of Fossil Fishes were but imperfectly under-
stood. Vague analogies were relied on to connect them with the types of living
genera, and the looseness of the received specific characters rendered it difficult
for the geologist to determine whether the specimens he collected were previously
recognised, or still nondescript. It is obvious that useful characters of fossil species
are chiefly to be obtained from those portions of their structure least subject to al-
teration from decay ; and as the exterior scaly envelopes of the primeval fishes are
usually the portions best preserved and most easily recognised in their rocky se-
pulchres, M. AGASSIZ was naturally led to study these with minute attention. This
acute observer speedily discovered that, in the form and connections of the scales,
he had a general character which would enable him to connect into very natural
groups, species differing from each other in size and form. On this basis he has
established his four Orders of Fossil Fishes — the Ganoidei, the Placoidei, the
Ctenoidei, and the Cyclodei — divisions named from the appearance of the scales.
The bones of the body, especially of the head and the teeth, are often found
in a state of high preservation, especially in our schistose rocks ; in the layers
of which the general form of the specimen is easily recognisable. M. AGASSIZ has
subdivided his Orders into several Families, also natural groups, founded chiefly
on the form and position of the teeth, the disposition of the scales around the
body, the osseous or fibrous structure of the skeleton, and the general form of the
body of the fish.
These Families, judging by then* living analogies, present other natural
groups, which he has considered as genera ; the principal characters of which
are drawn, as in existing fishes, from the number, form, and position of their fins,
which are often preserved, even in the most delicate articulations of their rays,
with wonderful precision, — from the structure of the tail, the principal organ of
progression, — from the arrangement of the teeth, — the form of the bones of the
head, and the manner in which the vertebral column is terminated.
VOL. XV. PART. I. B b
9() DB TRAILL ON FOSSIL FISHES FOUND IN ORKNEY.
The character of the species are drawn by this philosophic inquirer princi-
pally from the general form and size of the fish, — the external surface of its
scales, — then- relative size on the different parts of its body, — the nature of the
rays of the fins, especially of the first ray, — the form and size of the opercula or
gill-covers, and of the bones of the head.
When M. AGASSIZ first visited this kingdom, I submitted to him a consider-
able collection, which I had made, of the fossil fishes from the old red-sandstone
formation of Orkney ; among which he instantly recognised several new species,
and at least one genus, to him then totally unknown, to which he assigned the
generic name of DIPLOPTERUS ; but the species has remained to this day unde-
scribed. I have lately understood that a Diplopterus has been found in another
part of Scotland, and one in Ireland ; but whether identical with the Orkney spe-
cies I am unable to decide. Assuming to myself the privilege usually conceded
to the finder of a new species, and desirous of connecting with my country the
name of the celebrated naturalist, who has done so much to elucidate its Fossil
Ichthyology, I some time ago proposed to designate this species DIPLOPTERUS
AGASSIS, under which name I have already sent specimens of it to several Geolo-
gical Collections ; and now beg to present a specimen of it to the Royal Society,
along with some other fossil fishes from the same county.
During the late visit of the philosopher of Neufchatel to this country, I was
enabled to shew him an additional series of specimens from Orkney ; and he has
now ascertained that my collection contains the following fossil species from those
islands : —
1. Osteolepis Macrolepidotus.
2. Microlepidotus.
3. Cheirolepis Traillii.
4. Cheiracanthus Minor.
5. Diplopterus Agassis.
6. Diplocanthus Crassissimus.
7. Dipterus Macrolepidotus.
8. Platygnathus Paucidens.
9. Coccosteus Latus,
10. Pterichthys— Milleri?
In a short memoir which was read to the Royal Society of Edinburgh in
1833, and to the British Association in 1834, I stated that fossil fishes Avere found
in great number and finely preserved in a quarry at Skaitt, on the western coast
of Pomona, the largest of the Orkney Islands, at about two miles to the north of
a granite ridge which traverses part of the island for six miles. This, with a
small patch in the adjacent isle of Grsemsey, is the only granite in Orkney.
DR TRAILL ON FOSSIL FISHES FOUND IN ORKNEY. 91
The whole of that group, with these exceptions, consists of rocks which I consider
as belonging to the old sandstone formation.
As it is important to determine the geological position of these fishes, I shall
here give an abridgment of my notes on the geology of Orkney.
In this formation, massive sandstone, both red and yellowish, occurs in Hoy,
in Edey, at Holland-head and Getnip in Pomona. The principal rocks in all those
islands is a distinct sandstone-flag. In two or three points, as at Yesnaby in Po-
mona, and at How in Shapinshey, thin beds of limestone occur ; and at several
places the sandstone-flag passes into a slaty-clay, occasionally impregnated with
bitumen, as near Skaill, at Yesnaby, in Walls, and in the rock of Ruskholm, off
Westrey. The rocks are in some places intersected by trap-dykes. The largest
of these occurs in Hoy, opposite to Stromness : Several are found along the coast
from Breckness to Skaill, and in Shapinshey, on its southern shores, and at Long-
hope in Walls. From this sketch it will be seen that the geological formation of
Orkney is very simple and little varied.
The granite ridge on its eastern side appears here and there to pass into
gneiss, and in one point I observed a limited extent of mica-slate ; but in the
greatest part of its course, the rock immediately in contact with the granite is a
conglomerate with a sandstone base, containing fragments of these primary rocks!
This conglomerate passes by insensible shades into sandstone-flag, which has often
a dark iron-grey colour, from containing bitumen and oxide of iron.
It is between the layers of this sandstone-flag that the fossil fishes are found,
where it is quite schistose, and in fact is quarried in large slabs, varying from half
an inch to twelve inches in thickness. The fossil fishes at Skaill do not occur in
the upper layers of this rock. I observed in the quarry about three feet of soil
and debris of the rock, then nine feet of solid stone-beds ; and below these two
other thick beds of flag, in which the fishes are found. This was the lowest point
to which the quarry was wrought at the period of my visits in 1833 and 1834. I
found, in the same beds with the fishes, a few fossil plants, which seem to be
Algse or Fuci.
From geological position, from its connection with the massive sandstone,
and its vicinity to the granite ridge, I consider this flag to belong to the old sand-
stone formation ; which is confirmed by its identity with the Caithness flag in
appearance and in fossil remains. In fact, the organic remains would indicate
that this flag is very low in the series of that formation. Since 1834, fossil fishes
have been found in several other parts of Pomona. They are no less numerous
at Breckness, six or seven miles farther south than Skaill ; and fine specimens
have more lately been found in a quarry at Quoyloo, a mile to the north of the
first locality : I found scales, which I now consider as those of Platygnathus, near
Kirkwall, a distance of fourteen miles east of that point : Very fine specimens of
fossil fishes have also been found in the same species of flag at Hoxahead in the
92 DR TRAILL ON FOSSIL FISHES FOUND IN ORKNEY.
island of South Ronaldshey, which is twenty miles south-east from Skaill in a
direct line ; and I found a few scales like those of Kirkwall in the little island of
Papey-Westrey, which lies twenty-four miles north of the original quarry. From
these facts I have no doubt that attentive examination would detect fossil fishes
in many other parts of that group of islands.
The generic character of Diplopterus is,
Two equal dorsal fins opposite to two similar anal fins ; vertebral column
continued into the upper lobe of an even tail ; mouth wide, armed with strong
conical teeth.
This fish belongs to the order Ganoidei, and to the second family of that
order, the Sauroidei.
It is distinguished from Dipterus by the largeness of its mouth, and the form
of its tail ; — from Palceoniscus by the double dorsal and anal fins, and the nearly
even extremity of its tail. I shall not attempt to anticipate M. AGASSIZ in a full
account of the Orkney Diplopterus, which I know he is fully prepared to describe ;
but content myself with stating, that this species may be known by its wide
mouth, rounded snout, and large head, which forms nearly one-fourth of its
whole length, and is covered with large scales. A single row of moderately large
trigonal scales, with posterior convex edges (giving them a somewhat hatchet
shape), passes along the ridge of the back ; and from their sides proceed rows of
lengthened rhomboidal scales obliquely downwards, diminishing in size from the
back toward the abdomen. The scales are neither groved nor granulated, but
covered with a smooth shining enamel.
The dorsal and anal fins are large, rounded at their tips, and, like the lower
lobe of the tail, supported by numerous slender rays.
KOY/tL SOC. TRANS.
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1
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a- t
VI. — On the Mode in which Musket-Bullets and other Foreign Bodies become m-
closed in the Iwry of the Tusks of the Elephant. By JOHN GOODSIE, Esq.
M. W. S. Communicated by Professor Syme.
(Read 18th January 1841.)
MUSKET-BULLETS are occasionally found inclosed in ivory, and every anato-
mical museum contains specimens of this kind. Why bullets should be so fre-
quently met with in this situation, it is not easy to say ; the head of the animal
appears to be generally aimed at, and foreign bodies when they enter the tusks,
instead of being removed in the usual manner, are retained by the process, an
investigation of which is to form the subject of the present paper.
My attention was directed to this subject by Mr SYME, who submitted to me
for examination some highly interesting specimens of bullets in ivory, presented
to the Anatomical Museum of the University by Sir JOHN ROBISON. Sir JOHN has
also kindly afforded me an opportunity of examining some remarkable examples
of wounded ivory, and Sir GEORGE BALLINGALL has directed my attention to pre-
parations in his possession, which have satisfied me of the truth of those opinions
on the subject, which I shall now have the honour of submitting to the Society.*
One circumstance was at once detected in all these specimens, and its
importance was evident, as affording a clew to the explanation of the mode
of inclosure. The circumstance to which I allude is, that in none of the spe-
cimens are the bullets or foreign bodies surrounded by regular ivory. They are
in every instance inclosed in masses, more or less bulky, of a substance which,
although abnormal in the tusk of the elephant, is nevertheless well known to the
comparative anatomist, as occupying the interior of the teeth of some of the other
mammals, and usually considered to be ossified pulp. It was evident that the pulp
had ossified round the bullet, as the first step towards the separation of the latter
from it. In one specimen the bullet has become .enveloped in a hollow sphere of
this substance, on the surface of which the orifices of medullary canals are situated.
In other specimens the irregular ivory, which surrounds the balls, had become
smooth on its surface, the medullary canals had disappeared, and the regular
ivory had been formed in a continuous layer over the surface of the mass. In
* We are indebted for the specimens to the liberality of Mr RODGERS of Sheffield, who transmitted
to Sir JOHN ROBISON for examination, these as well as many other most remarkable examples of wounded
and diseased tusks.
VOL XV. PART I. 0 C
94 MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT.
one tusk a cicatrix was seen occupying the hole through which the ball had
passed, a circumstance which, when seen in similar specimens, has greatly per-
plexed anatomists. It was observed, however, that, in this instance, the shot had
passed through that part of the tusk which had been within the socket ; and
bearing in mind that the tusk is an organ of double growth, it appeared probable
that the shot had been plugged up from within by the ossified pulp, and from
without by the continued growth of cement, without any regeneration of the dis-
placed ivory ; a hypothesis which was afterwards verified by examination.
Before proceeding to give a more detailed account of this interesting process,
I shall state very briefly the opinions of those authors who have written on the
subject, so as to ascertain how near they had approached to the truth, and to
point out the fallacies which had led them astray.
KLOCKNER mentions a ball of gold which was found by a turner of Amster-
dam in the substance of an elephant's tusk. The longitudinal fibres of the tusk
surrounded the metal in an irregular manner, and were separated from the sound
ivory by a concentric chink situated at some distance from the ball.
CAMPER in the "Description Anatomique d'un Elephant Male," remarks,
that it is not unusual to see foreign bodies inclosed, or as it were soldered, into
the substance of the ivory. The same anatomist also figures and describes a
bullet which was inclosed in a very irregular mass of ivory, covered with long
appendages, which were directed parallel to the axis of the tusk. The metallic
bodies in question, he remarks, must have penetrated across the alveolus into the
hollow of the tusk, and must have remained for a long time in the substance
of the pulpy flesh which fills that cavity, because the ivory enveloped them on
all sides, and would at length have carried them beyond the alveolus by the in-
crease of the tooth. He supposes that the nodules which are formed around the
balls, and the very incomplete union of their fibres with the sound ivory, add
weight to this conjecture.
RUYSCH in his X, Thesaurus, Plate II., figures brass and iron bullets inclosed
in isolated nodules of irregular ivory.
BLUMENBACH considers the tusks of the elephant to differ from other teeth,
more particularly in the remarkable pathological phenomenon of bullets, with
which the animal has been shot, being found, on sawing through the tusk, im-
bedded in its substance in a peculiar manner. He looks upon this fact as im-
portant in reference to the doctrine of a " nutritio ultra vasa." He mentions a
tusk, equal in size to a man's thigh, in which an unflattened leaden bullet lay close
to the cavity of the tooth, surrounded by a peculiar covering, and the entrance
from without closed as it were by a cicatrix. From these facts BLUMENBACH con-
cludes that the elephant's tusk, when fractured or perforated, can pour out an
ossific juice to repair the injury.
Mr LAWRENCE, in his Notes to BLUMENBACH'S Comparative Anatomy, over-
MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT. 95
looking those cases (one of which is given in the text of his author) in which ci-
catrices have been seen filling up the orifices produced by balls, explains satisfac-
torily enough those instances in which no such cicatrices exist, and concludes by
denying the power of the ivory to throw out ossific matter as asserted by BLU-
MENBA.CH.
The author of the Ossemens Fossiles, in his chapter on the structure, deve-
lopment, and diseases of the tusks of the elephant, after stating that grooves and
notches on the surfaces of the tusks never fill up, and only disappear from the
effects of friction, allows that musket-balls are found in ivory without any appa-
rent hole by which they could have entered. He does not believe that the holes
are filled up with ossific deposition as HALLER and BLUMENBACH supposed ; but
maintains that they are never obliterated. He states that the ivory on the out-
side of the ball is natural, and that it is only the bone surrounding it which is
irregular. The phenomena are to be explained, he says, by supposing the balls
to penetrate the very thin bases of tusks in young elephants, so as to enter the
pulps when still in a growing state.
There appear, then, to be two circumstances, regarding which great doubts
still exist — first, whether a shot-hole is ever closed up ; and, secondly, how this
is accomplished in a non-vascular substance like ivory.
In proceeding to consider this subject, two facts must be borne in mind in
reference to a tusk. The first is, that the two substances of which it is composed,
ivory and cement, undergo no change of form or arrangement from vital action,
after they are once deposited ; the second, that it is an organ of double growth —
it is endogenous as well as exogenous, the ivory being formed from without in-
wards, the cement from within outwards.
As there are certain processes which invariably commence when a foreign
body passes through or lodges in the pulp, it will facilitate the conception of the
mode in which a bullet is inclosed if these be described first.
Recent researches have proved that the regular ivory of teeth is formed by
the cells on the surface of the pulp becoming solid from the deposition of earthy
salts in their walls and cavities. It is evident from this that, when a portion of
the surface of the tusk-pulp is destroyed by the passage of a ball, the formation
of ivory at that spot must cease. But we know that the formation of irregu-
lar ivory commences, which indicates the existence of a healing process in the
pulp. The mode in which the wounded pulp heals, cannot be ascertained ; but
it is accomplished probably by effusion and subsequent absorption of blood, de-
position of lymph, and regeneration of the peculiar tissue of the pulp. So far
this process is conjectural, but the irregular ivory formed by the regenerated pulp
is the subject of observation. When, the ball passes quite across the pulp the
track heals, but does not necessarily ossify, except in the immediate neighbour-
hood of the ivory.
96 MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT.
There are two exceptions, however, to the non-ossification of the track of the
ball, namely, the ossification which takes place round the bullet, and that which
occurs round the whole or any portion of the track, which may suppurate and
form a sinus or abscess. In both these cases deposition of irregular ivory takes
place, assuming the same characters as the irregular masses which appear at the
two extremities of the track of the ball through the pulp.
The ossification round the ball generally assumes the form of a hollow sphere.
Its surface exhibits a number of holes (which are the orifices of medullary canals),
and these are occasionally prolonged through stalactitic-looking processes, which
lie in the direction of the axis of the tooth, The ossification surrounding an ab-
scess or sinus assumes the appearance of a shell of variable thickness, and directed
towards one or both of the shot-holes.
When thin sections of this irregular ivory are examined under the micro-
scope, it is seen to consist of a transparent matrix, in which exist numerous me-
dullary canals, shewing traces of dried pulp in their interior. From these canals,
which correspond to the Haversian canals of true bone, secondary medullary ca-
nals, similar to those in the teeth of certain fishes, radiate. The sides and extre-
mities of these secondary medullary canals send off numerous minute tubes, which
are true Retzian tubes, and similar to those in the regular ivory, but not so closely
set. These Retzian tubes have a general radiating direction, and proceed in irregu-
lar wavy bundles, Avhich sweep past one another without mingling, but branching
particularly at their extremities. The great central medullary canals are very
numerous, and each of them has its own system of secondary canals and Ret-
zian tubes.
These individual systems, when seen in a mass of irregular ivory, appear
globular or spindle-shaped ; when viewed in section, they resemble circular or
oval opaque spots with a hole in the centre. These individual systems, however,
are not isolated ; for they communicate, first, by means of the central canals,
which constitute an inosculating system ; and, secondly, by the ramifying extre-
mities of the Retzian tubes, which communicate through the medium of cells
more or less minute, and which are more numerous in some places than in others.
The formation of the irregular ivory does not go on indefinitely : a limit is
set to its increase, and the changes which ensue at this stage of the process are
highly interesting. I have already mentioned the existence of the orifices of
Haversian, or medullary canals on the surface of the mass of irregular ivory.
When the further formation of this is to terminate, these orifices are gradually
closed, and appear like imperforated projections on the surface. It is evident,
therefore, that the inclosed vascular contents of the canals, that is to say, the
ramified processes of the tusk-pulp in the irregular ivory, are cut off from the sys-
tem. They dry up, and the formation of ivory in the interior ceases. The peri-
pheral surface of the irregular ivory is now, in reference to the general pulp, in
MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT. 97
the same relation as the whole internal surface of the irregular ivory of the tusk.
The pulp, therefore, becomes converted into ivory, not only on the whole internal
surface of the tusk, but also on the surface of the newly-formed mass. The cause
of the formation of the irregular ivory to a limited extent only, when it exists as an
abnormal structure, I have not been able to ascertain ; but its mode of develop-
ment and limitation is highly interesting, and forms a leading distinction between
a tooth and a true bone under similar circumstances.
From this description it is evident that the abnormal ivory in the elephant's
tusk strongly resembles, if it be not identical with, the peculiar substance which
fills the pulp-cavities of the tusks of the walrus and the teeth of the cetacea, first
announced as a distinct species of dentar tissue in a paper read before this So-
ciety five years ago by Dr KNOX, and since minutely described by RETZIUS, OWEN,
and ALEXANDER NASMYTH.*
This identity of a diseased structure in one animal with a normal structure
in another is remarkable, and must be looked upon as another instance indicating
the existence of a system of laws regulating the relations between healthy and
morbid tissues ; — laws which have been speculated upon, but have never been
sufficiently investigated by anatomists.
Having now given the anatomical characters of the abnormal ivory which
invariably surrounds musket-bullets and other foreign bodies which lodge in the
pulps of the tusks of the elephant, I shall proceed to state the various conditions
under which these enter the organ, and the changes which ensue.
Foreign bodies enter the tusk in three ways : First, through the free portion
of the tusk ; secondly, through that part of the organ which is contained in the
socket ; and, thirdly, from above through the base of the pulp.
First, When the ball hits the free portion of the tusk, if it only penetrates to
a certain depth of the ivory, no change whatsoever can take place. Neither the
cement nor the ivory can be reproduced. In course of time the hole may be obli-
terated, the ball may be got rid of by wearing down of the ivory, and the ivory
* CUVIER described this species of dental tissue in the tusk of the walrus, and compared it to pud-
ding-stone. Dr KNOX, in the paper to which I have referred in the text, affirmed that, in addition to
the cement, enamel, and ivory, a fourth substance, namely, the substance described by CUVIER, entered
into the formation of many teeth. He stated that, in the teeth of certain fishes, this substance, or a
tissue closely allied to it, constituted the greater part of their mass ; the other three elements having
disappeared or become greatly diminished in bulk or importance. RETZIUS has accurately described the
microscopic structure of this class of dental substances, as existing in different animals. Mr OWEN has
extended and confirmed the observations of RETZIUS. Lastly, to Mr A. NASMYTH belongs the merit of
having pointed out the resemblance which this kind of substance (which he denominates ossified pulp)
bears to diseased ivory in the tusks of the elephant, and still more closely to the substance which fills
the pulp cavity of the aged human tooth. In ignorance of Dr KNOX'S previous observations, he announced
this kind of ivory as a fourth dental substance.
VOL. XV. PABT I. D d
98 MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT.
under the hole may be strengthened by the formation of new substance. When
the ball is detained by the ivory, but penetrates so far as to wound the pulp, the
latter ossifies round it, and the ossified portion sooner or later becomes enveloped
in new ivory. If the ball penetrates the pulp, the latter ossifies round it, and be-
comes attached to the hole in the ivory. If the tusk is growing rapidly, and the
nucleus of pulp-bone does not speedily adhere to it, the ball will ultimately be
situated above the hole. The ball may also pass across the pulp, and become at
last enveloped, along with its bony envelope, in the ivory of the opposite wall.
Second, In the second class of wounds, in which the ball enters the pulp-ca-
vity through the socket and side of the tusk, the consequent changes seem to be the
following : first, ossification of the pulp surrounding the ball, and the ultimate appli-
cation of the mass to the hole in the ivory, and, as the latter is necessarily at this
part of its extent very thin, the hole is closed ; second, the application to the hole
in the ivory, and to the surface of the ossified pulp in it, of cement formed by the
internal surface of the tusk-follicle. For although the ball may have removed or
at least torn the follicle opposite the hole in the ivory, yet, as the tooth advances
in the socket, the ball will in time arrive at a sound portion of the latter. There
is a specimen on the table which proves that the wounded portion of the follicle
may perform this duty sufficiently well. In this specimen the external surface of
the cement exhibits a longitudinal fissure, with smooth rounded edges, resulting
from the defective formation of cement in the situation of a longitudinal rent or
wound in the membrane of the follicle, through which the ball had entered the
ivory. The hole in the ivory then being plugged up externally by cement, and
internally by ossified pulp, the case proceeds as in the last class of wounds, — the
ossified portion of the pulp surrounding the ball becoming inclosed in true ivory.
Third, When the foreign body enters from above, without wounding the tusk,
the pulp ossifies round it, and true ivory envelopes the mass, in the usual manner.
I have not seen any morbid ivory which could be referred to wounds of the class
now under consideration ; but a very interesting account is given by Mr COMB, in
the Philosophical Transactions,* of a tusk in which a spear-head was found, and
which could only have entered the cavity from the base of the pulp. Mr COMB
describes and figures the ossified portion of the pulp, and the manner in which it
had attached itself to the ivory, and become covered by it, so as to obliterate par-
tially, and to alter the relative width of the pulp-cavity.
The description I have now given of the changes which ensue on wounds of the
tusks of the elephant, explains many curious appearances in ivory, and the difficul-
ties anatomists and physiologists have had in understanding them. It explains
the drawings and descriptions of KLOCKNER, RUYSCH, and CAMPER; does away
with the necessity of supposing, with BLUMENBACH, that true ivory is regenerated,
* Phil. Trans. 1801.
MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT. 99
or that it can throw out ossific juice to produce cicatrices ; and leads us to believe
that CUVIER, in denying the possibility of the obliteration of a shot-hole, had
allowed himself to be deceived. All difficulties are got over, and contradictions
reconciled, by bearing in mind the different circumstances insisted upon in this
paper, namely,
1. That a tusk is an endogenous as well as an exogenous organ.
2. That the pulp forms irregular ivory round foreign bodies, and at wounds
on its surface.
3. That the membrane of the follicle is an important agent in closing up the
holes produced by foreign bodies which penetrate a tusk through the socket.
EXPLANATION OF PLATE I.
Fig. 1. A portion of a section of a wounded tusk ; a cement ; 6 regular ivory deposited previous to the
wound ; o irregular ivory deposited after the wound.
Fig. 2. A diagram illustrative of the mode of connection between the Retzian tubes of the primary and
secondary regular ivory, and the cells and Retzian tubes of the different mosculating systems of the
irregular ivory, after inclosure of a ball ; a cement with its osseous corpuscles ; b primary regular
ivory with its Retzian tubes ; c the ball ; d the irregular ivory with its systems of tubes and cells ;
e secondary regular ivory.
Fig. 3. A copper ball inclosed in a sphere of irregular ivory, on the surface of which are the orifices of
Haversian canals. Some of the orifices have closed, and present the appearance of irregular projec-
tions. The mass has begun to be attached to the regular ivory of the tusk, and would in time have
been inclosed in it. The ball must either have passed across from the opposite side of the tusk,
or must have sunk below the level of the hole by which it entered.
Fig. 4. Section of a tusk across the cavity of which a ball has passed, and become inclosed in the ivory
of the wall opposite the hole by which it entered. The hole is filled with irregular ivory, coated ex-
ternally with cement. The cement over the ball has been disarranged by the shock. This section
proves that the track of a ball across the pulp is not necessarily ossified.
Fig. 5. Section of a tusk across the base of which a spear-head has penetrated and remained in the
wound. The weapon has therefore been separated from the pulp by deposition of irregular ivory in
the form of a tube ; a cement ; b b irregular ivory deposited previous to the wound ; c c regular ivory
deposited after the wound ; d irregular ivory inclosing a vacant space e, the seat of an abscess or
sinus, and continuous with the cavity of /, a mass of irregular ivory (coated with regular ivory) in
the form of a tube surrounding the foreign body. As irregular ivory always contracts in drying, more
than any other kind of dental substance, that portion of the section marked g g has been bent out-
wards.
Fig. 6. The same section viewed in profile ; a the broken shaft of the spear ; 6 an irregular mass of ce-
ment formed round the orifice of the wound by the membrane of the tusk follicle, and which would
have closed the wound had the weapon been removed. The wound inflicted has in this instance, as
in many others, stunted the growth of the tusk at c c, so as to render the part formed after the in-
jury narrower and weaker.
Fig. 7. A longitudinal section of a tusk in which a gun-shot wound had terminated in abscess of the pulp ;
a a cement ; 6 6 regular ivory deposited before the injury ; c c regular ivory deposited after the in-
100 MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT.
jury ; d d irregular ivory bounding the abscess ; e e masses of cement and irregular ivory at the
margin of the shot-hole.
Fig. 8. The external aspect of a portion of a tusk, which had been transversely fractured ; a a the line
of fracture united externally by irregular masses of cement.
Fig. 9. The internal aspect of the same portion of tusk ; a a the line of fracture united by irregular
ivory, a portion of which is arranged in a reticular form. This reticular ivory is interesting, as af-
fording a natural analysis of the peculiar arrangement of parts in the irregular ivory described in
the paper. Each bar of the reticular ivory is traversed longitudinally by a medullary canal, from
which radiate secondary canals and Retzian tubes, the whole being coated with regular ivory. This
reticular ivory differs from the ordinary form of ossified pulp, only in the greater distance between
the Haversian or medullary canals, so that portions of the pulp have remained unossified between
them.
VII.— On tlie Theory of Waves. Part II. By The Rev. P. KELLAND, M.A.,
F.R.SS.L.$E., F.C.P.S., late Fellow of Queens'1 College, Cambridge; Pro-
fessor of Mathematics, fyc., in the University of Edinburgh.
(Read 18th January 1841.)
THE problems on which we were engaged in the preceding Memoir were the
following : — 1°, The complete determination of the velocity of transmission of a
wave in a fluid of any depth, provided the depth is uniform throughout ; 2°, an
application of the hypothesis of parallel sections to the problem in its more com-
plicated form, in which the depth is variable in the direction of the breadth of the
canal ; 3°, The investigation of the motion of a solitary wave. We propose in the
following pages to continue the same subjects, and to add the more difficult pro-
blem of initial motion.
The principle on which the determination of the velocity was made to depend
is this very simple one, that the variation of pressure in proceeding from point
to point in the direction of motion is the same, whether we suppose the pressure
a function of x and y, or a function also of z. The former hypothesis refers its
determination to the general properties of fluids, the latter to the particular state
of the fluid in question at the time. Art. 9.
This principle is a highly important one, but it requires a slight degree of
attention in its application. I deem it, therefore, not superfluous, in discussing a
question of so great importance as that now before us, to present other solutions,
in which the same principle is viewed in a totally different light. Having done
this, I shall give a complete solution of the motion of a wave in a canal of any
section, and an approximate one of the motion in a canal of variable depth.
Lastly, I shall consider the question of initial motion, not only in the case in
which the depth is small, but in the most general case.
SECTION IV.
46. We retain the following notation, which corresponds with that used in
Art. 20, &c.
VOL. XV. PART I. E 6
102 PROFESSOR KELLAND ON THE THEORY OF WAVES.
ct) = b(eKy + e-Ky)sm6 . (1)
-ct') = -l>(e*y-e-Ky)cos6 (2)
— 0K*-e-a*)sin0 ...... (3)
The equations of motion are (Art. 8.),
We proceed anew to the discussion of these equations, reserving only the
solution of the problem given in Art. 8.
By (4) and (5), _ .... (7) ;
the differential coefficients which have the symbols enclosed in brackets being
complete, the others partial.
d fdu du du\ d fdv dv dv\
Hence ^-[-rr + u^— + w TT~ ) =^- ( ~r; + M 3- + » ^- ) •
dy\dt dx dy) dx\dt dx dy)
d du d du .
But -j- -r=-rf • -3-, &c. = &c.
dy at at ay
d (du .du du\
3-lTT + M^~ + v^r~ I may be written
dy\dt d x dy)
d du d2 u du du d2 u du. dv
- . - + U -- 1 -- . -- h V -- 1 -- - .
dt dy dxdy dx dy d y2 dy* dy
0. ., T ... d fdv dv dv\
Similarly, the quantity ^ (j-( + u — + v — j may be wntten
d dv d2 v du dv d2 v dv dv
dt ' dx da? dx ' dx dxdy dx ' dy'
XT / d\du d du d du d du
«OW I -7-. ) -j-=-n •^- + T--J-M+^--^-"' which is less than the quantity
\dtj dy dt dy dx dy dy dy J
i • v d fdu\ . du du du dv du fdu dv\
which represents ^) by ^ - Ty + J-y . ^ or by j-y . (^ + ^).
'; But ^^=0 by (6) therefore the quantities l(^) and (^)g
incident.
PROFESSOR KELLAND ON THE THEORY OF WAVES. 103
/d\dvddvd2v d2 v T.--U-I j.-u ru j.-
(dl) Tx=Tt •dl*+d7*-u + J^ry'v> whlch 1S less than the yp¥+¥¥ or b? ? fi? + ?) ' that is b? ° (6)-
dx\dt) ' dx dx dx dy J dx\dx dy)
d (dv\ f d\dv
••• rf- (jjj and (jj) j~x are coincident.
Hence equation (7) gives
/ d\ du_ I d\ dv
\dt) ' 1y~ \d~t) ' dx'
which, by integration, becomes
dw dv
,_,
. . . • (8)
dy dx
This is the condition which we obtain, therefore, when p is a complete dif-
ferential of x and y. The other condition (6) is general, and must hold in all
cases of fluid motion.
47. We do not purpose to solve these equations, having already done so in
Art. 8. We proceed, then, to the discussion of the equations (4) and (5).
If C=0, as is the case when the solution assumes the form given it in Art. 8,
or when the motion is oscillatory, we perceive that udx + vdyisa, complete dif-
ferential of x and y, t being considered constant. Call i
d d(b
.: u=--!-, v=—£
dx dy
, dp fdu du du\ . /dv dv dv\
and -f- = ~ffdy— [ — +«— + v — ]dz— I +u — + v — )
p \d( dx dy) \dt dx dy)
Sd2(b d(b d2(b d(b d2 (b'\ ,
= —gdy— I - J- H — 2- . . — —-\ — 2- . y ) dx
\dtdx dx dx2 dy dxdyj
. _ _
\dtdy dx ' dxdy dy '
d2d> '. d(h d2
-—L- -¥. _
— . -- -—- -. _ _ —--
L dx dx2 dx dydx dy dy2 dy dxdy J
/ d2 d) , d2 d) , \
— ( - — dx H -- — dy I
\dxdt dydt y)
—"-»•{<$)'+(%)'}-<•% ' .;;.
all the differentials except that of y being performed as though t were constant.
By integration, then, we obtain
where f(t) is an arbitrary function of the time.
104 PROFESSOR KELLAND ON THE THEORY OF WAVES.
To obtain the pressure at the surface, we must write z instead of y.
48. Call P the pressure at the surface corresponding to a point, whose co-
ordinates are x and z ; then P + — § x + &c. is the pressure at another point of the
surface where the co-ordinates are x + Sz, % + -? 8z+ &c.
dx
But the pressure at the surface is constant ; consequently — - = 0.
Let u,, v,, -jfr &c., represent the values of u, v, -? &c. at the surface, or when
d I u t
x is substituted for y.
., ^P_ dz t du, du,dz dv,
111 Gil — ~ — —— Q ~ — """* I U . ~f~ U .—— 1- D •• '- —
dx dx \ dx dz dx dx
dv, dz\ d d\dz du. dv, d d d). .
Hence (5'+M/-r- + »,-r- + ;r- • —p \ ~r + u, T2 + ®, — + T- • — r-=0;
V dz ' dz dz dt/dx ' dx ' dx dx dt
an equation evidently coinciding with equation (7) Art. 9.
49. We have still another mode of obtaining the same result.
In fact, let us consider the pressure as a function of t, the time. If then we
admit that the solution of the problem is that given in equations (1), (2), and (3),
we must have -^-—b(eKy + e~"'y) sin 6, and consequently
U X
K
cos 6 + ¥((-) . . . (10.)
But as <£ enters merely as a symbolical abbreviation of a certain quantity,
we can take it of such a value that F (t)=0.
With this value of 0, it is evident that the value of P, given by equation (9),
will become P=f(t)—gh+ a circular function ofx—ct.
But the pressure at the surface must of necessity be constant ; we obtain,
therefore, f(i)—ffh + F (sm(a;— c^)) = a constant, for all values of x and t. Now
I COS
this cannot be the case unless/ (t) is a constant quantity; for by giving to x such
values that x—ct shall remain constant or differ by multiples of 2 IT, we may
render all the expression except f(t) constant for all values of t. Hence for such
values of x the expression assumes the form f(t)+ a const. = a const, for all values
of t. But this requires that/(£) be constant for all values of t.
We have therefore P = C -g s - 1 (M,2 + O - -?-' .
* at
PROFESSOR KELLAND ON THE THEORY OF WAVES. 105
Differentiating this with respect to t we obtain
dt \
' dt ' dx ' ' dz ' dt ' ' dz
, , ,
— + — 21' + . — 22. M H --- V-tJ =0
rf* d*2 d-erf* ' dzdt '
„ «/M. ~ rftv _ rfv. , „ »\du d2 n /ii x
or ^y + 2M,-' + 2,/_' + 2M/,^ + (^-0^ + -=0 .
The last equation is obtained by substituting for j-jy ^> their values
du. dv. j , ... du.f dv, ^dv.f du. ta n-nA ff\
-j-', — -i, and by writing — r-' for -3-^, and ^- for -—'... (6 and 8J.
«?/ dt dx dz dx dz
It is remarkable that this equation, which is the condition that the pressure
at the surface shall be constant, does not contain any differential with respect to
z explicitly.
By taking the small terms of an analogous equation, M. CAUCHY has obtained
results corresponding to the particular hypothesis, that the depth is infinite.
50. Let us substitute in our equation (11) the values of u, and vt given by
equations (1) and (2), and that of 0, given by (10). By denoting e"z +e~" ~ by S
and «"*-«—* by D, we get
-ffbDcos6-b2a . 4sin20 . c-263aS . D2 sin2 6 cos 6
_63 (C2.*_e— 2.*) g acos2 0COS Q + ba C2 s cos 0 + 2 p a S cos 0=0 ;
or
-62(e2a*" + e-2aOScos20 + 262S=^
a
or c2S-
or c"& —
a
which equation is identical with that at the end of Art. 20.
51. Thus we have three distinct but equivalent processes, by means of which
the same equation may be arrived at. It will not be worth while to follow the
different processes through the solution of the general problem. The result in
Art. 19 is in a form sufficiently simple. We propose rather to apply the formula
(11) to another case, that in which the velocity is expressed to two terms, of which
the second is not in the same phase as the first. Let us in fact assume
VOL. XV. PART I. p f
PROFESSOR KELLAND ON THE THEORY OP WAVES.
u = b (e"y + e-"y) sin 6 + a (e3^ + e~3a2') sin (3 6 +*)
cos - -.* cos
then W-(^
By substituting these values of u, v, $ when y—z, i. e. of «,,»,, 0, in equation
(11) and writing S3 for 02a~+3 cos 3 6 - 4 If c sin 2 6 + {2 S - S3 cos 6- S cos 3 6}
a a
+ 4a6eS4sin20-8a&cS2sin40
+ 4 a b c S4 sin 2 0-8 a 5 c S2 sin 4 6 + 6 c2 S cos 0 + 3 a c2 S3 cos 3 6 = 0.
We have already obtained this equation in a more general form, in the for-
mer Part.
v
SECTION V.
64. We turn our attention next to the case of waves proceeding along a canal
of given or of infinite width, but of variable depth, in the direction of motion. We
will commence with the case in which the depth gradually diminishes, so that
the bottom of the fluid is an inclined plane. It will be more simple in this case
to assume the plane which passes through the centre of the wave to be the plane
of x z. If, then, we write the values of u and v as originally obtained, they will be
« = b (e* y+h-« x + «—»•*-« *) sina (x-cf)
v=-b(e" 2/ + /t-^_ tf—y + *-««) cos a (x-cf),
where h— ax is the height of the plane of xz above the bottom of the fluid, or is
the statical depth at the point in question.
Let us conceive, then, that the above equations represent the velocities in the
case in question at the surface of the fluid when z is written for y ; z being now
very small. As long as the waves retain their /orw, this must be true very nearly
at least.
It must be observed that the same thing is not true to all depths, for the very
obvious reason, that at the bottom of the fluid the motion is no longer perfectly
horizontal. There will, therefore, be a perpetual impulse tending slowly to alter
the form of the wave. But, whatever be the form, it is possible to expand it in a
series of the following nature,
VOL. XV. PART I. G g
PROFESSOR KELLAND ON THE THEORY OF WAVES.
But -^ = the vertical velocity at the surface, which is a particular value of
the quantity v, and as v is very nearly equal to 0 when y + h-ax=Q, it follows
that k is very small, and for our present purpose may be neglected.
We may state the results at which we have arrived, by saying that ut and v
do not represent the velocities parallel to x and y in any case, but approach nearer
and nearer to those velocities, as the points to which they correspond recede fur-
ther from the bottom of the fluid. The quantity 6 is always supposed to be less
than 2 v, a supposition which is required by the circumstance, that we are about
to remove it from beneath the circular sign.
We suppose, then, that the above equations give the values of u and v at the
surface of the fluid, and shall apply the method of parameters to deduce from
them the variations of A, &c. The quantities \ b, &c. are now functions of x.
Since ^ + ~ = 0, we get, calling a(z + h-ax) ;
6 db _
cos
. y, ... sin 6 db . - _ ffl / - d a d c\
fef+e~ ?)— r- — + (ef+e • • • W
Thus it appears that b is constant, or at least varies only periodically,
Also a (z+h—ax)=f(z) by integrating 8.
/C*)
«= — T"—
2 + /t — a #
X- —
Let \o be the value of A when a?=0
A=?
M
from which equation we learn that the length of the wave diminishes directly as
the depth diminishes.
COR. The length of the wave varies as the depth, in the case in which motion
extends throughout the fluid.
55. Again, from equation (6) we obtain
,/,. (*-«0 j?
dx~ at
x — c t d .
—. -- T- log a
/ dx
_ -_
t dx °z+h—ax
_x — ct a
t ' z+&—az
dc a _ ax
dx z + h — axc~t(z + h — ax)
_ xdx ,
- -ax2 +
2d, because by the continual change of phase of the wave during the motion
from 0 to cc, the motion will not begin from the same place.
We have, in fact, \=X ( i _ ^L \
\ z + hj
axe t
that is,
From these formulae we learn two things, viz. that the velocity of transmission at
any point varies as the square root of the depth, or as the square root of the
length of the wave.
56. We might proceed by another method to obtain the variation of c from
the variation of \ : thus,
.
Equations (4) and (5) give us also,
F=--S.e"(my+n^ .mb, F=--Ze*(my+n-). nb.
We must obtain the particular values of n and b, which satisfy our problem
from the restrictions which the problem itself imposes on us.
Let us place the origin in such a point that when *=0, w=Q, and when y=o,
»=0, whatever be the value of a? or t.
If, as is commonly the case, the canal be symmetrical with respect to a ver-
tical plane running along its length, the origin will be situated at the bottom of
this plane, and the line in which this plane cuts the surface of the fluid, will be
the middle of the canal. Let the equation to a section of the surface of the ca-
nal made by a plane perpendicular to this line, or to the direction of motion, be
.'/=-H*);
VOL. XV. PAET I. I 1
PROFESSOR KELLAND ON THE THEORY OF WAVES.
then since w or F=0 when *=0; 2 e*mv . n b=0 .... (8)
and since v or F=Q when y=0; 2e"nz . mb=Q . . .' (9).
'/ * d 1 1
Also at the side of the canal, it is evident that -L=-/-—"\> '(«).
m, dz
Now vt which is the value of v at the side of the canal, may not be obtain-
able from the value of v given by the equations (4), (5), (6), (7), since it is pos-
sible that the discontinuity of the fluid may require a discontinuous function as
the expression for its motion in the neighbourhood of the sudden transition from
the fluid to the surface of the canal. Provided, however, the canal be not abrupt
in its curvature, and the motion be not very great in comparison with the mag-
nitude of the canal, it is clear that the values of v, and ?», will approach very near
to the values of v and rv at the surface of the fluid. In fact, we may safely argue
that the conditions of continuity are not more violated by putting v and w for
vt and m, at the surface, than they are by putting v and w themselves for the ve-
locities obtained from conditions belonging to the interior of the mass. With
these observations we shall adopt the following equation :
— ==%]/ (z) at the surface,
or 5^N=^'(^) at the surface ..... (10).
* (Z'-YZ)
We have written F (z, y] for F, &c.
Also, if we adopt only the large terms of equation 11, Art. 50, we shall have
Tg J
mff + -T-|- = 0 at the surface,
or
... e2=-^. -at the surface .... (11).
« /
Condition (9) is satisfied by giving to m two equal values with opposite signs
for every value of b and n. But since m2 + w2=l, the value of m is =fcVl-«2, and
consequently this condition merely directs that both values must be retained. We
1*1 i -j. f v t.f «»*+• — /i-tf) , Jt(m — ijl — »* v)j
may now eliminate m, and write /= 2 o{e *•
F=—
Condition (8) requires that F=0 when *=0. If y=v when z=0, this gives
2 b n {e" " V l -"" + e— " ^l~n'} = 0.
To confine ourselves to the most simple case, let us suppose »=0 ; then we
PROFESSOR KELLAND ON THE THEORY OF WAVES. 119
have 26«=0 (12). This is satisfied by giving to n pairs of equal values positive
and negative ; and thus we get as the general solution of the equation, subject to
our conditions
/= 2 b f e*
the 2 embracing all the positive values of n.
By equations (4) and (5) we obtain the values of F and F thus :
F= - 2 b Vl^r? [e* nz + «— ' n 2}{eK
F=-lbn {e«'^_e-«»"-]{eaVi=^
Thence equation (10) gives
at the surface.
Also equation (11) gives
g
~ a '
at the surface.
Equations (13) and (14) contain the solution of the problem.
60. APPLICATION. The most simple type which a wave can have is that which
is expressed by one function only. In this case 2 may be omitted, and the value
of (? is independent of y, or is the same throughout the whole mass ; all our pro-
cesses are consequently applicable without any limitation to this case, and we
may regard our solution as a complete one.
As an approximation, let us expand the exponentials contained in these
equations : by this means we get
£^MA<Sm^'/l .... . (15)
and S, Sm (1 - n*W h + DM DOT n A/!^?= D,, D,n » A/l^T2 (^' A)2 .
+ SnSmM2^'A + D^Sm«^"A , . (16)
If, for the sake of abbreviation, we write a for 4' h, and «' for 4" A, and 9 for
- , we shall have
by means of equation (15) \/t^i?as-Bpf»— , which, being substituted in (16), re-
^n Urn
duces it to
or SB DM S^I^TO + S
S,, D,, D»\/l^? a + Sm Dro Si » + SB Dn S
which is equivalent to
since SL-D;=S2n-D^4.
By means of this last equation and (15) we finally obtain
T)2 -_. a2 TO PL SH DK q
The first of these equations gives
S*, (1 - w2) = ns DJ, + 4 w9 + (D*m + 4) —
and the second D^= g-^ —
i + M^
PROFESSOR KELLAND ON THE THEORY OF WAVES. 123
or S^(l-W3)-n2(Sn-Dy-S^DnW?=w2a2D^
_§„_ nq /|-4rc2(a2-l)(l-2rc2) + rcVl
Dn-2(X-2w2) V I 4(l-2ny J
Again, .by the same two equations,
s _
Dm= a .
.
~
D,,
[77s» Pn 9 1 ~ » s»+aD«
* in
_, SnDny 1 ;T~ " )
JL ~r j
4 W
= 1 fLz«!s^a2D2)
. .SJJnS-l «2 J
4n
1/1 9 "49 \
/I — w4 _„ . 1 — n' VT\\
<= O~T; — ( D^ + 4 a 2D,,J
1+-^
4 '
D,,= 3*J_ (18)
v
From the same analysis we obtain
i - 5
1 — WJ
(19)
The equations (17), (18), and (19), give the limits to the value of n,
PROFESSOR KELLAND ON THE THEORY OF WAVES.
COR. For the case in which the section is triangular g=Q. In this case equa-
tion (17) shews that «2— 1 and 1-2 n2 must have the same sign : and equation (18)
that 1— 2w2 and w2(«2 + l)— 1 must have the same sign.
Therefore the three quantities a2-!, 1— 2w2, and n2(a2 + l)— 1 are positive,
aero, and negative together.
Now, the result obtained by an approximation was, that 1-2 «2=0. This re-
sult, then, corresponds to that triangular section for which «=l. In other cases
we find that, on the hypothesis of continuity which we now adopt,
.„ 11
if a -=±: 1 w ^ g -^ ^ + T '
;„ 11
if a^-1 n ^ ^^r -5 — T.
& a T i
In the case for which we are furnished with experiments, viz. that given by
Mr RUSSELL, the value of a was § (Report of British Association for 1837, p. 442).
114
For this case, then, we ought to have n^.^^- 5 — ^- ^
4 +
Mr RUSSELL himself is of opinion that n=\. I do not think that his expe-
riments warrant this opinion, and whilst I am not disinclined to admit that a
quantity a little less than | may suffice, I am still more confident in the truth of
results obtained from approximation, than in those obtained from the hypothesis
of continuity.
64. With respect to the height of the wave, we determine its value from the
equation
a dz
but «-£ Jfj .'A
py+^—vn^^a
Hence the elevation of the wave is
n.
ca
COR. 1. If the form of the wave can be expressed by one function,
This expression shews that the crest of the wave is higher at the sides of
the canal than in the middle.
PROFESSOR KELLAND ON THE THEORY OF WAVES. 125
COR. 2. If w2=H and e be the elevation in the middle of the canal, e' at any
point
COR. 3. If y be great
•( € : f: -. e •. 2 nearly,
that is the elevations increase in geometrical progression.
65. We have, in the next place, to give the general solution of this problem,
which, lest we trespass too long, we shall do with as much brevity as is con-
sistent with intelligibility.
In the first place, if 0 be that function of which the partial differential co-
efficients with respect to the three co-ordinates, represent the velocities in their
direction, we have
>-»CO x>CO
0 = 2/ / cos p x emy . en zf(m, n, i)dmdn
Jo Jo
subject to the condition m2+ns— ps>=0
,,eo /""co
» = 2/ / cospxemyenzmf(m,n,f)dmdn
J o *s a
•f
tv = lf f wspxemyenznf(m,n,f)dmdn
«/ It I/ 0
And the conditions (8) and (9) become
2/ / cospxemymf(m,n,f)dmdn=Q , . . (8')
2/ / cos p x en *mf (m, n, t}dmdn — Q ,'9'j
Jo Jo
Also equation (10) gives at the surface,
i
mcospxe"1* zen *f(m, n,f)dmdn
The equations (8') and (9') will be satisfied by supposing that n and m admit
each of equal values with opposite signs. This therefore gives us the following
values of u, v, it.
*P sin P* (emy + e-^y) (enf + e~n^f (m, n, f) dmdn
VOL. XV. PART I.
126 PROFESSOR KELLAND ON THE THEORY OF WAVES.
(m,n, /) dmdn
The equation w,g+ J- =0 gives for the surface,
which is satisfied by making
en z, _ — n Zl
d*f(m,n, t) +gn - 1 -=0 ; z, being the value of z for the surface. The value
**~*r
off(m, n, t) deduced from this equation is
f(m,n, *) = Acos\/N . * + Bsin\/N t; where
«**,_*—•*,
Ne — e
= a n
n*
Now equation (10') is reduced by multiplying up the denominator, and bring-
ing both terms to the same side. It becomes by this process
f«> fa>
21 j r / m v* zi — 'ft V- z,\ /
/ / cospx{m(e —e " ') (e
+J 0 \J 0
— 'ft V- z,\ / n z. — n z \
" ' ' '
, f) dmdn = 0.
This equation is satisfied, if we can assign such relations between m and n
that
m (e™ * ', _ e-m * */) (e« *> + e~n *) -n-Vz, (em ^^ + e~m^ *<) (enz>- e~n z') = 0,
which we evidently can do, since one term is positive, and the other negative.
Also, from the value off (int nl t) it is evident that
n en*>-e-™*'
, + e—n *,
We can approximate to the value of this expression just in the same way as
in the previous process ; thus the first equation gives nP-^z,—ri* zt-\'z,=§ ;
and the second c2=
Combining them, c2—
m- + n*
ffz, _ gz,-
-. — — + 1
the same result as that given by our approximation in the previous solution.
It is necessary to remark that m and n may in this case admit of an infinity
of different values : but since for them all the above equations hold, this circum-
stance has no effect whatever on the value of c. The most important consequence
which results from this general process is, the evidence which it affords in favour
of the truth of our previous conclusion relative to the form which the wave as-
PROFESSOR KELLAND ON THE THEORY OF WAVES. 127
sumes, viz. that it does not lag in the neighbourhood of the shallower part of the
canal.
SECTION VII.
66. The problem of determining the motion due to a slight disturbance, such
as an impact on the surface of the fluid, or the elevation or depression of a por-
tion, so as to leave it to regain its original position by disturbing the rest of the
fluid ; — this problem has occupied the attention of philosophers much, and it
would appear that little remains to be done on the subject. We shall, in what
follows, adopt the process employed by M. CAUCHY and M. POISSON, viz. that of
solving the general equation which results from the hypothesis, that the pressure
is a complete differential of the co-ordinates. We shall also adopt their solution
in its utmost generality. In so doing we must, however, express a doubt whe-
ther it is a complete solution of the problem. That modified form of it which M.
CAUCHY has adopted as the ground- work of his Memoir, we have no hesitation in
pronouncing far from complete. But to what state of motion the integral applies,
if not complete, we can hardly venture to guess. It is probably to a rippling
motion or slight, almost vertical, oscillation of the surface, which is very incon-
siderable compared with the depth. We make this remark from an examination
of the results which M. POISSON has arrived at. Yet though the equation be im-
perfect, it will undoubtedly serve as an approximate representation of the form
of the function on which the motion depends. A discussion of it, therefore, will
probably lead us to some important conclusions relative to the arrangement of
the particles at the beginning of the motion, though it fail to give a satisfactory
value to the length of the wave.
We adopt the usual notation, and suppose, as is commonly done, the distur-
bance to be small.
The equations of motion are,
d d) dd>
-~J--u, -f- = v
dx ay
d_u_dv
-
0 . . ' . . (3)
,g 1
where vt, -—• correspond to the surface of the fluid.
The integral of equation (1), to which we alluded in the preceding para-
graph, is
128 PROFESSOR KELLAND ON THE THEORY OF WAVES.
... (4)
the origin being placed at the quiescent surface of the fluid, so that z shall be a
very small quantity.
The symbol 2 is such that it expresses the sum of the two functions f(m, t\
f,(m, t), the latter being multiplied by sin mx; and it evidently requires that,
when it stands before sin m x the quantity not expressed to which it applies, it is
to have the negative sign.
Also equation (3) is
y^co ' 1
_./ - / A / m z — wi z-J-2 n\ j
g 2 / cos m xf(m, f)m(e —e ) dm
Jo
r*> d2f(m, t) . mz , —mz+Zh-. , n
+ 27 coswta; — ^—5 — - (e +e )dm=0.
Jo dl2
We can satisfy this equation by making
= -S.f°cosmx cos cmt (^ + e-™^ h} $(m)dnt
Jo
+ 2 f " cos m x sin c t (emy + e-Jaiy+^h') ^ (») dm.
Jo
Now one condition is, that when x=k, u=Q for all values of y, this gives
— sin mk(p (m) + cos mk(pt (m) = 0
— sin m k 41 (m) + cos m k -^ (m) = 0
(m) dm
~m y+2 A) tan m k $ (m) d m + &c.
=/ cosct(emy + e-my+2'1} -^^- cosm(x-k\
Jo cos m K
+ &C.
PROFESSOR KELLAND ON THE THEORY OF WAVES. 129
By altering -^M into 0' (m) to make the notation similar to that usually
0 cos m k
adopted, we get
" ~ ») cosm (*-*) rf«i
-)cosm(x-k}dm . . (6)
This value of (/>, it must be observed, has been deduced from the general
form by the aid of equation (3) which belongs to the surface, and as that
equation is only an approximation, so is this value of <£ itself only approximate.
The object of the following process is the determination of the functions $' and 4-'
by means of a knowledge of the initial state of the fluid.
67. Let us suppose that the motion has been produced by the sudden loosing
of a disk which kept a small portion of the fluid at a higher level than the rest.
The integral of the equation for the pressure is p= -gy--~—&c. + C,
therefore at the surface 0 = -g z - - + C,
or
the density being 1, and if + v2 very small.
Also <£, is the impulse on the surface, therefore when t=0, $,=0, -'=
,
it=:a,y=b, when b= — — '-- is the original form of the surface,
-*)<* "* • ' ' (7)
and ', '„ y, -47,, are all determined. It remains that we ex~
press the function 4' in terms of the given function /or its equivalent.
Denote a—k by a',f(a) by/ (a') ; x— k by of ;
then /(<*)=* ^ (e»' b + e~m 6+2 A) # (m) cosm Of dm
. . (8)
and our object is to obtain 0 in terms of /without the intervention of -4/; or to
eliminate •4*' between these two equations.
68. We shall make use of the following theorem in order to effect this pur-
pose.
THEOREM (See CAUCHY'S Memoir, Note xi.)
/•>»
If 2 / cos a' m <$> (m) d m =/ (a'), then will
\J 0
VOL. XV. PART I. Mm
130 PROFESSOR KELLAND ON THE THEORY OF WAVES.
/*»
2 / cos a? my (m) d> (m) dm
«/ 0
T f* CO /*CO _
= — / / y(fJL)f(ir)(cosfjiir—af + cosu.v + af)dlJ.da-
TTi/ o *x o
/CO /^«
dvcosfj.*- (fa! + -a+fd — •*}•=! da-cosfj. -a-f(cf + »)
U - CO
x>CO
=/ rfar COS //(»—«')/(«•)
i/ — co
r=—/ / cos //(»•—
TTv/ — cov/ o
. sine tdu. : (9)
when we have integrated the expression, we must write a/ instead of a'.
This is the complete value of 0 corresponding to our hypothesis.
Our next process is to obtain the values of u and v, corresponding to a given
canal.
70. CASE I. Let us suppose that y, b, and h, are small quantities. Neglect-
ing their powers,
sin * '
sn tg-<
P
PROFESSOR KELLAND ON THE THEORY OF WAVES. 131
and fp =9 (z + *) V? nearly.
d(b bJq ra cosu. (a — of} — cos/zo' .
Also u=-/=-^ I —/---= -smctd/J.
dx IT Jo Jj, VJ.b + h *
_ _ -v (In,
. f) — sin fji(rf + Vg(z + A) t) + sin p. (af — Vff (z -t- ti) t) | ->-
Now the integral / — f^rf/u is ^-whatever be q, provided it be positive.
*J o [A £
Hence, of the four integrals which make up the value of u, it is necessary,
in order that u may be equal zero, that all the quantities under the circular sign
should not have the same sign.
When t = o and xf ^ a
b I g ( IT 7T 7T TT
~
x' — a
If t^—j—, -- ., we obtain as the value
If
b ff ( -7T 7T 7T
~
b Iff
-2 ^e>+A-
If t^ -£- - * OT Cr4.'r_2[ '"I-
7T > — 7m \l i . T \ n >^ cy ~n — 7»i — "'
We must bear in mind that our results are mere approximations, and cannot
be expected to give any thing more than the nature of the disturbance!
It appears, therefore, that the different particles of the fluid are not put into
motion (at least horizontally) until such time, from the moment at which the
raised fluid is set free, as would be occupied by a body moving with a velocity
=*/0(z + K) in travelling from the nearest portion of the elevated fluid to the point
in question. This is a very important conclusion, and differs altogether from the
result obtained by Mr CAUCHY. It must be observed, that the demonstration
supposes the fluid free in both directions, a supposition absolutely requisite to the
form of the function which has been adopted.
Again, it is evident that not only is the velocity of transmission of the first
132 PROFESSOR KELLAND ON THE THEORY OF WAVES.
motion =^/g(z + K), but that every successive wave is transmitted with the same
velocity.
Also the coefficient of the velocity -^ varies inversely as V£Th, that is the
(velocity)2 a inversely as depth, therefore mass moved x velocity2 or vis viva is
constant.
Another, and, for our present purpose, a still more important result appears
from the form of the function ; viz. that the initial conditions which we have
assumed to exist must of necessity give rise to a wave transmitted in the negative
as well as in the positive direction. Thus the hypothesis belongs only to a canal
open in both directions. And farther, since the other hypothesis, that when '=0,
j?=0, and (j)=a constant, will give the sum of sines as the function correspond-
ing to the sum of cosines in the present case, it is clear that no hypothesis of this
nature can apply to the case of motion in a closed canal.
We must therefore look for some other process when we come to that case,
and proceed at present with the problem before us, admitting it to be restricted
to an open canal.
71. Let us now expand the different quantities which enter into the expression
for.
!_,—•*»(»+*)
5
3
+ *)*)
sin c^ t = sin fJL Vff (z + A) t—cosfj. Vg (z + h) 't . ^- (z + h)2 V ' g (z + h)
2 * 2 - 9 A2
-&c.
8
PROFESSOR KELLAND ON THE THEORY OF WAVES.
2-2//A + /X2 (y* + 2 h y + _2A2)
133
fJL(o + n)
The simple inspection of these formulse will shew that they will afford no
new terms in $ except those which are introduced by cos fj. \/g (z + A) . /.
But for instead of e»v + e-M+™, we have
dy
therefore the coeflBcient which involves y and b is
and -jZ is reduced to
«ff
rfrf)
«
dy
rfrf) *\/^ /*" sinua — a' + sinua'
« ^s — ~ " • / - - - - -
TT Jo (J.J/J.
u JLt X
P'
denoting
. t by p.
VOL. XV. PART 1.
N
PROFESSOR KELLAND ON THE THEORY OF WAVES.
rr - -; -
i cosup + d — a — cos a — a + o u.
\L
_^L (z + Kft/g (z + h) I sin /z p + a— a'-sin /zp — a + a'
+ sin /z £> + a' -f sin yu a' — £> 1 c?/>e
= an integrated function
If we confine our attention to waves transmitted in the positive direction,
this gives
function —
— cos a— <
or if p be greater than a + a', the factor is
><[' + 3 li
- « «
or » oc sn
-.
+ &c.
J
_____
o (p — a;
omitting a as a very small factor.
Hence it appears that the recurring function is independent of a, and conse-
quently that a small disturbance in a shallow canal will be transmitted in pre-
cisely the same manner, whether the quantity originally disturbed be small or not.
We cannot extend this memoir to other cases of our present hypothesis, but
must pass on to the more general problem.
72. CASE II. Suppose the expansion to be carried on in terms of e—f- *, &c.
This approximation is applicable to all conceivable cases of motion, and will con-
sequently deserve our careful consideration.
From equation (9) we have
d^__bVff r<» sin/i(
dy~ TT Jo ' ' — S11< f1'
— e
PROFESSOR KELLAND ON THE THEORY OF WAVES. 135
l_e— **(*+*)
Now c2=ff n - tt±h\=3 f as a first approximation.
— •*+*
_ e
Hence, approximately
= _ 6V> /*" sin/iCa-^Q + Bin/irf gin ,— , g_^ (6_y) .
7T •/« V/*
We can obtain a very important result from this equation when t is a very
small quantity. In that case,
bgt( a—a' a' 1
" V I (a - a')3 + (b^}* + of2 + (b-yf }
or by writing, as we ought, of for a'
_
~ -TT (ar1- a)2 + (6^)2
Let us transfer the origin to the middle point of the base of the parallelepi-
ped originally elevated, and put xf=x + ^;
a a
~2 * + ~2
1. If x be ^ ~ ; -j is negative, or the particles move downwards, as, from
J ay
the nature of the case, they must evidently do.
2. If x be very large, and b— y small, the latter may be neglected, and
d$_bgtl 1 1 \_ bgta
dy tr \ a a) ~
*-2 z+2
Hence sin c /=sin \/y /i t— \fg p e~2 ^ ^^'^ cos
3. -- will equal zero if
a
— -=0; i. e.
{36 PROFESSOR KELLAND ON THE THEORY OF WAVES.
or if *~ 4- (*-*)*=0.
Consequently the particles of the fluid which lie above the equilateral hyperbola
defined by this equation will commence to move upwards : those which lie lelow
it will commence to move downwards ; and those which lie along it will at the
first instant be at rest.
/ 2_o2\ _,b_ x2
4. -¥.= 9 — -0^7 where r, r' are the distances of the point
ay, 7T r . r *
whose motion is determined from the two extremities of the summit of the ori-
ginally elevated fluid.
Combining these remarks with the conclusions previously arrived at, Art. 70,
we conclude that no part of the fluid, except that which is in the immediate vici-
nity of the disturbed particles, commences to move with a wave motion ; but that
it gradually swells so as to diminish the quantity of fluid which actually consti-
tutes the volume of a wave.
These conclusions are of sufficient importance to warrant us in bestowing a
little more attention on this part of the subject ; especially as M. POISSON'S result,
although in some points the same as our own, in others differs materially from it.
For instance, M. POISSON'S line of no vertical velocity is a straight line.
73. Let us then determine the value of corresponding to very small values
oft:
a
We have
COR 1. +
We know that this equation holds true approximately for the surface : it ap-
pears from the results above, that at the very beginning of the motion the equa-
VOL. XV. PART I. 00
138 PROFESSOR KELLAND ON THE THEORY OF WAVES.
tion holds true at all points. It is, however, accurately true when I has a value
sin2 6 sin2 6'
only in the case in which — : -,— =0, that is, for the surface, or at least
near it.
Con. 2. When x lies between ~ and — „, b-y is zero at the commencement
A &
of the motion ;
.-. when t=Q, and b—y=Q
-7^= - bff, which we know to be correct.
Still supposing b— y=Q, we get
. ... j»*
d 2-TT/a2
-77=0 when t2= — ( -r- -
dt ct\4:
nr a
= — at the origin.
This gives the time at which the surface has attained the statical level.
COR. 3. If b-y be neglected in comparison with of, we have
^
4
or if x be large, y (2 (*— y) =*'2
^2= — 77T at the surface.
•?(6)
This expression gives the time at which the swell has attained its maximum.
COR. 4. The height to which it attains is approximately
,d(f> bfft2 a
~~ '
dz
x2— —
4
ba & ba
27r(6)
a
2~7T
This result is curious, inasmuch as it shews that the swell depends on the extent
of surface disturbed, and not on the magnitude of the disturbance.
PROFESSOR KELLAND ON THE THEORY OF WAVES. 139
2 12 . a2
LOR. 5.
... bgta
.: velocity =^7,
which shews that the actual velocity of a particle after a small time t varies inverse-
ly as the product of its distances from the two extremities of the displaced mass.
Con. 6. If a be small, velocity a inversely as square of distance from centre
of displacement, which is M. POISSON'S result.
74. Let us return to the value of -3* :
dy
d(b M/0 f"° sin u. (a — a') + sin uaf . / A —u.(b—z\, ,
It is -7-*-=— I-* / —"—srnVgiJLte ^" Z) d p. nearly
".'/ 7T Jo vM
_ b*/g rm cos (fJLa-a'-V^jj. t) - cos Qu a -" — -%- +,n1> V— 1 — g — " * ^~ *
cos n§e d
Jo
.
dA r -?
dt 'Jo e
<
/« ~
c
— — e + a A + const.
= 1 + aA
~~ 2" /*
/. by integration A . e = I da
Let An be the value of A when 0=0.
e 2+C.
Aa=r dae 2 + C = f dl>e~b'
J Jo
a'
and Ae 2 — A0 =
— a* Co- — —
~2~ ~2~ / j ~ 2
A ;= A,, e + e J dae
By putting « V-l and — w\/Hi successively for a, and adding, we get
/cos/td) e ^dip^fj'^e'^ + n I dae + jj / rfae ' =\'o"
"V W 2 J o A^u
since the last terms destroy each other.
(f)2 (p (T)2
«CO .. x» CO / — ~4~ d ^ — — — d ty \
Also / (f>cosn(be 2d(b = il (e 2 +e 2 ).
/o »/o \ /
Now /"'
=aA — e 2 T between limits ;
_
(/6 2 da
)
PROFESSOR KELLAND ON THE THEORY OF WAVES. 141
Hence
/" ae f"1
(p cos w 0 e J rfJ—1 —% \
-T=- . ^—5 — - I I + s — « / ,— e da\
vg-t fft \ ' «y~ »V— i /
and the second
2w 4W01 / wv — i ~2 / ""• " "~a
I i - f» i f>
'• 9?
- ^
1 + - — « _ e da
•)
dd)
- 2'TT '
r <*' —- r—a-
/ ~"2"j e 2 I e *
o/ c da=— --- »/ - 5
\r 2j e e da
WOW o/ c da=— --- »/ - 5 —
a a8
a' a' a? =^\2 + 2) = c as it evidently ought to be. Hence it appears that the instan-
taneous impulse conveyed to any point in the surface of the fluid is exceedingly
small.
2. If y=-h
sin /i (a -* + *) + sin //(*-*) e~*h
But
_2C ra sin /J. (a — x + k~) + sin fJL (x — k) —ph,, — /* -^. . -
"
_i x—k —\ a — x + k —\ x—k —\ a—x+k
tan — r— + tan — — -. tan -rrr- — tan _
A A on on
—l x—k —i a — x + k s
•tan -=-,-- + tan - -—. &c.
5 A 5 A
*> r ( * i- i i •<• &\ 3 1 /r t
_*^ } r~K x (f ~\ +i(f l:
TT I A :> V A / 5 \ A
— _ — _ a — j? +
" ~~ + ~
«-A 1 /x — k\3 I/x — k\5
"3A +3V3A j -51-3TJ
+ &c. &c.
2Cra la la
_____ -i ____
" -TT \ A 3 A 5 A
- -
3 W 333A; 3 53\A
+ &c. &c. |
= — -T nearly; if x—k be small and A considerable. Hence we
IT h 4
learn that the impulse instantaneously communicated to the bottom of the canal
varies inversely as the depth.
The few cases we have exhibited above, must not be supposed to include all
that our analysis is capable of developing. We have given these cases rather
144 PROFESSOR KELLAND ON THE THEORY OF WAVES.
as examples than as attempts to produce the complete solution of the problem.
Hitherto our endeavours to deduce a relation between the depth of the fluid and
the length of the wave have been unavailing, principally (as I think) from the
difficulty attendant on summing slowly converging series. I trust what has been
done will serve to introduce the subject to mathematicians of this country, who
do not appear as yet to have taken a very lively interest in the theory, zealous as
they are in prosecuting the experimental study of fluid motion.
( 145 )
VIII. — Examination and Analysis of the Berg-Meal, or Mineral Flour, found in the
Parish of Degersfors, in the Province of West Bothnia, on the confines of Swedish
Lapland. By THOMAS STEWART TRAILL, M.D., Professor of Medical Jurispru-
dence in the University of Edinburgh.
(Read 18th January 1841.)
IN 1832 or 1833, a peasant, in felling a tree in the forest about forty miles
above Degersfors, laid bare a substance strongly resembling meal, which, tempted
by its appearance, he baked with a mixture of rye-flour, and used as bread.
" All the world," says Mr Laing, "of this and the next parish, flocked to the spot
to take their part of this extraordinary blessing of meal, produced in the earth at
a time when they were reduced to bark bread. The functionaries of the district
at last heard of it, and gave orders that it should not be used until they had as-
certained that it was safe. Some of it was sent to Stockholm to be analyzed."
Mr LAING has stated, in his Tour, that it was said to consist chiefly of finely pul-
verised flint and felspar, with a residuum of organised matter ; but the propor-
tions, or the regular analysis, he could not learn.
Mr LAING procured specimens of this curious Berg^Meal ; and, on the return
of my friend and relative from his northern tour, he was so kind as put them into
my possession for examination, in the end of 1838.
I soon ascertained that this substance really contained organic matter ; for,
when heated, it first became black at a red heat, exhaling a smell like a mixture
of vegetable and animal matter, and when the heat was increased, it burnt to
snowy whiteness. By exposing a portion of it to a red heat in a glass tube, I
found that it gave out ammonia in sufficient quantity to restore the colour of
litmus paper, reddened by weak acetic acid.
Thus satisfied of the presence of animal matter in the Meal, I proceeded to
examine it with the microscope, and was surprised to find that it chiefly con-
sisted of organised bodies, of regular figures, which strongly resembled some of
the exuviae of Infusoria described by EHRENBERG.
Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 6. Fig. 6.
VOL. XV. PART I.
146 PROFESSOR TRAILL ON BERG-MEAL, OR MINERAL FLOUR.
The most conspicuous figures in the powder, when highly magnified, had the
form of thin, translucent, elongated, elliptical bodies, longitudinally divided by a
less translucent septum or canal, as in fig. 1. The largest of this form measured
0.006 of an inch ; but their general size was 0.002 in length, by 0.0005 in greatest
breadth. The elliptical body fig. 1, £., with darker margins, measured 0.006
by 0.0005. The other c was equal to 0.0006 by 0.0005. Mixed with these,
I observed many tubular bodies, some of which are straight, others gently curved.
Fig. 2 measures 0.002 by 0.0001 inch in diameter. Fig. 3 is a double tube of the
same length, but twice the breadth. Fig. 4 is a slender tube, the length of which
I forgot to measure ; but it seemed to me about one-third, at least, longer than
fig. 2. Fig. 5 is of various sizes ; but one of the most perfect measured 0.002
in length. The spicula, fig. 6, vary greatly in size, — from 0.0001 to 0.002. The
principal mass of the powder consists of fragments of the forms now described,
and of minute granules, which seemed to have a regular oval form, and could not
be above one thirty-thousandth of an inch in their longest diameter.
Anxious to ascertain whether, besides these bodies — which EHEENBERG would
consider as animal — the powder does not contain vegetable remains, 1 submitted
a part of it to Dr GREVILLE, who has favoured me with the following remarks.
" I have carefully examined the Berg-Meal, and find it full of siliceous re-
mains of minute animals. There appear to be a few forms, also, of those minute
Algce which have a siliceous structure ; especially the curved tubular bodies,
fig. 5, and possibly also the oval bodies, fig. 1. But if you consider EHRENBERG
as decisive authority, I can detect no form that, according to him, is not animal."
Dr GREVILLE is of opinion that the diatomacea are really vegetable productions,
and that the forms in question belong to that class of beings. Be this as it may,
it is sufficient to state that they are indisputably the remains of organised beings ;
and as the Berg-Meal contains organic matter destructible by fire, and, as I shall
presently shew, partially soluble in water, the peasantry of Swedish Lapland were
not so irrational in obstinately adhering to the secret use of their Berg-Meal, in
defiance of the local authorities, as we might, at the first glance of the subject, be
led to believe. Men accustomed by necessity to live on bark bread, found it no
unpalatable mixture with rye-flour ; and it has not the austere taste which the
bark of the pine, when best prepared, undoubtedly retains.
According to the testimony of CONDAMINE and HUMBOLDT, the natives on the
banks of the Maragnon and Orinopko, during periods of scarcity, eat with impu-
nity a species of fuller's earth, devoid of any nutritive principle. LABILLAEDIERE
states, that the aborigines of New Caledonia eat in great quantities a soft steatite,
consisting of magnesia, lime, and oxide of iron. The negroes, at the mouths of
the Senegal, and the blacks, imported as slaves into the New World, are well
known to mix clay with farinaceous food ; but the presence of organic matter in
PROFESSOR TRAILL ON BERG-MEAL, OR MINERAL FLOUR. 147
the Swedish Berg-Meal seems to give it a marked superiority, as a substitute for
food, over all the earthy substances which are said to enter into the repasts of
of the Ottomacks, the Papuas, and the Negroes.
ANALYSIS.
A.
This substance, which appears as a friable powder, is rather soft when rubbed
between the fingers; of a colour between greyish- white and wood-brown; blackens
at a red heat, giving out a faint, empyreumatic, ammoniacal odour ; and finally,
when the heat is increased, becomes of a pure white.
1. It does not dissolve in water ; but, by long digestion in distilled water, it
loses about seven pey cent, of its weight, and imparts a yellowish tint to the fluid.
This water is quite transparent, even after concentration ; yet, on standing for
between two and three weeks, a few gelatinous flakes appeared in it, but I found
the quantity inappreciable. It also afforded a perceptible, but inappreciable quan-
tity of some muriate.
2. When digested with strong sulphuric acid, it blackens, and a small portion
of earthy matter is dissolved.
3. Digested with hydrochloric or with nitric acid, a part of it is also dis-
solved.
4. The dissolved portion gave no trace of baryta, nor of strontia, nor of mag-
nesia, but a very slight one of lime, by the addition of oxalate of ammonia. The
presence of alumina was shewn by the addition of carbonate of ammonia to its
solution in nitric acid. Benzoate of ammonia, and ferro-prussiate of potassa, in
different portions of the neutralized solutions, indicated the presence of iron.
After these preliminary experiments, I made the folio wing experiments in order
to find the relative proportions of its ingredients.
B.
From the difficulty of depriving a powder containing organic matter, wholly
of water, without partial decomposition, I was under the necessity of repeatedly
performing the process of desiccation and incineration.
100 grains, gradually dried at a heat a little above 212°, were introduced into
a platinum-crucible and heated to redness. The mass first blackened and gave
out the smell already noticed — it was rather pungent ; and when litmus paper,
reddened by diluted acetic acid, was exposed to the vapour, its colour was imme-
diately restored ; and a rod dipt in hydrochloric acid, exposed to it, instantly pro-
duced white fumes ; shewing the evolution of ammonia. A full red heat, continued
for half an hour, converted it into a snow-white powder, which when weighed
before it was quite cold = 78 grains ; or the Berg-Meal by incineration had lost 22
per cent. The incineration was five times repeated on different quantities of the
148 PROFESSOR TRAILL ON BERG-MEAL, OR MINERAL FLOUR.
substance, with results so nearly similar, that I consider 22 per cent, as the real
proportion of this mineral destructible by a red heat : and as it had first been
carefully dried, that number may probably be fairly considered as an approxima-
tion to the quantity of organic matter which it contains.
C.
1. 78 grains of the incinerated Berg-Meal (B. 1.) were digested with sulphuric
acid, to which distilled water was added, and the digestion continued for 48 hours.
The clear liquid was drawn off by the pipette, and the residue, largely diluted
with distilled water, was thrown on the filter, when it was well washed, dried,
heated to redness in a platinum-crucible, and weighed while still warm. It
=71.13 grains, or 8.87 grains had been taken up by the acid.
2. Similar results were obtained by digestion with undiluted hydrochloric
acid, which became of a pale straw-colour. The residue very nearly agreed with
the above carefully performed experiment (C. 1.)
D.
1. 78 grains of the incinerated mineral were digested with hydrochloric acid
(in C. 2.) diluted with distilled water for 48 hours. To the solution neutral ben-
zoate of ammonia was added until all precipitation had ceased. The liquid
became turbid and yellowish-brown. Next day the precipitate, in bulky flocks,
lay at the bottom of the vessel, leaving the supernatant liquid colourless and
transparent. The addition of more of the test produced no further change in the
liquid ; and therefore I conclude that all the iron had been thrown down. The
clear liquor was withdrawn by the pipette ; the rest was thrown on the filter and
well washed.
2. I found it impossible to separate all the precipitate from the paper, but
having dried the part of the filter stained with the iron, I burnt it on a platinum
dish, moistened the ash with nitric acid, and exposed the whole to a strong red
heat. The residue was a reddish-brown oxide of iron which weighed 0.15 grain.
D.
1. To separate the alumine, 78 grains of the incinerated Berg-Meal were
digested in hydrochloric acid as before ; and when a diluted clear solution was
obtained, it was precipitated by carbonate of ammonia : a gelatinous greyish pre-
cipitate resulted, which adhered to the filtering paper. The greatest part of it
was removed before it was quite dry. This, when exposed to a red heat, had a
reddish-yellow colour ; and it was found that the iron was precipitated with the
alumine. The filter was burnt and treated as before (D. 2.), and the whole
together weighed 5.46 grains. The former experiment (D. 1.) had shewn that
the quantity of oxide of iron = 0.15 grain, and, therefore, the real quantity of
alumine in the Berg-Meal = 5.31 grains.
2. The examination of the residual liquid, after the separation of the iron,
PROFESSOR TRAILL ON BERG-MEAL, OR MINERAL FLOUR. 149
almost coincided to a few hundredths of a grain with this, which I considered as
the most accurate experiment.
3. In one small parcel of the Berg-Meal, differing a little in colour from that
of which the analysis is now given, I found a larger quantity of iron, and ahout
0.02 of a grain of lime : but as the iron in the Berg-Meal, by several experiments,
was only from 0.15 to 0.156, and the quantity of lime wholly inappreciable, I am
disposed to consider these discrepancies as arising from accidental causes ; and I
think we shall not greatly err in considering the following as the composition of
the Berg-Meal when dried.
22.00 Organic matter destructible by heat.
71.13 Silica.
5.31 Alumina.
0.15 Oxide of iron.
98.59
1.41 Loss.
100.00
In this loss must be included the trace of lime in the solutions, and still
slighter trace of muriates which the aqueous decoction exhibited. But I am
inclined to suppose, that the principal part of the apparent loss is to be attributed
to the difficulty of obtaining, in a state of uniform dryness, a powder which con-
tains matter destructible by heat.
It is quite obvious also, that in a powder exposed, as the Berg-Meal appears
to be in its native repository, to accidental mixtures from the influence of decay-
ing vegetables, and from the percolation of water charged with earthy matter, in
different situations, and even in different parts of the same bed, its accidental
ingredients may vary ; but this analysis sufficiently proves that its principal and
essential chemical ingredients are organic matter and silica, both derived from the
decomposition of beings once endowed with the principle of life.
Perhaps no geological speculation is more calculated to excite surprise and
admiration than a reflection on the countless myriads of animated beings, whose
remains, even to the naked eye, now appear to fill our calcareous formations and
our coal-beds : but how much is this sentiment increased, since EHRENBERG'S dis-
coveries have taught us to consider the chalk (which forms whole districts in
Europe), polishing slate, and some other minerals, as aggregations of the exuviae
of animals so inconceivably minute, that a single cubic inch of chalk contains
1,382,400 individuals ! ! The Berg-Meal of Swedish Lapmark adds another link
to the infinite chain of organized existences, whose delicate structure, symmetry,
and astonishing minuteness, are not among the least wonderful of the works of
the supreme CREATOR.
VOL. xv. PART i. R r
IX. — Farther Researches on the Voltaic Decomposition of Aqueous and Alcoholic
Solutions. By ARTHUR CONNELL, Esq., F. R. S. Ed.
(Read 15th February 1841.)
SINCE my last communication to the Society on this subject, I have continued
my experimental investigation of the proposed law which limited the direct action
of the voltaic current to the solvent, in solutions of primary combinations of ele-
mentary bodies in the more important solvents. All my farther researches have
confirmed the rule in regard to aqueous solutions ; and I feel now fully convinced
of its truth, although, in the mean time, I have had occasion to see a different
view advocated by some other experimenters, to whose opinions I shall afterwards
advert. Neither have I seen any grounds for altering my views in regard to alco-
holic solutions. In regard to ether, some experiments which I shall afterwards
mention, have satisfied me that it would be improper at present to include that
solvent in any general rule.
I. — Aqueous Solutions.
I need not revert to the proof adduced in my former papers* of the second-
ary decomposition of the hydracids in their aqueous solutions ; nor to that of the
secondary origin of iodine in a solution of bromide of iodine, f
With respect to the oxyacids, in addition to the experiments on the sulphu-
ric, boracic, and iodic acids, formerly detailed, which led to the inference, from
the quantity of gases evolved, that such acids are not directly decomposed in
their aqueous solutions ;:f I have now to mention a still more direct method of ar-
riving at the same conclusion in regard to iodic acid, and, by analogy, in regard
to other oxyacids. A moderately strong solution of iodic acid, mixed with a starch
solution, was placed in the tube B, § and was made positive by a power of 50 pairs
of two-inch plates ; whilst a starch solution placed in the tube A was made nega-
tive, the connection being by asbestos moistened with starch solution. Efferves-
cence soon ensued from both poles ; but in half an hour there was no trace of any
formation of blue matter at the negative pole or in any part of either tube. The
battery was then reversed, when blue matter appeared in two minutes on the
negative foil, without effervescence, or scarcely any. Thus, in the first position
* Edin. Trans, vol. xiii. p. 339, and xiv. p. 116. t Ibid. xiv. p. 119.
J Ibid. xiii. 338. § Fig. 1, PI. II. vol. xiv. Edin. Trans., bottom of Plate.
VOL. XV. PART I. S S
152 MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
of the battery, the iodine did not pass towards the negative pole, and the acid,
consequently, did not suffer voltaic decomposition ; whilst on reversal iodine very
soon appeared at that pole, by the reducing action of hydrogen.
In regard to oxides, it is not easy to obtain such direct experimental evidence,
because the metals of such as are soluble in water react on the solvent : but we
%
may take the decomposition of metallic oxides, as contained in soluble salts,
during which the metal frequently appears at the negative pole, as illustrating the
action on solutions of such oxides as are dissolved by pure water. It is now pretty
generally admitted, that when metal appears in solutions of metallic salts at the
negative pole, it is due to the reducing action of nascent hydrogen ; and this opinion I
have verified directly by finding that, when a solution of sulphate of copper was made
positive, by 50 pairs of 2-inch plates, and connected by asbestos with distilled water
which was made negative, neither metallic copper nor oxide was carried towards
the negative pole during half an hour's action ; whilst, on reversal of the battery,
the now negative foil was found in a quarter of an hour to be coated with metal-
lic copper without any elastic fluid from that pole. It was also found, by a simi-
larly arranged experiment with an aqueous solution of chloride of zinc, that nei-
ther zinc nor oxide was carried in a similar time to the negative pole, when that
pole was placed in distilled water ; but that, after reversal, metallic zinc soon
appeared at that pole, from the reducing action of hydrogen ; and holding, as I
do, from the experiments formerly detailed,* that chloride of zinc is dissolved as
a muriate, the above result affords the same illustration as that with sulphate of
copper. A similar result was obtained when distilled water was carefully poured
over a concentrated solution of muriate of zinc in a bent tube, instead of connect-
ing the liquids by asbestos, and the poles plunged separately into the two liquids ;
the only difference being, that, previous to reversal, a little oxide of zinc ap-
peared to be formed at the boundary of the water and the metallic solution.
I thought it likely that the employment of a negative pole of metallic tellu-
rium might have thrown farther light on this matter ; since, if the tellurium in
the solution of a common metal combines with hydrogen, as it does under ordi-
nary circumstances of voltaic action, no metal ought to be reduced from the
solution. But I found that, when so employed, copper and zinc still appear
at the negative pole. This will doubtless be thought by some a proof in favour
of the direct decomposition of the metallic oxide ; but, on due consideration, it
appears to me to be quite insufficient to establish it. If the oxide really suf-
fers direct decomposition, it seems evident that in the experiments above de-
tailed, in which metal appeared, on reversal, at the negative pole, that either it,
or at least oxide, ought also to have appeared proceeding towards that pole pre-
vious to reversal. It is impossible to perceive what should constitute the differ-
* Edin. Trans, vol. xiv. p. 12?.
AQUEOUS AND ALCOHOLIC SOLUTIONS. 153
ence between the two cases. The experiment with tellurium is therefore, I con-
ceive, to be explained simply by supposing that, in the presence of a readily re-
ducible metallic oxide, the nascent hydrogen rather combines with the oxygen of
that oxide than with tellurium.
In DAVY'S Bakerian Lecture of 1807, he states, that in one experiment,
where nitrate of silver was made positive, and distilled water negative, the asbes-
tos Avhich formed the connection was found to be coated with metallic silver. I
do not doubt the result ; but I conceive that, under the powerful voltaic action
employed (apparently 100 pairs of 4 or 6 inch plates), the oxide of silver carried
over to the negative side had suffered reduction either by the simple action of
light, or more probably by hydrogen evolved in the negative tube. I made the
same experiment, using only fifty pairs of 2-inch plates, and found that neither
silver nor oxide appeared on the asbestos in forty minutes, but, on reversal, the
negative foil was found fringed with metallic silver in half an hour. A strong
solution of nitrate of silver was also placed in a bent tube, and distilled water
poured above it. The negative foil was then plunged in the distilled water, and
the positive in the solution, but no oxide nor silver appeared anywhere in half an
hour, whilst, on reversal, metallic silver began to be formed on the negative foil
in ten minutes. What, then, is the difference between the two positions ? Simply
this, that, in the second, nascent hydrogen is evolved in the solution itself.
In addition to the proof formerly adduced* of the secondary origin of the
electro-negative constituent of the haloid salts in their aqueous solutions, I may
mention a very simple experiment which leads to the same conclusion, and from
being capable of extension, as shall be afterwards shewn, to alcoholic solutions of
those salts, throws light on their nature also. If an aqueous solution of iodide of
potassium is acted on, using platinum poles, iodine immediately separates at the
positive pole, and is dissolved by the liquid giving it a deep red colour. But if,
instead of platinum, a positive pole of zinc is employed, the liquid being in the bent
tube A, and the power fifty pairs of 2-inch plates, there is not the slightest
discoloration of the liquid ; but a speedy and copious deposition of oxide of zinc
takes place from the positive pole, with only a bubble or two of elastic fluid, whilst
at the negative pole there is brisk effervescence. These appearances are inexpli-
cable, unless on the idea of the secondary origin of the iodine ; and they are best
explained by assuming that the oxygen from decomposed water combines with
* Edin. Trans, xiii. 344, and xiv. 118.
154 MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
the zinc, and causes the precipitation of oxide of zinc in an apparently anomalous
manner at the positive pole ; and when platinum is used, it unites with the hy-
drogen of the acid of the salt, and liberates iodine. When chlorides, as those of
potassium or calcium, are employed, there is in like manner a separation of oxide
of zinc at the positive pole ; and a portion of the oxide which is taken up by the
acid is sometimes carried to the negative pole, where it separates along with re-
duced zinc.
I conceive that a sufficient number of cases has now been investigated to
warrant the general conclusion, that, " When aqueous solutions of primary com-
binations of elementary bodies are submitted to voltaic agency, the dissolved sub-
stance is not directly decomposed by the current, but only the solvent." The rule
of course does not embrace combinations of the second order, such as oxisalts, in
the solutions of which acid and base, as is well known, go to their proper poles,
under the direct influence of the current.
It does not appear to me to be necessary to dwell long on the views of MAT-
TEUCCI and Professor DANIELL, both of whom have recently advocated the pri-
mary origin of metal in aqueous solution, whether of haloid or oxisalts. MAT-
TEUCCI* argues, because a weak pile, incapable of decomposing distilled water,
effects the decomposition of haloid salt solutions, the haloid salts must be more
readily decomposed than water, and must be the subject of direct action in their
solutions. It is evident, however, that the affinity of the elements of water for
the constituents of the salts which they find at the poles, and the inferior con-
ducting power of the solutions, afford the true solution of this observation. He
also founds on some experiments with basic acetate of lead, which, he says, both
in its fused state and in solution, yields less lead than the equivalent proportion ;
but no account is given of the exact quantity got in the former situation, nor is
any accurate correspondence shewn to exist between the quantities in the two
cases, and the whole seems explicable on the idea of such a mode of union be-
tween acid and base as to make the salt less susceptible of voltaic action, and of
the reducing agency of hydrogen ; and, at all events, I conceive that the above
experiments afford direct proof that the origin of the metal is not due to primary
decomposition. Mr DANIELL'S views are to a great extent theoretical ; the direct
decomposition of the haloid salts being first assumed, and an attempt then made
to extend the analogy to the oxisalts, on the hypothesis that the latter, in solu-
tion, consist of metal united to acid, plus an atom of oxygen, and to embrace, on a
similar analogy, the ammoniacal salts on the idea of the existence of ammonium
in them. All these views must assume, as their basis, that metal passes by the
direct action of the current to the negative pole, an assumption which is, I con-
ceive, directly negatived by the experiments above detailed. These views are
* Bib. Univ.
AQUEOUS AND ALCOHOLIC SOLUTIONS. 155
equally inconsistent with the experiments so often detailed, shewing the secondary
origin of the electro-negative constituents of the haloid salts, and with the sepa-
ration of oxide of zinc from a positive zinc pole, as above detailed.
In the whole circumstances, there appears to be no reasonable doubt of the
general rule which has been above laid down. No binary combination of elements
gives way by direct action, in its aqueous solution ; in other words, of all simple
substances, oxygen and hydrogen are the most directly opposed in their electric
nature, and their combination yields the most readily to voltaic action. When
we rise to the next order of combinations, those of binary compounds themselves,
a different rule conies into operation ; for then the combination is decomposed
with the same facility as the solvent itself, acid and alkali going to then* respec-
tive poles at the same time as the elements of water, and, according to the expe-
riments of Mr DANIELL, in the same atomic proportion.
II. — Alcoholic Solutions.
Since my former communication, I have made a similar experiment on an
alcoholic solution of hydriodic acid, as those formerly detailed on alcoholic solu-
tions of haloid salts, and obtained a similar result.
Alcohol of 0.793 at 62° F. was charged in a little WOLFE'S apparatus with hy-
driodic acid gas, which had been passed over fused chloride of calcium, and was
then placed in a tube A* and connected by asbestos with two others B and C,
containing distilled water ; A being made negative and C positive by a power of
72 pairs of 4-inch plates. Gas soon arose from both poles, but during the first
twenty minutes no formation of iodine was any where observed, nor any acid re-
action except in A. Afterwards a brown discoloration was observed at the posi-
tive pole in C, and at the same time an acid reaction at the same place, and on
the asbestos between A and B, and a trace on that between B and C. In half
an hour the appearances were the same, but more decided. No iodine was any
where observed but in C. The battery was then reversed, when a brown stream
from liberated iodine instantly descended from the positive pole, without any
elastic fluid from that pole, and with effervescence from the negative pole.
This experiment would of course have had more analogy to those with aque-
ous solutions, if the tubes B and C had contained alcohol instead of water ; but
the very feeble conducting power of the former liquid prevented its employment,
and the dissolving of any substance to favour the conduction would have interfered
with the delicacy of the reactions. The phenomena are, however, best explained
on the view that the water of the alcohol only suffers direct decomposition.
The appearances, when a positive pole of zinc is used in alcoholic solutions
of the haloid salts, are instructive, because they tend to identify the circumstances
* Fig. 2. Plate II., Ed. Trans, xiv.
VOL. XV. PART I. T t
156 MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
both of solution and of voltaic action, with those in aqueous solutions of the same
substances.
When a saturated solution of well-dried iodide of potassium in alcohol of 0.7918,
at 66° F., was thus acted on by 50 pairs of 2-inch plates in the bent tube, p. 153,
oxide of zinc, after a short time, separated at both poles, without any appearance
of iodine,* and without effervescence at the positive. These appearances can
only be explained on the idea of the secondary origin of the iodine, Avhich appears
when, instead of zinc, platinum is employed ; and are conformable to the view of
the direct decomposition of the water of the absolute alcohol ; and the appearance
of oxide of zinc at the negative pole, whether it could only have come by solution
and voltaic transference, leads, I conceive, to the view that, even in alcoholic solu-
tions of haloid salts, at least those of moderate strength, the salt decomposes the
water of the absolute alcohol, and exists in solution as a hydracid salt. But to
this latter matter I shall afterwards recur.
When a solution of chloride of lithium, the salt having been heated until it
began to rise in vapour, and then dissolved by heat in alcohol of the above
strength, was acted on in the same manner, oxide of zinc separated after a little
at the negative pole, with effervescence from that pole, but none from the posi-
tive ; and it was somewhat uncertain whether any separation of the oxide took
place on the positive side ; but little doubt could exist that the oxide originated,
as in the case of iodide of potassium, by the action of the oxygen of water on the
zinc, and subsequent solution and transference of the oxide formed. The princi-
pal condition of the deposition of oxide of zinc at the positive pole, whether in
aqueous or alcoholic solutions, appears to be a pretty rapid formation from brisk
action ; and the less powerful the acid, and the less its quantity drawn to the
positive side, the more of the oxide separates previous to solution and trans-
ference.
When an alcoholic solution of fused chloride of calcium was employed, there
was a slight appearance of deposition on the negative side, but none on the po-
sitive, and no effervescence at the latter pole ; the whole action being retarded by
the coating of lime which the negative foil soon acquired. With an aqueous so-
lution of chloride of calcium, oxide of zinc separated at both poles.
In regard to alcoholic solutions, therefore, I have seen no reason to depart
from the general rule formerly proposed respecting them.
With respect to pyroxylic solutions, I hav^e made few experiments ; because,
if the general rule holds good in regard to alcohol, there can be little doubt that
it will embrace pyroxylic spirit, since, as I formerly shewed, the decomposition
of its water is much more readily effected than that of alcohol. I found, experi-
* The zinc pole usually gets slightly blackened both in alcoholic and aqueous solutions, but
this darkish matter was carefully examined and found to be merely oxidated zinc.
AQUEOUS AND ALCOHOLIC SOLUTIONS. 157
mentally, that when a solution of dry iodide of potassium in rectified pyroxylic
spirit was placed in a tube A,* and water in a tube B, the two being connected
by asbestos, and A made negative and B positive by 50 pairs of 2-inch plates,
although iodine soon appeared in the neighbourhood of the positive pole in B, yet
it was accompanied by acid passing into the water of B; and, after forty minutes'
action, these appearances continued the same, only more decided, and without
any appearance of iodine elsewhere. There is little doubt that the nature of the
action was just the same as in aqueous and alcoholic solutions.
In the whole circumstances, although the evidence may not be of quite so
decided a character in some of the cases of alcoholic solutions as in regard to
those in water, still I think there need not be much hesitation in laying down, as
a still more general proposition than that above stated, that " When solutions of
primary combinations of elementary substances in water, and in those liquids,
such as alcohol and pyroxylic spirit, which contain water as such as an essential
constituent, are submitted to voltaic agency, the dissolved substance is not di-
rectly decomposed by the current, but only the water of the solvent."
III. — Ethereal Solutions.
Previous to my former communications, I had been unable to find any sub-
stance which, by solution in ether, led to any decided symptoms of decomposition
under voltaic agency, whether of the dissolved body or of the solvent ; and I was
thus led to expect that a general rule would be found to exist, by which both that
liquid and all bodies dissolved in it resist such agency. This led to the parti-
cular form which I formerly proposed provisionally for the general law on the
subject ; but I have since seen cause to strike ether out of the rule entirely, until
farther light can be thrown on the appearances which some of its solutions pre-
sent under electric action.
I have found that, when highly rectified ether was saturated with dry muriatic
acid gas, and the solution submitted to the action of a moderate voltaic power,
elastic fluid was given off from the negative pole, and none from the positive, and
that the solution acquired a yellow colour, and, on subsequent evaporation, yielded
a little of a less volatile liquid, smelling of chlorine. The gas, when examined in
the voltaic eudiometer, appeared to be hydrogen, retaining some ethereal vapour
even after being washed with water, as a little carbonic acid resulted from the
detonation with oxygen.
When dry hydriodic acid gas was conducted into ether, in a little WOLFE'S
Apparatus, the liquid immediately separated into two layers, — a lower, dense,
and deep red, and an upper, slightly coloured, which, under voltaic agency, yielded
gas from the negative pole.
* Fig. 1, PI. II., Edin. Trans, vol. xiv.
MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
In regard to the latter of these experiments, there can be no doubt that, in
saturating the ether with hydriodic acid gas, decomposition took place ; and al-
though the nature of this decomposition was not fully investigated, it seems pro-
bable that the lower liquid consisted principally of iodised hydriodic acid, result-
ing from the combination of^oxygen, derived from the ether, with hydrogen, of a
portion of the hydriodic acid ; on which view, water, of course, would be formed,
and become the subject of the subsequent voltaic action. During the saturation
of ether with muriatic acid, no signs of decomposition were visible ; but still it is
not improbable that some internal changes may have taken place, and water re-
sulted from the action, united to muriatic acid. Unless such a view be adopted,
I should be inclined to hold that there really was direct decomposition of the mu-
riatic acid by the voltaic current ; for when I recollect that pure ether resisted
very powerful voltaic currents, and that even potash, which has so wonderful an
effect in promoting the galvanic decomposition of the water in absolute alcohol,
did not make ether more susceptible of electric agency, I cannot allow myself to
suppose that the decomposition, in the case of ethereal solutions of the hydracids,
is that of water entering into the constitution of ether ; but adhere to the original
view, that ether contains no water, and that alcohol consists of ether and of water.
Under the circumstances, the advisable course evidently is, to omit ether al-
together from any general rule as to the voltaic decomposition of solutions, and to
limit such rule, as above done, to water, and such solvents as have been ascer-
tained to contain water as an essential constituent.
IV. — On the state in which the Haloid Salts are dissolved by Water and Alcohol.
I formerly endeavoured to shew, by acting on aqueous solutions of haloid salts,
—both poles being placed beyond the solutions in distilled water, — and comparing
the results with those obtained by using alcoholic solutions, that the salts exist
in the aqueous solutions as hydracid combinations.* The evidence on the subject
is, however, quite sufficient, even without any illustration from alcoholic solutions,
as the following observations will, I hope, shew.
It is frequently difficult, particularly in the case of iodides, to observe any
acid reaction at the positive pole, when both poles are plunged directly into the
solution, on account of the reducing action of oxygen on the acid formed. And
even in those cases where acid is observed, that circumstance will not of itself il-
lustrate the state of solution ; because it might be held that acid is formed by
secondary action at the negative pole, from whence it is drawn to the positive.
In this way only — on the hypothesis of solution as haloids and direct voltaic de-
composition of water only — could the separation of reduced metal at the negative
be accounted for. A doubt might also exist whether the acid reaction at the pole, in
* Edin. Trans, xiv. 127.
AQUEOUS AND ALCOHOLIC SOLUTIONS. 159
so far as observed, might not arise from an oxyacid formed by secondary action at
the positive. All such objections are, however, obviated, by placing the poles be-
yond the solution, so as to get quit of secondary actions ; and we thus readily ob-
serve the transference of acid in all cases in which it takes place, by saving it from
secondary decomposition. In this way I shewed, in numerous instances, that acid
and alkali went to their respective poles, and that the acid, passing, was the
hydracid. These facts, wherever they are observed, are, I apprehend, quite suffi-
cient to prove the haloid to be dissolved as a hydracid salt ; for, even laying aside
for a moment the experiments by which I have endeavoured to shew that the ha-
loids, if existing as such in water, are not directly decomposed, let us take the
different views of the nature of the galvanic action which suggest themselves when
both poles are plunged into the solution in the ordinary manner, and consider them
on the supposition that haloids are dissolved as such.
First, let us suppose that only one of the two substances — water or haloid,
it matters not which — is decomposed, it is evident that we cannot account for
the production of acid, where secondary action is excluded. Next, let us suppose
that both substances are decomposed, and that either the elements, going to the
same pole, unite on their journey, or, by an interchange of elements, the oxygen
of water unites with the metal of the haloid, and the hydrogen of the water with
the electro-negative constituent of the haloid. The former of these alternatives is
contradicted by the fact that the acid formed is a hydracid ; and the latter, although
it might account for the formation of acid and alkali, would not account for the
liberation of the electro-negative constituent of the haloid at the positive pole, and
of hydrogen in fixed and definite proportion at the negative, whatever be the
strength of the solution. It appears to me, then, to be sufficient, in order to prove
the aqueous solution of a haloid as a hydracid salt, to shew the separation of the
hydracid by voltaic action, under circumstances which exclude secondary action.
It must, however, always be remembered, that although such production can
be readily shewn in many cases of haloids, it does not necessarily follow that this
should hold in all cases. We are, of course, best prepared to expect it in the case
of haloids, of which the constituents have the strongest affinities for oxygen and
hydrogen, — such as the ordinary haloids of the bases of the alkalies and alkaline
earths. And, accordingly, I shewed that it applied to chlorides and iodides of
potassium and calcium. But farther, it was found to hold good in regard to the
ordinary haloids of the common metals of strong affinities, such as zinc. I was
prepared, however, to consider it as doubtful what might be the result in regard
to those of the noble metals. Accordingly, when a moderately strong solution of
chloride of gold was placed in the tube B*, and connected by asbestos with the
* Fig. 3, PI. II. Edin. Trans, xiv.
VOL. XV. PART I. U U
160 MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
tubes A and C, which were filled with distilled water, A being made negative and
C positive by a power of 50 pairs of 2-inch plates, no decided indications of the
formation of acid were obtained during an hour's action ; for although, latterly,
there was a slight acid reaction at the positive pole, it was not greater than distilled
water itself might have yielded, and there was a trace of alkali at the negative.
Before, however, deciding conclusively that chloride of gold in solution does not
yield to voltaic action, it would be necessary to repeat the experiment with a more
powerful current, because it may possibly only be a case of more difficult electric
resolution. In such cases, also, atomic constitution may have a considerable, if
not the principal, influence on the result.
Whenever we have obtained an instance of the decided formation of acid in
the above circumstances, we may conclude, with every probability, that all haloids
of the same nature and atomic constitution, of metals of equal or more powerful
affinities, are in the same situation. Thus, having verified the rule for chloride of
zinc, we may conclude that all protochlorides of more electro-positive metals, such
as manganese, cerium, magnesium, barium, potassium, &c. are dissolved as mu-
riates. On the other hand, for the whole series of metals, of less powerful affi-
nities, as well as for all haloids of more complex atomic constitution, the matter
will still require to be investigated, and I propose to make some further researches
on the subject.
In regard to sal ammoniac, I found that it was resolved into acid and alkali
in the above circumstances ; a result shewing that, in solution at least, it is simply
muriate of ammonia, and cannot be justly regarded as chloride of ammonium.
The same reasoning above applied to the results with ordinary haloids, can
be readily extended to the hypothetical chloride of ammonium ; and to complete
the evidence on this point, I found that a solution of muriate of ammonia yielded
the definite quantity of hydrogen from the negative pole.
The experiments with a positive zinc pole lead to the same result, at least
when taken in conjunction with those, shewing that the haloids, if viewed as
existing as such in solution, are not directly decomposed. The oxide of zinc,
which is dissolved and transferred, must have been taken up by acid which had
been previously drawn to the positive side.
The analogy of the action with a positive zinc pole in alcoholic solutions of
haloid salts, as formerly described, leads, by similar reasoning, to the view that,
in moderately strong solutions of that description also, such as those of chloride
of lithium, iodide of potassium, and moderately saturated alcoholic solutions of
chloride of calcium, the haloid decomposes the water of the alcohol, and exists in
solution as an oxisalt. Many of the phenomena of the voltaic action on such
solutions will thus receive a more ready explanation than on the idea of these
salts being dissolved as haloids ; such as the appearance of alkalies and earths at
the negative pole, which will thus result directly from the decomposition of a
AQUEOUS AND ALCOHOLIC SOLUTIONS. 1 61
hydracid salt, instead of supposing the secondary action of hydrogen on the haloid,
and reaction of the metal on water.
We cannot easily get the same direct evidence on this subject by the method
applied to aqueous solutions, of placing the poles in water beyond the solution,
because, from the inferior conducting power of the alcoholic solution, less acid
will be separated, if it truly exists, in the liquid ; and we cannot distinguish
whether it may not come from the point of junction of the alcoholic solution with
the water in which the poles are placed. Hence, I believe that, in formerly con-
trasting the results with alcoholic and with aqueous solutions, the conclusion that
no acid was formed in the former solution was incorrect ; and I think it more
likely that the acid formed was confounded with that from the point of union. It
is fortunate that there is no real need for this illustration in proof of the decom-
position of water by haloid salts.
If alcohol dissolves haloid salts as hydracid salts, there can be little doubt
that pyroxylic spirit does the same : I incline to think that the greater solvent
powers of the latter fluid than the former in regard to some substances, such as
barytes, is due to its greater absolute quantity of water, although not greater
atomic proportion.
V. — On the Conducting Power of Solutions.
Without going the length of holding that the additional conducting power
bestowed on water by dissolved substances, is exactly proportional to the degree
of chemical change, under voltaic action, resulting from the dissolved body, there
seems in every instance in which increased conducting power is bestowed, some
chemical change, or at least voltaic transference, attending the increase of con-
duction. This chemical change may result either from the direct action of the
current or from secondary agencies ; and both circumstances lend their aid, where
they occur, in augmenting conducting power.
In the case of salts, the voltaic separation of acid and alkali at once explains
the result, and in many of such cases we have an additional effect from secondary
actions at one or both poles.
Acids alone in solution, as is now generally known, and as I have myself
verified experimentally, for sulphuric acid and the hydracids, undergo transference
to the proper pole ; which circumstance appears to be the primary cause of their
promoting conduction. In some instances secondary actions at the poles also
contribute to the result.
To ascertain whether alkalies have a similar action by suffering transference,
a moderately strong solution of caustic potash was placed in a tube B connected
as in fig. 3* by asbestos, moistened with distilled water, with two tubes, A and
* Edin. Trans, xiv. Plate II.
162 MR CONNELL ON THE VOLTAIC DECOMPOSITION OF
C, containing distilled water, A being made negative, and C positive, by 72 pairs
of 4-inch plates. The whole tubes were covered with a close glass covering, a
piece of turmeric paper having been introduced into the liquids A and C, between
the asbestos and the poles. In a few minutes alkali was indicated at the negative
pole, and went on increasing during half an hour, whilst the test-paper in C was
not discoloured, shewing that the effect in A was not due to capillary action.
The experiment was then stopped, when the water in A, although not alkaline to
test-paper throughout, became decidedly so by concentration, whilst that in C
shewed no alkali even after concentration.
In the experiments also, already detailed, in which acid and alkali were
separately drawn to the poles in distilled water, from saline solutions, the alkali
usually reached the pole as soon as the acid.
There can thus be no doubt that by voltaic action the alkali in an aqueous
solution is transferred to the negative pole.
Water coloured by bromine gives sensibly more effervescence under galvanic
action than distilled water, shewing a superior conducting power of the solution.
The manner in which such simple substances increase the conducting power
of water requires a little investigation. Chlorine, bromine, and iodine, are gene-
rally admitted not to be conductors themselves ; and, even if a little doubt may
exist as to iodine in a state of fusion, it is scarce possible that the minute quantity
of it in an aqueous solution can operate in that way.
To ascertain whether such substances are capable of transference in solu-
tion, an aqueous solution of bromine, with a little undissolved bromine at the
bottom to maintain a state of saturation, was placed in the tube B, the arrange-
ment being in all other respects the same as in the last described experiment, with
a solution of potash; and after nearly an hour's action of 72 pairs of 4-inch
plates, no discoloration from transference of bromine could be observed in the
water either of A or of C, and the latter had only a scarce perceptible smell of
bromine, which I believe was due to the secondary decomposition of a trace of
hydro-bromic acid, drawn into C, as both the liquids B and C shewed some
degree of acid reaction.
An aqueous solution of iodine was then substituted in B for that of bromine,
a little iodine being also left at the bottom, and all other circumstances the same,
and the battery recharged. After an hour's action there was no appearance of
iodine either in A or C.
From these experiments it is obvious that neither of these substances are
transferred in solution under voltaic agency. We must, therefore, look for some
other explanation of the increased conducting power ; and that which readily
occurs is a secondary action at the negative pole, by the union of hydrogen with
the dissolved substance. To determine the accuracy of this view, the current
from 50 pairs of 2-inch plates was passed at the same time through a solution
AQUEOUS AND ALCOHOLIC SOLUTIONS.
of bromine and diluted sulphuric acid, and the hydrogen evolved from the two
negative poles collected ; when, after half an hour's action, 0.13 C I were collected
from the sulphuric solution, and only a bubble the size of a pea from the brome
solution. The difference had evidently combined with bromine.
When an aqueous solution of iodine, which had been previously purified by
sublimation, solution in alcohol, and precipitation by water, was substituted for
that of bromine, the action was much more feeble. In a quarter of an hour, only
a small bubble of gas was collected from each negative pole ; and in two and a
quarter hours 0.1 C I from the sulphuric solution, and 0.077 C I from the iodine.
It is thus evident that, both in the case of bromine and iodine, the action is
increased by the combination of the dissolved substance with hydrogen of the
decomposed water, but that, as was to be expected, this circumstance occurs to a
much larger extent in the case of bromine than of iodine.*
On connecting the rules regulating the voltaic decomposition of solutions
and the transference of substances held dissolved, we observe that no sub-
stance, whilst in a state of transference, suffers direct voltaic decomposition.
Acids and alkalies suffer transference, but not direct decomposition. On the other
hand, salts, whether oxyacid or hydracid, are not transferred, but are resolved into
their constituent acid and alkali.
We cannot, however, say, that every substance which is not transferred is
directly decomposed. Thus we can hardly doubt that such combinations as bro-
mide of iodine do not suffer voltaic transference, seeing that their constituent
elements, when separate, are not transferred ; and we have farther seen that this
combination is not directly decomposed in solution. Probably, also, some cases
of chlorides exist, in which, from peculiarity of atomic constitution, or other
circumstances, there is neither transference nor direct decomposition.
* Long after these experiments were made, and conclusions drawn, I observed that M. BECQUEREL
had also found that bromine and iodine, in solution, unite with hydrogen under Galvanic Agency.
L'Jnstitut. .Tuin, 1840.
EERATUM in former Memoir, vol. xiv. p. 133, line 2, for latter read former.
VOL. XV. PART I. XX
( 165 )
X. — On the Preparation of Paracyanogen in large quantities, and on the Isomerism
of Cyanogen and Paracyanogen. By SAMUEL M. BROWN, M.D. Communicated
by ROBERT CHRISTISON, M.D., F.R.S.E., &c.
(Read 15th February 1841.)
THE design of the processes described in this memoir was to decompose the
bicyanuret of mercury at such a temperature, and under such a degree of pressure,
as to secure the simultaneous extrication of the two equivalents of cyanogen, or
their elements, in the expectation that they should come off united, and produce
the interesting compound of nitrogen and carbon, isomeric with cyanogen, Para-
cyanogen : And that result was sought in the belief that it would illustrate the
chemical theorem of the existence of bodies which, though composed of the same
elements in the same proportions, yet differ as widely from each other in chemical
properties and mechanical conditions, as one element differs from another.
I. History of Paracyanogen. — M. GAY-LUSSAC* observed, in the course of his
admirable researches on the prussic acid, that it is spontaneously decomposed on
exposure to light, ammonia being liberated and a brown solid matter deposited.
From experiments made in vacuo it appeared that these were the sole products of
the reaction of the elements of the acid on each other, so that the deposit neces-
sarily contained nitrogen, and, without analysis, it was inferred to be " un azoture
de carbone."
When M. GAY-LUSSAC proceeded to the discovery of cyanogen and the com-
position of the cyanurets, he procured cyanogen from the prussiate of mercury,
which he represented as a true bicyanuret. Among other processes, he had
recourse to the decomposition of the mercurial cyanuret by the oxide of copper,
in order to determine the quantitative composition of cyanogen. The results of
this analysis coincided with those of his other methods, and confirmed his view
of the nature of the so-called prussiate ; but there was one circumstance which,
at first sight, seemed to throw suspicion on these conclusions. " Cependant, s'il
en est ainsi, pourquoi reste-t-il une matiere charbonneuse lorsqu' on decompose le
cyanure par la chaleur? Cette difflculte m'embarrasse' pendant quelque terns;
mais je crois etre parvenu a la re'soudre." He then states that he found, that, when
the carbonaceous matter, now known by the name of paracyanogen, is left in the
retort after the reduction of the cyanuret by heat, nitrogen appears in the gaseous
product in such a proportion as very nearly to make up the equivalent weight of
* Ann. de Ch. 1815.
VOL. XV. PART I. Y y
166
DR SAMUEL BROWN ON PARACYANOGEN.
cyanogen with the nitrogen and carbon of the solid residue ; and from this obser-
vation it was concluded that the residue in question was a carburet of nitrogen,
containing less nitrogen than cyanogen.
In A.D. 1829, Professor JOHNSTONE published some interesting analyses of this
substance, from which it appeared to contain nitrogen and carbon in the very
same ratio as cyanogen itself. His results were received with some distrust ; but
only on account of the singularity of the inference to which they conducted, iso-
meric bodies being then comparatively unknown. Some analyses of LIEBIG'S did
not at first bring out exactly the same proportions as those of Mr JOHNSTONE, but
in the summer of A.D. 1835, they examined the subject together in the presence
of Dr GEEGOKY, and their results accorded with the former observations of the
British chemist, who subsequently published an elaborate memoir on paracyano-
gen in the Transactions of the Royal Society of Edinburgh for 1838. That memoir
contains satisfactory and numerous analyses of the carbonaceous matter under
consideration, all of which tend to establish the proposition that it is isomeric
with cyanogen, and that, consequently, the volume of cyanogen produced from
cyanuret of mercury by heat is less, exactly in proportion as the quantity of para-
cyanogen left in the retort is greater. The analyses were made by decomposing
paracyanogen by means of oxide of copper and bichromate of potash, collecting
the gaseous products, removing the carbonic acid from different volumes of the
mixture, and finding the proportional volumes of nitrogen ; for example, with the
former reagent a mixed product wr u, of which
90.0 vols. left 32.6 v. nitrogen,
92.9 ... 30.1
293.0 ... 98.0
and with the latter,
94.5 vols. left 33.5 v. nitrogen,
129.0 ... 43.0
108.0 ... 36.0
175.0 ... 58.5
These ratios, taken in connection with the ascertained composition of cyanuret of
mercury, prove that the subject of analysis is composed of nitrogen and carbon in
the proportion of 1 : 2. The composition of gaseous cyanogen is N 4- C2.
II. Properties of Paracyanogen. — We are indebted to Professor JOHNSTONE
for all that has been published about the properties of paracyanogen. Prepared
by heat from the cyanuret of mercury, it is a brown solid, more or less dark-
coloured and dense according as it is procured at higher or lower temperatures,
varying in these respects from the condition of a loose, nut-brown, hygrometric
powder, to that of a compact, black scoria. It cannot, however, be made to assume
the latter form without the loss of some of its nitrogen; the more suddenly it is raised
DR SAMUEL BROWN ON PARACYANOGEN. 107
to a white heat, and the shorter the time it is kept at that temperature, the less ni-
trogen is lost. The change which it suffers from elevation of temperature resembles
that which the same process produces on carbon, boron, and silicon ; after ignition
it is very difficult of decomposition, and indisposed to enter into combination. It is
soluble in cold concentrated sulphuric acid, and yields a deep-brown, semi-trans-
parent solution, from which I have found that it gradually falls, unchanged and
anhydrous, on prolonged exposure to the moisture of the atmosphere. This is the
only way in which pure paracyanpgen can be prepared, for, taken as it occurs in
the retorts, it is saturated with cyanogen, which adheres to it with great obstinacy ;
and I have never seen a specimen which did not leave an evident, though inap-
preciable, residue after the action of sulphuric acid, as might have been expected
from GAY-LUSSAC'S observation that, when paracyanogen remained in his retorts,
he always found traces of nitrogen in the cyanogen collected. It likewise dissolves
in nitric and hydrochloric acids, but to a much smaller extent. It is insoluble in
water, alcohol, ether, oils. When the sulphuric acid solution is poured into water,
there falls a bulky hydrate of paracyanogen. This hydrate is produced in several
humid reactions, such as that of cyanogen dissolved in alcohol and exposed to the
influence of light ; but it is unnecessary to refer to them, as it is with the produc-
tion of anhydrous paracyanogen by fire that the present inquiry has to do. These
proximate characters are exceedingly well marked, and are quite sufficient for
the discrimination of the substance to which they belong.
In the memoir of A. D. 1838, Mr JOHNSTONE states that paracyanogen is slowly
resolved by heat into cyanogen, but without alluding to the experiments which
led to this conclusion. As I had not only never succeeded in producing such an
effect upon .the pure anhydrous substance, prepared by the process which has
been indicated above, but had invariably obtained results directly negative of his
proposition, viz. the extrication of unmixed nitrogen, I requested Mr JOHNSTONE
to inform me of the manner in which his experiments had been performed. That
chemist kindly gave me to understand that he had never effected the total re-
solution of the solid into the gaseous isomeric, and that the process by which he
had produced the partial resolution, consisted in keeping paracyanogen (procured
as the residue of the preparation of cyanogen) at a low red, followed by a higher
heat, for sometime, and collecting the gaseous product, which came away less and
less rapidly as the operation was continued. Now, I had separated cyanogen in
this way from common paracyanogen, but always mixed with more or less nitrogen,
less at the beginning and more towards the end of the process, till there was ex-
tricated nitrogen alone ; and had inferred that the cyanogen had been retained in
the paracyanogen, which yielded it, by its absorptive power. This inference was
suggested and corroborated by the considerations that paracyanogen is peculiarly
fitted, by its mechanical form, for retaining gases ; that its chemical relation to
cyanogen renders it particularly adapted to the absorption of that gas, and that
168 DR SAMUEL BROWN ON PARACYANOGEN.
cyanogen is presented to it in the most favourable condition for retention in a
process of which they are simultaneous products ; and the following selection of
simple experiments ratifies the suggestion.
A quantity of paracyanogen was heated, the first product was rejected till
the air of the little apparatus, and any gaseous matters which the subject of ex-
periment might have absorbed from the atmosphere, were expelled, and then 32,
18, and 28.5 volumes were successively collected and examined ; the first was
found, after the removal of cyanogen by potassa, to contain 13.3 vol. or 41.5 per
cent., the second 14 vol. or 77.7 per cent., and the third 2(5 vol. or 92.8 per cent,
of nitrogen ; the volume of nitrogen being greater, and of cyanogen less, as the
operation was prolonged. The paracyanogen, which yielded these mixed volumes,
was then found to give off nothing but nitrogen.
Again, a parcel of the same paracyanogen was kept a week in a vessel full of
chlorine, by the copious absorption of which it was changed in appearance, having
assumed a very light brown colour. One part of this product, treated as in the
former case, first gave away chlorocyanic acid alone at a temperature somewhat
lower than that of red heat, and then, at a more exalted temperature, unmingled
nitrogen. Another portion was boiled several hours in water with a little carbo-
nate of potass, filtered, dried at 212°, and decomposed by heat; the first 30.1
volumes of the product suffered a diminution of only 0.1 vol. by the action of
potassa ; and the subsequent volumes suffered none.
These observations confirm the rationale which I have given of the appear-
ance of cyanogen at the beginning of the decomposition of paracyanogen procured
in the ordinary way ; especially when they are viewed in connection with GAY-
LUSSAC'S discovery of traces of nitrogen in cyanogen produced from bicyanuret of
mercury at high temperatures. And the fact that pure paracyanogen (precipitated
by the atmospheric moisture from the sulphuric acid solution of the common pro-
duct) does not aiford the slightest appearance of cyanogen, warrants the conclu-
sion that paracyanogen, once formed from cyanogen (or its elements), cannot be
rechanged into cyanogen by heat. Indeed, it would have been anomalous if it
had been otherwise ; for it will be found in the sequel, that the higher the tem-
perature at which bic}ranuret of mercury is decomposed, the greater is the quantity
of paracyanogen produced ; and how should the same cause which converts the
cyanogen of the mercurial salt into paracyanogen transform the latter into its
gaseous isomeric again ?
III. Experiments upon the Preparation of Paracyanogen, — The following expe-
riments were made with bicyanuret of mercury, formed by the reaction of hydro-
cyanic acid, prepared by GEIGEE'S process, on the peroxide of mercury, and sub-
sequently ascertained to be pure by a humid analysis.
DR SAMUEL BROWN ON PARACYANOGEN.
They are presented in the form of a list selected from many others, so as both
to exhibit the process of observation which led to the last of them, and illustrate
the conclusion deducible from the whole series, viz. that the greater the pressure,
up to a certain degree, under which the haloid is decomposed, the greater the
quantity of paracyanogen produced. Accordingly, although the two last may ap-
pear to supersede the rest, they would in reality be inconclusive as to the in-
fluence of gradually increased pressure without them. They are all described with
what may seem to be unnecessary minuteness, partly because they are the first
recorded experiments of their kind, and partly because it will be necessary to
make particular references to them in future communications.
1. A quantity of bicyanuret was thrown on an iron plate, previously heated
to a temperature much higher than the point of decomposition of the salt, yet
considerably short of that at which paracyanogen enters into combustion. Decom-
position instantly ensued, and there remained a residue of nearly half the bulk of the
cyanuret employed, which was found to be paracyanogen by the appropriate tests.
This was repeated several times at different temperatures, within the same range,
and with the evident result, that the speedier the decomposition, i. e. the higher
the temperature at which it was effected, the greater the bulk of the solid nitro-
carbon product. This rude experiment led to the next, in which the pressure of
cyanogen passing through a capillary tube was partly substituted for quick de-
composition.
2. Some cyanuret was introduced into a tube of German glass, sealed at one
end, which was then drawn out from two inches above the surface of the con-
tents into a very fine capillary, a foot and a half in length. The containing ex-
tremity was suspended in a large spirit-lamp flame till the decomposition was
completed. During the operation, the opening of the capillary was carefully
watched for cyanogen by a lighted taper, but no combustion or other evidence of
gaseous escape ever appeared, the great pressure given by the long capillary hav-
ing prevented freedom of passage. An apparently full proportion of mercury had
sublimed into the upper two inches of the wide part of the tube ; and there re-
mained below a quantity of brown matter, occupying nearly the same space as the
original cyanuret. The residue in this case consisted of paracyanogen, cyanogen
mechanically retained, and a few little globules of mercury, but not a trace of un-
reduced cyanuret. This trial was also repeated several times, and always gave
similar results : when the drawing of the tube was less capillary there took place
escape of cyanogen, and less paracyanogen was left. These two tentative experi-
ments conducted to the following attempts to obtain numerical results.
3. A strong test-tube, weighing 117.1 grs., was charged with 14.9 grs. of cya-
nuret, equal to 132 grs. It was drawn out at two inches from the bottom to
about five inches, and an inch above this to a foot in length, neither of the draw-
ings being quite so fine as in the second experiment. Heat was now applied,
VOL. XV. PART I. Z Z
170 DR SAMUEL BROWN ON PARACYANOGEN.
quickly raising the cyanuret to a full red ; mercury sublimed, some cyanogen was
observed to escape, and after the operation the apparatus was sealed down by the
blowpipe into small pieces, which, together, weighed 130.85 grs., indicating a loss
of 1.15 gr. ; whereas, if the products had been mercury and cyanogen, the loss
would have been 3.1 grs. The paracyanogen remaining in the tube weighed 2.3 grs.,
and, with the exception of retained cyanogen, was pure. Thus, 2.3 grs. of the cyano-
gen of 14.9 grs. of cyanuret, appear to have been transformed into the solid isome-
ric ; but 2.3 grs. + 1.15 gr. is a slightly greater weight than that of all the cyanogen
contained in the weight of salt decomposed ; an error which is to be accounted for
by the hygrometric property of paracyanogen, and the small but appreciable loss
sustained by glass-tubes when much drawn out.
16.4 grs. were treated exactly as in this experiment, the drawing having been
made more capillary ; and there was no loss, but the product contained slight traces
of undecomposed cyanuret, so that the value of the result was diminished.
4. A quantity of cyanuret, weighing 10.81 grs., was put into a strong test-
tube, three inches long, which was then bent to an obtuse angle in the middle,
and six inches of thermometer tube, of so fine a bore that quicksilver neither rose
in it spontaneously, nor could be forced up by suction, was tightly sealed into the
open extremity. The containing part was held in a large spirit-flame, so as to
keep the rest of the apparatus out of the heated current ; and at the end of the
process there was found to be a loss of 1.5 gr. The mercury had sublimed past
the bend, at which the tube was then broken across. The upper part, with the
mercury, weighed 124.8 grs., and lost 7.8 grs. by the removal of its contents ; while
the lower, containing paracyanogen, weighed 43.4 grs., and, on being emptied and
cleaned out by means of black oxide of copper, lost 1.5 gr. Now, 2.2 grs. — cya-
nogen of 10.81 grs. of bicyanuret of mercury ; so that all the cyanogen but 0.7 gr.
was, in this case, produced as paracyanogen. But 7.8 grs. of mercury implies a
loss of 0.8 gr., to be accounted for partly by experimental error, and partly by the
first loss of 1.5 gr. during the process; for 1.5 gr. first loss, + 1.5 gr. paracya-
nogen, -|- 7.8 grs. mercury, = 10.8, — a weight short by only 0.01 gr. of that of the
salt submitted to decomposition.
5. Eight inches of the strongest green glass-tube, one-third of an inch in dia-
meter, sealed at one end, and bent to an angle of about 130° between the third
and fourth inches from the bottom, having been tared, some well-dried crystals of
bicyanuret of mercury were introduced, and found to weigh 10.6 grs. The open
end was hermetically sealed. The containing limb of this little shut retort was
put into a jacket-tube, and surrounded by fine sand within the jacket. It was
suspended half an hour in a very large spirit-flame, at the end of which time com-
plete decomposition had been effected, except that a very small quantity had been
carried up with the mercurial vapour. After the reduction of the traces in the
bend, the apparatus was found to have gained 0.05 gr. from the sand, or otherwise.
It was filed across at the knee over a sheet of clean paper ; a slight explosion
DR SAMUEL BROWN ON PARACYANOGEN.
took place, and the odour of cyanogen was evident. Cyanogen having been dif-
fused away, and replaced by air, the two pieces, with their contents, weighed
390.5 grs., 1.7 gr. having been lost by explosion and diffusion ; mercury was sub-
limed away from both, and they weighed 383.1 grs., giving 7.4 grs. for mercury.
Paracyanogen was now removed, and the tubes cleaned with oxide of copper, when
they weighed 381.7 grs., giving 1.4 gr. for paracyanogen. These three weights of
cyanogen, mercury, and paracyanogen, make up 10.55 grs., less by only 0.05 gr.
than that of the original compound ; and the first (1.7 gr.) may be so divided be-
tween cyanogen and mercury as exactly to complete their ratios. In this expe-
riment, 1.4 gr. of cyanogen was changed into its solid form.
6. 16.25 grs. of the salt were put into a green glass-tube, three inches long, and
weighing 116.55 grs., the gross being 132.8 grs. The mouth of the tube was
plugged half an inch down with stucco-paste ; the whole was imbedded in a stucco-
mould, and immersed in a sand-bath, which was kept near the low red heat for
more than an hour. Freed from the mould and carefully cleaned, it was exa-
mined : 0.9 gr. of mercury was procured from the plug ; 13.1 grs. of brown pro-
duct mixed with mercury taken from the tube, and 0.4 gr. of incrusted paracya-
nogen removed by oxide of copper, so that there had taken place a loss of 1.85 gr. ;
and this experiment shews that, even under the pressure of a stucco-plug, more
than half an equivalent of cyanogen is given off in the form of paracyanogen.
This modification was tried thrice with analogous results ; at least half of the
cyanogen having been transformed in every case.
7. 50 grs. were closely packed in a small iron bottle fitted with a screw-stopper,
which, though tight, had been observed, in a previous experiment, to admit of the
passage of mercurial vapour under high pressure. Having been weighed, it was
enclosed in a shut crucible, and kept more than an hour at a low red heat, after
which it was found that the screw had allowed the expected exit, and that the
total loss was only 1.0 gr. greater than the weight of the mercury. The fixed
residue was good paracyanogen, containing no traces of either mercury or unde-
composed salt, but having lost some of its nitrogen. The loss of nitrogen was dis-
covered by the action of concentrated sulphuric acid. When it is taken into con-
sideration that the 1 gr. of total loss must be at least partly attributed to the ex-
trication of nitrogen from produced paracyanogen, the transformation effected by
this experiment appears to be very complete.
8. 32.15 grs. were crushed into a strong test-tube, which was sealed close
to the surface of the cyanuret, and immersed three hours in a boiling linseed-
oil bath. It seemed from without to be thoroughly decomposed, the charac-
teristic brown powder, with globules of mercury interspersed, having replaced
the white needles. Having been first weighed, it was filed across over a sheet
of paper ; a trifling explosion took place ; the scattered product and the pieces
of the tube, weighed together, indicated a loss by explosion of 0.5 gr. Thus
the pressure of contained air and 0.5 gr. of cyanogen, at the boiling heat of
172
DR SAMUEL BROWN ON PARACYANOGEN.
oil (600°), had hindered the further extrication of cyanogen during three hours.
However, all the remainder of the cyanogen had not been separated from the
mercury as paracyanogen ; the solid product was a mixture of that principle,
mercury and bicyanuret, only two-thirds of the last having been decomposed.
This oil-bath experiment was repeated several times with a view to finishing the
reduction by prolonging the operation, but in eight trials the packed tubes
burst in about nine hours ; and when removed before that time the cyanuret
was never found to have been completely decomposed. In one case, for example,
130 grs. gave two-thirds of its nitro-carbon product as paracyanogen, while the
cyanogen set free, as indicated by the loss after explosion, was only 0.9 gr. In
this form of the process the mercury is so intimately mixed up with the paracy-
anogen as not to be visible till it be ground under water ; they may be separated
either by levigation, which is a very tedious process, or by rubbing the mixture
gently in a leaden mortar, which absorbs the mercury. It is rather difficult to
separate paracyanogen entirely from the surface of the lead, on account of its ad-
hesiveness ; and for the purposes of analysis it is necessary to weigh the mixture,
to weigh the little mortar before and after the trituration, and to subtract the first
from the second weight of the mortar for the mercury, and the weight of mercury
from that of the mixed product for the paracyanogen.
9. In order to discover the degree of pressure under which the gaseous pro-
duct of these experiments is separated from the mercury in the solid form, I con-
structed a sort of differential barometer on the principle of the law of aerial elas-
Fig. 1. Fig. 2. Fig. 4.
n
Fig 3.
5.0
9.O
10 In.
'e
jTT
DR SAMUEL BROWN ON PARACYANOGEN. 173
ticity, commonly known as the law of BOYLE and MABIOTTE. A (fig. 1) is a very
thick and strong glass- vessel, somewhat of the shape and size of a common spirit-
lamp, with a strong tubular and well ground opening in one side. B is a brass
collar, an inch and a half in length, fitted closely round the neck of A with brazier's
cement ; the upper half of the interior of B is a female screw. C D (fig. 2) is a
barometer tube of the greatest strength which is made, thirteen inches long ; the
upper ten inches are graduated from above downwards, every inch being divided
into tenths ; at the tenth inch is fitted on the immoveable brass collar E, the part
e being cubic, and fitted with a detached crane-lever (fig. 3), ef being a round
disc fitting tightly down on the top of B, and d' being a male screw fitting that of
B. F (fig. 4) represents a thick glass tube-retort, the beak of which is nicely
ground into the tubular opening of A, fig. 1.
The method of using this instrument is exemplified in the details of the
experiment. C D was filled with quicksilver, inverted and screwed at d' into the
collar B, a well cut and greased leather disc having been interposed between the
top of B and the under surface of d ; it was fastened with the aid of the crane-
lever K. Quicksilver had been previously introduced into A to the height of the
tubular opening, so that the open end of C D was now submerged. The apparatus
was thrown on its side and shaken gently till the quicksilver fell in C D to the ninth
inch. The tube-retort was charged with bicyanuret and adapted to the tubular
opening with an air-tight cement, the junction being likewise thickly luted with a
paste of gypsum and gum-arabic, which sets very hard. Having remained two
days in this condition, the retort was put in a jacket-tube, and surrounded by a
large spirit-flame till the reduction appeared to be completed. In the mean time
the quicksilver in the meter-tube was watched ; it steadily ascended with a velo-
city manifestly diminishing with the increase of the height, till in twenty minutes
it reached 5.1 in. where it stopped. The flame was now withdrawn, equilibrium
of temperature restored, and the quicksilver fell to 8.1 in. ; from which it was in-
ferred that the quantity of cyanogen which had been liberated was measured by
the ascent of 0.9 in. ; while the maximum pressure under which the decomposi-
tion had been effected was measured by the ascent of 3.9 in. The apparatus was
taken down, and it was found that the reduction had been finished, so that cyano-
gen is given off from bicyanuret of mercury as paracyanogen, when decomposed
under a pressure bearing the same proportion to that of one atmosphere, as 9 in.
of the meter-tube to 5.1 in., i. e. according to the law of elasticity, a pressure of
1.76 atmospheres. The phenomenon may, for all that this and similar experi-
ments can determine, take place at lower degrees of tension, but I do not know
how the minimum may be estimated.
•
IV. Practical Observations. — 1. Such are the experiments which have been
made on the transformation of cyanogen by fire. As processes, they contain
VOL. XV. PART I. 3 A
174 DR SAMUEL BROWN ON PARACYANOGEN.
two elements of action, high temperature and great pressure ; the former be-
ing the sole principle of experiment 1, the latter of experiment 8, and both
being concerned in the other seven. It is impossible to change a whole equi-
valent of cyanogen by this kind of procedure, for no apparatus can be so filled
with salt as to leave no space for extricated gas, and, as has been several times
observed already, paracyanogen absorbs it largely. Whatever may be the value
of the foregoing results as the first-fruits of a new field of chemical investigation,
viz. the decomposition of compound bodies under greater than atmospheric pres-
sure, and at temperatures higher than their natural points of reduction, they at
least supply the desideratum of a simple process for the large preparation of a
curious substance, which eminently deserves to be studied, but has hitherto been
procured only in small residual quantities. Process. — Let any quantity of cyanu-
ret be tightly packed into a tube of cast copper, eight inches long and two-thirds
of an inch in diameter, shut at one end and open at the other ; let the mouth be
plugged an inch down with stucco-paste, and a little fire-clay put over the stucco ;
and, after the tube has been luted and dried, let it be kept half an hour at an
obscure red heat. The greater part of the nitro-carbon product remains in the
form of paracyanogen. If it contain unreduced cyanuret it must be returned, if
it contain mercury it may be cleaned in a leaden mortar, and it may be rendered
perfectly pure by solution in concentrated sulphiiric acid. By this and similar
processes I have made paracyanogen by the drachm instead of the grain, having
always procured about two-thirds of the Avhole weight of nitrogen and carbon.
The mercury may be collected by adapting a conducting tube and receiver to the
copper-tube and plug. This process may be variously modified. I employ two
copper-tubes, one of which terminates at its open end in a male screw, and the
other in a female. The latter, thrice as long as the former, is charged, and the
two are firmly screwed together so as to give very great, but not fixed, pressure,
for the screws always permit gaseous passage in such circumstances.
V. The Constitution of Paracyanogen. — It is isomeric with cyanogen. Ana-
lysis thus suggests two possible arrangements of its components : It may be re-
garded as a compound of two combined atoms of nitrogen and four combined
atoms of carbon, and represented by the symbol N2 + €4 ; or, it may be viewed as
a combination of two atoms of cyanogen, with the symbol Cy + Cy, or Cy2. These
are the only schemes of constitution which can be formed, without supposing radi-
cals which are not known to exist, and modes of combination of which there is no
known example. Both of them assume the combination of " equal and similar" *
, * I have borrowed the phrase " equal and similar" from geometry, because several atoms are equal
which are not similar. It implies identity both of atomic weight and of true isomorphism, both of force
and of form.
DR SAMUEL BROWN ON PARACYANOGEN. 175
atoms ; the former of two nitrogens with one another, and four carbons ; the latter
of two cyanogens. The former, however, supposes a combination of two nitrogens,
which is decomposed by the decomposition of its compound with the carbon ; for,
by whatever process paracyanogen be decomposed, nitrogen is liberated. Now, it
is not easy to conceive of a compound of two atoms of nitrogen, once combined, be-
ing resolved into its constituents by (for example) elevation of temperature ; and
this reflection, simple as it is, applies to every case in which chemists have hitherto
represented two equal and similar atoms as combined. If there be any analogy be-
tween the union of equal and similar atoms, and that of two unequal and dissimilar
atoms, it should be broken up only by analogous forces. Now, heat decomposes a
compound of the latter kind by driving away the more volatile, or liquefying the
more fusible element ; and if the true symbol of paracyanogen were N2 + C4, heat
should extract from it neither nitrogen nor carbon, the elements of a compound
of two nitrogens being equalty volatile, and those of a compound of four carbons
equally infusible. For these reasons I set aside the ordinary doctrine of the con-
stitution of paracyanogen, and adopt the alternative, which is both simpler and
more consistent with the results which have been described above. Two atoms of
cyanogen are, by an artifice, separated simultaneously from one of mercury ;
they come away as paracyanogen — a new form ; and the most direct inference
is, that the product is a compound of one cyanogen, as such, with another. It
has been sheAvn that the solid isomeric cannot be resolved by heat into two equi-
valents of cyanogen, which is the best and only possible confirmation of the con-
clusion that it is a true cyanide of cyanogen, decomposed neither by heat, because
its constituents are equally volatile, nor by electrolysis and reagents, because it is
a perfectly neutralized combination. Heat and reagents decompose, not paracy-
anogen, but its constituents, producing from each one of nitrogen and two of carbon,
and making up, for an equivalent of the whole, two of nitrogen and four of carbon.
According to the same principle, the symbol of cyanogen is not N + C2, but
NC + C. But it is unnecessary to generalize the proposition which has been laid
down, as the method of doing so is very simple ;* suffice it, that if it be admitted,
it affects the whole doctrine of chemical constitution, and strikes at the root of
a hypothetical inference regarding affinity, which has been promulgated by syste-
* For example, the carbo-hydrogenous series of isomeric bodies would be represented thus : —
Methylene, . . ( C2 H2 ) — Me ; .
Olefiantgas, . . ( C4 H4 ) = Me +Me ;
Oil gas, . .' ( Q H8 ) = Gift. + Gift. ;
X, an unknown form, ( CjeHis) = Olg. -j-Olg.;
\Cetene, . . ( C32H32 ) = X + X ; =16
| Naphthaline, . . . = Na. ; eq. 1.
( Paranaphthaline, = Na. -f- Na. ; eq. 2. ; and so on.
176 DR SAMUEL BROWN ON PARACYANOGEN.
matic writers ever since the term was defined by BOERHAAVE, and is now calcu-
lated to impede the progress of discovery, viz. that the attraction of affinity
between dissimilar atoms is identical with, or analogous to, the attraction of
cohesion between similar atoms.
In conclusion, this view of isomerism, and the relation of cyanogen to para-
cyanogen, is further recommended by the consideration, that it affords a practical
foundation for a likely hypothesis of the constitution of the so-called chemical
elements, and points out the way in which such a hypothesis may be either estab-
lished, or overthrown by experimental observation. Let it be supposed that
several of the elemental groups are so many series of isomeric forms, and it is at
once to be inferred that heat, electrolysis, and reagents, shall all be incapable of
decomposing them, as has been found in the actual practice of the laboratories of
modern Europe by innumerable trials. If, to take one instance, sulphur (16 or 2)
be an isomeric form of oxygen (8 or 1) which it as much resembles in chemical
properties as it is conformably contrasted with it in mechanical condition, it must be
impossible to extract oxygen from it by any analytical force which has yet been dis-
covered ; and the only method in which it shall be possible to prove that such is
the mutual relation of these two elements shall be to have recourse to synthesis,
and convert oxygen into sulphur. It is within the scope of this hypothesis that
the various elements may all be isomeric forms of one truly elementary substance ;
but it would be out of place to indulge in such speculations at present. I should
not, indeed, have alluded to the general conclusions regarding the constitution of
paraeyanogen, and the isomerism of elementary bodies, deducible from the pre-
ceding inquiries, if I had not succeeded, by the farther application of the same
method of experimental investigation, in obtaining results which, if there be no
fallacy in the facts brought under my notice, — and I have not hitherto been able to
detect any, — seem to establish the substantial identity or isomerism of two fa-
miliar bodies hitherto supposed to be elementary.
177 )
XL — On the supposed Progress of Human Society from Savage to Civilized Life,
as connected mill the Domestication of Animals and the Cultivation of the Ce-
realia. By JOHN STARK, Esq. F.R.S.E. &c.
(Read 1st March 1841.)
I. — SUPPOSED PROGRESS OF HUMAN SOCIETY.
IT is a general belief that Man, in his supposed progress from Savage to
Civilized Life, has passed through three distinct stages or periods, each one lead-
ing a step forward in the road to social improvement. These stages are asserted
to be, 1. The Hunter State; 2. The Pastoral State; and, 3. The Agricultural State.
Allusions to these different stages crowd the pages of the historian, the philosopher,
and the poet ; and arguments are founded on, and deductions drawn from, these
states of existence, as if they were ultimate truths, neither to be discussed
nor dissented from. It is the object of this paper to question the existence of
these separate states, their necessary connection with one another, and the end to
which ultimately they are supposed to lead.
Among the earliest writers who treat of the first ages of the world. is HESIOD,
the Grecian poet, a contemporary of HOMER, who li ved about a thousand years
before the present era. His story of PROMETHEUS and PANDORA, as well as his de-
tail of five different periods which had preceded the time when he wrote, are evi-
dently taken from some of the floating traditions of the early history of the world
met with in all countries. The first period is termed the Golden Age, referrible,
it is supposed, to the state of man in Paradise ; the second is entitled the Silver
Age, which may allude to the antediluvian period ; the third is the Brazen Age,
which, from some of its characteristics, would seem to refer to the state subse-
quently termed the Hunter's State ; the fourth is the Age of Heroes ; and the fifth
the Iron Age, or Agricultural period.*
LUCRETIUS, the Roman poet and philosopher, follows in describing the early
stage of man's existence as little better than that of the beasts. But afterwards,
according to the same authority, men built huts, clothed themselves with skins,
and learned the use of fire ; the power of forming sounds and language followed ;
and, finally, towns were erected and governments established.!
* Works and Days, Book I. translated from the Greek by THOMAS COOKE.
t T. LUCRETIUS CARUS, De Natura Rerum, lib. v.
VOL. XV. PART I. 3B
178 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
OVID follows HESIOD in his division of the Ages, but makes them in number
only four ;* and HORACE, in a well known passage, records the general ideas pre-
valent as to man's degraded origin. f
Such were the opinions of the ancients as to the early state of human society,
— opinions which have influenced the details of almost all subsequent writers.
Dr FABER, it may be remarked, considers that the mythology of the ancients
recognises two golden ages ; the first coinciding with the Creation, the second co-
inciding with the period which immediately succeeded the Deluge. The modern
theories, founded on these statements, are such as I shall now shortly notice.
" In temperate climates," says Lord KAMES, " the original food of man was
fruits that grow without culture, and the flesh of land animals procured by
hunting. A fawn, a kid, or a lamb, taken alive, and tamed for amusement, sug-
gested probably flocks and herds, and introduced the shepherd state." — " Neces-
sity, the mother of invention, suggested agriculture. When corn, growing spon-
taneously, was rendered scarce by consumption, it was an obvious thought to pro-
pagate it by art."t
Many other writers of celebrity, among whom may be mentioned Principal
ROBERTSON, Baron CUVIER, and Sir HUMPHRY DAVY,§ have adopted this theoretical
opinion in regard to the progression of the human race from savage habits to civi-
lized life. || " In the earliest ages," says M. VIREY, " human societies were scat-
tered over the surface of the globe, living on the fruits of the chase, fishing, and
on the wild herbs which a beneficent Nature made grow under their feet. The
increase of the numbers of individuals upon a soil which the plough had not yet
fertilized, the scarcity of game, the difficulty of subsisting in severe seasons, forced
men to rear cattle to feed upon in these necessities, and they became shepherds.-
Supported, then, on the milk of their cattle, and clothed with their fleeces, their
manners became polished, and their minds accustomed to contemplate nature.
But even the resources of the pastoral life, in spite of the dispersion of families
and nations to new lands, became too limited for the increase of the human race,
and the earth began to be appropriated, and the labour of the ox to be applied to
the cultivation of the soil. To this succeeded the settlement of men in cities and
towns, the rise of the arts, and the division of employments which characterize
civilized life."**
The author of the " Wealth of Nations," and his latest illustrator Mr M'CuL-
* Metamorph. lib. i. t Sat. iii. v. 199, &c.
{ Sketches of the History of Man, i. 46, 47. § Consolations in Travel, p. 76.
|| The traditions of the Chinese, separated as they are, in many respects, from every other people,
correspond, according to Dr THOMAS YOUNG, with the classical theory of man's savage original and pro-
gressive civilization. Dr YOUNG himself, like most other philosophers, takes the truth of the theory for
granted. Supp. Encyclop. Brit. Art. CHINA.
** Nouv. Diet, de 1'Histoire Naturelle, tome xv. Art. L' HOMME.
FROM SAVAGE TO CIVILIZED LIFE.
LOCH, Mr MALTHUS, Mr SADLER, and every other writer on the progress of society,
adopt the same theory ; and even Mr ALISON, in his work on Population, published
within these few months (1840), argues as if these were fixed and marked periods
in the progressive civilization of man. In fact, though founded in fable, or the
dreams of ancient poets, and though such a gradation has never yet been pointed
out as existing by those who take its existence for granted, yet such is the influ-
ence of classical associations on the spread of knowledge, that, till lately, this se-
ries of advancing links in the scale of human improvement has never been chal-
lenged.
In drawing up a few popular lectures for a local scientific association, my
attention was first called to the improbability of such a series of progressive
changes ; and the result of my inquiries was, that such a progress is not supported
by the evidence of recorded observation, and is opposed to the statements of the
oldest written records of the human race.
On further investigating the subject, I found that the theory of human so-
ciety, in its earliest stage, being originally savage, had been called in question by
several writers. Soon after the publication of Lord KAMES'S Sketches of the History
of Man, the doctrine which his Lordship maintained, in common with many others,
as to man's savage original, was animadverted on in a Letter addressed to him by
Dr DAVID Doio of Stirling, which, with a second Letter on the same subject, which
personal communication rendered unnecessary to be transmitted, was afterwards
published in 1792. Dr DOIG supports the propositions, that the more populous
and extensive kingdoms and societies were civilized at a period prior to the records
of history ; that degenerated races or savage tribes can never recover then* pris-
tine condition without foreign aid ; that there seems to be in human nature an
innate propensity to degeneracy ; and that if all mankind had been once in the
savage state, they not only never could have arrived at any considerable degree
of civilization, but would have sunk lower and lower, till degraded to the level
of the beasts that perish.*
The next writer I have met with who questions man's savage original, is Mr
JOHN BIED SUMNEE, in a work entitled " A Treatise on the Records of Creation,"
which was published in 1816 in two volumes 8vo. " The barbarous state of the
inhabitants of countries newly discovered," says he, " then* general ignorance of
arts and deficiency of morals, has naturally introduced a vague idea that man was
originally, at his birth or creation, a savage. But according to the Mosaic account,
* For the knowledge and perusal of this scarce and, I believe, little known book, I am indebted to the
kindness of JOHN GORDON, Esq. of Cairnbulg. The first Letter is dated 20th December 1774, the second
March 12. 1775 ; but they were not published till 1792. The title of the volume is, " Two Letters on
the Savage State, addressed to the late Lord KAIMS." The advertisement, detailing the author's pur-
pose in writing and afterwards publishing them, is written by the Rev. Mr GLEIG, afterwards a bishop of
the Scottish Episcopal Church.
180 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
which agrees, too, with the suggestions of reason, the savage state was not the
primitive state of man."*
In 1830, Dr ROBERT HAMILTON of Aberdeen, in a posthumous " Essay on the
Progress of Society," followed Mr SUMNER in asserting that man was not, in his
earliest state, an ignorant savage. " Revelation does not favour this opinion,"
says he ; " history does not prove it ; the fables of the poets are unworthy of
credit ; and the reasonings which have been adduced in support of it are ex-
tremely conjectural."! But Dr HAMILTON, except in this passage, does not allude
to the subject further, and the remainder of his Essay is occupied with other
topics.
The theory of the progress of human society from savage to civilized life was
afterwards questioned by the present Archbishop of Dublin, who states " the im-
possibility of men's emerging unaided from a completely savage state ; and, con-
sequently, the descent of such as are in that state (supposing mankind to have
sprung from a single pair) from ancestors less barbarous, and from whom they
have degenerated. The first race of mankind seem to have been placed merely
in such a state as might enable and incite them to commence and continue a
course of advancement.":):
The theory of savage original was also attacked in 1834 by Mr CHARLES TIL-
STONE BEKE, in a work entitled " Origines Biblicse, or Researches in Primeval
History," of which only one volume has been published. § Mr BEKE, however,
does not go so far back as the original creation of man for proofs of the earliest
state of civilization, but takes his stand on the fact, that " the present human race
has sprung, not from a common ancestor in a primitive state of society, but from
one who was himself a member of a previous social state, which had already ex-
isted for many ages ; that whatever may have been the natural state of the first
man ADAM, the progenitor of the antediluvian world, the contemplation of that
state cannot aid us in the consideration of the primary condition of the postdilu-
vian world, which takes its origin from NOAH and the seven other persons saved
in the Ark, who were members of an artificial, and most probably a highly ad-
vanced state of society." ||
Within these few months (October 1840), another work has appeared, en-
titled " The Natural History of Society in the Barbarous and Civilized State ; an
Essay towards discovering the Origin and Course of Human Improvement. By
W. COOKE TAYLOR, Esq. LL.D. of Trinity CoUege, Dublin."** In this work, Dr
* Records of Creation, i. 47.
t The Progress of Society. By the late Rev. ROBERT HAMILTON, LL.D. F.R.S. Lond. 1830.
| Introductory Lectures on Political Economy, p. 129. Lond. 1831.
§ Origines Biblicse, or Researches in Primeval History. By CHARLES TILSTONE BEKE. Lond. 1834,
8vo.
II Ibid. i. 49. ** In two volumes 8vo. London, 1840.
FROM SAVAGE TO CIVILIZED LIFE. 181
TAYLOR maintains that civilization is natural to man ; that barbarism is not a
state of nature ; and that there is no prima facie evidence for assuming it to be
the original condition of man.* Far, however, from regarding with mortification
the circumstance that I have been anticipated in some of my views on this
subject by the appearance of this work, I consider such a coincidence as a proof
of the general truth of the positions assumed, that more than one mind has
been verging to the same conclusions. It were to have been wished, at the same
time, that Dr TAYLOR had noticed Dr DOIG'S Letters, Mr SUMNER'S work, Mr BEKE'S
work, or the prior one of Professor HAMILTON ; for, though he may have carried
out the illustration of the proposition to a greater length than these gentlemen,
the merit of challenging the received theory is unquestionably due to them.
In such circumstances, I should not have thought of laying my particular
views on this subject before the Society, had the opinion advanced, and so well
illustrated in some of its details, by Dr TAYLOR, been in all points the same as my
own. But, besides other considerations, there are two elements which enter into
my theory of man's early civilization, which are totally omitted or opposed in the
statements of the writers to whom I have alluded, and which it is impossible to
separate from the consideration of his social condition, — I mean the domestica-
tion of animals and the cultivation of the Cerealia : And while I attempt to shew
that the supposed progress of man from a savage to a civilized state is an un-
founded assumption, flowing from the dreams of poets or the theories of philoso-
phers, I shall also endeavour to make it evident, that races of domestic cattle and
the cultivation of the Cerealia must have been contemporary with the earliest
existence of the human race.
According to some French writers, man has arisen to what he is at present
from very humble beginnings indeed. LAMARCK more than hints that some spe-
cies of the Quadrumanous animals, or Apes, may, from the exigencies of their
situation, have given up their natural propensities, and learned to walk, and speak,
and think, by some fancied necessity of a progressive development of faculties.
A similar opinion was entertained by Lord MONBODDO.| M. BORY DE ST VINCENT,
following in the same train, thinks that a progress may be traced from the apes
and orang to the Hottentot, and from the Hottentot to the most civilized races.
The sexual propensity, according to this author, brings the male and female to-
gether ; the long helplessness of infancy secures the family alliance ; and hence
follow tribes or connected families. Thunder has struck down trees in the ancient
forests, or a crater has poured out ignited lava on the vegetation, and thus the use
of fire was learned by man 4
BUFFON supposes that the first Man, though fashioned in his body and organs
* TAYLOR'S Natural History of Society, i. 19. t Origin and Progress of Language, i. 272.
} Diet. Classique de 1'Hist. Nat. Art. L'HoMME.
VOL. XV. PART I. 3 C
182 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
in the most perfect state, could know nothing till experience had taught him the
use of his senses ; and supposing such a being awakened, in the plenitude of his
powers and with the faculty of speech, to the objects of the world around him,
he has given a very interesting and, I believe, philosophical account of his first
sensations.*
SHARON TURNER in one place represents the first pair as utterly ignorant at
first of every thing, and having to acquire the knowledge of whatever there was
to know by gradual sensations as they should occur, and totally incapable of fore-
seeing any result or of distinguishing good from evil, until, by slow and progres-
sive experience, they should learn what was either, or what would become such.
— And again, " ADAM could not, at his creation, be perfect in knowledge, because
he would have it all to acquire, and must begin his earthly existence without
any."f
Dr ADAM FERGUSON, forgetting for a moment that the state of the first pair
bore no analogy to their future oifspring, observes, that " the individual in every
age has the same race to run, from infancy to manhood ; and every infant or ig-
norant person now, is a model of what man was in his original state."!
And Sir HUMPHRY DAVY, supposing that the first created man had certain
powers and instincts, such as now belong to the rudest savages of the southern
hemisphere, observes, — " Their progress from this early state of society to that of
the highest state of civilization and refinement may, I think, be easily deduced
from the exertions of reason, assisted by the influence of the moral powers and
of physical circumstances. "§
Such are some of the representations of man's early state given by writers of
no mean celebrity ; and such are some of the degrading theories which would
bring down man to the level of the beasts around him. Several of these opinions
have apparently their origin in the fables of ancient poets ; but even those
more modern and plausible theories, which suppose savage man capable, in the
* BUFFON, par SONNINI, xx. 51. | Sacred History of the World, ii. 253, 293.
| Essay on the History of Civil Society, p. 7- By ADAM FERGUSON, LL.D. Lond. 1793.
§ Consolations in Travel, or the Last Days of a Philosopher, p. 76. In this little work, though Sir
HUMPHRY makes one of the speakers in his Second Dialogue question the classical theory of man's savage
origin, yet this is so feebly done as to imply the author's want of confidence in the position his opponent
is made to assume ; and even the appeal to the first book of MOSES is modified by passages, in which the
author shews his leaning to the doctrine of savage original and progressive advancement. In the VISION,
which is the base of the first two dialogues, the human race are described as advancing through all the
classical periods, from the mute savage of Horace up to the pastoral and agricultural life. But Sir
HUMPHRY fails to shew how his supposed instincts could ever lead man to sow or reap, or tame animals,
and none of the speakers in the dialogue explain how man, created savage, could ever have risen above
that condition. Afterwards, however, he makes another speaker concede that man was created, not a
savage (as formerly represented), but perfect in his faculties, and with a variety of instinctive powers
and knowledge, and that he transmitted these powers and knowledge to his offspring. (P. 100.)
FROM SAVAGE TO CIVILIZED LIFE. 183
course of long ages of experiment, of acquiring a knowledge of himself and the
external world around him by his own unaided exertions, are founded on hypo-
theses equally without foundation. No authority is referred to — no evidence is
produced — not a single recorded instance is pointed out of the circumstances they
allege, beyond the suppositions of those poets and philosophers, — for assuming the
facts to be as they have stated them. That man, in certain states of civilization,
and with the transmitted knowledge which is the appanage of his race, is capable
of increasing his dominion over nature to an incalculable extent, and even of dis-
covering his progressive improvement here to be connected with a future state of
existence, is apparent from many considerations. But it is equally apparent, even
on the recognised principles of philosophic observation, that if man had been cre-
ated a degraded being, procuring his scanty subsistence from the spontaneous
produce of nature, he never could, by his unaided exertions, have risen above
that state, — he never could have arrived even at the first period of the philoso-
phical gradation, or the hunter's state ; for the hunter's state necessarily presup-
poses knowledge which an acorn-eating savage could not possibly acquire. Man
has none of the instinctive propensities which guide the lower animals to their
food with unerring certainty. He must be trained to be what he is ; and the
transmitted knowledge which he inherits as the descendant of a civilized proge-
nitor, though it may be so far lost or deteriorated, cannot be acquired by the un-
taught exertions of the savage. Though the habit of flying from predaceous ani-
mals did, according to LAMARCK, lengthen the limbs and quicken the pace of the
gazelles and antelopes,* so as to produce, through ages of practice, the present
handsome and light forms which these animals now bear ; yet, extravagant as
this theory is, it would not be more so than that which would suppose a naked
and fruit-eating savage, with no instinctive propensities for blood and animal fibre,
no means of pursuit, and no implements of chase, to discover that the animals
which fled from him would serve him for food.
But not only was man, according to the opinion of some authors, created a
savage, scarcely raised above the animals around him, but, in the opinion of others,
he was created a mute savage ; and hence it has been the object of philosophers,
taking this also for granted, to trace the steps which led him, from natural signs,
to acquire articulate speech.f Dr ADAM SMITH, in his " Dissertation on the Origin
of Languages," endeavours to trace these fancied steps. " Two savages," says he,
* Philosophic Zoologique, tome i. p. 255.
t According to LAMARCK, the dominant race, or man, having multiplied their wants as society be-
came more numerous, felt the necessity of communicating their ideas to their companions. The result
was, to augment and vary the signs proper for the communication of these ideas ; and pantomimic signs,
and all possible inflections of the voice, having failed to keep pace with the multitude of acquired ideas,
they came at last, by redoubled efforts, to form articulate sounds. From thence the origin of the admi-
rable faculty of speech. (Philosophic Zoologique, torn. i. 356, 357.)
184 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
" who had never been taught to speak, but had been bred up remote from the
societies of men, would naturally begin to form that language by which they
would endeavour to make their mutual wants intelligible to each other, by utter-
ing certain sounds whenever they meant to denote certain objects. Those objects
only which were most familiar to them, and which they had most frequently oc-
casion to mention, would have particular names assigned to them."* Dr SMITH
does not say, in direct terms, that such indeed was the state of our first parents ;
but if speech was not the gift to our race of the Great CREATOR, the situation he
supposes must have been theirs.
According to Dr REIDJ and DUGALD STEWART, $ natural language preceded
the formation of artificial language, and artificial signs must have been the effect
of convention. The natural signs consist " in certain expressions of the counte-
nance, certain gestures of the body, and certain tones of the voice," of which the
pantomimes of the Roman stage furnished an example. This natural language
declined, according to the philosophical theory, in consequence of the use of
artificial signs. " As ideas multiply, the imperfections of natural language
are felt, and men find it necessary to invent artificial signs, of which the meaning
is fixed by mutual agreement." But this opinion as to the origin of language,
adopted or assented to rather in compliance with classical associations than his
own convictions, is modified by Mr STEWART in another passage, where he says,
that — " When we consider what a vast and complicated fabric language is, it is
difficult for us to persuade ourselves that the unassisted faculties of the human
mind were equal to the invention." § And it is remarked by Dr ADAM FERGUSON,
" that the speculative mind, in comparing the first and last steps of the progress,
feels the same sort of amazement with a traveller who, after rising insensibly to
the slope of a hill, comes to look from a precipice of an almost unfathomable
depth, to the summit of which he scarcely believes himself to have ascended
without supernatural aid." || I have further to remark, that although Mr STEW-
ART, in referring to the early periods of society, when, according to the universally
adopted theory of man's savage original, everything was to be learned ; and con-
sidering, in accordance with this theory, " by what steps our rude forefathers must
have proceeded in their attempts towards the formation of a language, and how
the parts of speech arose," — prefaces his remarks with the observation, that he
does not mean to prejudge the question, " Whether language be, or be not, the
result of immediate revelation ?"^| and though he gives it as his opinion that the
* A Dissertation on the Origin of Languages, appended to the second volume of the Theory of Mo-
ral Sentiments, seventh edition, Lond. 1792, vol. ii. pp. 402, 404.
f Inquiry into the Human Mind, chap. iv. sect 2.
{ Elements of the Philosophy of the Human Mind, iii. 2, 3. § Ibid. vol. iii. p. 25.
|| An Essay on the History of Civil Society. By ADAM FERGUSON, LL.D.
\ Elements, iii. 26.
FROM SAVAGE TO CIVILIZED LIFE.
human faculties are competent to the formation of a language, yet his purpose is
only to trace the steps which men, left entirely to themselves, would be likely to
follow, in then- first attempts to communicate their ideas to each other.*
Now, if it has been ascertained beyond doubt that speech is purely imitative ;
if the cases of individuals who have been born deaf, and, in consequence of never
hearing articulate sounds, are themselves dumb, be taken into consideration, it does
not appear how mute savages could, in any length of time, learn the use of arti-
culate signs. And the cases Avhich have occurred of human beings, left at an
early age to their own resources, afford further evidence that the acquisition of
speech by individuals in that situation was hopeless, f
It is certain, therefore, that the use of speech must have been an attribute of
the first pair ; and that, whatever was the future progress of language, its origin
cannot be referred to the untaught ingenuity of dumb savages, but must start at
a point when articulate speech was equal to all the physical and intellectual
wants and enjoyments of man. It has been observed by more than one author
of eminence, that the general analogy which runs through all the forms of human
speech is in favour of the idea of its being an original attribute of our first pa-
rents. "Whence has arisen that analogy," says Mr STEWART, "which runs
through the mixture of languages spoken by the most remote and unconnected
nations, and those peculiarities by which they are all distinguished from each
other ?"t — "From the country of the Eskimoes to the banks of the Oroonoko,"
says M. HUMBOLDT, " and again, from these torrid banks to the frozen climate of
the Straits of Magellan, mother tongues, entirely different with regard to roots,
have (if we may use the expression) the same physiognomy. "$ — " With man,"
observes Dr FERGUSON, who differs from most of the writers I have named on this
* Lord MONBODDO sets out with the proposition, that articulation is altogether the work of art or
habit, and that ages must have elapsed before language was invented. Origin and Progress of Lan-
guage, i. 71.
The result of an experiment made by one of our kings (JAMES IV.), and recorded by LINDSAY of
Pitscottie, of sending two children under the care of a dumb woman, to be reared on the island of Inch-
keith till they came of age, is not mentioned. But there can be no doubt of its termination. They were
expected to speak Hebrew. (Chronicles of Scotland, p. 250. By ROBERT LINDSAY of Pitscottie. Edin-
burgh, 1814.)
" Were it possible," says Dr SMITH, "that a human creature could grow up to manhood in some so-
litary place, without any communication with his own species, he could no more think of his own cha-
racter, of the propriety or demerit of his own sentiments and conduct, of the beauty or deformity of his
own mind, than of the beauty or deformity of his own face." (Theory of Moral Sentiments, i. 277, 278.)
f See account of Peter the Wild Boy, and other instances, in MONBODDO'S work on the Origin and
Progress of Language. Edinburgh, 1773>
+ Life of ADAM SMITH, LL.D. p. 47. 4to> Edinburgh, 1811.
§ Personal Narrative, iii. 245.
VOL. XV. PART I. 3 D
186 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
point, " society appears to be as old as the individual, and the use of the tongue as
universal as that of the hand or foot."*
Such are some of the statements hazarded by philosophers and historians re-
lative to the earliest ages of human society. In discussing this subject, it appears
somewhat strange that the traditionary accounts of DIODORUS SICULUS and HERO-
DOTUS, and the early poets, should alone have formed the groundwork of the phi-
losophical theories of man's origin and progress, in opposition to the narrative of
such origin and progress contained in the First Book of MOSES. That this sacred
Book is not referred to as authority on the subject by a certain class of philoso-
phers may proceed, in some, from the mistaken idea they entertain of reference to
such authority superseding all further argument or inquiry. But there are others
who, in the investigation of the works of nature, the structure of their own minds,
or the history of their race, systematically avoid allusion to the Great FIRST
CAUSE, as if their own delegated and limited powers were sufficient, in all the re-
lations of mind and matter, to lead to final results without supposing His agency,
or tracing the operations of His hand. It is gratifying to think that the present
race of investigators are of a different character ; and in the boundless field of the
Natural Sciences, — in the world of Mind and Matter within us and around us, —
it is one aim of modern philosophy to trace the indications of infinite wisdom and
beneficence, unfolded at every step of its progress.
In this instance, I refer to the Scripture account of the origin of man and
of his subsequent progress, so far as there detailed, as the most ancient, the
most rational, and the only true account of the early history of our race. The
facts there recorded are further corroborated by all that is known from other
sources, of the spread of man, the traces of his progress, and by the existing mo-
numents of the earliest times.
According to this authority, then, which is indisputable, man was not, at his
first creation, a mute and rude savage, totally ignorant of everything around him
till taught by experience, and not amenable to moral responsibility. On the con-
trary, the Scripture teaches that man was, at his creation, not only endowed with
all the physical perfections belonging to our race in the highest degree, but also
with all the intellectual information necessary to the happiness and enjoyment of
the most perfect human being. GOD did not create man a mute savage on the banks
of the Ohio or the Euphrates, with a spear in his hand, and an instinctive thirst
of blood to urge him to his prey : — HE did not place him on a barren shore, to feed
upon the blubber of the stranded whale : — HE did not destine him to feed upon the
acorns of the forest, or scratch up edible roots from the soil to satisfy his hunger ;
but HE placed him in a garden, rich in all the productions of vegetable life, and
* Essay on the History of Civil Society, p. 9.
FROM SAVAGE TO CIVILIZED LIFE. 187
enlivened by all the forms of animal creation, that could minister to his wants or
pleasures, and give him a
— choice
Unlimited of manifold delights.
Neither was the proverbial idleness of savage life the lot of the first man ; for
his mental faculties were exercised in naming, according to their different natures,
the various races of animals ; and exercise was provided for his physical frame,
in keeping and dressing the garden in which he was placed.
In accordance with the Sacred Record, MILTON asserts, in his unrivalled
poem, that man was not created a mute and ignorant savage, but endowed with
all the physical and intellectual powers which distinguish the human race from
every other class of animated beings. He was not made, as the philosophical theory
supposes, a little higher than the brutes, but "a little lower than the angels;1'
and though, since the introduction of moral evil, his tainted nature has indicated
a downward progress, yet unfading traces remain of that Divine image in which
he was originally created. In describing the inmates of Eden, MILTON says,
Two of far nobler shape, erect and tall,
Godlike erect ! with native honour clad,
In naked majesty, seemed lords of all ;
And worthy seemed, — for in their looks divine,
The image of their glorious Maker shone. — Book iv.
And afterwards, in making ADAM describe his first sensations when he awoke to
life, he introduces him as saying thus —
To speak I tried — and forthwith spake ;
My tongue obeyed, and readily could name
Whate'er I saw. — Book viii.
And again, in introducing him as naming the inferior creatures, these verses
occur :
As thus HE spoke, each bird and beast behold
Approaching, two and two ; these cowering low,
With blandishment each bird stooped on his wing.
I named them as they passed, and understood
Their nature. With such knowledge GOD endued
My sudden apprehension. — Book viii.
If anything required to be added to this, the fact of the Great Creator hold-
ing converse with the first of his creatures, and placing him in a station of mo-
ral responsibility, leaves no room to doubt of either ADAM'S moral or intellectual
endowments. Through him was to descend to his progeny the knowledge which
was to guide their future progress.
In accordance with the same views, Bishop STILLINGFLEET observes, that " if
man were not fully convinced, in the first moment of his creation, of the being of
Igg MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
Him whom he was to obey, his first work and duty would not have been actual
obedience, but a search whether there was any supreme, infinite, eternal Being,
or no, and whereon his duty to him was founded, and what might be sufficient
declaration of his will and laws, according to which he must regulate his obe-
dience."* And in another passage, after some important observations on man's
knowledge as respects his fellow-creatures, and of the nature, being, and proper-
ties of those things which he was to use, he concludes as to the first man, that,
" as he was the first in his kind, so was he to be the standard and measure of all
that followed, and, therefore, could not want any thing of the due perfections of
human nature."!
It thus appears, that the brutal or savage origin of man, and his gradual at-
tainment, through ages of experiment, of the faculty of speech, and the use of
his intellectual powers, is not warranted by any thing recorded of his origin or
early history. Had he been created a dumb savage, a dumb savage he must for
ever have remained. Had the spontaneous fruits of the forest been his instinctive
food, he never could have learned to use any other ; for instinct only teaches to
take what nature provides, and with the instruments which she has furnished.
No process of thought or reflection could be able to convey to a frugiverous ani-
mal the idea that living creatures might be converted into food. The classical
theory, besides, in advancing from feeding on acorns and fruits to pursuing wild
animals for their flesh, and taming them in numbers, goes much too far at one
step to render it in the slightest degree probable. An acorn-eating savage might,
by some possibility or chance, take to the rearing of the fruits or seeds that pro-
duced his accustomed food ; and thus step from the first to the last link in the
progressive chain of civilization, without altering the nature of his food. But the
step from fruits to flesh — from roots to living fibre — is one which involves, even
in its supposition, such a violation of all probability, as to forbid the idea that
this can be the process followed by nature.
Those authors who represent the first pair to have been created mute sa-
vages, living on the spontaneous productions of the garden or forest, forget that,
if such had been the case, they never could, by their unaided exertions, have risen
beyond that state. If the hunter's state, according to others, was the earliest
form of human society, how, it may be asked, did man discover that the objects
of his pursuit would serve him as food ? Is there any analogy between feeding
on acorns or apples, and the raw flesh of animals procured by hunting ? Had man
an instinctive predilection for carnage — an irresistible appetite for living prey ?
It is impossible to answer these questions in the affirmative. If this were indeed
Man's destination, his physical conformation would have been adapted to this
* Origines Sacrse, &c. i. 2. By EDWABD STILLINGFLEET, D.D. late Bishop of Worcester.
t Ibid. i. 4.
FROM SAVAGE TO CIVILIZED LIFE. 189
mode of procuring his food. Like other predaceous animals, the structure of whose
members are all in strict conformity with their destined mode of life, man must
have had fangs to tear, and claws to seize, his living prey, if such were to have been
the principal or sole means of procuring his food. Besides, the hunter's state, as
practised by tribes of savages known to Europeans, presupposes knowledge of va-
rious kinds to a considerable extent, both in regard to the habits of the animals
and the implements of the chase. And it does not appear by what process of re-
flection or experiment, savages, ignorant of the use of dressed food, or of fire to
dress it, could have acquired the knowledge of this necessary of life. M. BORY
DE Sx VINCENT may talk of the electric fluid kindling into flame the dry woods, or
craters of volcanoes throwing out red-hot embers, and raising into temporary fires
the surrounding vegetation ; but savages, to whom fire and its uses were unknown,
could not, even from these appearances, have learned its use in dressing food or
producing heat. A philosopher of the present day, with all the knowledge and
appliances of modern science, might, from the accidental burning of a forest or the
vegetation kindled by a volcano, form some idea of the uses of an agent such as
this, both in regard to the preparation of food and the production of heat ; but to
suppose an ignorant savage, without even the knowledge that food required dress-
ing, or that there was any heat independent of the sun's rays, — to suppose such
a being to discover that, from the friction of two pieces of wood, or by striking a
flint on a piece of iron, he could produce living flames, is to take for granted the
most improbable of all propositions.
But, granting for one moment that wild fruits produced spontaneously, and the
animals supplied by hunting, formed the food of the earliest races, the question
must recur, How did these hunters acquire the knowledge that the animals they
pursued in the field or forest could be tamed and reared beside their huts ? It
appears far more probable, that the animals least capable of escaping the arts
of the hunter would have been extirpated by the increasing population, unless
they had existed in untold numbers, and over territories beyond the range of the
hunting-ground.* And even from the taming of a single fawn or kid, procured
alive by accident, as Lord KAMES supposes to have been the case, it could scarcely
be inferred that the whole race, and other races of independent animals, could be
made to contribute to the increasing wants of man. The savages of North
America have not tamed the bison of their prairies nor the tapir of their marshes;
and indeed there is no recorded and authentic instance of hunting-savages tam-
ing wild animals and subjecting them to their use, or rising by their own efforts
from the hunting to the pastoral state.
Besides, it is a well ascertained fact, that all herbivorous animals have an
instinctive dread of their natural enemies, the predaceous races, and fly at their
approach. And to this instinctive distrust, which makes the deer or the antelope
* RAYXAL'S Hist, of East and West Indies, Book xviii.
VOL. XV. PART I. 3 E
190 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
fly from the lion or tiger, the preservation of the species is to be attributed. If
the lion and tiger are provided with fangs and claws for the purpose of procuring
food suitable to their carnivorous propensities, so the more timid animals, which
form their prey, are provided either with weapons to defend themselves so far
when in numbers, or speed to distance their enemies in the chase. But man has,
confessedly, none of that instinctive ferociousness which impels him to feed on
living prey ; neither the structure of his body nor the arrangement of his mem-
bers is calculated for such a mode of acquiring food ; and when he hunts down
animals as a portion of his subsistence, he does so from knowledge previously ac-
quired by individuals of his race, and with implements suited to the nature of the
animals pursued.
And if the transition from the hunting to the pastoral state seems extremely
improbable, — and, if we may judge from not one instance of this transference
having been observed, we may say impossible, — by what train of circumstances
could an entirely pastoral people become agriculturists ? If the seeds of the agri-
cultural plants do not grow spontaneously, — and there is no evidence of their do-
ing so anywhere, or to any useful extent, — where did these early essayists in cul-
tivation procure their supply of seeds ? What could induce them to attempt the
transformation, by cultivation, of a sterile herb (according to BUFFON) into wheat ?
or what could teach them that, after years or ages of experiment, a barren grass
(according to other authors) would appear in their fields as oats or barley ? No
pressure of population — no reflection on the processes of nature which they wit-
nessed around them, — could lead men, ignorant of seeds beyond the produce of the
forests, to conceive that the small seeds of the grasses, buried in the ground,
would, after a time, be replaced twenty-fold, even if they escaped destruction from
their multiplied herds.* And it is not very evident how men, in that degraded
situation, could first ascertain that the labour of the horse and ox might be made
available for the cultivation of the ground.
But in point of fact, this fancied gradation has no existence in nature.
" Throughout all America," says Dr ROBERTSON, "we scarcely meet with any
nation of hunters which does not practise some species of cultivation;"! the
Koords in Mesopotamia unite the pursuits of shepherds and cultivators ;| and, ac-
cording to HUMBOLDT, tribes of savages exist in South America, who, assembled in
villages, cultivate the plantain tree, cassava, and cotton. § A species of agricul-
ture— the cultivation of maize — existed in America long before the arrival of
the Europeans : and, as in mockery of the classical stage of pastoral life, the
Indians of this great Continent have overleaped this intermediate step, of which,
perhaps, they were not aware, and joined a species of agriculture to the pursuit
of hunting. HUMBOLDT accounts for this anomaly in human progression by stat-
* MALTHUS, Essay on the Principle of Population, p. 43, 4to edition.
t ROBERTSON'S America, ii. 117. J BUCKINGHAM'S Travels in Mesopotamia, i. 300.
§ Personal Narrative, iii. 211.
FROM SAVAGE TO CIVILIZED LIFE.
ing, that they had none of the animals which furnish milk in abundance ; that
their immense plains, more fertile than the Steppes of Asia, remained without
herds ; and that, in consequence, in America " the intermediate link is wanting
that connects the hunting with the agricultural nations."* In Asia and Africa,
the same practice prevails among all the ruder tribes. There are few or none,
whatever be their more general mode of procuring food, — whether it be hunting
or fishing, — that do not raise some species of root or fruit, in addition to what they
otherwise procure. The really pastoral tribes of mankind, on the other hand,
confined to immense plains where agriculture is impracticable, were pastoral from
the beginning, and promise to be so in all time coming, f
The use of fire, and the preparation of food in some way or other, are uni-
versal among the human race ; and in the rudest state in which man is now found,
there are arts exercised in the procuring and dressing of his food, in the prepara-
tion of his clothing, or the erection of his habitation, which he never could have
acquired but from progenitors more advanced in civilization than himself. The
universality of these arts, when added to the traditions of the most barbarous
tribes and the general and acknowledged filiation of their languages, point out
a less base original of the race than the degrading theories of the classical writers
have supposed.
If civilization were, indeed, the slow result of experience, the earliest savages
must have been ages in acquiring even the necessaries of the most humble form
of human society. Instinctive feelings, common to all animals, might have led
them to satisfy their hunger from the acorns of the forest, and assuage their
thirst at the running stream. But it does not appear how their knowledge of
digging the soil for edible roots, or cultivating the most simple herbs, could ori-
ginate without supernatural aid ; and if man had been created a savage, without
the knowledge of speech, a savage he might have for ever remained among the
beasts of Eden, distinguished only by his form from the creatures around him.
The theories of philosophers as to acquired information, however just when ap-
plied to man in his ordinary descent, have no analogy when considered in refe-
rence to the first man. He must, in the nature of things, have been endowed with
speech, — intuitive perceptions of external nature and its relations, — the knowledge
* Personal Narrative, iv. 319.
t " The circumstances of the soil and the climate determine whether the inhabitant shall apply him-
self chiefly to agriculture or pasture ; whether he shall fix his residence, or bo moving continually about
with all his possessions." (An Essay on the History of Civil Society. By ADAM FERGUSON, LLD.
p. 162.)
" The wide extended plains inhabited by the Tartar tribes, without a shrub, which the Russians call
Steppes, are covered with a luxuriant grass, admirably fitted for the pasture of numerous herds and
flocks." The inhabitants are " necessarily condemned to a pastoral life." (An Essay on the Principle
of Population, &c. 4to. p. 92. By T. R. MALTHTJS.)
See also ALISON on Population, vol. i. p. 21, 22 ; and HEERBN'S Manual of Ancient History, p. 16.
192 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
of the Deity and moral responsibility, else our race had never gone beyond those
tribes of animals which, with much of the human form, have never advanced one
step from their original condition. If the first man's knowledge was not intui-
tive— had not been communicated directly to him by his Maker, — he never could
have availed himself of any one of the advantages which knowledge is supposed
to give to rational beings. By no mental process could he have ascertained that
seeds buried in the soil would be multiplied twenty-fold by an unknown process,
or that the animals which fled at his approach might be tamed and increased at
his will. And none of the ordinary sources of knowledge, the result of slow ex-
periment or years of observation, open to the ingenuity of his descendants, could
have been available to the first agriculturist and shepherd.
II. — DOMESTICATION OF ANIMALS.
II. I now come, in the second place, to make a few observations on the Do-
mestication of Animals, which is considered by many to follow, as a necessary
consequence, the civilization of man. This also, according to the classical theory,
was a work of time ; and the results of domestication, as now seen, the ultimate
effect of ages of training. Even the opinions of the few who have questioned the
theory of man's savage origin are, on this point, in accordance with the supposi-
tion which assumes that all animals were originally wild, and required to be
caught and tamed, and trained to obedience, before becoming useful to man.
But this assumption, like that of man's savage origin, rests upon similar baseless
assertions, and is equally devoid of truth as probability.
The error, on the one hand, has originated in supposing man to have been
created a savage, little better than a brute, and in supposing that all his subse-
quent improvement, even the power of speech, originated from the exercise of his
own physical and intellectual faculties ; and, on the other, in omitting to take
into consideration two indispensable elements of increase and civilization, without
which, indeed, man could not, confessedly, have advanced a single step, — I mean
the possession of Domestic Animals and the Cultivation of the Cerealia. The ani-
mals they suppose to have existed in a wild state, till the period of society ar-
rived when it became necessary for the demands of an increasing population that
they should be tamed ; and the seeds of the Cerealia, or grains, it is not explained
how, were to be at the command of the multiplied shepherds, whenever they
were forced to exchange the pastoral life for one devoted to the tillage of the
ground. No even plausible grounds are stated how or where these necessary ap-
pendages to civilized life should be found in numbers or quantity when so wanted,
and if such auxiliaries were within reach at these uncertain periods, why might
their use not have been contemporary with man's earliest existence ? why might
he not have reaped all the advantages which their possession implies, from the
FROM SAVAGE TO CIVILIZED LIFE. 1J)3
beginning ? In fact, there is nothing in the statements of those who support the
theory of gradual taming and ages of training beyond conjectural assertion or gra-
tuitous assumption.
" A fawn, a kid, or a lamb," says Lord KAMES, " taken alive, and tamed for
amusement, suggested, probably, flocks and herds, and introduced the shepherd
state."*
According to BUFFON, " the most feeble species of useful animals have been
first reduced to domesticity. The sheep and goat have been acquired before hav-
ing tamed the horse, the ox, or the camel."f And again, " Man changes the na-
tural state of animals in forcing them to obey him, and subjecting them to his
use. A domestic animal is a slave which amuses him, which serves him, which
he abuses, which he alters, and changes its country and nature."}
In another place, the same naturalist writes thus : " It is by the power of his
mind, and not by physical force, that man has subjugated animals. In the ear.
liest times, all were equally independent. Man, become criminal and ferocious,
was little calculated to tame them. Time was necessary to approach, to ob-
serve, to choose, to subjugate them. It was necessary that he himself should
become civilized, to be able to instruct and command ; and the empire over
animals, — like all other empires, — was not founded, but with the progress of
society. "§
To the same effect writes the Abbe RAYNAL. " Men," says he, " While they
live at large, never bring any of the animal species under their subjection. All
the knowledge they have is to destroy them. The taming of animals is always
posterior to the social state. The taming of animals, as well as all the other use-
ful arts, was doubtless one of the inventions of society."]]
" A savage," says ROBERTSON, " is the enemy of the other animals, not their
superior."^
" In the domestication of animals and the cultivation of plants," says Mr
LYELL, " mankind have first selected those species which have the most flexible
frames and constitutions, and have then been engaged for ages in conducting a
series of experiments, with much patience and at great cost, to ascertain what may
be the greatest possible deviation from a common type which can be elicited in
these extreme cases."**
To nearly the same purport writes Dr TAYLOR, the latest author on the sub-
ject. " The art of domesticating animals," says he, " and so completely changing
their nature as to efface the original type, requires more intelligence than we are
accustomed to suppose, and it is not easy to conceive how the attempt could have
been originally suggested. It is also very singular, that the number of domesti-
I
* Sketches of the History of Man, i. 46. f Histoire Naturelle, edit. SONNINI, xxix. 239.
I Ibid. xxii. 65. § Ibid. xxii. 70. || History of East and West Indies, Book xviii.
^ ROBERTSON'S History of America, ii. 124. ** Principles of Geology, iii. 74.
VOL. XV. PART I. 3 P
194 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
cated species has not been increased by the lapse of time, though, at first sight,
there are many of the untamed animals which might have been subdued and ren-
dered serviceable." * And Baron CUVIER, when speaking of the dog as a powerful
ally of man against the other animals, characterizes its domestication as the most
complete, the most singular, and the most useful conquest our race has ever
made.f
Such are the statements in authors regarding the domestication of animals.
Like the supposed civilization of man, it was conjectured to be a work of slow de-
grees, brought about by the efforts of ages, and effecting such changes in the ha-
bits and structure of the animals, that their original type is unknown ; i. e. that
there are no existing races in a wild state resembling the domesticated individuals,
and from which they may be said to be derived, But upon what authority do the
tamers of animals rest for this supposed course of training, which fits animals
naturally wild for domestication ? None whatever, beyond the dreams of poets
or the fanciful theories of philosophers. The very first step in the proposition is
entirely conjectural. It being taken for granted that the species of cattle now
domesticated existed originally in a wild state, the ingenuity of naturalists has,
in consequence, been taxed in vain to find out the original types and their original
country. The result of these investigations is thus stated by DESMAREST, one of
the most celebrated modern zoologists, in the case of the ox, and the same may
be said of all the others. " The domestic ox of Europe," says he, " of which the
primitive source seems lost, has been transported into all the countries where
Europeans have established colonies." \
While the geographical limits of many families of animals can be distinctly
defined, — while climate and soil confine certain races to certain localities, beyond
which they cannot exist, — it is remarkable that the ox, the sheep, the goat, the
horse, the dog, the most extensively useful of all the domesticated animals, have,
like man, scarcely any limit to their range. Wherever civilized man is found,
there are these animals, or some of them, varied in many particulars to adapt
themselves to their different locations, but still the same species, with the same
general capabilities,
The naturalists who have ventured to assign a peculiar country to the do-
mesticated animals as their original one, universally point out the ancient seats
of human civilization in Asia as the place of their origin. Thus, "the horse,"
says DESMAREST, " originally from the plains of Tartary, has been transported by
man wherever he has established himself, over the vast countries of Asia, Europe,
Africa, and America," Asses, it is said, are found in a wild state, in innumerable
troops in the country of the Calmucks ; the country of the sheep is the ancient
world ; and the ox is found in all the countries where Europeans have established
* The Natural History of Society in the Barbarous and Civilized State, &c. i. 195, 196.
t Ri-gne Animal, i. 152. J DESMAREST, Mammalogiu, 494.
FROM SAVAGE TO CIVILIZED LIFE. 195
themselves. Though many places are indicated where the sheep, the goat, the
horse, are apparently in a wild state, yet, for reasons to be mentioned afterwards,
the probable explanation of the fact is, that these apparently wild races have taken
their origin from stragglers from the herds introduced by man.* It is well known
that, in some cases, this has happened, as in South America, where the horses,
from domesticated sources, have increased to a great extent; and the horned
cattle, sent to the Llanos by CHRISTOVAL RODEIGUEZ about the year 1548, no less so :
And if, in such circumstances, and in so short time comparatively, these animals
have established themselves, and become in many respects wild animals, is it not
a fair conclusion, that the domesticated species now found wild along the tracks
of human migration, and nowhere else, may have become so from the same cause ?
And this conclusion is supported by the fact, contrary to all analogies of other
wild animals, that when these reputed wild races are taken, even in adult age,
they are speedily reclaimed, and become again the associates of man.f
In 1825, M. F. CUVIEE published two Essays, one on the Sociability of Ani-
mals, | the other entitled an "Essay on the Domestication of Mammiferous Ani-
mals ;"f the opinions expressed in which derive weight, not only from the cha-
racter of the author, but from the opportunities he enjoyed of studying the habits
of animals. This celebrated naturalist ascribes the domestication of animals as
owing to what he terms an instinct of sociability, — a social instinct in the creatures
themselves, accompanied with qualities to aid its influence. " To attain an ob-
ject," says he, " it is necessary to know it ; and how could the first men who asso-
ciated themselves with animals have known this object ? And had they conceived
it hypothetically, would not their patience have been exhausted in vain efforts,
from the innumerable attempts they would have had to make, and the great num-
ber of generations on which they would have to act, in order, after all, to arrive
only at superficial results." || So far M. CUVIER writes with the caution of a phi-
losopher. He afterwards goes on to state, as the result of all his knowledge and
all the experiments that had been made in the taming of animals, that no con-
ceivable training, without a particular disposition in the animals to attach them-
selves to man, could have ever effected this object.
With regard to the effects of the social instinct of gregarious animals as in-
ducing them more easily to come under the protection of man, if the effect of this
social instinct were to render all gregarious animals of equally easy acquisition, I
* " The natural state of the horse, it may be said, is not that of freedom, but of domestication."
(Illustrations of the Breeds of Domestic Animals in the British Islands, No. vi. p. 6. By DAVID Low,
Esq. F.R.S.E.)
t DESMAREST, Mammalogie, 422.
\ De la Sociabilite des Animaux, Mem. du Mus. xiii. 1. " It is difficult to conceive how they could
commence and maintain the submission of animals without this disposition to sociability, if we consider,
above all, at what time of human civilization the domestic animals appear to have become so." (P. 19.)
§ Memoires du Museum, xiii. 406. U Ibid.
10(5 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
should at once grant the principle as a chief means of their domestication. But
all gregarious animals, as M. CUVIER remarks, are not found capable of domesti-
cation. The greater number of the untamed Ruminants herd together in flocks ;
the zebra, the wolf, the hysena, the beaver, are found in companies, and are yet
untamed by man. And even the tribes of quadrumanous animals, or apes, most
nearly resembling the human form, though with hands at their extremities capa-
ble of performing all the actions of human beings, are yet the untamed denizens
of the forest. Domestication is not, therefore, the necessary or sole result of the
social instinct of gregarious animals, even carried to a high degree, else all grega-
rious animals would be equally capable of this domestication. And though it be
true, as a general rule, that no solitary species, however easy it may be to tame
the individuals, has ever afforded domesticated races, yet the common cat forms
an instance of an exception to this rule. A particular disposition in the animals
themselves — an instinctive propensity to attach themselves to the human race, — is
therefore necessary, as M. F» CUVIER has stated, to their complete domestication.
This tendency in certain animals to become the associates of man, has been
noticed by other observers. " It has been proved," says BUFFON of the goat,
" that these animals are naturally the friends of man, and that, in inhabited places,
they do not become wild."* — " Compare the docility and submission of the dog,
with the distrust and ferocity of the tiger ; the one appears the friend of man, and
the other his enemy."f The wild cattle of the island of Tinian, met with by Lord
ANSON in his voyage, } were not at all timid, and they had no difficulty in getting
near them. The wild horses of the Llanos, according to HUMBOLDT, are easily re-
duced to servitude, and then- good qualities developed. § The goats met with at
the island of Bonavista by an early voyager, followed the negroes with a kind of
obstinacy ; and, according to Dr RICHARDSON, there is no difficulty in approaching
the Rocky Mountain sheep, which, in the retired parts of the mountains, exhibit
the simplicity of character so remarkable in the domestic species. ||
A late writer on the " Influence of Domesticity upon Animals,"^[ M. DUREAU
DE LA MALLE, after asserting that the origin and country of our domestic animals
had been sought for in vain, states, in apparent opposition to this, that all the
tamed animals existed in a wild state in Europe in the time of ARISTOTLE ; and
that, in four hundred and fifty years from ARISTOTLE to PLINY, the domestication
of animals had but slowly extended. It is conceded at once, that the domesti-
cated species of animals might be found in a half wild state wherever human set-
tlements had introduced them, at the period alluded to, as at present : and the
* BUFFON, Hist. Nat. xxiii. 99. t Ibid. p. 67.
| ANSON'S Voyage round the World, 4to, p. 309. Lond. 1776.
§ Personal Narrative, iv. 340. In Paraguay, they are put in harness when caught, and a day is
sufficient to tame them. (ROBERTSON'S Letters on Paraguay, ii. 6.)
|| Fauna Boreali-Americanse, p. 279.
^f De 1'Influence de la Domesticite sur les Am'maux, Ann. des Sciences Nat. xxi. 52.
FROM SAVAGE TO CIVILIZED LIFE. 107
subsequent remark, that no new animals had been added to the number of do-
mesticated species then known in the space of 450 years, is likewise consonant
to what I hold to be the truth. For it is a singular fact, and borne out by all ob-
servation, that no new species of domestic animal of any consequence has been
added to those which have been the property of man from the first times. The
animals at present domesticated have been so from the earliest period of human
history ; in all man's wanderings, they have accompanied his progress ; and it is
only in regard to America, the first settlers in which Continent may have been
driven from then* native shores by a thousand ways which may easily be con-
ceived, that the migrations of the race seem to have been without the cattle
of the Old Continent.
It is, besides, incumbent on those who support the poetical and philosophical
theory, to point out, in the course of ages, a single instance of an important ani-
mal having been added to the stock of the domesticated races. All the ani-
mals now known as the property of man — the goat, the sheep, the ox, the dog,
the horse, the ass, the hog, &c. — were the companions of man from the earliest
times. The arts of Greece and Rome, the reasonings of philosophers, or the songs
of poets, have not enabled them to seduce or charm one animal more from the
wilds, or to add one individual to the domesticated races, though Africa and Asia
were ransacked for animals to exhibit in the shows of the Roman people, and
forms, never seen in Europe before, were displayed in numbers to the Roman
citizens. The camel, from its limited geographical range, is only known in do-
mesticity ; and all the reputed wild animals of the domesticated species have ori-
ginated from them alone. Surely if the training of animals has been progressive,
as alleged, some of the reputed savages of the ancient world might have left one
or two useful creatures untamed by them, for the benefit of modern philosophers,
and to illustrate their theories. Let the adherents of the theory of taming, and
domestication, and gradual change, make an experiment upon the fox, — said by
JOHN HUNTER* to be one of the progenitors of the dog, — let us see foxes protecting
in place of pillaging the poultry yard, — and this not in the case of an individual
fox, but of the whole race of foxes in the country, — and then there will be some
shew of reason for supposing that the domesticated animals were thus subjected
to the service of Man.
M. BUREAU DE LA MALLE concludes the paper to which allusion has been
made, with the announcement of the result to which, he says, he has been led by
his researches, and that is, that he believes it may be affirmed that the greater
portion of our domestic species of animals is originally from Asia, and have been
transported to Western Europe by early wanderers from the first habitations of
man.
As to what some authors say of the original types of the races of cattle being
« Phil. Trans. 1787, p. 253.
•
VOL. XV. PAET I. 3 G
] 98 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
unknown, and of tamed animals, on returning to their original wild state, resum-
ing the characters of their original condition, — this, too, is an assumption without
evidence to render it even probable. The existence of embalmed animals in the
tombs, and of figures on the monuments, of Egypt, shew, that at least for three
thousand years there has been no essential change in form and structure.* The
wild horses of the Tartarian plains, the wild horses of South America, have re-
turned to no common type materially different from the races from which they
are descended ;f and the black cattle of the Llanos are of all the colours of the
domestic varieties. Even the dogs introduced by Europeans to various countries,
and which have become wild, have not, in the course of years, reverted to their
supposed original sources, and become wolves and jackals, but obstinately remain
dogs still, in defiance of all theories to the contrary.
That the domestication of cattle was not the slow result of experiments con-
tinued for ages, is farther demonstrable from the rapid increase of population in
the early periods of the world. This increase could not have taken place if agri-
culture, including the domestication of cattle and the cultivation of the Cerealia,
were then unknown, and the first tribes had roamed over the extensive hunting-
grounds of a world to be peopled, or gleaned their meagre food from the sponta-
neous produce of the woods and fields. The American races did not advance far
in agriculture, according to Dr ROBERTSON,! as they had no tame animals, and
knew none of the useful metals.
The writers on population have almost universally agreed as to the principle,
that the numbers of mankind could not increase to any marked extent without
pasturage and agriculture; and, of course, in compliance with the prevailing
theory, all their disquisitions have reference to the hunting, the pastoral, and the
agricultural state, as stages naturally produced in savage human nature by the
pressure of numbers on the amount of food.$ "The first hordes," says Baron
CUVIEB, in compliance with the prevailing theory, "made little progress. Re-
duced to live by the chase, by fishing, or by wild fruits ; obliged to give all their
time to the search of subsistence, they could not multiply much, because all the
game would have been destroyed. Their arts were limited to the construction of
huts and canoes, to cover themselves with skins, and fabricate bows and arrows."
And again, " When they had tamed the herbivorous animals, they found, in the
possession of numerous flocks, a certain subsistence, and some leisure, which they
* HASSELQUIST'S Travels in the Levant, 90, 91. f HUMBOLDT, Personal Narrative, iv. 340.
J History of America, ii. 11?.
§ Mr MALTHUS, however, is of a different opinion. " If hunger alone could have prompted the sa-
vage tribes of America to such a change in their habits, I do not conceive that there would have been a
single nation of hunters and fishers remaining ; but it it evident that some fortunate train of circum-
stances, in addition to this stimulus, is necessary for this purpose." (An Essay on the Principle of Po-
pulation, &c. By T. R. MALTHUS, A.M. 4to, p. 43.) And in another place, he says, " It may be said,
however, of the shepherd as of the hunter, that, if want alone could effect a change of habits, there would
be few pastoral tribes remaining." ' (P. 92.)
FROM SAVAGE TO CIVILIZED LIFE. 199
might employ in extending their knowledge ;" and he then states, as the third
stage in the progress of civilization, that " man did not multiply his species to a
great degree, and extend his knowledge and his arts, till the invention of agricul-
ture, and the division of the soil into hereditary properties."*
" Accustomed, as we are," says Mr ALISON, " to the powers which ages of civi-
lization have conferred upon mankind, and to the complete subjugation of ani-
mals which has resulted from the extension of his numbers, we can hardly ima-
gine the difficulties with which our forefathers had to contend when society was
in its infancy, and when the human race were placed in the midst of boundless
forests and morasses, only to become the prey of the innumerable savage animals
by whom they were peopled."! And m a passage immediately after, on consi-
dering the precarious situation of the supposed savage state, the few individuals
who, in that state, survive infancy, and their want of skill in the arts which
minister to the necessities of life, — " it seems," says he, " surprising how his num-
bers could have ever increased." And he can only account for this by supposing
" the unlimited operation of the principle of increase" to be essential, both in the
savage and pastoral state, to the extension and improvement of the human race.
Assenting, as I willingly do, to the proposition, that man could make
little or no progress in numbers or civilization without domestic animals and
the cultivated grains, the writers who adopt the progressive theory fail to shew
how, in the nature of things, the hunter of wild animals could be converted into
their protector ; and how, even supposing one animal to have been accidentally
tamed, he could from thence conclude that the species might be rendered domes-
tic. What could induce the first man, if created a savage, and feeding on acorns
and the apples of the wood, to think of killing the animals around him, and using
them as food ? There is no instinctive thirst of blood in the nature of man, I have
already observed, to lead him to seize and devour living prey. And, even on the
supposition that, by an instinctive propensity, he was led to kill and devour ani-
mals, how could he suppose that such animals could be tamed and reared in num-
bers around him ? Every timid or herbivorous animal flies by instinct from its
natural enemy ; and if savage man were that enemy, it is not easy to see how
they ever could have been domesticated.
On the other hand, if it can be proved, from the earliest histories of the race,
that the knowledge of agriculture, including the pasturage of flocks and the cul-
tivation of the Cerealia, were known to the first man and his immediate descend-
ants,— then all imaginary theories of progressive improvement from the savage
* R£gne Animal, i. 78.
t The Principles of Population, and their Connection with Human Happiness,!. 10. By ARCHI-
BALD ALISON, Esq. F.R.S.E.
Professor Low considers the ox and sheep, domesticated from the earliest records of human
society, to have been instruments, under Providence, for leading man from the savage state. (Illustra-
tions of the Breeds of Domestic Animals in the British Islands, No. iv, p. 11. By DAVID Low, Esq.
F.R.S.E.)
200 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
state, must be looked upon as little better than idle dreams. The first descendant
of the first man, according to the sacred historian, was a " tiller of the ground ;"
his brother was " a keeper of sheep ;" and both of these occupations are given as
contemporaneous with one another, and with the existence of men. And such
was the increase of population, that the son of Cain gave his name to a city. The
nomade or pastoral life, to which the neighbouring country was well adapted, is
not characterized as a separate mode of living till some considerable time after-
wards. The use of metals, and the practice of at least one of the fine arts, is
recorded in the short narrative given by Moses ; and every circumstance referring
to the race, entitles us to conclude, that a high state of civilization — at least a
state equal to all the wants of society at this period — prevailed among the de-
scendants of the first pair.
It is to be remarked, besides, as supporting the contemporaneous existence
of domesticated cattle with man, that, in the sacred narrative, they are distin-
guished by a parenthetic clause, separating them from the other beasts. " And
God made the beast of the earth after his kind, and cattle after their kind."
(Gen. i. 25.) And again, " And Adam gave names to all cattle" &c. (ii. 20.) And
afterwards, " Let him have dominion over the cattle" (i. 26.) The same phrase
is used when narrating the animals that went into the ark : " Every beast after
his kind, and all the cattle after their kind" And this interpretation of the pas-
sage is fully warranted on the authority of another inspired writer. In the 8th
Psalm, alluding to the high rank of man in the scale of created beings, this pas-
sage occurs : " Thou madest him to have dominion over the works of thy hands —
all sheep and oxen, yea, and the beasts of the field." The corresponding phrase
for " cattle" in the former passage is here " sheep and oxen."
III. — CULTIVATION OP THE CEREALIA.
I now come, in the third place, to make a few remarks on the Cerealia, or
cultivated grains, as connected with the third stage of man's supposed progress
from savage to civilized life. These, like man himself, and the domesticated ani-
mals, are supposed to have attained their present productive powers, through long
ages of experiment ; and some writers have considered it as a signal triumph of
art over nature, to have improved barren grasses into the wheat, barley, and oats
of the present day. Thus BUFFON states, in regard to wheat, " Wheat, for ex-
ample, is a plant which man has changed to that point, that it nowhere exists in
a state of nature." * — " The same corn (says Sir HUMPHRY DAVY) which, four
thousand years ago, was raised from an improved grass by an inventor, worship-
ped for two thousand years in the ancient world under the name of Ceres, still
forms the principal food of mankind." f And Dr TAYLOR, in his lately published
* BUFFON, xxiii. 177. t Consolations in Travel, or the Last Days of a Philosopher, p. 36.
FROM SAVAGE TO CIVILIZED LIFE. 201
work, asserts something to the same effect. " The fact that natural productions,"
says he, " became so altered by cultivation as to lose their original characteristics,
is an incentive both to industry and ingenuity. We do not know what was the
original type of wheat, oats, or barley ; but we may reasonably conjecture, from
this very circumstance, that the Cerealia, in their wild state, were not well suited
to human sustenance." *
The native country of wheat and rye is unknown (says PARMENTIER), though
cultivated over all Europe.f Barley (says Bosc) was brought from Upper Asia,
where OLIVIER has found it in a wild state.:): And DE CANDOLLE is of opinion,
that " when the introduction of cultivated plants is of a recent date, there is no
difficulty in tracing their origin .; but when it is of high antiquity, we are often
ignorant of the true country of the plants on which we feed." §
Lord KAMES, forgetting, or not being aware of, the fact that the Cerealia are
never found growing spontaneously, at least to serve to any extent as human
food, takes it for granted that wheat, rice, barley, &c., must have grown sponta-
neously from the creation ; and his reason for this opinion is certainly a pretty
strong one ; "for (says he) surely when agriculture first commenced, seeds of
these plants were not procured by a miracle." ||
The ancient historians, connecting the traditions of their deities with the
acknowledged benefit of the cultivated grains to man, have referred to Isis, the
Egyptian Ceres, as having found the vine, and wheat, and barley, growing wild
in the valley of Jordan, and introducing them into cultivation among the early
Egyptians.^ A late writer on the Cerealia, M. BUREAU DE LA MALLE, following
the indications of these ancient writers, fixes upon Nysa, in the plain of Jordan,
as probably the native country of the Cerealia, from whence they were spread
over all the civilized world, wherever man settled in his peregrinations. The Isis
of the Egyptians, transferred into the goddess of corn and husbandry, — the Ceres
of the Greeks and Romans, — the rites of her worship, it is said, indicated the pro-
gress of agriculture in the Roman Empire.
But if agriculture was the third and most improved stage in the gradation of
human civilization, and if it be ascertained that the Cerealia grow nowhere spon-
taneously, Lord KAMES' s question, where the seeds should come from, when the
pastoral tribes took to cultivating the ground, is one that must puzzle the sup-
porters of the classical theory. If the spontaneous growth of these plants, to the
extent of serving for human food, be taken for granted, the necessity of agricul-
* Nat. Hist, of Society, ii. 87. t Nouv. Diet. xxiv. 27. J Ibid.
§ THEOPHKASTUS and PLINY give the Indies as the country of barley.
|| Sketches of the History of Man, i. 45.
U " In the East, it was in Babylonia, according to HERODOTUS and DIODORUS SICULUS, where the
grains grew naturally, — the very place which may be regarded as the cradle of civilization." — DBS LONG-
CHAMPS, in Diet, des Sciences Naturelles, torn. xix. Art. FROMENT.
VOL. XV. PART I. 3 H
202 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
tural operations to produce them is not apparent ; and if it be supposed that the
pastoral tribes of the second stage were agriculturists to a certain extent, so as to
render the transition to the further cultivation of the soil a matter of slight change
in habits, then the characterizing this mixed state as a purely pastoral one, is not
in consonance with the stages theoretically marked out in the progress of civili-
zation. But there is no evidence of the Cerealia growing spontaneously to any
extent, even in those countries where the geographical range adapted to their
culture has been considered most favourable. The discovery by botanists of
plants of wheat, or barley, or oats, in particular situations, where men are or
have been, is no evidence of spontaneous production. In Europe none of the Ce-
realia are found growing spontaneously ; and even where seeds have been left on
the fields by accident, two or three years has been ascertained to be the limit of re-
production, at least as to wheat and barley. A single unfavourable season — a pre-
mature frost (as M. BUREAU DE LA MALLE observes) — might be sufficient to destroy
the uncultivated and ungathered grains in the greater part of Europe, and the spe-
cies be exterminated, were not the seeds collected and preserved by human care.
Similar atmospheric or other causes may act upon the Cerealia wherever cultiva-
ted, and hence the failure of observers to recognise the country where these plants,
so necessary to man, grow in spontaneous luxuriance.
M. BUREAU DE LA MALL'E has besides remarked, that to ascertain the fact of
the cultivated grains growing spontaneously, would require the observation of
years. In the Bois de Boulogne, for instance, where some of the allied troops had
bivouacked, the seeds of the oat vegetated and reproduced from 1815 to 1819.
And travellers, finding wheat or barley growing, from a similar cause, in coun-
tries near the supposed natural habitat, or the places of their original cultivation,
might be wrong in recording, from one observation, that peculiar locality as the
native country of the plant. Nay, more than this, the evidence of even years of
reproduction would scarcely be sufficient to establish a country as the native or
original one of any of the cultivated grains ; for in the neighbourhood of Buenos
Ayres, the oat, introduced by Europeans, has been said to reproduce itself for
more than forty years. This statement is made on the authority of M. AUG. DE
ST HILAIRE, who for six years witnessed the fact.
Of the identity of the presently cultivated species of wheat and barley with
the grains known under these names by the ancients, there is no sort of doubt ;
for, by the preservation of these grains in the monuments of Egypt, the fact has
been ascertained beyond all question. The wheat preserved in vessels found in
the Tombs of the Kings at Thebes, and of which the colour and form are unaltered,
appeared to M. BELILLE and others perfectly indentical with modern wheat*
The culture of this grain has in Egypt been continuous for ages ; and the spikes of
* Ann. des Sciences Nat. ix. 6l.
FROM SAVAGE TO CIVILIZED LIFE. 203
wheat sculptured upon the Zodiacs of Thebes and Esne', are apparently of the
same species as at present cultivated. In the bread found in the tombs of Upper
Egypt, Mr BROWN found many grains of barley entire, and perfectly similar to
those of the present day. This fact is corroborated by other observers. M. RAS-
PAIL having examined specimens of the grains found by M. PASSALACQUA in an
Egyptian tomb, ascertained them to be the Triticum vulgare and the Hordeum
mdgare of modern botanists. The grains in this case appear to have been partly
roasted, were of a reddish colour, and larger than the European wheat.* For
three thousand years, then, it is proved that these grains have undergone no per-
ceptible change ; so that all the theoretical speculations of fanciful writers as to the
improvement of the Cerealia by the cultivation of ages, and the loss of the origi-
nal type, fall to the ground, and the merit of " converting a sterile herb into corn,"
remains with the inventor of the tale.
M. BUREAU DE LA MALLE concludes, that, besides the valley of the Jordan,
the chain of Lebanon, or the portion of Palestine and Syria which adjoins Arabia,
ought to be considered, with great probability, as the native country of the Ce-
realia.
That the valley of the Jordan, and the districts now mentioned, are places
where the Cerealia were cultivated in ancient times, is at once conceded ; because
they are countries which were early tenanted by families of men. But that the
valley of the Jordan, or Palestine, were the sole places from whence the cultivated
grains emanated, is not warranted from any source but the traditions of the Egyp-
tian priesthood, retailed by historians. The true history of the Cerealia, similar to
what has been stated as to the domestication of cattle, may be traced to a more dis-
tant period, and to a higher source, than the Isis of the Egyptians and the banks of
the Jordan. I have no hesitation in stating, upon the authority of the most sacred
of all records, and that statement is corroborated in every particular by the facts of
history, the observations of naturalists, and the nature of things, that the know-
ledge and cultivation of the Cerealia must have been communicated to the first man.
Far from the hunting state — or the pastoral state — being the earliest or the most
natural state of man, it is declared in Scripture, in express terms, that man's first
occupation was to " dress and keep" the garden in which he was placed ; and after
the fall, his eldest son was an agriculturist — " a tiller of the ground." There is
no gradation of savage to barbarous — from barbarous to civilized life ; no evidence
of brute intelligence, to be improved in after ages to the height of reason, and the
moral responsibilities of an intelligent being. Man was created a being as perfect
as any of his future race ; and however the knowledge of his descendants was to
* Mem. du Mus. d'Hist. Nat. xv. 145. — The wheat grown in Abyssinia is, according to BRUCE,
smaller than the Egyptian wheat.
204 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
be acquired, from infancy to manhood, from his example and instruction, — his
knowledge was the immediate gift of God to the first of his creatures.*
The negative proof, then, of naturalists being unable to refer to any particu-
lar country where the Cerealia grow spontaneously, — the positive evidence that
the wheat and barley of the ancients were precisely of the same species as those
now cultivated, — and the fact that these grains have never been found wild or
growing spontaneously, but in places frequented by man, lead to the conclusion,
that the knowledge and cultivation of the Cerealia were coeval with man's exist-
ence. It may be mentioned, besides, as strongly indicative of the fact that the
Cerealia are nowhere found in quantity but where man has carried them in his
progress, that in the Lists of Plants stated as indigenous in the Levant, almost all
the genera Triticum and Secale are found ; while in South America, MM. HUM-
BOLDT and BONPLAND found no species of wheat (Triticum), and only one species
of barley (Hordeum ascendens). This fact would also indicate, that the early
wanderers from the Old Continent had been driven thither by accident, or ex-
tended their families in circumstances which prevented them from carrying with
them the cattle or the grains of their forefathers. Unlike many other plants with
a circumscribed geographical range, wheat, barley, oats, and rye, are found in
almost every place where there are tribes of men. And it is farther a curious and
unaccountable circumstance, except in one view, that these grains are never found
in a wild state, available to any extent for the purposes of man. Their continu-
ance depends upon their cultivation. Everywhere they are found to die out, if left
to the spontaneous care of nature. Even in modern agriculture, and over most
of Europe, a change of seed is occasionally necessary to ensure good crops ; and
the business of the farmer is a kind of continued experiment upon the soil he cul-
tivates, to stop the retrograde tendency of the grains to become less prolific. This
remarkable fact verifies in a striking manner the truth of that denunciation passed
on the father of our race, " In the sweat of thy face shall thou eat bread ;" and
affords another instance of the coincidence which students of nature are often
obliged to remark between what is taught in the Book of Nature, and the Book
of Revelation.f
* The Cerealia seem to be particularly indicated in the following passage of Genesis : — " Behold I
have given you every herb bearing seed, which is upon the face of all the earth ;" — and to distinguish
these seed-bearing herbs from trees, the latter are mentioned by name in what follows : — " and every tree
in which is the fruit of a tree yielding seed ; to you it shall be for meat." (Gen. i. 29.) And connecting
this with what is related in a subsequent passage, when the denunciation was passed on our race — " In
the sweat of thy face shalt thou eat bread,1' it appears almost certain that the Cerealia were known to
man from his origin.
t The sire of gods and men, with hard decrees,
Forbids our plenty to be bought with ease,
And wills that mortal man, inured to toil,
Should exercise, with pains, the grudging soil.
VIRGIL, Georg. B.
FROM SAVAGE TO CIVILIZED LIFE. 205
But even supposing, with some philosophers, that Man at his creation had to
acquire by slow experience a knowledge of the objects around him, what could
his boasted reason, exerted for the first time, have taught him, either regarding
the taming of cattle, or the cultivation of the Cerealia ? How could he, a priori,
know that, by burying in the ground the ripened seeds springing spontaneously
for his use, they would reproduce their seeds again, increased twenty-fold for
one? The thing is impossible. Accident, in the course of years, might have
thrown such an instance in the way of a rational creature trained to observation
from infancy, and reflection might have suggested analogies between the annual
reproduction of fruits and that of grains ; but long years of experiment must have
retarded the general acquisition of such knowledge. Neither is it very evident
how individuals, living on fruits of much superior size to the cultivated grains,
could first come to the knowledge that the minute seeds of the grasses might be
made available for food. And it is more surprising still, that these early agri-
culturists should fix at once upon all the available Cerealia, proper for the food of
man, and leave nothing to be added to the stock of cultivated grains, by the in-
genuity of the thousands of generations who have succeeded them. " All animals,"
says Lord MONBODDO, " are directed by instinct to search for, to find out, and to
make use of the food which Nature has provided for them. But it has not di-
rected nor instructed them to multiply that food, and to make the earth produce
more than it naturally produces. In other words, instinct does not teach us to
till, sow, or plant."* If the first man had been created a savage, and left to the
acquisition of knowledge by his own unaided efforts, ages might have elapsed and
found him a savage still. And without the aid of cultivated grains from the com-
mencement of his progress, and a knowledge of their use as food, the population
of the globe would have been limited to scattered tribes of rude savages, scantily
extended over the wastes of creation.
It is besides a strong presumption of the truth of the views now submitted
as to the domestic animals, and the knowledge of the cultivation of the Cerealia
being the gift of his Maker to the first man, that in all the traditions of the an-
cient nations, the discovery of the grains — the domestication of cattle — the in-
vention of writing, &c. are specially referred to their divinities or divine benefactors
in the earliest periods of the world. The worship of Isis in Egypt, and the rites of
Ceres in Greece and Rome, have reference to knowledge communicated to the
human race by means beyond human ; and thus the scattered traditions of dis-
tant nations not only afford evidence of man's origin from a common stock, but
confirm in a singular manner the recorded facts of his early history.
Having thus shewn, as far as the limits of a single paper permitted me, that
man was not created a mute savage, but a rational and intelligent being, endowed
by his Maker with all the attributes of man in his best estate, it remains to be
* Origin and Progress of Language, vol. i. Book ii. p. 273-4.
VOL. XV. PART I. 3 I
206 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
accounted for how the race should have declined to barbarism and savage life.
Between the period of the Creation and the Deluge, no facts are recorded concern-
ing individual portions of the race, with the exception of one family. Beyond
that family " all flesh had corrupted their ways." Whether a physical degrada-
tion accompanied this moral declension, is not apparent ; but as far as regards
the civilization of the race, and the knowledge of the arts previously practised,
the survivors of the Deluge were the depositaries and the examples to their future
descendants. That their situation was not one of savage barbarity, nor of feed-
ing upon acorns, or hunting wild animals, is evident from the Sacred Record.
And it is fairly presumable, that all the arts and sciences of the antediluvians—
their knowledge of the true God and his worship, — were the property of the se-
cond progenitors of the human race, and communicated to their descendants.
What the state of the human race was at this time, is apparent from the
Sacred Record. Agriculture, horticulture — the vine and the olive — flocks and herds,
— were the known resources of the children of Noah ; and however from soil, cli-
mate, or relative situation, it became necessary for particular families, his descen-
dants, to choose the pastoral or agricultural life as their chief employment or
means of support, yet the adoption of the one did not necessarily exclude the
knowledge or practice of the other. No one, from finding a country more fit
for pasturage than tillage, necessarily excludes from his mind or practice, the
arts by which grains are raised and food provided ; on the contrary it is pre-
sumable, and indeed certain, that even the pastoral tribes raised a certain
quantity of corn for the supply of their families and flocks.* Besides, there are
large portions of the globe unfitted for the operations of agriculture. The Penin-
sula of Arabia, abounding in vast sandy deserts, is almost wholly occupied by no-
made races ; and Central Asia, for the most part a bare table land, without fo-
rests, has been inhabited by wandering tribes of pastoral people from the com-
mencement of history. The nature of the country fixes the wandering and pas-
toral mode of life upon the races inhabiting such districts ; and when the want of
irrigation and other causes renders the raising of crops to any extent impossible,
pasturage over immense districts is the necessary and chief occupation of the in-
habitants.
The Book of Job, written, it is conjectured, centuries before the time of Moses,
and at least a thousand years before the poems of Homer and Hesiod, may be re-
ferred to as evidence of the state of civilization and knowledge at that early period
of the history of Man. The vine and the olive were cultivated (xv. 33.) ; the
ground ploughed for the growth of corn (i. 14.) ; metals used for domestic purposes
(xxxvii. 18.) ; the horse trained for war ; musical instruments were in use ; writ-
ten characters employed (xix. 23, 24.), and astronomy studied. The evidences of
a highly civilized society are prominent in all the details of this vivid picture of
ancient manners ; and as to its own composition, according to Dr MASON GOOD,
* Genesis, xxiv. 32.
FROM SAVAGE TO CIVILIZED LIFE. 207
" nothing can be purer than its morality, nothing sublimer than its philosophy,
nothing simpler than its ritual, nothing more majestic than its creed."*
The state of society after the Deluge, may thus be considered as one in
a comparatively high degree of civilization. Soon after that event, the mul-
tiplied descendants of the patriarch combined to erect a city and a tower ; and
his great-grandsons, Nimrod and Asshur, are recorded as the founders of large
cities,f ^e ruins of which now remain, a testimony of the truth of the Sacred
Record. There is here therefore no grounds for the supposition that the race
were savage, or had risen from savage progenitors. The arts, the animals, and
the grains of former ages, were the property of the descendants of Noah, who
dwelt in the plain of Shinar ; and from this starting-place are to be traced, in the
traditions, histories, and monuments of the race, the dispersion of the various fa-
milies who were to people the most distant quarters of the world.:):
The mode in which the human race spread over the world after this period —
the routes pursued by the various families — and the foundation of cities and civi-
lized governments, — it is no part of my intention, veven if I Avere qualified for the
task, to enter upon. I confine myself to establishing the propositions, That man
was at his creation a civilized being, endowed with all the physical and intellec-
tual powers necessary to his state as a moral and responsible agent, and requisite
to enable him to acquire a more intimate knowledge of the creation around him :
That the domestic animals, created for his iise, were his companions, and obedi-
ent to his will, from the beginning : That the cultivation of the Cerealia was the
earliest occupation of the human race : That, prior to the Deluge, the human race
had planted cities and practised many of the more useful arts : and, That the sur-
vivors of the Deluge started with all the knowledge of their predecessors — the
possession of the domesticated animals, and the grains necessary to their processes
of agriculture. These propositions being granted, it belongs to the philosopher or
statesman, to trace the causes, physical and moral, which have reduced the de-
scendants of a highly civilized people to the degraded state in which many tribes
of men are now found. Is there a downward tendency in the constitution of
man ? — Have nations, like individuals, their beginning, their increase, and their
end — their rise and fall? Does history and observation demonstrate, that the
* The Book of Job literally translated, by J. MASON GOOD, F.R. S. Introd. p. i.
t Genesis, xi. 4. — x. 10.
I " The boundless riches of the Babylonian fields gave birth," says Mr ALISON, " even in the first
ages, to those stupendous cities from whence the enterprise of commerce dispersed the human race in
every direction through central Asia ; while the uniform pasturage of the Scythian wilds spread before
them a vast highway stored with food, by means of which they could penetrate with ease to the remotest
extremities of the old world." — ALISON on Population, i. 22.
" Supposing Babel or Babylon to have been the centre of irradiation — how easy was the transit for
HAM'S descendants into Africa by the Isthmus of Suez; into Europe the path was still more open for
those of JAPHET ; and as the stream of population spread to the east, the passage to America was not
difficult to those who had arrived at Behring's Straits." — KIKBY'S Bridgewater Treatise, i. 76.
208 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY
tendency of the human race is in most circumstances to degenerate from the civi-
lized to the savage state — in place of rising from savage to civilized life ? What-
ever be the elements of this retrograde progress, there is no doubt of the fact.
All history is full of instances, of regions occupied by civilized people, being now
the abodes of hordes of barbarians. The almost obliterated remains of Babylon —
the ruins of Thebes — the monuments of Egypt — the total disappearance of the
ancient commercial republics of Carthage and her allies — even the ruins of Athens
and Rome — teach the lesson, that neither science nor art, neither philosophy nor
religion, have been hitherto effective in stopping this downward progress — this
descent to barbarism and savage life.
With regard to the progress of this degradation, it must necessarily have
been gradual, as to the first emigrants from the centre of civilization and know-
ledge. Removed by choice or from necessity, as then* numbers augmented, to
greater distances in the yet unpeopled wastes, much of the original knowledge in
the arts might have been lost, from no call being made in their circumstances for
their use. The occupations of the new settlers would naturally depend much
upon the nature of the country and climate in which they found themselves even-
tually placed. And it is no stretch of imagination to suppose, that many of these
scattered families or tribes, in then- migrations through unpeopled wastes, might
gradually lose much of the knowledge of their forefathers. It is besides not im-
probable, that many parties of the earlier wanderers, cut off by accidental circum-
stances easily supposed — driven out to sea or carried down a river in their primitive
boats — might in many cases be transported beyond reach of communication with
other families of then* race; and thus, deprived of the domesticated animals and the
use of the grains, degenerate into a ruder and more savage mode of life.* That in
some such way as this the American Continent has been peopled is rendered pro-
* " Very few of the numerous coral islets and volcanoes of the vast Pacific, capable of sustaining a
few families of men, have been found untenanted ; and we have therefore to inquire whence and by what
means, if all the members of the great human family have had one common source, could these savages
have migrated. COOK, FORSTER, and others, have remarked that parties of savages in their canoes must
often have lost their way, and must have been driven on distant shores, where they were forced to re-
main, deprived both of the means and of the requisite intelligence for returning to their own country.
Thus Captain COOK found on the island of Wateoo three inhabitants of Otaheite, who had been drifted
thither in a canoe, although the distance between the two isles is 550 miles. In 1696, two canoes, con-
taining thirty persons, who had left Ancorso, were thrown by contrary winds and storms on the island of
Samar, one of the Philippines, at a distance of 800 milesr In 1721 two canoes, one of which contained
twenty-four, and the other six persons, men, women, and children, were drifted from an island called
Farroilep to the island of Guaham, one of the Marians, a distance of 200 miles." — LYELL'S Principles
of Geology, iii. 157.
KOTZEBUE mentions an instance of four persons being drifted in an open boat to the distance of 1500
miles. Captain BLIGH with eighteen persons in an open boat traversed, in forty -one days, a distance of
3618 miles, from near Otaheite to Timor in the Indian Ocean ; and a number of other instances might
be mentioned from the narratives of travellers, of the spread of the race in circumstances where the know-
ledge and habits of civilized life might be so far lost in the necessities of their situation.
FROM SAVAGE TO CIVILIZED LIFE. 209
bable, from the circumstance that the horse and the ox were not known in Ame-
rica till a late period — that at the point where the continents approach, and stroll-
ing hunters might pass from the one into the other, there are some animals
common to both — and that all the traditions of the different tribes refer to ances-
tors more civilized, from whom they have descended.
The numerous remains of a more civilized people than the present races in
North and South America — remains of the same nature in the wilds of Tartary
and Siberia — the tombs, the tumuli, and fragments of ancient art, found all over
both continents, — demonstrate not only the identity of the races, but the degra-
dation that has followed since their original settlements.
" The barbarism that prevails throughout these different regions," says HUM-
BOLDT, " is perhaps less owing to a primitive absence of all civilization, than to the
effects of a long degradation. The greater part of the hordes which we designate
under the name of savages, descend probably from nations more advanced in cul-
tivation."* And in another place he says, " Savages are for the most part de-
graded races, remnants escaped from a common shipwreck, as their languages,
their cosmogonic fables, and a crowd of other indications seem to prove."
If such has been unquestionably the downward progress of the human race
in all past ages, and in regard to even the most civilized and greatest communities
which have ever existed, the cause of that declension is a subject for the deepest
consideration, in regard to the stability of our own unparalleled state of social
life. What is calculated, in our case, to arrest us in the^climax of our national
greatness — to stop the flowing tide that has swept away the arts and civilization
of every former people ? At the pinnacle of power, " beyond all Greek, beyond
all Roman name," is it inevitably necessary that we should decline ! — that our
I
sun should go down as theirs — and all our arts and sciences, and improvements,
be lost in a flood of barbarism ! It is the business of the philosopher, the duty of
the statesman — the object of all — to inquire into the causes of the apparently
fated decline of all human communities ; and to ascertain whether moral degra-
dation, like the same cause among the antediluvians, may not be the forerunner
of national ruin.
* Personal Narrative, iii. 208. " How can we distinguish the prolonged infancy of the human race,"
says HUMBOLDT, " if it anywhere exists, from that state of moral degradation in which solitariness, want,
compulsory misery, forced migrations, or the rigour of the climate, obliterate even the traces of civiliza-
tion ? If every thing1 which is connected with the primitive state of man, and the first population of a
continent, could from its nature belong to the domain of history, we should appeal to the traditions of
India, to that opinion so often expressed in the laws of Menore and in the Kamajan, which considers sa-
vages as tribes banished from civil society, and driven into the forests." — HUMBOLDT'S Personal Narra-
O *
tive, iii. 203.
VOL. XV. PART I. 3 K
210 MR STARK ON THE SUPPOSED PROGRESS OF HUMAN SOCIETY, &c.
NOTE. — Since the preceding remarks were submitted to the Society, a Memoir, by M. J. J. VIREY,
entitled " Des Causes Physiologiques de la Sociabilite chez Animaux, et de la Civilization dans 1'Homme,"
has been read before the Royal Academy of Medicine at Paris. An abstract of this paper is given in
the " Bulletin de 1' Academic Royale de Medecine" for February last. M. VIREY, in this memoir, fol-
lows the classical theory of the gradual progress of society from the savage state to civilized life ; asserts
intellectual superiority to be the universal cause of subordination ; and, with regard to the domestic ani-
mals, endeavours to shew that debility of constitution is the physiological cause of their submission to
man. As none of the considerations adverted to by this gentleman affect the statements I have sub-
mitted to the Royal Society, I have not considered it necessary to notice them further.
PLATU II
Sac. 7'rtM.i . vo/ '. /.)./> 2/t
,t! /.<•///! '< • /,l7/ny'- />/'"'
( 211 )
XII. — De Solariis in Supracretaceis Italics Stratis repertis. Auctore JOANNE
MICHELOTTI.
Abdita quid prodest generosi vena metalli
Si cultore caret t LOGAN. Carm. in Pison.
(Bead 15th March 1841.)
MULTIPLICES Solariorum species, genus testaceorum constituentes, ad Turti-
nacea LAMAHCK, ad Gasteropoda CUVIER, pertinens. quse in geologicis Italise stratis
reperiuntur, monographico modo investigare fortasse prsestat. Ratio nee am-
bigua ; varise enim dubitandi rationes vigebant, turn circa numerum et nomina
specierum, turn circa earundem citationes, et auctorum dissensiones, nee non
potissimum circa relationes specierum quee in Italicis divisionibus sup)*acretacece
formationis adsunt, sive in se spectatis, sive prout cum viventibus conveniunt aut
discrepant.
Hisce ambagibus preecludendi viam ratus, ubi hujus pulcherrimi generis spe-
cierum enucleationem componerem, ad hoc animum revolvi, historian! ejusdem
prorsus omittens, quoniam earn persolverunt viri clarissimi T. et G. B. SOWEHBY,*
DES HAYES,! KIENER.|
Quum autem in qualibet monographic/, icones maxima prsebeant subsidia,
atque ea ex natura et oculari inspectione depromere oporteat (quod optimus
amicus, atque zoologise cultor HENRICUS MELLA, mihi prsestitit), itaque eas solum-
modo species enumeravi, quas speciatim conspicere potui, magisque vulgatas in
Taurinensibus collectionibus esse comperi ; nee inutilem prorsum laborem sus-
cepisse ratus, ubi et insignis hujus Regise Societatis favor, et naturalis historiae
cultorum indulgentia atque humanitas accedat.
Dabam, 22. Mense Majo 1840. Aug. Taurinorum.
Spec. N. 1. SOLARIUM STRAMINEUM, Lamarck. Nobis fig. 1, 2, 3. Tab. II.
Testa orbiculato-convexa, tranversim sulcata, longitudinaliter striata; ultimo
anfractu ad peripheriam planulato-bisulcato ; umbilico patulo, leviter cre-
nulato ; sutura canaliculata.
Habitat penes Tranquebar, et in Mari Mediterraneo.
* The Mineral Conchology of Great Britain, — Genera of Shells,
t Coquill. Foss. des environs de Paris, vol. ii. pag. 212.
J Collect, des Coq. viv. cahier de Cadran.
VOL. XV. PART I. 3 L
212 CHEVALIER MICHELOTTI DE SOLARIIS
Fossile in agro Vicentino, Parmensi, Astensi : specimina parva : item in collibus
Dertonensibus, specimina majora sed rariora.
GMELIN, Syst. Nat., pag. 3575. Trochus stramineus.
CHEMNITZ, Conch. Cab. vol. v. tab. 172, fig. 1699.
LISTER, Conch, tab. 635, fig. 23.
BRANDER, Foss. Hanton. pag. 10. tab. 1, fig. 78.
SOLDANI, Saggio, tav. x. fig. 61.
LAMARCK, Anim. s. Vert. vol. vii. pag. 4. Solarium stramineum.
BROCCHI, Conch. Foss. Subap. vol. ii. pag. 359. Solarium canaliculatum.
SOWERBY, Miner. Conch, vol. vi. pag. 43, tab. 524, fig. 1.
DEFRANCE, Diet, dcs Scienc. Natur. torn. 55, pag. 485.
DES HAYES, Coq. Foss. torn. ii. pag. 220.
PHILIPPI, Enum. Mollusch. Sic. pag. 173. Solar, stramineum et Sol. canaliculatum.
BRONN. Lethaea Geogn. pag. 1039.
KIENER, Spec. General des Coq. viv. 28, Liv. genre Cadran, pag. 11, tab. iii. 4.
Haec species trochiformis est, spiram gerit depressam : ejus anfractus numero
quinque, leviter convexi sunt, sutura aliquantulum canaliculata sejuncti ; ultimus
subrotundus ; duobus cingulis marginalibus tertioque minore ad peripheriam in-
structus: sulci transversi, striis longitudinalibus decussati, indeque granulati;
umbilicus leviter crenulatus, ad latera subcanaliculatus ; carina mediana con-
spicua.
Quatuor species recenset clariss. LEA, in opere cui titulus, Contributions
to Geology, nominibus Solarium Henrici, Sol. ornatum, Sol. elegans, Sol. cancel-
latum, quos varietates tantum Solarii straminei esse autumo.
Spec. N. 2. SOLARIUM PSEUDO-PERSPECTIVUM, JBrocchi. Nobis, fig. 4, 5, 6. Tab. II.
Testa orbiculata, subconvexa, Isevi ; anfractibus margine exteriore acuto, superne
bisulcato, subtus sulco unico, umbilicum amplum, plicato-crenatum cingente ;
apertura depressa.
Habitat
Fossile in Etruria, in agro Boroniensi ; Parmensi, atque collibus Dertonensibus.
• . BROCCHI, Conch. Foss. Subap. pag. 359, tav. 5, fig. 18, a. b.
BORSON, Sagg. Oritt. pag. 88.
DEFRANCE, Diet, des Scienc. Natur. vol. 55, pag. 488. [Solarium complanatwn.
BRONN, Italiens tert. Gebilde, pag. 62.
PHILIPPI, Enum. Mollusch. Sic. pag. 174.
De hac specie verba faciens clar. BROCCIII ait, Dubitare se num in Solario
tiybrido quidpiam consentaneum Solario pseudo-perspectiw adsit ; verumtamen,
sive forma conoidea quam apertura, et sulcorum dispositiones Solarii hybridi, satis
IN SUPRACRETACEIS ITALIC STRATIS REPERTIS.
superque ostendunt maxumam diiferentiam inter Solarium pseudo-persjiectivum
et Solarium hybridum intercedere.
Clariss. BRONN, in suo Indice Testaceorum Italise, proprium nomen vocabulo
a BROCCIII adhibito ad hanc speciem indicandam adjicerc posse antumavit; quam
agendi methodum modis omnibus impugnare oportet. Primo enim Linnaeana
nomina Linnaeanis speciebus adjicimus, licet generibus adauctis; ita non absimili
modo BROCCIII atictoritatem prse oculis habere debemus, ubi de iis agatur speciebus
quse eundem laudant auctorem.
Hisce alia accedunt : nemo est qui ignorct BROCCIII, in pretiosissimo suo opere
Testaceorum Italiec (ut claris. Anglic! scriptoris voce utar*), indicasse genera sive
LINN^EI, sive LAMARCKII in speciebus ab eodem enumeratis, nihil itaque erat cur
nostra setate Risso, BRONN aliique, BROCCHI auctoritatcm expungant ut propriam
apponant. Neque hie evanescit dim" cultas : nostrum est specierum et scriptorum
auctoritatem firmam tenere, neque ita partitiones jactare ut temporis progressu
nihil certi remaneat.
Spec. N. 3. SOLARIUM LUTEUM, Lam. Nobis, fig. 10, 11, 12. Tab. II.
Testa parvula, ovbiculato-conoidea, ad peripheriam bisulcata, ultimo anfractu ad
marginem inferne bicingulato, laevigato ; umbilico angusto, crenis sulco discretis.
Habitat in maribus Novae Hollandise et penes Messinam.
Fossile in collibus Taurinensibus, raro.
LAMARCK, Anim. sans Vertebr. vol. vii. p. 5. viv.
PHILIPPI Enum. Mollusch. Sic. pag. 174, N. 2, tab. 10, fig. 22.
BRONN, Lethaea Geogn. pag. 1047.
KIENER, Coll. Coq. viv. pag. 9, tab. iv. fig. 9.
Anfractus hujiis speciei sunt convexiusculi, Isevigati ; peripheria duobus
cingulis distincta ; facies inferior vix convexa, Isevissima, umbilici margine sulco
parum profundo sejuncto. Operculum tenuissimum est, corneum, multispiratum.
Nescio qua de causa in stratis supracretaceis superioribus nee adhuc reperta
est, quum ipse earn in collibus Taurinensibus invenerim.
Differentia est ct extat inter icones quos prsebct clar. KIENER, et quos exhibet
claris. PHILIPPI ; specialern posterioris scriptoribus cognitionem sequi malo.
Spec. N. 4. SOLARIUM NEGLECTUM, mihi. Fig. 7, 8, 9. Tab. II.
Testa orbiculato-conoidea, apice obtuso ; anfractibus convexiusculis, laevigatis,
ad suturam tribus sulcis granulosis instructis ; ultimo ad peripheriam
angulato-rotundato ; basi Isevigata, umbilico mediocri, margine crenato,
crenis sulco distinctis ; apertura mediocri, depressa.
* MANTBLL, The Wonders of Geology, vol. i. pag. 193.
214 CHEVALIER MICHELOTTI DE SOLARIIS
Habitat
Fossile in colle Taurinensi, raro ; in agro Astensi, Parmensi, frequenter.
BON. Cat. del Muz. Zool. di Torino, M. S. n. 571. Solarium sulcatum.
PUSCH, Polons Palseont. tab. x. fig. 11, a. b.
Hsec species ferme conica, circa sex anfractus ostendit, qui penes suturam
tribus sulcis ferme sequalibus prsediti sunt, atque in interstitiis adsunt duse par-
vulse costulae granulosae. Cseterum facies sive inferior quam superior laevigata
est ; peripheria marginis posterioris anfractus rotundata est, atque in ima facie
duos sulcos cernimus ; umbilicus vix elatus, atque ejus latera distincte canali-
culata sunt ; apertura aliquantulum depressa atque dilatata est.
Nonnullae species huic affines eidem accedere videntur ; inter quas potissimum
numerabo Solarium patulum atque Solarium caracollatum LAMARCKII. Circa
priorem speciem, quum nimis brevis ejusdem exaratio sit penes LAMARCK, quum
eadem pluribus aliis conveniat speciebus, ideo ad descriptiones clar. vir. SOWERBY
atque DES HAYES confugiendum.
De Solario patulo haec habet SOWERBY : " The umbilicus is curiously and
beautifully ornamented with a crenulated border, surrounded by a row or two
of small denticulaa. The flattish disk-like surface swelling a little, has longi-
tudinal striae with more or less fine transverse marks over it. The outer angle
of the shell is sharpest, the upper surface of the edge is milled, as it were, with
oblique transverse striae, causing small oblong risings like the oblique milled
edges of guineas. The shell is also longitudinally striated beneath." ( Vide
Miner. Conch, of Great Brit. vol. i. p. 35). Ex sulcis longitudinalibus itaque, e*.
aperturaa indole, atque margine, metienda sunt quae differentias indicant inter
Solarium sulcatum et Solarium neglectum.
Verumtamen quum species Solarii patuli a LAMARCK descripta, ea prope
Lutetiis inveniatur, idcirco confugere debemus ad descriptionem claris. DES HAYES
ut ejus characteres cognoscamus : idem ait : " Ce cadran est orbiculaire, sa
spire, plus ou moins eleve"e, est toujours obtuse au sommet ; les tours qui la com-
posent sont au nombre de neuf ou dix ; ils sont e"troits, ordinairement aplatis,
quelquefois un peu concaves transversalement. Ils sont lisses, et cependant le
dernier examine" a la loupe offre quelques stries transverses obsoletes. La suture
est superficielle, tres-fme ; elle est bordee en dessus de granulations tres-fines, et
on remarque quelquefois au dessous de petits plis longitudinaux. La circonfe"rence
du dernier tour est fort aigue, care"nee ; la base de la coquille est largement
ouverte par un ombilic simple et continu, dont le bord interne, non saillant, est
couronne" par un rang de granulations, qui s'effacent presque entierement dans
quelques individus. L'ouverture est un peu oblique a 1'axe ; elle est petite, qua-
drangulaire ; ses cote's sont presque e"gaux : ses bords," &c.
Patet igitur, sive ex numero anfractuurn, eorumque suturis, et depressione,
IN SUPRACRETACEIS ITALIC STRATIS REPERTIS. 215
nec non ex peripheria et apertura in Solaria patulo, distinctiones adesse inter
Solarium neglectum et Solarium patulum.
Claris. PUSCH, in egregio opere circa fossilia Polonise, varietatem Solarii cara-
cottati agnoscere credidit in Solario neglecto ; sed minus apte, sulcorum enim pree-
sentia vel defectus alicujus momenti est : hoc fundamento innixi, LAMARCK,
SOWERBY, DES HAYES, aliique, species constituerunt ; alioquin vero vel ipse PUSCH
discrimen inter Solarium carocollatum, et Solarium umbrosum BRONGNIART ad-
misisse constat ; ergo potiore jure discrimen inter Solarium neglectum, et S. cara-
collatum admittendum : adde, in Solario neglecto strias longitudinales deficere,
tres sulcos penes anfractuum suturas extare, granulationibus interpositis, basim-
que depressam esse.
Celeb. BONELLI in hac specie Solarium sulcatum LAMARCK agnoscere credidit,
quam speciem in agro Parisiensi tantummodo reperiri LAMARCK scripsit; licet
autem et DES HAYES altum de hac specie silentium servet, notare juvabit, gene-
ricam nimis LAMARCKII deftnitionem esse, atque, hac seposita, ex peripheria, an-
fractuum suturis, differentia existere.
Spec. N. 5. SOLARIUM AMBROSUM, Brongniart. Nobis 13, 14, 15. Tab. II.
Testa orbiculato-depressa, subdiscoidea ; anfractibus planis, sutura canaliculata
discretis, sulcis transversis, profundis ; ultimo anfractu ad peripheriam ob-
tuse angulato, angulo utrimque marginato : umbilico magno canaliculate,
late crenato ; crenis sulco distinctis.
Habitat
Fossile penes Sultia, raro ; in colle Taurinensi, frequenter.
BRONGNIART, Mem. sur le Vicentin, pag. 57, tab. ii. fig. 12.
BRONX, Ital. tort. Geb. pag. 63.
DE LA BECHE, Man. of G-eol. tert. gr.
Hsec species ferme discoidea spiram gerit obtusam ; anfractus numero quin-
que aliquantulum convexi, atque disjunct! sunt in vim cavitatis : externa facies
pluribus sulcis instructa est, at in ultimo anfractu quinque tantum sunt : inter-
stitia in supremis anfractubus sunt granulosa, in postremis Isevigata. Margo ob-
tuse angulosus, utrinque duobus sulcis profundis distinctus ; umbilicus late patet,
atque crenatus ; crenis sulco profundo discretis ; apertura magis lata, quam longa.
Clar. BRONGNIART, in opere citato, notat Solarium plicatum LAMARCK magis
accedere ad hanc speciem quam alise ; verumtamen discriminis ratio non in eo
ponenda quod in Solario umbroso granulationes desint ; vidimus enim in supe-
rioribus anfractibus Solarii umbrosi earundem signa adesse, sed quia in Solario
umbroso desunt longitudinales plicae quas observamus in Solario plicato : prseterea
in Solario plicato sulcus dilatatus est circa granulationes, quum stricte et minus
profunde pateat in Solario umbroso.
VOL. xv. PART i. 3 M
216 CHEVALIER MICHELOTTI DE SOLARIIS
Neque relationes omnino deficiunt inter Solarium umbrosum, et Solarium
Icevigatum; sed ubi KIENER audiamus disserentem de Solario Icevigato, liquido
patet hujus specie! umbilicum coarctatam esse, ejusdemque granulationes parvas,
et sulcum granulosum ; prseterea strias tantummodo, non sulcos, in superna facie
adesse.
Sp. N. fi. SOLARIUM MILLEGRANUM, Lamarck. Nobis fig. 16, 17. 18. Tab. II.
Testa orbiculato-convexa, ad peripheriam compressa-angulata, scabra ; striis sul-
cisque transversis, granulosis : inferna facie convexa, striis longitudinalibus,
creberrimis ; umbilico patulo, crenato.
Habitat
Fossile in agro Parmensi, frequens ; in collibus Dertonensibus, raro ; in colle Tau-
rinensi, rariss.
Var. «. variet. minor, periph. leviter sulcata.
LAMARCK, Anim. sans Vert. vol. vii. pag. 6, n. 8.
BRONN, Ital. tert. Geb. pag. 64, n. 335.
JAN, Catal. pag. 6, n. 10.
Hsec species ferme conoidea sex anfractuus gerit, quorum priores aliquan-
tisper planulati sunt, inferior convexus est, variis granulationum ordinibus, et qui
in supremis minus patent: inferior facies pariter granulationibus gaudet, ese-
demque potiores circa umbilicum quam circa marginem : umbilicus est amplissi-
in us ; apertura subrotunda.
Spec. N. 7. SOLARIUM PULCHELLUM, mihi. Fig. 19, 20, 21. Tab. II.
Testa superne planulata; anfractibus sulcis granulosis, regularibus, ultimo ad
peripheriam angulato-carinato, inferne convexo; sulcis transversis; inter-
stitiis granulosis preedito ; umbilico lato, margine crenato, crenis duplicatis.
Habitat
Fossile in collibus Dertonensibus, raro.
Hsec species valde prsecedenti accedit, atque forsitan aliis inventis ejusdem
varietas censebitur ; verumtameu usque nunc talia discrimina adsunt, ut non
dubitem novum eidem tribuere nomen, in vim potissimum quod omnino supenie
planulata sit, quod in superna facie sulci longitudinales omnino deficiant, quod
interior canalis minus elatus sit, atque peripheria minus acute carinata.
Spec. N. 8. SOLARIUM CANALICULATUM, Lamarck. Nobis Fig. 25, 26, 27. Tab. II.
Testa orbiculato-conoidea, apice obtuso ; anfractibus convexiusculis cingulatis ;
cingulis granosis, depressis, peripheria rotundato-carinata, transversim sul-
IN SUPRACRETACEIS ITALIC STRATIS REPERTIS. 217
cata ; facie inferna ad marginem canaliculata, sulcis longitudinalibus exa-
rata ; umbilico mediocri ; apertura ampla, subquadrangulari.
Habitat
Fossile in agro Astensi, Parmensi ; in Etruria, in Anglia,
BRANDEU, Foss. Hant. pag. 10, tab. 1, fig. 7, 8.
LAMARCK, Ann. du Mus. torn. iv. pag. 54, N. 3.
BROCCHI Conch. Foss. Subap. vol. ii. pag. 360 (variet. Solarii pseudo-perspectivi.)
LAMARCK, Anim. sans Vert. vol. vii. pag. 5, N. 3.
BORSON, Mem. Orilt, vol. Accad. di Torino, pag. 89, N. 3.
DEFRANCE, Diction, des Scienc. Natur. torn. Iv. pag. 485.
DESHAYES, Coq. Foss. vol. ii. pag. 220, N. 8. tab. xxiv. fig. 19, 20, 21.
BONELLI, Coll. Mus. Zool. M. S. Solarium crcnulosum.
Haec species ferme conoidea superius, inferne convex iuscul a, superficies sul-
cis longitudinalibus et transversis utrinque signata ; umbilicus mediocris, canali
elevato ; plicae interiores nee adeo distinctse, nee adeo frequentes, ut in Solario
millegrano.
De hac specie sentiebat BROCCHI, dun varietatem Solarii pseudo-perspectivi
indicabat ; hinc ille " cingulis argute crenulatis ;" et alibi, " tutta la superficie e
segnata da cordoncini piatti elegantemente cancellati," &c. Non itaque uti BRONN
placuit de alia specie sentiebat.
Nuperrime cum optimo amico L. BELLARDI hanc speciem enumeravimus, in
memoria quam Regise Academise Scientiarum Taurinensibus voluminibus com-
prehensa est.
Spec. N. 9. SOLARIUM LYELLII, mihi. Fig. 28, 29, 30. Tab. II.
Testa conica suturis granulosis, interstitiis sulcis longitudinalibus, obliquis prse-
ditis ; peripheria angulato-crenata ; facie inferna subconvexa, sulcis transver-
sis, striisque longitudinalibus ; umbilico mediocri, crenato ; crenis dilatatis,
canali elato ; apertura subrotundata.
Habitat
Fossile in collibus Dertonensibus, raro.
Mira sane species, possidens quatuor vel quinque anfractus, qui superias circa
suturas granules! sunt ; cseteroquin variis sulcis longitudinalibus, confertis, de-
flexis instruct! sunt ; peripheria angulata, sulcis quoque transversis distincta :
basis convexiuscula, umbilicum gerit mediocrem, ex quo crenulationum indicia
ad peripheriam se protrahunt, et sulcos transversales secant ; apertura ferme ro-
tundata, depressa est.
Ex hisce liquet, in vim prsecipue peripheriae Solarium variegatum et Solarium
luteum differre ab hac specie ; in vim sulcorum et apertura differre a Solario Icevi-
gato, uti cseterorum adjuncta huic separation! comparate ad alias species favet.
Hanc speciem claris. CAR. LYELL dicavi, cui aliquid ob benemerita ejusdem
studia circa fossilia Italiae pro viribus meis tribuendum esse duxi.
218 CHEVALIER MICHELOTTI DE SOLARIIS.
Spec. N. 10. SOLARIUM HUMILE, mihi. Fig. 22, 23, 24. Tab. II.
Testa superne subconica, inferne valde convexa : anfractibus superne costalis fre-
quentibus, transversis, granulosis, sequalibus, suturis indistinctis ; periphe-
ria acutissima, inferne late canaliculata ; umbilico mediocri, canali elevato :
apertura trigona.
Habitat
Fossile in colle Taurinensi.
Hsec species possidet quatuor anfractus, qui superius planulati sunt, atque
ita conjunct! ut vix ac ne vix quidem suturse indicium habeas : in omni superficie
adsunt tot costulse transversim eleganter granulosse, atque inter se sequales.
Ultimi itidemque valde convex! anfracti peripheria est acutissima, sulco inferne
late patente circumdata : ex hoc sulco usque ad umbilicum adsunt minuti sulci
transversi ; umbilicus mediocris est, creni crassiores, et apertura subtrigona.
Nuper recensitse species probant duas tantummodo species cum viventibus
convenire ; sed altius res repetenda est ; omnes enim quum pertineant ad mio-
cenica vel pliocenica strata, patet tres species unice pertinere ad antiquiora strata,
scilicet, Sol. umbrosum, SoL Lyellii, Sol. humile ; quatuor species communem habere
sedem, scilicet, Sol. neglectum, Sol. millegranum, Sol. stramineum, Sol. pseudo-
perspectivum. Illud insuper adjiciendum, unicam speciem quse reperitur in stra-
tis pliocenicis convenire cum viventibus, scilicet Solarium luteum ; qui, licet nee
adhuc repertum sit in stratis supracretaceis superioribus, tamen extitisse constat,
quum et antiquitus viguerit, et hodie vivat.
Quum melioris notse scriptores judicent ferme omnes hujus generis species
in [ndico mare degere, uti major testaceorum pars ad Gasteropoda pertinens,
concludendum itaque est principium illud, quod clarissimi geologise cultores*
posuerunt, in miocenica setate feliciorem aerem in hisce Italise regionibus vi-
guisse, sensimque earn mutationem prout ea hodie est secutam fuisse, jure meri-
toque defendi posse.
* LYELL'S Principles of Geology, vol. iv. WEBSTER, Geolog. Trans. SEDGWICK et MURCHISON,
Proceedings Geol. Society of London, 4. ed. 1829. DESHAYES, Coquill. Foss. vol. ii. pag. 772. et seq.
DE LA BECHE, Geol. Manual. PHILIPPS, Guide to Geology. LEA, Contribut. to Geology, pag. 14.
MANTKLL, Wonders of Geology, vol. i. pag. 83.
S E 1 S M O M K T E R
K, L
I
Fin. 4.
PLATE m.Rmjal X >c . hviif. [•:,.!, .
fu. 2.
I . . I
fn I'liui /.'/*• i v////>//
,\\;ilt- ti> /-.ft/'/t'i/i'ii ll'iU' <>l' /'cr/rif nifi-i'-
( 219 )
XIIT. — On the Theory and Construction of a Seismometer, or Instrument for Measur-
ing Earthquake Shocks, and other Concussions. By JAMES D. FOHBES, Esq. F.R.S.
Sec. R. S. Ed., Professor of Natural Philosophy in the University of Edinburgh.
(Read 19th April 1841.)
HAVING been requested to act on a Committee of the British Association,
appointed to devise and apply methods for measuring the comparative intensity
of earthquake shocks, and having been shewn several ingenious contrivances by
Mr DAVID MILNE (who suggested the inquiry) Lord GREENOCK, and other per-
sons, an apparatus occurred to me which should unite the requisites of Simpli-
city, Compactness, Comparability, and an easy adjustment of Sensibility accord-
ing to circumstances.
Mr MILNE had not failed to distinguish the ends for which instruments (which
for obvious reasons were to be self-registering) ought to be devised, such as the
measurement of horizontal concussions, of vertical elevation, and of heaving or
angular motion of the surface. It is no part of my present object to consider the
probable movements of the soil in earthquakes. I limit myself to the description
of a single instrument intended to measure lateral shocks, such as are expe-
rienced by objects placed upon a table which is abruptly shoved forwards.
A heavy pendulum suspended from a frame in such a manner that the iner-
tia of the bob should cause it to oscillate when its centre of suspension had been
displaced by the movement of the frame with which it was connected, had already
been suggested for the purpose. To obtain sufficient sensibility, a pendulum of
great length would be required, nor could the sensibility be altered according to
circumstances, being wholly independent of the weight of the bob. The unwieldi-
ness of a pendulum ten or twenty feet long alone forms a strong objection to this
apparatus.
The elegant inverted Pendulum or Noddy contrived by the late Mr HARDY,*
suggested to me a different arrangement. The instrument is seen in Elevation,
Section, and Plan, in Plate III. Figures 1, 2, and 3. A vertical metal-rod A B,
having a ball of lead C moveable upon it, is supported upon a cylindrical steel- wire
D, which is capable of being made more or less stiff by pinching it at a shorter or
* Described by Captain Kater, Phil. Trans. 1818.
VOL. XV. PART I. 3 N
220 PROFESSOR FORBES ON A SEISMOMETER FOR MEASURING
greater length by means of the screw E. It is evident that, by adjusting the stiff-
ness of the wire, or the height of the ball C, we may alter to any extent the relation
of the forces of Elasticity and of Gravity, and consequently render the equilibrium
of the machine in a vertical position stable, indifferent, or unstable. Since, then,
a lateral movement, which carries forward the base of the machine, can only
act upon the matter in C through the medium of the elasticity of the wire, the
stiffness being diminished, or the weight increased, the tendency of the rod to
right itself may be diminished in any proportion, and that irrespectively of the
dimensions of the instrument.
The wire D being cylindrical, the direction of the displacement occasioning the
shock will at once be indicated by the plane of vibration of the pendulum, which,
being once put in motion, will oscillate backwards and forwards many times before
coming to rest. The pendulum is adjusted to the vertical position by four anta-
gonist screws e e e e, acting on a ball and socket arrangement/!
The self-registering part of the apparatus, which Mr DAVID MILNE has termed
a Seismometer, was arranged by that gentleman and by Mr JAMES MILNE, the
ingenious artist who constructed it. It consists of a spherical segment H I K of
copper lined with paper, against which a pencil L, inserted in the top of the pen-
dulum-rod, is gently pressed by a spiral spring. The marks thus traced on the
concave surface indicate at once the direction and maximum extent of the pen-
dulum's vibration. The arrangement of the pencil is seen upon a larger scale in
Fig. 4, where L is the pencil as before loosely fitting the cylinder b c, and pressed
upwards by the spring a. The whole pencil-case moves stiffly on the extremity
B of the pendulum-rod, so as to adjust the pressure against the paper.
HA.RDY'S instrument was intended simply for ascertaining the stability of the
support for a clock. The spring was a piece of flat watch-spring — the plane of
its motion was parallel to that of the pendulum of the clock whose influence was
suspected, and the time of oscillation being adjusted accurately to seconds by
screwing the bob up or down, the repetition of impulses always isochronal,
though individually feeble, at length urged it into considerable arcs of vibration,
if the beam or wall on which it stood was not perfectly stable. The instrument
under consideration, on the other hand, has a free vibration in every vertical
plane, the time of its oscillation is immaterial, except in so far as the sensibility
is increased as the time is greater ; HARDY'S instrument collects the effect of a
series of isochronous impulses, this one registers the maximum effect of a single
and insulated one in direction and in intensity: HARDY'S was an indicator of in-
stability, this (as we shall see) furnishes a measure of the cause of a concussion.
The admirable advantage which the balance of the gravitating and elastic
forces affords will appear from the following considerations : —
I. We must first attend to the friction which must be overcome in order to
carry the pencil across the surface receiving the trace. The moving force of the
EARTHQUAKE SHOCKS AND OTHER CONCUSSIONS. 221
pendulum will be greater as its inertia increases, in consequence of which the bob
lags behind the movement of the frame to which it is attached by the elastic
wire, which frame carries along with it the concave surface over which the pencil
will therefore be dragged. To overcome the friction of the pencil, we must there-
fore increase the mass of the pendulum.
II. The mass of the pendulum cannot be changed without modifying the sen-
sibility of the apparatus ; that is, the maximum vibration which a given shock
will produce. But the desired sensibility is easily maintained by the pinching
screw E, which must be employed to shorten the free part of the elastic wire (or
a thicker Avire may be introduced), until the sensibility is exactly as great as
may be required.
III. Hence one and the same instrument may have any required sensibility
given to it, and that wholly irrespective of its dimensions. The sensibility depends
upon the force tending to restore the pendulum to its position of rest when the dis-
placement = 1. The time of vibration depends on this quantity. Hence the time
of vibration is the test of sensibility. As the condition of equilibrium approaches
to indifference, the sensibility increases without limit.
IV. However weak the spring may be, and however great the sensibility, it
is plain that, on the present construction (for others might easily be suggested
which should give a different result), the displacement of the bob and pencil can-
not by possibility exceed the forward motion which the earthquake is understood
to communicate to the stand (which may be screwed to a floor). The inertia of
the pendulum cannot do more than leave the extremity B as much behind A as
the earthquake has shifted A forwards. If this effect be worth measuring at all,
the lateral vibration of the ground must be a sensible quantity, and there is no
difficulty in constructing an instrument on any scale, from an inch to 10 feet in
length, in which (the time of oscillation being the same, — say one second) the maxi-
mum vibration shall have the same linear magnitude. The only consideration
is, that the range may be sufficiently great to exhibit the stronger shocks without
giving an inconvenient curvature to the apparatus ; and for that purpose I have
thought that a radius of 20 inches and a diameter of 10 inches for the spherical
segment is sufficient.
V. If it be desired to magnify the scale of displacements, this may still be
done without any increase of dimensions. Let the bob C (Plate III. Fig. 1,) be
lowered upon the rod A B, so as to stand at only one-half or one-third of its
height : — let the mass be increased so as to overcome the friction of the pencil as
efficaciously at this diminished leverage ; and let the spring be adjusted so as to
give the same sensibility as before ; the displacement of the bob will be the same
as at first, but the displacement of the pencil will be magnified two or three times,
according to their relative radii.
In practice, the pencil will not describe precisely lines upon the sphere,
222 PROFESSOR FORBES ON A SEISMOMETER FOR MEASURING
but very elongated ellipses. Hence it will be easy to distinguish the mark made
by the first oscillation of the pendulum, which will always be contrary to the
direction in which the vibration of the ground takes place.
There is one peculiarity arising from the construction of the instrument,
which, at first sight, perhaps, we should scarcely expect. The maximum dis-
placement we have seen to depend solely upon the time of one vibration, and it
may be the same (for small shocks) on whatever scale the instrument is con-
structed. We might expect, however, that the taller instruments would oscillate
longest, and be most easily set in motion ; but the contrary is the fact. This
arises from the circumstance, that the stiffness of the spring must increase with
great rapidity as the length of the pendulum becomes greater, — that, consequently,
the elastic wire bends in all its length, unlike the feeble flat spring of HARDY'S
instrument, which doubles over almost at a point. The elastic wire, therefore,
tends to vibrate back and forwards many times before the inertia of its load has
suffered a complete vibration to take place, and even the flexure of the pendulum-
rod, by the powerful elastic action of the wire, will cause it to perform subordi-
nate oscillations, which have a tendency to destroy one another, and to bring the
whole to rest. This is a decided advantage when the object is (as in the present
case) merely to register the first or maximum displacement, and I find that, with
the size of the instrument which I have recommended (a 20-inch pendulum), the
effect is sufficient and well marked.
In proceeding to investigate mathematically the action of such an instrument,
and to shew how it may be most advantageously adjusted to inform us of the
intensity of earthquake shocks, I must repeat, that I proceed upon the very limit-
ed hypothesis that the kind of shock desired to be measured consists in a lateral
heaving of the earth's surface through a certain space with a uniform velocity,
commencing and terminating abruptly. Except under such limitations, it is im-
possible to obtain rigorous conclusions. Experience alone can shew how far such
conditions correspond with fact ; but, unless theory indicate arrangements for
testing their admissibility, our knowledge is likely to remain as indefinite as it is
at present.
I. The pendulum (Plate III. Fig. 1.) being displaced, to find the force tending
to redress it.
Let F = the force in grains, which, when applied to the rod AB at distance
= 1 from the centre of motion (a point in the spring D), will balance the force
of the spring when the lateral displacement is also = 1.
k = radius of gyration of the pendulum, which will be nearly equal to the
distance of the centre of the ball C from the middle of the wire D.
M = weight of pendulum in grains.
6 = angular displacement.
EARTHQUAKE SHOCKS AND OTHER CONCUSSIONS. 223
F
The elastic force for unity of displacement at radius k is equal to ^ .
F
For an angular displacement 0 or distance k 6, it is T-#. This tends to redress C.
The effect of gravity in displacing C is
MA sin 0, '
or Mk6 nearly, when the displacement is not large.
Hence the pressure on C tending to stability is
The accelerating force on C is
g being the accelerating effect of the force of gravity. Hence equilibrium is
Stable
h
as=r=: =
unstaoie
I
When the pendulum-rod forms an angle & with the vertical, the displacement
s of the ball, which moves with a radius k, is k 6. Hence Q — s-, and the redressing
/C
force is (by Eq. (a) )
And if being the elastic action of the Avire on C for s = 1) as above ; Eq. (6).
VOL. xv. PART i. 3 o
224 PROFESSOR FORBES ON A SEISMOMETER FOR MEASURING
Therefore
(ds\ 2
Tt) = ~
When s = 0 and y = 0, -r- — — V (for the point A begins to move with a velo-
city V),
d~e ~ ~^
ds 1 . — 1 s
dt= .,. . ; and e= ——7- sm — =-, A/ 0 + c'.
When s = 0, t = 0 .-. d = 0,
V
s = 77/r «n («/#»*) (5).
V
The greatest value of s = ± ~T~T> ............ (&*)•
occurs when J $ .t= 90°, 270°, &c.
orwhen '=-''&c ......... (6>
In order that the movement should not be oscillatory, V 0 . t must be always
-^ 90° for all values of t ;— or V 0 ^ ^ •
When « is infinite ^ 0 ^ 0, which is impossible, if 0 be a redressing force at all.
III. To determine the motion of the pendulum after the motion of the base
suddenly stops.
Whilst x varies uniformly (with velocity = V)
"
Let x abruptly cease to increase when t = T (and then let s = S)
T) ...... (7).
By (1) the displacement S is then (y_VT) ....... (8),
y =. V T + S = V T - sin (V . T).
v
. . . (9);
EARTHQUAKE SHOCKS AND OTHER CONCUSSIONS. 225
C is proceeding in space with this velocity, and under the action of a force s,
always tending to the point A (now stationary).
In this second stage
T=- 4>s as before;
At the moment that s — S, -^ became = -^, because x ceasing to increase, y hence-
forth = s.
rf?
Hence, by (9) when s = S, - - = V {1 - cos + , or /=
-v/U'+^S2-^
'--L -•~~1. ^ -iv
When * = T , * = S
• (12).
-» -r v • T - • *r ~ j
i i
Let sin"
The greatest (±) value of s is when V 0 (* - T) + © = 90°, 270° &c. ; and it is then
+
It recurs regularly (±) as ,/ ^> • t increases by TT, or as
*7r
# hicreases by — r (15).
v/ , the point A must be moved forwards before
C has sensibly changed its position. This follows from Eq. (16) which is equiva-
lent to
,/2=2V2 vSV^V^T) ........ (2Q)
To find the value of s,* when =0 (compared to V).
Differentiating numerator and denominator,
2 V2 T sin (J(f) . T) . d . V (ft . _ V2Tsin
dfy~ J
which is still when =0.
EARTHQUAKE SHOCKS AND OTHER CONCUSSIONS. 227
Differentiating again, v' T> (coWjK T W ft =v»T«cos(J0.T) . .(21).
When =0, ai = v»T» orS,=VT (22)
or exactly the displacement of A.
[6.] Hence (where is small, and T not very great, so that cos (JQ - T) is
nearly 1), s, is greater as is less, and its greatest value is VT.
[7.] Since, by the action of a short sudden blow, s, can never be greater than
V T, there is no advantage obtained by using a tall instrument, since, evidently,
the smallest and largest alike can only exhibit a deviation due to the whole late-
ral displacement of the foot of the pendulum.
IV. To deduce the duration and measure of the lateral shock of an earth-
quake from observation.
For a given velocity V, and given stiffness of wire (V = const.), the final de-
viation will increase from T = 0 to T= ~ U>y (18)) .
Therefore, by having instruments for which „/ (f> varies, we may make sure
j, rm
that T < -7-r» and between these limits the displacement will measure the dura-
\V 0
tion of the shock for a given velocity V.
To eliminate the velocity ; Let different instruments be provided for which
V varies. This is inversely as the time of one vibration backwards or forwards,
determined by the difference of two values of t in (6), viz. JL.
Then the maximum vibration of each instrument (consistent with the limi-
tation of T) being observed, may be called s, and «,, the corresponding forces being
0 and '.
By (16)
0V = 2V2(l-cos(V0'.T) j
Dividing the second by the first,
.
versin (V 0 . T) . A tube of German glass, three inches long, weighing 90 grs. was charged
two-thirds full (8 grs.), and heated first one hour to about 800° Fahr. and then
another to the lowest visible glowing temperature. The object of this experiment
was to produce some silicon without acting on the apparatus. The contents hav-
ing been thrown into melted chlorate of potassa, the unchanged paracyanogen was
burned away, and silicon remained diffused through the chloride ; carbonate of
potassa was added in excess, and the whole once more ignited in the same pla-
tinum crucible ; the white saline product was decomposed by hydrochloric acid,
and the solution dried and ignited, all in the original crucible ; and there was
obtained 1.7 gr. of silicic acid. The weighed tube was cleaned, weighed again,
and found to have sustained no loss ; and there was no visible trace of action on
the glass. Similar results were obtained by several repetitions of this mode
of making the experiment of the reduction of paracyanogen. This observation
* Elements of Chemical Philosophy, pp. 478-489.
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 235
supplies the desideratum in the first three, and establishes the conclusion that
the silicon, which appears in these experiments, is produced from the para-
cyanogen itself, and is not extracted from any part of the apparatus in which it
is conducted through the steps of the operation ; and abundant additional evi-
dence of this will be adduced in the progress of the investigation.
The success of these last two experiments, however, does not provide us with
the means of determining with exactitude that the nitrogen of a given weight of
paracyanogen is wholly dispelled, and that the four equivalents of carbon are the
sole factors of the silicon which remains ; for they were made with crude paracy-
anogen, which, as has been already observed, always contains both cyanogen and
traces of silicon itself, previously produced by the transformation of carbon. Here
it is worthy of remark, as a criticism on the manner of analysis followed by Mr
JOHNSTONE in his examination of this substance, that a specimen might contain
both of these impurities in any proportion, and yet yield to the reaction of oxide
of copper, or chromate of potassa, carbonic acid and nitrogen mingled in the
ratio of 2 to 1 ; and this both explains and reconciles his results with the seem-
ingly incongruous observation of GAY-LUSSAC, that the cyanogen, driven by high
temperatures from the bicyanide of mercury, always contains traces of nitrogen,
and my own, that paracyanogen, prepared by fire, almost invariably contains
appreciable traces of free silicon.* It is equally deserving of observation, how-
ever, as a comment on the great process of the history of sciences, that, but for
the partial and consequently erroneous procedure of the distinguished analyst in
question, the isomerism of cyanogen and paracyanogen might not have been yet
discovered.
At first I thought that the difficulty resulting from the presence of silicon
and cyanogen in crude paracyanogen might be overcome by having recourse to
the purified substance ; but, in fact, paracyanogen which has been subjected to the
process of purification, by sulphuric acid and exposure of the solution to the damp of
the atmosphere, is no longer one of the most attenuated of solid forms, but a pretty
dense powder, intermediate in character between the crude and the ignited prin-
ciples, which cannot be reduced by any elevation of temperature, however pro-
tracted, short of that of ignition ; and the objection to such a temperature has
already been stated. An accident, the investigation of which forms the subject
of the next section, eventually led to a method which will be described in the
third part of the present inquiry.
Before leaving the production of silicon from uncombined paracyanogen,
there is another mode of operating to be mentioned, and it is equally remarkable
for simplicity and freedom from any intelligible source of fallacy. As the nu-
* Op. cit. sect. i. compared with the results given in this section of the present paper.
236 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
merical result is somewhat unsatisfactory on account of the circumstances which
have just been mentioned as affecting the condition of anhydrous paracyanogen,
it is here presented in the form of an experimental formula. Process — Triturate
crude paracyanogen with an excess of carbonate of potassa, and fuse the mixture
two hours at a full white heat in a closed platinum crucible. Paracyanogen dis-
appears ; there is no free carbon in the white saline product ; but it yields a con-
formable proportion of silicic acid, when treated in the ordinary method of analysis
for that compound. There must be a considerable excess of carbonate ; for, as
will be shewn immediately, platinum is apt to draw off some of the silicon in its
jn-ocessus e latenti, unless it be well protected. This process is more striking when
subborate of soda is substituted for potassa ; for when the product is treated with
acids there is no effervescence of carbonic acid ; and it must be remembered, once
for all, that in every professed process of transformation, the disappearance of
carbon is to be accounted for, as well as the new formation of silicon.
In conclusion, the average results of my observations on crude paracyanogen,
prepared in the apparatus described in the introduction, are, that it contains very
nearly a third of its own weight of condensed cyanogen, and that it yields, to the
three operations which have just been described, a weight of silicon never less
than an eleventh, and never more than a twelfth, under the calculable weight of
constituent carbon, the cyanogen of absorption being dissipated in the course of
the processes.
II. — On the formation of mixed Amorphous Compounds of Silicon with Copper, Iron,
and Platinum, by the reaction of Paracyanogen on these Metals.
1 . The double copper-tube, described in the fourth section of my paper on
Paracyanogen, having been packed with bicyanide of mercury, and accidentally
kept at a white heat for more than an hour, it was found on examination to con-
tain not a trace of paracyanogen. It was lined with a film, more than a line in
thickness, of a very friable, reddish, metallic substance, which separated from the
copper on concussion, and fell out in broken blistered scales. Pulverised, it lost
its metallic lustre, and assumed a dingy brown-black colour. Nitric acid dis-
solved copper and left a fine^black powder, like well triturated charcoal, which
was observed to be distinctly brown when viewed by light transmitted through
water holding it in suspension. The rigorous application of the reagents men-
tioned above (pp. 247-8) proved it to be silicon. The copper compound was
several times made intentionally, -and the result of three analyses was, that it
contained from 30 to 40 per cent, of silicon. This and the two substances which
follow are said to be mixed, because, in accordance with the principle of definite
proportions, which is now universally recognised as the law of chemical constitution,
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 237
they must be regarded as mixtures of two or more definite compounds. The for-
mation of these mixed metallic products explains the necessity of care in the per-
formance of the process for paracyanogen.
2. An analogous mixed compound of iron is procured by a similar procedure
with the iron high-pressure tube. It requires a higher temperature, and contains
a larger proportion of silicon.
3. A new platinum crucible was half filled with paracyanogen, and ignited
for three hours. On being opened, it was empty and clean, the metallic lustre
having been only slightly dimmed. This was repeated, till the metal would ab-
sorb no more of what was yielded to it by the paracyanogen. It was now grey
and brittle ; and, on analysis of 20 grs. of the broken crucible, was found to
have been composed of platinum and silicon, containing nearly 4 per cent, of the
latter. This analysis was effected by the reaction of nitro-hydrochloric acid ; and
the undissolved residue, a mixture of silicic acid and a black powder, having been
fused with carbonate of potassa, the silicic acid was separated by the ordinary
process, and the constituent silicon was inferred by calculation.
The singularly powerful attraction of platinum for silicon has been often ob-
served. DESCOTILS ignited it in contact with incandescent charcoal, and procured
a frangible substance, which he represented as an indefinite combination of plati-
num and carbon. M. BOUSSINGAULT examined the same product, and found it to
be a true siliciuret. BERZELIUS* accounts for its formation by supposing that
the metal decomposes the silicic acid which is known to exist in charcoal, and
appropriates the base, while, it is to be presumed, the oxygen disappears in the
form of carbonic acid. This rationale is certainly incongruous with the general
plan of chemical reaction as now understood, and appears to be a mere evasion
of an apparently insurmountable difficulty ; for silicic acid, whether nascent or
produced, may be ignited in platinum crucibles with true carbon, in any excess,
without being decomposed, the carbon being taken in, and the silicic acid left un-
touched. But for this the common analysis for silica would in many cases be
nugatory. It must be remembered that charred wood is not carbon, but contains
a large proportion of some exorganic compound of that element, especially if it
have been produced at low temperatures ; it forms artificial tannin with nitric
acid, another exorganic proximate which I have tried in vain to produce with true
carbon, however finely divided, such as is prepared by the decomposition of the
solid iodide of carbon. Grant that common charcoal contains a compound radi-
cal analogous in constitution to paracyanogen, and BOUSSINGAULT'S siliciuret of
platinum is explained ; it may have been produced by transformative decomposition.
This postulate is rendered probable by Mr JOHNSTONE'S observations on the coals,
* Traite de Chimie — BERZELIUS, par VALERIUS, 1838, p. 426.
VOL. XV. PART I. 38
238 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
and those charred products of the ferroprussiates which will be investigated in
another section ; and especially by BOUSSINGAULT'S own observation that the reac-
tion of carbon, yielding no silica on combustion, produced no siliciuret, for such
carbon must have been truly mineral, and not exorganic like charcoal.
III. On the quantity of Nitrogen separated from Paracyanogen tvken it is changed
by heat into Nitrogen and Silicon.
It has been already implied that the quantity of silicon obtained from paracy-
anogen corresponds with that of the carbon known to exist in this compound.
The accidental observations of the foregoing section suggested the following me-
thod of determining that during the transformative process the whole of the
nitrogen is given off as such.
1. Five grains of paracyanogen, prepared with extreme care, were mixed with
little shreds of fine platinum foil, weighing twice as much as would have sufficed to
absorb all the silicon which could be extracted from the paracyanogen employed.
The weighings and mixture having been made in a glass-tube, closed at one end,
the open extremity was drawn out just above the contents, and bent over. A
spirit-flame was applied to every part of the containing tube in succession, and
the separated gases collected over mercury. Without interval it was raised to a
full red heat by means of the spirit-blast lamp,* and this temperature was kept
up as long as any thing was given off. After the operation, the little retort was
found to contain nothing but the siliciuretted platinum described in II. 3. As
for the gaseous products, it may be observed that as much of the air of the appa-
ratus as possible was expelled before the application of the spirit-lamp and the
collection of the products ; and, being altogether certainly not more than 0.01 gr. as
well as partly balanced by the attenuated nitrogen which could not be driven out of
the tube at the close of the operation, it could not introduce any error worthy of ob-
servation in an analysis of this kind. The whole product was 8.9 cubic inches at 60C
Fahr. and 30° bar. Potassa removed C. I. 3.8 of cyanogen, or 2.1 grs., and shewed
that the original 5 grs. was equivalent to only 2.9 grs. of true paracyanogen.
There thus remained C. I. 5.1 or 1.56 gr. of nitrogen, produced from 2.9 grs. of pa-
racyanogen, the calculations from measures to weights being made on the data of
GAY-LUSSAC, and the due corrections according to rule.
2. Fifteen grains of the same parcel were ignited in a clean little platinum cru-
cible, from which the air was carefully excluded. The loss sustained was 10.59 grs.,
* The convenient little furnace, here referred to, is described and figured in Dr COKMACK'S Monthly
Journal of Medical Science for March 1841.
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 239
and, according to the foregoing experiment, 6.3 grs. of this were cyanogen, so that
4.29 grs. of nitrogen were driven away from 15- — 6.3=8.7 grs. of paracyanogen.
The inference from these experiments is, that two equivalents of nitrogen are
thrown off from paracyanogen when it is changed into silicon and nitrogen ; that,
in other words, silicon is isomeric with carbon. This is only indirect evidence
that the silicon is derived solely from the carbon of the paracyanogen ; but I can-
not devise another method of determining the point, and it appears to be suffi-
ciently decisive. It may be added that the solid products of these experiments
were examined, and found to consist solely of platinum and silicon, the weights
of the latter, calculated from the silicic acid produced by it, being conformable
to the combining proportions of paracyanogen and carbon.
In the repetition of these analyses, it must always be borne in mind that
different specimens of paracyanogen contain different proportions of condensed
cyanogen. One specimen yielded me more than 40 per cent. It depends partly
on the temperature at which it is formed, there being also less risk of appreciable
traces of silicon in the product the lower the temperature ; and partly on the
form of apparatus employed, or rather on the degree of pressure under which the
bicyanide is decomposed. Let a specimen be tested before it be analyzed : If
it be wholly soluble in concentrated sulphuric acid, it is fit for analysis, and the
quantity of cyanogen it contains will be discovered in the course of the operation.
IV. On the production of the Siliciuretfrom the Paracyanide of Iron.
The fourth part of the inquiry was devoted to the production of siliciuret of
iron from the paracyanide of the same metal ; and particular attention is solicited
to it, because the experiments are simple in design, infallible, and easy of execu-
tion on large quantities of material, while some of the products are as beautiful
as they are striking. The results, which have been obtained in the course of a
lengthened investigation, are embodied in the following formulae for the prepara-
tion of the siliciuret from the paracyanide, a method which is resorted to for the
sake of brevity
It is necessary to premise, that the paracyanide of iron used in my experi-
ments was obtained from the ferrocyanide of potassium by the action of sulphur, in
the following manner : — An equivalent proportion of well-dried ferrocyanide of po-
tassium, intimately mixed in powder with three equivalents of sublimed sulphur,
was heated six hours to the lowest glowing temperature of iron in the dark, in a
strong sealed tube, from which the access of air was prevented by drawing the open
end into a capillary. The product, having been quickly reduced to a fine powder
while yet warm and in a dry atmosphere, was introduced into a percolating tube
three feet in length, half an inch in diameter, and tapering at the dropping ex-
tremity to the width of a line. Linen having been bound over the dropping hole,
240 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
a column of alcohol was poured upon it ; and after it had passed through, in the
course of eight hours the same quantity of pure water was sent through, and was
followed in its turn by alcohol. The magma was shaken up a little way in the
tube, and the aperture sealed ; and the open extremity, hitherto corked, was then
drawn out to a capillary bore. The adhering spirit was distilled away towards
the capillary, and the product obtained dry in the form of a light mouse-brown
powder. A careful analysis, and the observation of its chemical properties, appear
to warrant the conclusion that this body is composed of paracyanogen and iron,
and that it is the true compound radical of the ferrocyanides ; but it would only
interrupt the continuity of the present investigation to discuss this subject in the
present place, and it must consequently be reserved for a separate memoir. It is
sufficient to mention at present, that the substance in question contains nitrogen,
carbon, and iron, in the ratios of 1, 2, and 1, and that it is called the paracyanide
of iron in this section and the next. It needs scarcely be added, that, whether or
not it be the radical of the ferrocyanide of potassium, that salt certainly contains
its coefficients, and may accordingly be substituted for it in transformative experi-
ments, the supernumerary cyanide of potassium being calculated for as an inci-
dental and inactive ingredient. The compound, which has given rise to these re-
marks may be readily procured in larger quantities, by putting the mixture of sul-
phur and ferrocyanide of potassium into one of the porous clay-bulbs of LESLIE'S
hygrometer, luting up the little stem, and heating it a few hours to the lowest
visible heat of iron in the dark, immersed in a sand-bath or, better still, in stucco
powder. Sulphocyanide and cyanide of potassium are, as it were, filtered through
the sphere, and the paracyanide of iron is left within in such a state of aggrega-
tion, that it may be washed in water with impunity if it be not exposed to the
air. The processes of the section may now be introduced.
1. Take the paracyanide of iron, and having introduced it into a crucible of
Berlin porcelain, lute on the lid with a strong fire-clay. Put it within two Hes-
sian crucibles, filling the empty space with stucco powder, and placing some
heavy body above the enclosed crucible. Apply the fiercest heat of a powerful
wind-furnace for two hours.
There are two products in this experiment. The crucible is lined with a crust
of an intensely hard, greenish- black substance, resembling obsidian, and contains
a coaly powder, aggregated into little masses. These are of the same chemical
composition, the latter being unfused and amorphous, the former fused and semi-
crystalline ; but the description of the semicrystalline product is reserved till the
next paragraph. The amorphous substance, treated according to rule, yields
silicic acid and peroxide of iron. This and all the following experiments may be
performed, either in porcelain crucibles, or vessels of hammered iron. With the
latter there can scarcely be any fallacy ; and, if there be, it is entirely removed
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 241
by fusing carbonate of potassa in them, and discovering not a trace of silicic
acid in the salt ; and, even with the former, it is easy to remove the possibility
of error by producing, in successive operations, more siliciuret in each than its
own weight.
It is evident that the ferrocyanide may be substituted for the paracyanide in
this formula, the cyanide being sublimed away by the heat of the furnace. In
one crucible of the capacity of an ounce, and weighing 500 grs., one operation
produced 165 grs. of the semicrystalline siliciuret of iron, and the third repetition
raised the weight above that of the crucible itself. By working a strong iron
tube, like that Avhich is figured in the introduction, several times, and then re-
moving the iron, partly by oxidation and partly by solution in acid, there was ob-
tained 234 grs.
The analytical method by which this product was examined, consisted in re-
ducing it to a state of fine division in a steel mortello, rubbing it up with a large ex-
cess of pure carbonate of potassa, and fusing the mixture in a platinum crucible ; the
silicate of potassa, having been dissolved away and filtered, was then decomposed
by an excess of hydrochloric acid, and the silicic acid was separated by desicca-
tion, ignition, and elutriation ; and the constituent silicon was calculated for.
The very same operation, performed in an iron crucible, separated the iron in a
peculiar condition which will be explained at the end of the next section. The
average result of the application of this double process to the following products
was, that they are all of the same composition, and contain 28.5 per cent, of silicon,
the remaining weight being iron ; and the inference is that they are disiliciurets,
as might have been divined from the composition of the paracyanide and the
conclusion regarding the relation of silicon to paracyanogen, which has been al-
ready stated.
2. The best way to procure the semicrystalline product of the foregoing pro-
cess is this : Mix ferrocyanide of potassium with its own bulk of cyanide of potas-
sium, and treat it exactly in the same manner, only for thrice as long a time ; the
supernumerary cyanide acts as a non-reactive flux, and is ultimately driven off
by the fire. In this case there is no amorphous siliciuret, but the crucible, or iron
tube, is lined with a fine smooth cake of the semicrystalline substance, to the
depth of a line and a quarter for every operation, and it may be repeated till the
vessel be nearly full. It adheres to the porcelain ; but, if the crucible be broken
into fragments, it may be picked off with a knife. It is stratified, and readily
separates into layers. Jetty as it is in mass, when pulverized it is a light-coloured
powder, of a greenish-grey hue, being the whiter the more finely it is triturated ;
but, whenever it is immersed in water, or moistened by any other liquid, it re-
sumes the dark appearance of the mass. When broken down and examined by
the microscope, it is seen to be perfectly transparent ; and in fine powder, the
VOL. XV. PART I. 3 T
242 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
little fragments are colourless like glass. In fine, it is possessed of the crystalline
structure without the crystalline form. Its specific gravity is 2.11.
3. Introduce an ounce of anhydrous ferrocyanide of potassium, mixed with
twice as much cyanide of potassium,* into a Berlin crucible of the capacity of five
ounces, and lute the lid tightly on, without leaving any aperture for the escape of
volatile products. Put the whole into a large earthen crucible, half full of gyp-
sum paste, and then filled with the same, so as to include the smaller crucible in
a mass of stucco. After setting, and desiccation at 400°, let it be heated to the
highest red in a wind-furnace for eight hours.
The design of this process is twofold ; to hinder, by pressure, the quick de-
composition of the constituent paracyanogen, and prevent the sublimation of the
ingredient and superadded cyanide; and, by this double artifice, to produce the slow
transformative decomposition of the former floating free in the liquefied excess of
the latter, in the expectation that, in accordance with the indications of a great
many proximate trials, the siliciuret should be evolved crystalline in both struc-
ture and form. The product is interesting : water dissolves out the cyanide, and
there remains neither paracyanide nor carburet, but a large-grained sediment of
transparent, nearly colourless, and very hard little crystals of siliciuret of iron.
They resemble white sand, or cut-glass ; and can be pulverized only in a steel
mortello. Reduced to an impalpable powder, and ignited in the air, they oxidate,
and are changed into a red calx, from which hydrochloric acid extracts peroxide
of iron and separates silicic acid. Chlorate of potassa may be deoxidated on them,
in any excess, without producing the slightest effect. They decompose melted
carbonate of potassa with eifervescence, silicated alkali and iron, in the peculiar
condition already noticed, being the products of the reaction. When prepared
during a longer time, and at a lower temperature, than has been directed above,
they are opaque, like white enamel ; heated to a red heat out of the air, they
become clear and colourless ; and, when subjected to the power of a full white
heat in shut iron tubes, they assume a green tinge, and resemble the chrysolite.
Their specific gravity is 2.53. This number was found by introducing 10 grs. of
the sand into a common density-bottle, which was then weighed after it had been
filled up with distilled water: The latter weight, subtracted from the known
weight of the bottle when filled with water alone increased by 10 grs., gave the
weight of a volume of water equal to the bulk of 10 grs. of the substance under
examination. They are infusible by the common blast-furnace of the smithy and
the ordinary blowpipe, so that the sand cannot be run into large masses ; but,
* The cyanide of potassium employed in the performance of these experiments was partly prepared
from the ferrocyanide of potassium by heat, and partly procured from a London manufactory ; but in both
cases it was ascertained to be completely free of silicic acid.
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 243
when the operation is conducted on a large scale, there often occur imperfect
crystals of considerable dimensions, varying from a fourth to half an inch.
Sometimes they are found in the form of irregular globular bodies, pitted on
the surface, and cellular within; and, indeed, the particles of the sediment
under examination generally present a somewhat rounded appearance at the
edges, although they affect the octohedral shape, and are many of them seen
to be very perfect octahedres when viewed on the field of the microscope. In one
operation I procured half an ounce of these little eight-sided crystals, and have
worked with glass, porcelain, black lead, iron, and platinum vessels, with equal suc-
cess. This is a difficult process, however, and one must be content to make seve-
ral trials before a fine product be obtained ; but, although it is not easy to produce
a perfect specimen, it is the simplest thing in the world to satisfy one's self of the
change which is effected. Nay, it is impossible to make cyanide of potassium by
the common process without performing this transformation ; for, if the charred
product be washed, and inspected with a good microscope, the crystals are seen
bright and clear among the paracyanide ; and the latter may be burned and dis-
solved away, so as to leave the siliciuret by itself. The more care bestowed on the
operation, the greater the proportion of crystallized product ; and the quantity is
only increased by previously adding cyanide, and observing the precautions of the
formula which has been given. I have examined many such products, prepared by
others in ordinary routine as well as by myself, and have never failed to confirm
this observation, till I have at length come to the conclusion, that the production
of silicon from paracyanogen has been performed by every one who has decom-
posed the ferrocyanide of potassium by heat, in order to procure the cyanide of
the same metal. This explains the fact, that Berzelius found the charred product
under consideration to yield its own weight of peroxide of iron on simple combustion,
and inferred that it was therefore a bicarburet of that metal : It may have been
paracyanide mixed with some unobserved and unburned siliciuret. Analogous
compounds of copper, bismuth, and some other metals, have been formed in a
similar way, but it is unnecessary to describe them at present.*
* These products were described in a paper read before the British Association in 1839, and pub-
lished, in abstract, in vol. ix. of its Transactions. They were described as crystallized carburets ; but I
distinctly stated that I had not analyzed them, and grounded my conclusion regarding their composition
solely on synthetic evidence ; and so far I was really in the right, for, although they are siliciurets, their
ingredients are carbon and iron. I then believed them to be true carburets, having been misled by the
observation, that a mixture of the crystalline and the uncrystalline products gave carbonic acid with oxide
of copper, the uncrystallized product being now known to be mere unreduced paracyanide of iron. As my
inaugural dissertation was never published (except an unimportant subsection of it), I gratefully acknow-
ledge the honour conferred on it by the Medical Faculty of the University of Edinburgh, by taking this
opportunity of stating that the investigation of this process was the main subject of one of the four Prize
Theses for 1839.
244 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
In conclusion, it is worthy of remark, that the preparation of these crystals
illustrates the formation of the diamond by natural operations, inasmuch as there
is quite as great, and the very same, difference between the amorphous and the
crystallized siliciurets, as there exists between the carbon of the laboratory and
the gems of Golconda. In further exemplification of the principle, it may be
added that I have obtained crystallized granules, which appear to be pure silicon,
by submitting a mixture of paracyanogen, and a large excess of cyanide of potas-
sium, to the operation which has been described in this paragraph ; but their pu-
rity has not yet been certified by a synthetic experiment.
V. On the preparation of Silicic Acid by the reaction of Carbonate of Potassa on the
Paracyanide of Iron, free and combined.
The facts contained in the preceding section, taken in connection with the
process for preparing silicic acid which is mentioned at the conclusion of the first,
naturally led to the experiments which form the subject of this, the last part of
the inquiry.
1. A quantity of paracyanide of iron was mixed with four times its weight of
carbonate of potassa, and the mixture ignited in a shut crucible, made of ham-
mered iron, during the space of four hours, and at a full white heat. On being
opened, the saline product presented a fine rose-red colour, which disappeared on
the affusion of water ; by the action of which the whole mass was resolved into a
transparent solution, and a loose, partially aggregated substance, resembling spongy
platinum in external appearance, which will be alluded to presently. Suffice it here,
that the latter is a pure metallic oxide. In repeating this experiment, it was occa-
sionally found that the solution of the saline product was tinged blue, that colour
being changed into a fine rose tint by evaporation to dryness, and restored by the
action of water. But, if the operation be not prolonged beyond four hours or there-
abouts, for 3000 grains, it is wholly or nearly colourless. Hydrochloric acid dis-
pelled carbonic acid, and threw down hydrated silicic acid from the solution under
examination ; and, after desiccation, followed by ignition and elutriation, the latter
was obtained anhydrous and insoluble. 3.04 grs. of silicic acid were extracted from
5 grs. of paracyanide of iron. In performing this process, and especially with a
view to numerical results, it is almost always necessary to purify the silicic acid.
The mode of purification which I adopted simply consisted of a repetition of the pro-
cess of separation : The product of silicic acid was ignited in three times its weight
of carbonate of potassa ; the silicate of potassa was dissolved out by water, and the
potassa was more than neutralized by hydrochloric acid ; the acid solution having
been evaporated to dryness, the solid residue was ignited in a clean iron cru-
DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 245
eible ; the chloride of potassium was removed by water, and the silicic acid left
anhydrous, undissolved, insoluble in boiling acids, decomposing fused carbonate of
potassa with effervescence, and forming by the last reaction either a deliquescent
salt or a dry glass, according as the proportion of potassa is greater or less. I
have sometimes found it necessary to repeat this twice, especially when working
with the ferrocyanide of potassium on the large scale.
2. The same process was performed on the common ferrocyanide of potassium,
and with the very same result. 5.4 grs. of silicic acid were procured from 30 grs.
of the ferrocyanide of potassium.
3. An iron crucible, in which the foregoing experiment had been made on a
large scale, was, in the interval between two operations with the ferrocyanide of
potassium, filled with carbonate of potassa, and heated to a full white heat for five
hours. The salt was then tested in vain for the presence of silicic acid. This ap-
pears to be a crucial experiment ; for, if it were possible that hammered iron
should contain silicon or silicic acid, and yield them up to the action of carbonate
of potassa with paracyanide of iron, in sufficient quantities to account for these
results, it should certainly, a fortiori, produce the same effects with potassa alone.
Besides, the same iron crucible was, in one instance, employed seven times succes-
sively, and no difference was observed in the several products.
4. The same process was tried twice in a platinum crucible, with complete
success.
5. The same experiment was performed on the ferrocyanide of potassium,
with the borate of soda instead of the carbonate of potassa. The product Avas
quite analogous to that which has just been described, with the important differ-
ence, that hydrochloric acid produced no effervescence of carbonic acid, a circum-
stance which illustrates the fact, that the carbon of the materials is not changed
into carbonic acid, even if such a supposition were allowable. In fine, as has been
once observed already, the disappearance of the carbon of the substances subject
to these operations, has to be considered and explained, as well as the prodiiction
of silica from them.
6. During the last week, a crucible of the capacity of a pound and a half has
been worked seven times with 3334 grs., 2000 grs., and other similar quantities of
the ferrocyanide of potassium in succession. The products were all preserved ;
and, after ignition and purification, there were obtained 9334 grs. of silicic from
3240 grs. of ferrocyanide, although some of the product was lost in two of the
operations. The only purpose to be served by the notice of a rude experiment
VOL xv. PART i. 3 u
246 DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN.
like this, is to indicate the scale of operation on which the process has been tried,
and found sufficient.
It must now be added in conclusion, that in experiments described in this
section as well as some of those previously mentioned, the carbon of the ferrocy-
anide of potassium is not the only element which seems to undergo transformation.
The loose partially aggregated substance like spongy platinum, which is left un-
dissolved during the action of water on the red matter in the crucible, does not
present the characters of iron or any of its oxides, but possesses, so far as I have
yet examined it, all the characteristic properties of the inferior oxide of rhodium.
In particular, the metal which may be extracted from it has the colour and infu-
sibility of rhodium ; it does not undergo any change whatever on being acted
upon by the concentrated or diluted acids either with or without the aid of heat ;
it is not corroded even by nascent chlorine ; but it becomes oxidated when heated
in contact with the air ; and, when it is projected in powder into melted bisul-
phate of potassa, sulphurous acid is given off, and there is produced a yellow
salt, wholly soluble in water. This subject I have investigated in its details, and
intend to make them public ere long. At present it appears to be necessary to
mention the facts in a general way, lest the occurrence of them should embarrass
any one who may be induced to revise the researches which form the main object
of this memoir.
Such are the experiments which have been made on this case of elemental
transformation. It must be confessed that the results which have been obtained
are of a kind, not only so unexpected, but so directly contrary to the doctrine of
chemical affinity, which has been entertained ever since the conception of the
force productive of combination was first expressed by that term, as to warrant
the scepticism of men of science. In truth, although I have performed the act of
transformation more than a hundred times, it has always been with fear that the
products of the several processes have been examined ; but nature has, in every
instance, either disappointed my apprehensions, or rendered apparent failures
both intelligible in themselves, and confirmatory of the general initiative of the
inquiry. Accordingly, it is with some confidence that I solicit the repetition of
these experiments, although I will await the issue of this appeal to the incorrupti-
ble judgment of experience with anxiety proportioned to the earnestness with
which I have pursued the investigation.
HADDINGTON, 20th May 1841.
( 247 )
i
XV. — On the Anatomy of Amphioxus lanceolatus ; Lancelot, YARRELL. By JOHN
GOODSIR, M. W.S., Conservator of the Museums of the Royal College of Surgeons
in Edinburgh.
(Read 3d May 1841.)
THE genus Amphioxus was instituted by Mr YARRELL for the reception of a
singular little animal which he received from Mr COUCH. The characters of this
genus, as given in the History of British Fishes,* are, " Body compressed, the
surface without scales, both ends pointed ; a single dorsal fin extending the whole
length of the back ; no pectoral, ventral, anal, or caudal fins ; mouth on the under
part of the head, narrow, elongated, each lateral margin furnished with a row of
slender filaments."
My attention was particularly directed to Mr YARRELL'S description of the
Lancelet, by an announcement by my friend Mr FORBES, at the Newcastle Meet-
ing of the British Association, of the capture of two specimens on the Manx coast.
• With his characteristic liberality, that gentleman has put these two specimens into
my hands, with a request that I would employ them for the purpose of drawing
up a detailed account of the animal.
Unwilling to mutilate both, I have confined my dissections to one of the in-
dividuals, and have been fortunate enough to detect its leading anatomical pecu-
liarities, to verify most of the observations of the anatomists who have preceded
me in the investigation, and to correct what appeared to me to have been errors
in their observations. To complete the history of the Lancelet, however, an ex-
amination of it when alive in sea- water must be undertaken. In this way only,
can certain points in its structure and actions be explained, and light be thrown
on the economy of one of the most anomalous of the vertebrated animals.
The first notice which we have of the Lancelet is in the Spicilegia Zoologica
of PALLAS,| wno received his specimens from the coast of Cornwall. Although
he observed its ichthyic characters, he allowed himself to be misled by its other
peculiarities, and particularly by the membranous folds of the abdomen. He de-
scribed it well, but placed it in the genus Limax, under the designation Limax
lanceolatus.
Professor JAMESON has directed my attention to the first volume of STEWART'S
Elements of Natural History,}: in which the Lancelet is described as a, Limax with
* YAURELL'S History of British Fishes, vol. ii. page 468. f PALLAS, Spic. Zool. x. p. 19. t. i. fig. 11.
t STEWART'S Elements of Natural History, 2d ed. vol. i. p. 386.
VOL. XV. PART I. 3 X
248 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
the specific designation lanceolaris. Mr STEWART'S description is evidently an
abstract from that of PALLAS, to whom he refers. He had, however, a right ap-
preciation of the essential characters, as he states that the animal is " hardly a
Limax."
It is to Mr YARRELL, however, in his most valuable work on British Fishes,
that we are indebted for the first detailed account of this animal. He recognised,
in his solitary specimen, the Limax lanceolatus of PALLAS. In his description,
which is in other respects most correct, he has omitted the lateral membranous
folds of the abdomen, so well observed and embodied in the description of PALLAS.
Mr YARRELL observed the vertebral column, the ichthyic lateral muscles, dorsal
fin, intestines, and ovaries, and transferred the animal, therefore, to the Verte-
brata. He placed it in the family Petromyzida?, near the cyclostomous fishes, as
he considered the fringed mouth, the armed lingual bone, the absence of eyes, and
the want of pectoral and ventral fins, to be structural characters sufficient to con-
nect it with the Lamprey and Myxine. For its reception he constituted a new
genus, AMPHIOXUS. and described the species under the designation lanceolatus,
looking upon it as the lowest in organization in the class of Fishes.*
Mr COUCH, the indefatigable ichthyologist of Polperro, who supplied Mr
YARRELL with his specimen, published in the Magazine of Natural History, July
1838, a short paper, in which he gave some additional details of structure observed
before the animal had been immersed in spirits. He considered it to be a fish
with sixty vertebrae. He observed the anal fin, which had escaped Mr YARRELL
in the preserved specimen ; he also described what he considered an anomalous
kind of fin rays, in the form of transverse bows or arches, the curve forming the
support of the fin, the pillars probably resting on transverse spinous processes of
the vertebrae. He observed that these peculiar rays did not extend to the caudal
portion of either the dorsal or anal fins. In his second specimen, on which the
observations of structure were made, he could detect none of the ova which were
so conspicuous in the first.
I was not aware till I had almost finished my examination of the Lancelet,
that any thing farther had been published on the subject. A few Aveeks ago, how-
ever, I observed in the Proceedings of the Berlin Academy for 1839,f an abstract
of a paper on Amphioxus lanceolatus by Professor MULLER. From this abstract
it appears that Professor RETZIUS of Stockholm has written a short memoir on the
subject, in which he has announced the fact, observed by himself and Professor
SANDEVALL, that the chorda dorsalis does not pass into a cranium, but terminates
at a point behind it. Professor RETZIUS describes the spinal marrow as termina-
ting considerably behind the anterior extremity of the chorda dorsalis, in a brain
* YARRELL'S British Fishes, loc. cit.
t Bericht iiber die zur Bekanntraachung geeigneten Verhandlungen der Konigl. Preuss. Akademie
der Wissenschaften zu Berlin. Nov. 1839, p. 197.
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 249
exhibiting scarcely any dilatation. He perceived a dark point which he supposed
might be the rudiment of an eye, but he could observe no cerebral nerves. He
saw numerous ribs, but no branchial clefts, and described a large opening at the
posterior extremity of the gill-cavity, which he supposed to be a branchial open-
ing similar to those in the myxine.
MULLER'S own observations were made upon Mr YARRELL'S specimen, and
also upon two sent to him by RETZIUS. He verified RETZIUS' and SANDEV ALL'S
account of the chorda dorsalis, on the sheath of which he perceived circular fibres.
The oral filaments he described as consisting of central and tegumentary portions.
The black spot or rudiment of an eye he could not detect. He observed the
general structure of the branchial cavity, ribs, and vessels, but did not determine
the existence of the branchial aperture described by RETZIUS. He states that the
intestine terminates anteriorly in a cul-de-sac, a little behind which the branchial
cavity opens into it on the left side. He supposed that some glandular streaks
on the walls of the cul-de-sac of the intestine represented the liver, and considered
a row of glandular masses on each side, consisting of cells containing dusky oval
bodies as the ovaries. After some remarks on the structure of the muscles and
skin of the Lancelot, Professor MULLER states the necessity for farther observa-
tions to ascertain the details of its structure.
The only specimens of the Lancelot, then, which have been examined are
PALLAS' specimen, Mr COUCH'S two specimens, one of which is in the possession
of Mr YARRELL, the specimens examined by RETZIUS, SANDEVALL, and MULLER,
and the two in my own collection. Two specimens, I believe, exist in the Museum
of the Zoological Society of London.*
Having now stated what has already been done in the anatomy of this re-
markable animal, I shall proceed to describe in detail the structure of the speci-
men I have depicted, reserving for the concluding part any general observations
1 may have to make on its structure and zoological character.
The dimensions and weight of the specimen of Amphioxus which has afforded
the materials for this paper, are, length 2 inches ; depth, a little before the middle,
2 lines ; weight 8 grains. The other specimen in my possession is half an inch
shorter, and not so favourable for examination. They were dredged up by Mr
FORBES from a sand-bank, in deep water, on the east coast of the Isle of Man,
were extremely active, and resembled, on superficial inspection, small sand-eels.
On each side of the abdomen are two longitudinal membranous folds, and behind
them an anal fin, omitted in Mr YARRELL'S description. The folds commence,
minute, on each side of the hyoid apparatus, pass back on the sides of the abdo-
men, increasing in breadth till they are as broad as one-fifth of the depth of the
* Magazine of Natural History, July 1838.
250 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
animal ; they then diminish and terminate at the point where the lateral muscles
approach on each side of the intestine, that is, at the junction of the middle and
posterior thirds of the animal.
The anal fin is a fold of integument, which, commencing at the point where
the abdominal folds terminate, is continued to the anus, where it is interrupted,
but reappearing behind it, and becoming broader, passes on to be continuous with
the dorsal fin at the extremity of the tail. The existence of a median fin in front
of the anus is, as has been observed by MULLER, very remarkable ; but it is in ex-
act accordance with a fact mentioned to me by Professor AGASSIZ, that in certain
fresh-water fishes, the development of which he had watched, a fin of this kind,
with rays, exists for a short period of their embryonic existence, and then dis-
appears.
ANATOMICAL DESCRIPTION OF THE AMPHIOXUS.
Osseous System.
Neuro-skekton. — The osseous system, properly so called, consists of a " chorda
dorsalis" tapering at both ends, without the vestige of a cranium, and of a dorsal
and ventral series of cells, the germs of superior and inferior interspinous bones
and nn rays. The " chorda dorsalis" consists of sixty to seventy vertebrae, the
divisions between which are indicated by slight bulgings, and lines passing obliquely
from above downwards on the sides of the column. In this way a separation into
individual vertebrse is rather indicated than proved to exist ; for although the
column has certainly a tendency to divide at the points above mentioned, yet that
division is rather artificial than natural. There is no difficulty in ascertaining
above sixty divisions, those at each end above the number stated run so much
into one another that no correct result can be obtained.
The chorda dorsalis is formed externally of a fibrous sheath, and internally
of an immense number of laminae, each of the size and shape of a section of the
column at the place where it is situated. When any portion of the column is
removed, these plates may be pushed out from the tubular sheath, like a pile of
coins. They have no great adhesion to one another, are of the consistence of
parchment, and appear like flattened bladders, as if formed of two tough fibrous
membranes pressed together.
As the fibres of the sheath are principally circular, provision is made for
longitudinal strains on the column by the addition of a superior and inferior ver-
tebral ligament, as strong cords stretching along its dorsal and ventral aspects.
The superior ligament lies immediately under the spinal cord, and may be recog-
nized as a very tough filament, when the column is torn asunder, or some of the
vertebrse removed. The inferior ligament may be raised from the inferior surface
of the column in the form of a tough ribbon. From the sides of the column apo-
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 251
neurotic laminae pass off to form septa of attachment between the muscular
bundles ; and along the mesial plane above the column, a similar lamina separates
the superior bundles of each side, and by splitting below and running into the
sides of the column, forms a fibrous canal for the spinal cord. Foramina exist all
along the sides of this canal for the passage of the nerves. A similar septum is
situated along the inferior part of the column, from the part where the inferior
muscular bundles unite at the anus, to the extremity of the tap. Along the
superior edge of the aponeurotic septum, between the dorsal muscular bundles,
and stretching from the anterior point of the vertebral column to a point beyond
the anus, and half embedded* between the superior extremities of the muscles, is
a series of closed cells of a flattened cylindrical form, adhering firmly to one an-
other by their bases, so as to present the appearance of a tube flattened on the
sides with septa at regular distances. Each of these cells is full of a transparent
fluid, in the centre of which is an irregular mass of semi-opaque globules, appa-
rently cells. This series of cylindrical sacs consists of the rudiments of inter-
spinous bones, and probably of fin rays, and is attached below to the fibrous inter-
muscular septa, half covered on each side by the lateral muscles, and enclosed
above by the tegumentary fold which constitutes the dorsal fin.
A similar series of cells, with the same relations, is situated on the ventral
surface of the body, and stretches from the spot where the abdominal folds termi-
nate, to a point nearly opposite the termination of the dorsal series.
Splanchno-skeleton, — The splancho-skeleton consists of a hyoid apparatus
and a series of branchial ribs, seventy or eighty on each side. This division of
the skeleton will be described along with the respiratory apparatus, with which
it is intimately connected.
Nervous System.
The spinal cord is situated on the upper surface of the chorda dorsalis, en-
closed in the canal formed in the manner above described. When the whole
length of this canal is displayed by removing the muscles, and then carefully
opened, the spinal cord is seen lying in the interior, with nerves passing out from
it on each side. It stretches along the whole length of the spine, is acuminated
at both ends, and exhibits not the slightest trace of cerebral development. In its
middle third, where it is most developed, it has the form of a ribbon, the thick-
ness of which is .about one-fourth or one-fifth of its breadth ; and along this por-
tion, also, it presents on its upper surface a broad, but shallow groove. The other
two-thirds of the cord are not so flat, and are not grooved above, are smaller than
the middle third, and taper gradually ; the one towards the anterior, the other
towards the posterior extremity of the vertebral column. A streak of black pig-
ment runs along the middle of the upper surface of the cord. It is situated in the
groove already described, and is in greater abundance anteriorly and posteriorly,
VOL. XV. PART I. 3 Y
252 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
where the nerves pass oft' at shorter intervals, than at the middle or broadest part
of the organ. From fifty-five to sixty nerves pass off from each side of the cord ;
but, as the anterior and posterior vertebrae are very minute, and run into one an-
other, and as the spinal cord itself almost disappears at the two extremities, it is
impossible to ascertain the exact number, either of vertebrae or of spinal nerves.
These nerves are not connected to the spinal marrow by double roots, but are in-
serted at once into its edges in the form of simple cords.
The nerves pass out of the intervertebral foramina of the membranous spinaJ
canal, divide into two sets of branches, one of which run up between the dorsal
muscular bundles (dorsal branches) ; the other (ventral branches) run obliquely
downwards and backwards on the surface of the fibrous sheath of the vertebral
column ; attach themselves to the antero-posterior aspect of each of the inferior
muscular bundles, and may be distinctly traced beyond the extremity of each
bundle. When an entire animal is examined by transmitted light, and a sufficient
magnifying power, the anterior extremity of the spinal cord is observed, as before
mentioned, to terminate in a minute filament above the anterior extremity of the
vertebral column. The first pair of nerves is excessively minute, and passes into
the membranous parts at the anterior superior angle of the mouth. The second
pair is considerably larger, and, like the first pair, passes out of the canal in front
of the anterior muscular bundle. The second pair immediately sends a consider-
able branch (corresponding to the dorsal branches of the other nerves) upwards
and backwards, along the anterior edge of the first dorsal muscular bundle. This
branch joins the dorsal branch of the third pair, and, passing on, joins a consider-
able number of these in succession, and at last becomes too minute to be traced
farther. After sending off this dorsal branch, the second pair passes downwards
and backwards on each side above the hyoid apparatus, and joins all the ventral
branches of the other spinal nerves in succession, as its dorsal branch did along
the back. This ventral branch of the second pair is very conspicuous, and may
be easily traced along the line formed by the inferior extremities of the ventral
divisions of the muscular bundles, the ventral branches of the other nerves joining
it at acute angles between each bundle. It may be traced beyond the anus, but
is lost sight of near the extremity of the tail. Twigs undoubtedly pass from the
spinal and lateral nerves towards the abdominal surface of the body, but, on ac-
count of their minuteness, and the difficulty of detecting them in detached por-
tions of the abdominal membrane, they could not be satisfactorily seen.
When a portion of the spinal cord is examined under a sufficient magnifying
power, it is seen to be composed entirely of nucleated cells, very loosely attached
to one another, but enclosed in an excessively delicate covering of pia mater. The
cells are not arranged in any definite direction, except in the middle third of the
cord, where they assume a longitudinal linear direction, but without altering their
primitive spherical form. The black pigment, formerly mentioned as existing
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 253
more particularly on the upper surface and groove, is observed to be more abun-
dant opposite the origin of the nerves ; and, as it is regularly arranged in this
manner in dark masses along the anterior and posterior thirds of the cord, the
organ in these places, on superficial inspection, resembles much the abdominal
ganglionic cord of an annulose animal. Along the middle third the pigment is
not so regular, but appears in spots at short intervals. When any portion of the
cord, however, is slightly compressed, and microscopically examined, it becomes
evident that there is, along the groove and mesial line of its upper surface, a band,
consisting of cells of a larger size than those composing the rest of the organ.
Some of these cells only are filled with black pigment, but all of them contain a
fluid of a brown tint, which renders the tract of large cells distinctly visible.
When the compression is increased the cells burst ; and the fluid which flows from
the central tract is seen to contain jet-black granules, which may be detected as
they escape from the cells.
The nerves consist of primitive fibres, of a cylindrical shape, with faint longi-
tudinal striae. The primitive fibres of a trunk pass off into a branch, in the usual
way, without dividing ; and, where the trunks join the spinal cord, the primitive
fibres are seen to approach close to it, but without passing into it. The greater
part of the slightly protuberant origin consisting of the nucleated cells of the cord,
with a few pigment cells interspersed, the exact mode of termination of the cen-
tral extremities of the primitive nervous fibres could not be detected.
Muscular System.
This system is highly symmetrical, consisting of a series of lateral muscular
bundles, corresponding in number, size, and position, to the vertebrae of the
" chorda dorsalis." These bundles have a general resemblance to the division of
the lateral muscles of the higher fishes. Each bundle consists of a dorsal and
ventral portion. The dorsal passes from the lateral line, on a level with the ver-
tebral column, backwards and upwards ; the ventral passes from the same level,
downwards and backwards. The inferior bundle is the longest ; and both of them
have a somewhat conical shape, and are attached to the spinal column and skin
by the aponeurotic septa formerly described. The fibres of these muscles pass
respectively from before, obliquely upwards and downwards, almost, but not com-
pletely, in the direction of the muscular bundle, along that portion of the trunk
occupied by the branchial portion of the intestinal tube. The ventral bundles pass
half-way over the dilated cavity, and terminate in blunted extremities, which are
attached to the skin, and to the walls of the branchial compartment, so as to dilate
it for the reception of sea- water. Beyond the anus the ventral bundles are attached
to each side of the fibrous septum above described, meeting below in a sharp ridge.
Between the anus and the branchial cavity, where these muscles inclose the diges-
tive portion of the intestinal tube, they do not meet completely below, but are
254 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
connected by an aponeurosis, which forms a strong tendinous arch at the point in
front, where the muscles separate more completely. The whole cavity of the
trunk, which is occupied by the intestinal tube, is lined by a fine aporieurotic
membrane, which, about the lower edge of the lateral muscles, becomes muscular,
and shuts in the whole of the inferior part of the trunk from the mouth to the
tendinous arch formerly described. This abdominal muscle consists of two layers
— an external, apparently longitudinal ; an internal, transverse.
The only muscle in the lancelet for performing a special function is a flat
bundle, connecting and bringing together the two halves of the hyoid apparatus,
for the purpose of closing the mouth.
Under the microscope the primitive fibres of the lateral muscles exhibit the
usual transverse strise, but are not collected into fasciculi, constituting imme-
diately the mass of the tissue. Transverse striae are not observable in the fibres
of the abdominal muscle.
Intestinal System.
This system appears as a tube passing nearly in a straight line from mouth
to anus. It consists of two portions — an anterior, large and dilated, and appro-
priated to the respiratory function ; and a posterior, small, of pretty uniform
calibre, and constituting the proper digestive apparatus. The respiratory portion
of the canal will be described afterwards in connection with the vascular system.
The mode in which the digestive communicates with the branchial department of
the tube could not be satisfactorily made out. It appeared, however, that the
branchial cavity, becoming smaller, curved slightly of itself towards the left side,
and then proceeded directly, and without any change in its calibre, to the anus.
The anus is in the form of a longitudinal slit.
There is not the slightest trace of a liver, or of any other assistant chylo-
poietic viscus. The gut was full of a brown granular matter, tinged, probably, by
a bilious secretion from the walls of the bowel.
Respiratory System.
This system is constituted by the anterior compartment of the intestinal tube,
on the walls of which a peculiar vascular arrangement exists for the aeration of
the blood, and the complicated skeleton superadded, for the efficient performance
of that function.
In connection with the respiratory apparatus, I shall, as formerly proposed,
describe the splanchno-skeleton. This division of the osseous system consists of a
hyoid apparatus, and of a range of branchial ribs.
The hyoid apparatus supports the mouth, and guards its entrance. The
mouth is in the form of a longitudinal slit, and is bounded on each side by the
two divisions of the hyoid apparatus. Each of these consists of seventeen pieces
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 255
articulated together. From each of these pieces, except the first, a ray proceeds,
those at the extremities of the two divisions being shorter than those at the centre.
The anterior extremities of the two divisions, or branches of the apparatus, meet at
the anterior superior angle of the mouth ; and the two posterior, after curving for-
ward, meet at the posterior inferior angle. The various pieces of which this appa-
ratus consists have the consistence of cartilage. They are hollow along the bases,
and to the points of the rays. Their cavities appear to be full of a transparent
fluid, containing here and there masses of globular cells, exactly similar to those
in the interspinous bones. This part of the skeleton is covered by the integuments,
and by the membrane of the branchial cavity. A fringe of the integument sur-
rounds the hyoid rays, extending a little beyond their bases. This fringe must
be considered as the lip or margin of the mouth, the hyoid rays, although occa-
sionally dependent, belonging properly to the cavity of the mouth. The rami of
the hyoid are brought together, and the mouth closed, by the transverse muscle
formerly described.
Immediately behind the hyoid apparatus the branchial cavity commences,
and continues as a dilated tube, which at last contracts, and becomes continuous,
as formerly described, with the digestive portion of the intestine. The walls of
the two anterior thirds of the branchial cavity are strengthened on each side by a
series of transparent cartilaginous, highly elastic, hair-like ribs, which are imbed-
ded in their substance. The upper extremities of these ribs are fixed in two
streaks of a tough white substance which runs along on each side of the inferior
surface of the chorda dorsalis, on the sides of the inferior longitudinal ligament.
The inferior extremities of the ribs terminate in a more complicated manner.
Each alternate pair of ribs bifurcates. The inferior branch of the rib on each side
meets its fellow of the opposite side at an angle in the median line. The superior
branch curves up also, and meets that of the other side. The non-bifurcated ribs
are shorter, and terminate in a line with the bifurcation of the neighbouring pairs.
There results from this arrangement a sort of skeleton canal, the walls of which
are completed by membrane. There are from seventy to eighty ribs on each side.
Their general direction is from above downwards and from before backwards, but
more perpendicular than the ventral bundles of the lateral muscles, with which
they form acute angles. Along the edges of these ribs vessels pass for the per-
formance of the respiratory function, and the canal above described contains the
branchial artery or heart.
Vascular System.
In the canal which has been described as passing along the inferior wall of
the branchial compartment of the intestinal tube, a vessel runs. This vessel dimi-
nishes anteriorly ; and, posteriorly, it also diminishes, and is lost in the direction
of the digestive tube. Valves, if they exist, have not been detected in this tube.
VOL. xv. PART i. 3 z
256 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
At the extremities of each pair of bifurcated ribs the abdominal vessel just de-
scribed gives off a primary branch, which passes along the edge of the rib, sending
secondary branches at regular intervals and at right angles to the other primary
branches on each side. Along the opposite sides of all the ribs another set of ves-
sels may be seen, passing on to the chorda dorsalis, enlarging as they advance,
and sending off secondary branches at right angles. When near the heads of
the ribs, these vessels anastomose in semicircular loops, the canals of which are of
large calibre, and the walls provided with distinct circular fibres. From the
angles between each of these loops, and continuous, therefore, with the primary
branches, smaller trunks pass on to the median line, and enter, opposite to their
fellow at the other side, into a small longitudinal vessel which runs along the
whole length of the chorda dorsalis, between the heads of the ribs, and on the
inferior surface of the inferior longitudinal ligament. This vessel is the Aorta,
and distributes arterial branches to the various parts of the body.
Generative System.
This system consists of a series of somewhat irregular, bean-shaped, granular
bodies, situated each on the inside of the inferior extremity of the ventral portions
of twenty or thirty of the muscular bundles of the middle third of the animal.
These masses are attached to the internal surface of the aponeurotic lining of the
abdomen, on the outside of the branchial chamber. No duct or outlet could be
detected. Each mass, under the microscope, displayed a congeries of cells of
various sizes, evidently incipient ova or sperm cells. The individual did not ap-
pear to be in season.
Tegumentary System.
The skin is remarkably thin, but tough ; and exhibits neither scales, pigment,
nor metallic lustre, except at the base of the dorsal fin, along which, or the upper
edge of the interspinous bones, a silvery band of considerable strength passes.
The skin, under the microscope, displays minute parallel striee, which occasionally
cross one another. The beautiful iridescent tints which it exhibits, both before
and after detachment, appear to be caused by these stria; ; and the same structure
probably produces similar phenomena in the aponeurosis which lines the cavity
of the abdomen.
CONCLUDING REMARKS.
At a very early period in the development of every vertebrated animal, the
cerebro-spinal axis presents the appearance of a white elongated streak. At the
same period, and in accordance with this simple condition of the nervous central
organ, the skeleton consists of a chorda dorsalis, and, very soon afterwards, of
some of the peripheral elements of the spinal column. A central organ of circu-
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 257
lation, in the form of a tube on the anterior inferior aspect of the embryo, inva-
riably coexists with the simplest forms of the nervous and osseous systems.
Branchial clefts and a liver are parts of the embryo of the vertebrated animal
which are never found to accompany a cerebro-spinal axis of the simplest form,
or a heart before it becomes divided into compartments.
No adult vertebrated animal has hitherto been described which at all ap-
proaches in organisation the simplicity of the embryonic forms to which allusion
has just been made. Such an animal, a being perfected before the appearance of
branchial clefts, might have been conceived ; and, from the laws of organic deve-
lopment, its position in the system might have been indicated. As Amphioxus
makes a close approximation to this simplicity of type, it may be useful to con-
sider the relation of its different organs one to another.
One of the most remarkable peculiarities in the Lancelot is the absence of the
brain. RETZIUS, indeed, describes the spinal marrow as terminating considerably
behind the anterior extremity of the chorda dorsalis, in a brain which exhibits
scarcely any dilatation ; but careful examination of the dissection of my own spe-
cimen, which I have also submitted to the inspection of Dr JOHN REID, and of
other competent judges, has convinced me that the spinal cord, which may be
traced with the greatest ease to within 1-1 Gth of an inch of the extremity of the
chorda dorsalis, does not dilate into a brain at all. It may be urged that we
ought to consider the anterior half of the middle third of the spinal marrow, where
it is most developed, to be the brain, and all that portion of the chorda dorsalis
which is in connection with the branchial cavity, as the cranium. That this does
not express the true relation of the parts, is evident from the fact, that this por-
tion of the cord, to its very extremity, gives off nerves, which are too numerous
to be considered as cerebral, but more especially from the mode of distribution of
the first and second pairs, which, in my opinion, proves the anterior pointed ex-
tremity to be the representative of the brain of the more highly developed verte-
brata. A brain of such simplicity necessarily precludes, on anatomical grounds
alone, the existence of organs of vision and of hearing. These special organs, de-
veloped in the vertebrata at least, in a direct relation with the cephalic integu-
ments and the brain, could not exist, even in the form of appreciable germs, in
the Lancelet. The black spot which RETZIUS took for the rudiment of an eye may
probably have been, what also deceived me at first, a portion of the black mud
which floats about in the branchial cavity, and which adheres obstinately to the parts
in the neighbourhood of the oral filaments. The first pair of nerves, although
very minute, in accordance with the slight development of the parts about the
snout, and the want of special organs of sense, might, from their position and re-
lations, be considered as corresponding to the trifacial in the higher vertebrata.
The second pair appears to be the vagus, not only from its distribution as a longi-
tudinal filament on each side of the body, as in other fishes, but also from its rela-
258 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATTJS.
tions to the hyoid apparatus and branchial cavity, to which division of organs the
eighth pair of fishes is specially devoted. The distribution of a branch of this
nerve, however, along the base of the dorsal fin, and the course of the posterior
part of the main branch, would appear to shew that this nerve, which I have pro-
visionally denominated the Vagus, is, in fact, the trifacial, which, in the higher
fishes, is not only distributed to all the fins, but holds exactly the same relations
to the dorsal and anal fins, and to the spinal nerves, as the nerve now under con-
sideration in the Lancelet.
The peculiarities in the structure of the spinal cord are not less remarkable
than those of its configuration. It is difficult to understand, according to the re-
ceived opinions on the subject, how a spinal cord destitute of primitive fibres or
tubes, and composed altogether of isolated cells, arranged in a linear direction
only towards the middle of the cord, can transmit influences in any given direc-
tion ; and more especially how the tract of black or grey matter, if it exercises
any peculiar function (excito-motary) communicates with the origin of the nerves.
The nerves, also, are remarkable, originating in single roots, and containing in
their composition one kind only of primitive fibres (cylindrical).
In reference to the skeleton of the Lancelet, it is evidently of the simplest
kind. If we limit the term skeleton to the Neuro-Skeleton, this animal possesses
only the primitive form of such a skeleton — a chorda dorsalis without any cranial
enlargement, with a dorsal and ventral series of germs of interspinous bones and
fin rays — peripheral elements of a spinal column.
From a consideration of the particular class of embryonic forms to which this
fish corresponds, we could not expect either bone or cartilage in the composition
of its skeleton. Accordingly, the skeleton consists of a series of sacs, assuming
particular forms according to their several positions : flattened in the chorda dor-
salis, cylindrical in the fin bones. These sacs are easily derived, according to esta-
blished histological laws, from the primitive nucleated cells which constitute the
tissue of their representatives in the embryo, and contain, in their interior, cells,
or the nuclei of cells. This view of the tissue of the skeleton of the Lancelet is
based on a law of organization which is not usually recognized in questions like
the present, viz. that adult organs representing embryonic organs, are altered so
as to be fit for the performance of their functions, but never so far as to depart,
either in tissue or form, from the type of their corresponding embryonic organs.
The arch-shaped fin rays, described by Mr COUCH, are merely the dissepiments
between the cylindrical germs of the fin bones.
The leading peculiarity of the Lancelet, considered as a representative of an
embryonic form in the adult series, is the want of true gills or branchial arches —
the deficiency of branchial clefts. RETZIUS, indeed, describes an opening at the
posterior part of the branchial cavity, which he compares to the adominal open-
ings in the Myxine ; but as I have been unable to discover this opening in my spe-
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 259
cimens, I agree with MULLEB in considering its existence as highly problematical,
and I shall proceed to demonstrate that, in accordance with the plan on which the
other organic systems of this animal are formed, such an opening into the branchial
chamber could not exist. The abdominal openings in the Myxine are the result of
the closure of its numerous branchial clefts by the integuments. They are analogous,
in fact, to the branchial orifices of the tadpole, immediately before cessation of the
aquatic respiration. The respiratory apparatus of the Myxine, then, although infe-
rior in functional activity to that of other fishes, is actually referable to a more ele-
vated type. The Myxine possesses a brain in which the central masses are consider-
ably evolved, and a nervus vagus of sufficient development. The brain of the Lance-
let, again, is reduced to a mere filament, and the existence of a nervus vagus appears
to be highly problematical. These considerations, and the fact that branchial
openings have not been detected by YARRELL, COUCH, MULLER, or myself, must
lead to the conclusion that this fish has either never had branchial clefts at any
period of its existence, or that if it at any time had them, they must have totally
disappeared. I am inclined to believe that the former is the real state of the case,
not only from the views already urged in reference to the other organs in this
animal, but also from the consideration that if these clefts had ever existed their
traces would have remained. As the seventy or eighty pairs of branchial ribs
cannot be looked upon as true branchial arches, and as we cannot suppose that
any vertebrated animal could have so many branchial fissures, we are driven to
the conclusion that the Lancelot never had at any period of its existence true
branchial arches and clefts, and that the ribs have been developed for a special
purpose — for a mode of branchial respiration hitherto undescribed in the class of
fishes.
The Lancelet respires by receiving sea- water into the anterior compartment
of its intestinal tube — this cavity is kept dilated by the elasticity of the numerous
filamentous ribs, and this dilatation may be increased by the action of the super-
imposed ventral bundles of the lateral muscles. It is contracted by the action of
the abdominal muscle. This is a mode of respiration similar to that which pre-
vails in the tunicated mollusks. It is interesting to observe that the branchial
membrane of the Lancelet is exactly similar in its peculiar vascularity (ramifications
at right angles) to that which lines the branchial cavity of the mollusks just
specified.
If the branchial membrane were examined in the living animal, it would un-
doubtedly exhibit cilia in as great abundance as in the branchial membrane of the
ascidice, and such a ciliary arrangement must constitute one of the active agencies,
not only in renewing the supply of water for respiration, but also in conveying
food to the orifice of the digestive portion of the intestinal tube. As in the ascidice,
the entrance of the intestino-respiratory canal is guarded by filaments. The hyoid
filaments of the Lancelet performing the same office as the filaments at the oral
VOL. XV. PART I. 4 A
260 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
orifice of the ascidice, acting as a sieve in preventing the entrance of foreign bodies,
or of food, which it has neither jaws to comminute, nor powers of stomach to
digest.
The branchial ribs I do not consider as parts of the neuro-skeleton, as they
bifurcate to inclose the heart, this organ in the Lancelet being contained in a sac
resembling the cartilaginous pericardium of some other fishes. They are repeti-
tions of the hyoid bone developed for a new form of branchial apparatus. They
are true splancho-ribs, parts of a splanchno-skeleton, and analogous to the car-
tilages of the trachea and branchial tubes (also repetitions of the hyoid bone) of
the higher vertebrata. Some of these splanchno-ribs, had branchial clefts been
developed, would have become true branchial arches ; but just as in the vertebrata
above the fishes, in which the branchial clefts have disappeared, and tracheal car-
tilages have become developed, so in this animal, in which the branchial clefts
have never appeared, cartilaginous arches have become necessary for its peculiar
aquatic respiration.
The hyoid filaments of the Lancelet must not be considered as the analogues
of the branchiosteogous rays, which spring from the peripheral aspect of the bone,
but as developed forms of the teeth or tubercules which are ranged along the cen-
tral aspect of the branchial apparatus of the higher fishes, and which are occa-
sionally highly developed for similar purposes. As the upper jaw is developed
from a cranium, and the lower jaw is formed at a period posterior to the appear-
ance of the hyoid bone — the absence of these two bones is a necessary consequence
of the inferior position of the Lancelet in the series of vertebrate forms.
The plan of the circulation is simple, and in accordance with the primitive
condition of the respiratory apparatus, both functions being performed in a man-
ner closely resembling that observed in certain annulose animals. The dorsal ves-
sel corresponding to the heart or branchial artery, and the abdominal vessel to the
aorta of the Lancelet, the lateral communicating vessels of certain of the rings in
the annelide performing the respiratory function, like the vessels of the branchial
chamber already described. The development of cardiac septa and of a liver follow
closely, if they do not accompany, the branchial fissures. The absence of such
fissures in the Lancelet sufficiently explains this deficiency of parts usually con-
sidered essential to the vertebrated animal.
For similar reasons, true renal and generative organs do not appear in this
animal.
The double row of isolated generative organs are in the normal position of
their embryonic representatives, and not more advanced in organization than the
Wolfftan bodies at their first appearance. How the contents of these ovisacs or
sperinsacs are conveyed to the exterior, it is difficult to say. If the abdominal
opening described by Professor RETZIUS actually exists, it appears to me much
more probable, -that it is an opening, not into the branchial, but into the peritoneal
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 261
cavity, as in certain of the higher fishes, and that it performs the double function
of admitting sea- water for peritoneal respiration, and for allowing of the exit of
the ova and sperm from the cavity of the abdomen, into which they are cast from
the glandular organs attached to its lining membrane. This hypothesis, which I
have had no opportunity of verifying, gets rid of the difficulty in a satisfactory
manner, explains to a certain extent the observation of RETZIUS, and is in accord-
ance with the type of formation in the class.
Viewed as an entire animal, the Lancelet is the most aberrant in the verte-
brate sub-kingdom. It connects the Vertebrata not only to the Annulose animals,
but also through the medium of certain symmetrical ascidise (lately described by
Mr FORBES and myself*), to the Mollusks. We have only to suppose the Lance-
let to have been developed from the dorsal aspect, the seat of its respiration to be
transferred from its intestinal tube to a corresponding portion of its skin, and
ganglia to be developed at the points of junction of one or more of its anterior
spinal nerves, and inferior branch of its second pair, to have a true annulose ani-
mal, with its peculiar circulation, respiration, generative organs, and nervous
system, with supra-cesophageal ganglia, and dorsal ganglionic recurrent nerve.
As some fishes undergo metamorphoses after leaving the ovum, the question
naturally suggests itself, is the Lancelet an adult fish ? May it not be the young
of some fish in one of the stages of growth ? The uniformity of every specimen
of it hitherto described, and the peculiar toughness and firmness of its tissues,
appear to be decisive of its being a perfect animal.
In regard to the zoological position of Amphioxus, Mr YARRELL was correct in
giving it the lowest place in the class of fishes ; but if the details of its structure,
and the anatomical considerations which this paper contains, be correct, the genus
can no longer be retained in the same family with Petromyzon and Myxine, but
will assume an ordinal value in any new arrangement of the class.
If genera allied to Amphioxus are at present in existence, they are probably
not numerous ; but in the ages which have passed since the development of ani-
mal forms commenced, a-branchiated fishes may have been more common ; and
the paleontologist, when his attention is directed to the subject, may probably be
able to refer some anomalous organic remains to extinct fishes of this order.
* Report of the British Association, 1840.
262 MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS.
EXPLANATION OF PLATES IV. V.
PLATE IV.
Fig. 1. A lateral view of Amphioxus lanceolatus. As the specimen when sketched was slightly com-
pressed between two plates of glass, it is represented of greater depth than the animal exhibits in its
natural condition, a The mouth, with the oral filaments ; b the abdominal fold of the left side ; the
fold is semitransparent, so that the lower surface of the abdomen is seen through it ; c the anus, with
one fin before, and another behind it ; d the dorsal fin ; the vesicular germs of the rays are seen in
all these fins, and the splanchno-ribs are also visible through the abdominal parietes ; e the length
of the specimen.
Fig. 2. The abdominal aspect of the specimen, a The mouth ; b 6 the abdominal folds ; c the anus ;
d the heart.
Fig. 3. A lateral view of the same specimen after the removal of the integuments, including the abdomi-
nal folds, and the soft parts of the fins, a The mouth, with the oral filaments ; b the abdominal
muscle, with the splanchno-ribs seen through it ; c c the heart ; d the anus ; e the vesicular germs
of the rays of the anterior ; / those of the posterior anal fin ; these germs do not, like the soft parts,
extend to the extremity of the tail ; g the germs of the rays of the dorsal fin, which, like those of the
anal fin, do not extend along the tail ; h h the lateral muscular bundles separated by the needle, so
as to display in their intervals the " chorda dorsalis," and the dorsal and ventral branches of the
nerves ; i the first pair of nerves ; k the second pair, analogous to the trifacial, the dorsal and ventral
branches of which extend along the bases of the fins to join the branches of the other nerves. This
dissected specimen is flattened by slight compression, in order to display the various parts with
greater distinctness.
Fig. 4. The integuments have been removed from the tail, but the abdominal folds have been left. The
. abdominal muscle, and the branchial compartment of the intestinal tube, have been opened longitu-
dinally, a little to the right side of the mesial line, a a The two divisions of the hyoid bone ; b b the
internal surface of the branchial chamber, through the walls of which the " chorda dorsalis," the
nerves, and the ventral bundles of the muscles, are seen ; c c the heart, with the splanchno-ribs
passing off from it on each side towards the " chorda dorsalis ;" d d the abdominal muscle ; e the
digestive portion of the intestinal tube proceeding to the anus ; f gg the abdominal folds.
Fig. 5. The neuro-skeleton, consisting of a a the " chorda dorsalis," 6 6 the vesicular germs of the dorsal
fin rays, c those of the anterior, and d those of the posterior anal fins.
Fig. 6. The nervous system, a a The spinal cord ; b the first pair of nerves ; c the dorsal; d the ventral
branch of the second pair.
Fig. 7- The intestinal system, a The branchial compartment ; 6 the digestive compartment of the intes-
tinal tube ; c the mouth ; d the anus.
Fig. 8. The vascular system, a a The heart ; 6 b the primary branches, or branchial arteries ; c c the
branchial veins uniting in loops, from the angles between which, trunks convey the blood into a a the
aorta.
MR GOODSIR ON THE ANATOMY OF AMPHIOXUS LANCEOLATUS. 263
PLATE V.
Fig. 1. a Portion of the " chorda dorsalis," to show the circular fibres of the sheath ; I the superior ;
c the inferior longitudinal ligament.
Fig. 2. A portion of the sheath ; shreds of the aponouroses adhere to it.
Fig. 3. One of the compressed vesicles which occupy the interior of the sheath, and compose the mass of
the " chorda dorsalis."
Fig. 4. Some of the compressed vesicles removed from the sheath, to shew their relation one to another.
Fig. 5. Five of the cylindrical cells, from the dorsal fin, to shew their relative positions, and the masses
of cells which they contain in their interior.
Fig. 6. A single cell.
Fig. 7- A portion of the spinal cord, from its anterior third, magnified, to shew the black matter which
runs along the median line, and the origins of the nerves.
Fig. 8. A portion of the middle third, highly magnified to shew the nucleated cells of which it is com-
posed, and the larger cells of the dark median band. Some of the cells of the dark band are filled
with black pigment granules, which are represented escaping under the compression.
Fig. 9. A portion of the spinal cord, magnified to shew the origin of the nerves by single roots, and with-
out the insertion of the primitive fibres of the nerves into the substance of the cord.
Fig. 10. Primitive fibres of a nerve.
Fig. 11. A transverse section of the spinal cord, to shew the groove on its upper surface, and the black
matter on the floor of the groove.
Fig. 12. Primitive fibres from one of the lateral muscles.
Fig. 13. The eighteen pieces of one of the divisions of the hyoid bone. The anterior piece carries no ray.
Fig. 14. A few of the splanchno-ribs to shew their relations to the heart, aorta, and branchial vessels,
a a The ribs which bifurcate ; b b the simple ribs ; c c a portion of the heart with four branchial
arteries ; d d a portion of the aorta with eight branchial veins.
Fig. 15. A portion of the aorta to show the mode of connection between the aorta and branchial venous
trunks and loops.
Fig. 16. A portion of the heart to shew the mode in which the arteries leave it. The heart or ventral
vessel is somewhat flattened, its upper and under walls meeting at an acute angle on each side.
Fig. 17. The lower end of one of the lateral muscular bundles, magnified to shew th6 position and con-
figuration of one of the generative organs.
Fig. 18. Portions of four pieces from the hyoid bone, magnified to shew the mode of connection, also
the cavities, and irregular masses of cells which they contain.
Fig. 19. One of the generative organs, highly magnified under compression, to shew the nucleated cells
of which it is composed.
VOL. XV. PART I. 4 B
Plato IV
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( 265 )
On the Action of Water upon Lead. By ROBERT CHEISTISON, M.D., F.R.S.E.,
Professor of Materia Medica in the University of Edinburgh.
(Read 7th February 1842.)
IN an experimental inquiry into the action of water on lead,* published by
me in 1829, in continuation of some previous researches by GUYTON-MORVEAU, it
was stated as the general result, that all very pure waters, such as distilled wa-
ter, rain, and melted snow, act upon lead, — dissolving a trace of it, and causing
the formation of an insoluble carbonate of lead in large quantity. It was like-
wise shewn, that this action is prevented by the existence of neutral salts in solu-
tion ; so that most terrestrial waters, as they contain saline matter, act feebly
and only in circumstances favourable in other respects. Farther, it appeared to
flow from comparative experiments, that this preventive power depends upon the
acids of the salts, and not upon their bases ; — and that their energy as preventives,
that is, the minuteness of the proportion required to annihilate the action, is in.
the ratio of the insolubility of the compounds which the acids of the salts are
capable of forming with oxide of lead.
Since the time when the investigations now referred to were first made pub- '
lie, my attention has been repeatedly recalled to the subject by divers interesting
facts connected with the economic use of lead, which have illustrated practically
the conclusions drawn from experiments conducted in the laboratory. Two of
these facts, which relate to the employment of lead as the material for water-
pipes, are so remarkable in their circumstances, that I am induced to lay them
before the Society. On the one hand, they shew that the action of water on lead,
notwithstanding its serious consequences, and all that has been written respect-
ing it, does not seem to have attracted the attention among such professional men
as engineers, architects, and others, which it unquestionably deserves. And on
the other hand, when taken along with the general principles formerly established
by me, they point out the risk of the action of water on lead-pipes being unex-
pectedly developed, where due care is not taken, but at the same tune fix the
conditions in which the action may be foreseen, and likewise provide a simple
and efficacious remedy.
As an appendix to this communication, I propose also to take notice of a
topic of more purely scientific interest, — namely, a question which has arisen
* Treatise on Poisons, first edition, 1829, p. 384.
VOL. XV. PART II. 4 C
266 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
since I first wrote on this subject, as to the exact nature of the substance formed
by the action of water upon lead.
The first fact to be mentioned has been already briefly alluded to by me in a
former publication in 1836.* But its circumstances appear to merit a more de-
tailed statement.
A few years ago, the water of a spring was introduced into the mansion of
Dalswinton in Dumfriesshire, by a lead-pipe, from a distance of three-quarters
of a mile. While on a visit there in the autumn of 1834, only a few days after
operations were finished, and the water was flowing into the great cistern for sup-
plying the house, my attention was called one morning by one of the guests to
the water-bottle on his dressing-table, and a tumbler of water which had been
poured from it. The bottle was lined with a thin white incrustation of a pearly
lustre ; and the water, which had stood some time exposed to the air, presented
a thin film of the same appearance over its whole surface. The cause being at
once suspected, we proceeded with our host, Mr LENY, to examine the great cis-
tern into which the water was discharged directly from the pipe. Here we found
the water entirely covered with a similar film, and the bottom and sides of the cis-
tern lined with a loose pearly Avhite incrustation, in such quantity as to appear as
if painted with white paint. It was also remarked, that water fresh drawn from
the pipe was perfectly transparent at first, but, on exposure to the air, quickly
presented the white film seen in the tumbler. It needs scarcely be stated, that
• the appearances now mentioned were recognised as the result of the action of the
water on the lead of the pipe. And it may be added, that the white substance
was afterwards ascertained to be a carbonate of lead.
I confess that the observations thus made surprised me not a little. For
being told, the previous autumn, that it was proposed to bring into the house in
lead-pipes the water of this spring, which had long enjoyed a high character in
the neighbourhood for purity, I made an experiment for the purpose of discover-
ing whether it could be safely conveyed in lead ; and finding that several pieces of
fresh-cut lead retained their lustre almost untarnished when immersed for four-
teen days in a tumbler of the water, I concluded that it contained salts enough to
prevent corrosion of the lead. I did not at the time advert to the difference be-
tween an experiment in which some ounces of water were left at rest on a few
square inches of lead, and one in which a column of water only three-quarters of
an inch in diameter flowed constantly over a surface of nearly 800 square feet.
The means of clearing up the cause of the action, by analyzing the water,
were not within my reach. It was presumed, however, from the general princi-
ples established by previous inquiries, that the reputation of the spring for extra-
* Treatise on Poisons, third edition, p. 489.
PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 267
ordinary purity was not without foundation. Accordingly, it afterwards appeared
from analysis to be very unusually pure. Oxalate of ammonia occasioned a white
haze, and slowly a very scanty white precipitate, shewing a trace of lime. Phos-
phate of ammonia had no effect at first, on being added to the water after removal
of the lime ; but in the course of some hours, a few microscopic shining crystals
formed on the glass, thus indicating a trace of magnesia. Nitrate of baryta,
however, did not affect the water in the slightest degree, proving the extreme
scantiness of sulphates. And nitrate of silver caused only a faint opalescent
whiteness ; so that even the muriates were present in unusually small quantity.
On concentrating the water it was found that the salts existing in it were hydro-
chlorates, sulphates, and carbonates of lime, magnesia, and soda, and that the
hydrochlorates greatly predominated. A minute estimate of the several ingre-
dients was not attempted, because unnecessary. But their total amount proved
to be only 0.554 of a grain in 11,860 grains, or gdbsth-* Water taken direct from
the pipe, and kept for some days well corked in a bottle, was quite transparent
when first poured out ; but, on being slightly concentrated by boiling, a few white
shining crystals of great delicacy were formed. These, when detached and washed
with distilled water, disappeared in water acidulated with nitric acid ; and on this
solution being evaporated to dryness, there was obtained a trace of crystalline
powder, which, when re-dissolved, gave a fine yellow precipitate with bichromate
of potash, and a black one with sulphuretted hydrogen, — clearly proving the pre-
sence of lead dissolved in the water. ,
On referring to what has been stated in my account of my first experiments
respecting the action of water on lead, it will readily appear why this water
should have oxidated and dissolved the metal of the pipe. The spring is not only
one of very great purity, but the protective salts contained in the water likewise
consist chiefly of those whose preventive power is the feeblest of all the natural
ingredients of springs. For in my experiments on the small scale, it did not ap-
pear that the hydrochlorates effectually prevented the action of distilled water,
unless present in the proportion of a 2000th at least.
It remains to take notice of the remedy applied in this case. When a similar
instance happened at Tunbridge, in 1814, — with the additional circumstance that
its nature was not discovered till lead-colic began to appear among the irunates
of the houses supplied with the water, — the only satisfactory remedy which could
be thought of, was the expensive one of removing the pipes and replacing them
* On again lately analyzing the water, I found the solid residuum to be exactly one grain in 17,500.
Nitrate of baryta, after twenty-four hours' rest, occasioned an exceedingly scanty deposite of sulphate ;
and the residuum left, on evaporating 17,000 grains, effervesced very slightly with diluted nitric acid.
The sulphates and carbonates were thus again proved to exist in very minute proportion. In this water
a stick of polished lead became tarnished in an hour ; and in four days a little white powder formed on
the bottom of the vessel under the lead.
268 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
with others of cast-iron ; and this was accordingly done. Reflecting, however,
upon what I had observed in many experiments with weak solutions of neutral
salts, and remembering that in general, after the action had gone on slowly for
some weeks, it gradually became less and less, while, at the same time, a firmly-
adhering film formed on the lead, consisting of carbonate mingled with a salt of
oxide of lead in union with the acid of the salt in solution, and that, when lead so
lined was transferred even into distilled water, no action seemed to take place, — I
conceived that an effectual remedy might be provided by producing, in like man-
ner, an incrustation of the same kind on the inside of the pipe. For this end, it
was proposed to leave the pipe for some months filled with a weak solution of
phosphate of soda, in the proportion of a 25,000th part, which is somewhat
stronger than what had seemed sufficient to prevent the action of distilled water
on the small scale. It was hoped that a fine film of mixed carbonate and phos-
phate of lead would thus be formed while the water was at rest, which Avould
adhere so firmly as not to be swept away when the water was allowed to flow,
and which would serve as a lining to prevent the contact of the running Avater
with the metal. Circumstances prevented this plan being tried at once ; and in
the mean time it was judged right to try the effect of forming a lining of car-
bonate of lead, by leaving the water at complete repose in the pipe, so as to
allow the carbonate to crystallize slowly and firmly on its interior. This expe-
riment was attended with complete success. The pipe was kept full of the
spring- water, and without water being drawn from it, for four months. The water
was then found to flow without any impregnation of lead, and has done so ever
since.
The other incident I propose to describe occurred last year at Buchan-ness
Lodge, a cottage-residence of the EARL of ABERDEEN. It resembles the former
singularly in all its leading circumstances.
In the beginning of June last, Mr JOHNSTON of Peterhead was requested to
visit professionally the housekeeper of the Lodge, who was affected with indigestion
and constipation ; — from which, however, under his directions, she speedily reco-
vered on this occasion. Six weeks afterwards he was requested to visit her again,
and found her then affected with vomiting, constipation, severe spasmodic pain at
the pit of the stomach, retraction of the umbilicus towards the spine, great weak-
ness of the limbs, and other symptoms of less note, which it is scarcely necessary
to particularize in this communication, but which are proper to the severe form of
colic occasioned by slow poisoning with lead. After treating the case judiciously
for three days, Mr JOHNSTON was surprised to find, that, notwithstanding frequent
temporary benefit, no permanent amelioration had taken place. At last, on the
third day, while considering the circumstances of his patient's illness, his atten-
tion was drawn to the water-bottle on her dressing-table. It was lined with a
PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 269
white shining incrustation, and the surface of the water was covered with a film
of similar appearance. On inquiry, he learned that the water always presented
this appearance after being exposed for some time, but that it was quite transpa-
rent when first drawn ; and he afterwards personally verified these facts.
Being well aware of the action of water on lead, and of the consequences of
the insidious introduction of the compounds of that metal into the human body,
Mr JOHNSTON, with much discernment, although he had never seen a case of lead-
colic before, was strongly inclined to believe that he had to deal with that dis-
ease. He suspended his ultimate decision, however, until he had an opportunity
of examining chemically the substance deposited by the water. This he found to
be soluble in weak acetic acid ; and the solution gave a white precipitate with
sulphuric acid, a white one with carbonate of potash, a yellow one with iodide of
potassium, and a black one with sulphuretted hydrogen. The last test, an ex-
tremely delicate one, likewise made the water itself brown. As these results
left no doubt Avhatever of the presence of lead in the water, he could as little
entertain any doubt of the nature of the housekeeper's illness. She Avas treated
accordingly, recovered slowly but steadily, and in October was quite well. She
had resided in the house, and constantly used the water for eight months before
her final severe illness ; but for some months previous to that attack, she had
been often annoyed with stomach-complaints and constipation. Her niece, a girl
of twelve, who had been residing with her for a few weeks only, was also attacked
Avith these premonitory symptoms of lead-colic ; but she soon recovered under
Mr JOHNSTON'S care. No other person had resided for any length of time at the
Lodge during the period in question. LORD ABERDEEN had been there with some
friends for a feAv days only.
Mr JOHNSTON, Avith Avhose approbation, as well as the sanction of LORD ABER-
DEEN, the facts of this incident are made public, consulted me respecting it about
the middle of September, and aftenvards communicated much additional infor-
mation,— partly, indeed, in reply to suggestions made by me. The folloAving is a
short narrative of the Avhole particulars. The Avater Avas first introduced into the
house in the summer of 1840, by a lead-pipe from a spring at the distance of
rather more than half a mile. The spring Avas purchased for the purpose, as it
had been represented to be of fine quality ; and an analysis, by a chemist in
the neighbourhood, appeared to sheAV that it was of unusual purity, and contained
very little saline matter. This will presently be seen to be by no means the
case.
The pipe had been in use for several months before the housekeeper went to
reside at the Lodge. When Mr JOHNSTON first examined the water, it had been
in constant use for twelve months. And yet it continued to impregnate itself
with lead to the last : In the water, Avhen fresh draAvn, he could detect lead by
sulphuretted-hydrogen eAren without concentrating it.
VOL. XV. PART II. 4 D
270 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
The architect, under whose directions the water had been introduced into the
house, was slow to believe that the housekeeper really suffered from the effects of
lead, or that the water was impregnated with this metal. Even the condition of
the principal cistern, which was found in precisely the same state as at Dalswin-
ton, did not open his eyes altogether to the truth, and indeed rather impressed
him with the notion that negligence in cleaning the cistern was the source of any
mischief that might actually have arisen. This was not surprising. For it was
plausibly argued, that such accidents had not been observed in other places, and
more especially at Aberdeen, where lead is prevalently used for conducting water ;
and the architect was probably unacquainted with the scientific details of the sub-
ject, as they have been hitherto little dwelt upon except in works on Toxicology.
It has been just stated, that the spring was purchased as one of great purity,
represented from actual analysis to " contain but a very small quantity of solids."
I therefore inferred, that, like the water of Dalswinton, it was too pure for the
preventive power of the usual neutral salts of springs to be efficaciously exerted.
Being anxious, however, to fix positively the circumstances connected with so
remarkable an instance of the action of a natural water on lead, I obtained some
of the water for examination. It was transmitted by Mr JOHNSTON with all due
care to ensure its purity. The result is, that, although by no means the sort of
water it was alleged to be, the circumstances of the case come precisely under the
general principles established by me in 1829.
The water is clear, colourless, and without taste. Polished lead immersed in
it becomes tarnished in a few hours, but undergoes no farther change in fourteen
days. Twenty thousand grains evaporated to dryness left a residuum, which, after
exposure to a low red heat, weighed 4.482 grains, indicating a 4460th of solids.
Hence the water is far from being a pure spring- water : It is not more so than
that of many streams in the Scottish Lowlands. It contains, in fact, so large a
proportion of salts, that, if these were of the ordinary kind, lead Avould scarcely
be acted on by it at all. But its ingredients are chiefly the least energetic in pre-
ventive power of all the salts usually found in terrestrial waters. Oxalate of am-
monia has at first no effect, but slowly causes a slight haziness ; which in some
hours gives place to a scanty white precipitate, indicating the presence of a mere
trace of lime. Phosphate of ammonia has no effect even after twenty-four hours ;
but when the water is much concentrated, this test occasions a crystalline pre-
cipitate, proving the existence of a minute trace of magnesia. Nitrate of baryta
produces slowly a very scanty precipitate. As neither this precipitate, nor the
saline residuum obtained by evaporating the water to dryness, presents any effer-
vescence with diluted nitric acid, the water does not contain any carbonate. The
barytic precipitate from 4375 grains of water weighed 0.218 of a grain, and there-
fore corresponded with the small proportion of only a 32,000th of some sulphate,
either sulphate of soda or probably sulphate of lime. Nitrate of silver, however,
PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 271
occasions at once a dense milkiness and white precipitate, shewing the presence
of a large quantity of muriates. Lime and magnesia being present only in the
most minute proportion, it is evident that the chief base in union with the muri-
atic acid is soda ; which farther appears from the cubical tendency of the crystals
obtained by evaporation. It therefore follows, that this water contains about a
4500th of its weight of muriate of soda, the merest traces of sulphates and muri-
ates of lime and magnesia, and no carbonates of any kind. Since carbonates and
sulphates are the most energetic of the preventive salts usually met with in ter-
restrial waters, and the muriates, the only salts here present in any material
quantity, do not act as preventives effectually unless in at least double the propor-
tion observed in my analysis, it is easy to understand why the lead was so readily
attacked in this instance.
When the fact of the water being poisoned with lead was clearly ascertained,
it was at first proposed at once to substitute iron pipes for those of lead. But Mr
JOHNSTON suggested that a trial should be made of a weak solution of phosphate
of soda, as explained above, and recommended in 1836 in my " Treatise on Poisons."
The experiment was accordingly tried by keeping the pipes constantly full of a
solution containing a 27,000th of phosphate of soda. For three weeks no improve-
ment took place ; but it was found that owing to a leakage in the pipe, the solu-
tion required to be constantly renewed, and was therefore never completely at
rest. As it appeared essential to secure this last condition, the leak was found
out, though not without difficulty, and was properly stopped. Fourteen days
afterwards the spring water was readmitted, and a manifest improvement was
ascertained to have taken place, although lead was still contained in the water.
The solution being replaced, another trial was made in the course of six weeks
more ; and sulphuretted-hydrogen then barely tinted the water. A third exami-
nation was made fourteen days later ; and after the water had been running for
some time, sulphuretted-hydrogen did not in the slightest degree affect it. The
last report I have from Mr JOHNSTON, dated the 27th of January, states that the
solution had been withdrawn for a month previously, — that the water had been
kept running constantly for several days before it was subjected to examination, —
and that no trace of lead could be detected in it by careful analysis.
From the facts now detailed, together with the results of my former inquiries,
the following conclusions may be drawn as to the employment of lead-pipes for
conducting water.
1. Lead-pipes ought not to be used for the purpose, at least where the dis-
tance is considerable, without a careful chemical examination of the water to be
transmitted.
2. The risk of a dangerous impregnation with lead is greatest in the instance
of the purest waters.
272 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
3. Water, which tarnishes polished lead when left at rest upon it in a glass
vessel for a few hours, cannot be safely transmitted through lead-pipes without
certain precautions.*
4. Water which contains less than about an 8000th of salts in solution can-
not be safely conducted in lead-pipes, without certain precautions.
5. Even this proportion will prove insufficient to prevent corrosion, unless a
considerable part of the saline matter consist of carbonates and sulphates, espe-
cially the former.
6. So large a proportion as a 4000th, probably even a considerably larger
proportion, will be insufficient, if the salts in solution be in a great measure
muriates.
7. It is, I conceive, right to add, that in all cases, even though the composi-
tion of the water seems to bring it within the conditions of safety now stated, an
attentive examination should be made of the water, after it has been running for
a few days through the pipes. For it is not improbable, that other circumstances,
besides those hitherto ascertained, may regulate the preventive influence of the
neutral salts.
8. When the water is judged to be of a kind which is likely to attack lead-
pipes, or when it actually flows through them impregnated with lead, a remedy
may be found, either in leaving the pipes full of the water and at rest for three
or four months, or by substituting for the water a weak solution of phosphate of
soda in the proportion of about a 25,000th part.
It may be mentioned, that the most convenient way to detect lead in water
is, first, to examine what separates on exposure to the air by dissolving it in warm
acetic acid, and testing the solution with sulphuretted-hydrogen, iodide of potas-
sium, and bichromate of potash, — then, if this process fail, to concentrate the
water to an eighth part, and again test any insoluble matter which separates, —
and lastly, failing this procedure also, to evaporate the water to dry ness, subject
the residue along with charcoal to a red-heat, act on what remains with warm
diluted nitric acid, and test the solution when filtered and neutralized with an
alkali. It may admit of question, whether, in the event of lead being indicated
in the last way only, the very minute quantity which may then be present can
prove detrimental. But this is a topic which it is foreign to my present object to
enter into.
* Conversely, it is probable, though not yet proved, that, if polished lead remain untarnished or
nearly so for twenty-four hours in a glass of water, the water may be safely conducted through lead-
pipes.
PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 273
As connected closely with the subject of the preceding observations, I beg to
append a few remarks on the nature of the compound of lead which is formed in
the course of the action of water on the metal.
Where salts are present, whose acids are capable of forming insoluble com-
pounds with oxide of lead, the deposit which gradually forms on the lead consists
partly of these compounds. But where a substance is produced which floats
loosely in the water, as in the action of distilled water ; or where the water, from
being clear when fresh drawn from a pipe, deposits a white precipitate on exposure
to the atmosphere — as in the instance of the two spring- waters mentioned above
— a compound of a different kind is produced. That which is formed in distilled
water is the only variety produced readily in sufficient quantity for examination.
GUYTON MORVEAU thought this substance was the hydrated oxide of lead.
From my experiments, published in 1829, 1 was led to infer that it is carbonate
of lead, for it effervesces strongly while dissolving in diluted acids ; and it appeared
to me to be the neutral carbonate (PbO + C02), partly because no other carbonate
of lead was known at that time to chemists, and partly because, when deprived
of hygrometric water by a temperature of 212°, its loss of weight, on being subse-
quently heated to redness, corresponded closely with the theory of its elements
being united in the proportion of a single equivalent of acid and oxide. In 1834,
however, Captain YOHKE, who made some interesting experiments on this subject,
— without being, for some time, aware of those previously conducted by me, —
thought, in the first instance, that the substance formed in distilled water was the
hydrated oxide : but he afterwards found reason for considering that it contained
both carbonate and hydrated oxide of lead, although in proportions variable and
not definite.
It appears improbable, that a substance which puts on invariably and entirely
a crystalliform appearance, as this compound does when formed in distilled water,
should be a mere mixture, of indefinite composition. Accordingly, I find that it
is for the most part, and under certain conditions invariably, a regular definite
compound of the carbonate and hydrate of the oxide of lead.
If lead be immersed in distilled water deprived of its gases by ebullition, and
exposed to atmospheric air which has been freed of carbonic acid by solution of
potash, the water soon becomes turbid and the lead tarnished, and there is slowly
formed on the lead a crust of transparent microscopic crystals, presenting trian-
gular and quadrangular facettes, and on the bottom of the vessel a whitish powder
with a shade of leaden blue, and not crystalline. Both the crystals and powder
are soluble, without effervescence, in nitric acid, and convertible into a yellow
powder, with disengagement of much moisture, when they are heated to redness
VOL. xv. PART ii. 4 E
274 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
after having been dried at 212°. This is evidently a hydrated oxide of lead. The
powder becomes carbonated when left exposed to the air, even in the dry state.
When the action of the water takes place in the air, the product is more
abundant, and seems to consist entirely of a mass of white, pearly, microscopic
crystals. These acquire a pale gray tint, when removed from the water and al-
lowed to dry spontaneously. When examined in water with a powerful compound
microscope, they present the appearance of a congeries of thin tables. The pri-
mitive form of the table is probably the equilateral triangle, the crystals being
therefore thin sections of a regular tetrahedre. Some crystals present the trian-
gular form (1.), but with the angles always slightly truncated ; others, by exces-
sive truncation, have become hexagons (2) ; others present slender radiating lines,
dividing the hexagon into six constituent equilateral triangles (3) ; and others of
the latter construction assume the appearance of rosettes, probably by erosion of
the angles of the hexagon (4).
When 28.62 grains had been dried at 180°, they lost only 0.01, on being
heated to 250° ; and no further change took place till the temperature rose to
350°, at which point moisture began to be slowly discharged. A low red heat ex-
pelled much carbonic acid and a considerable quantity of water.
An apparatus was constructed for transmitting the disengaged gas through
fragments of chloride of calcium to absorb the moisture, as well as for collecting
the dry gas over mercury. When the whole gas and water had been expelled by
heat, air, previously deprived of carbonic acid gas and moisture by means of
caustic potash, was passed through the tubes composing the apparatus, for the
purpose of driving into the gas-jar the carbonic acid left in the tubes. The volume
of carbonic acid was then ascertained by absorption with solution of potash, and
properly corrected to the temperature of 60° and the barometric pressure of 30
inches. The results obtained with 24.20 grains of the substance formed in large
quantity by the continuous action of distilled water for twenty months, were —
Oxide of lead, .... 21.035 grains.
Carbonic acid (5.588 cubic in.), . . 2.641 . . .
Water, ..... 0.535 ...
24.211 grains.
These numbers correspond nearly with the theory, 3PbO+2C02 + Aq; that
is, a compouud of three equivalents of oxide of lead, two of carbonic acid,- and one
of water, — or rather, a compound of two equivalents of carbonate of lead in union
PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 275
with one equivalent of hydrated oxide of lead. The exact numbers by calculation,
supposing the oxide correct, are 21.035 oxide, 2.656 acid, and 0.540 water. The
slight deviation in my numerical results for the carbonic acid from the exact ato-
mic numbers, probably depends on some of the protoxide of lead having absorbed
oxygen from the atmospheric air passed through the tubes at the close, while heat
was applied to the oxide, so that some of it became red oxide of lead.
This experiment was repeated with 27.965 grains, and the products were —
Oxide of lead, * . "' . . . 24.275
Carbonic acid (6.33 cubic in.), '/' . ''."" 2.992
Water, . . 0.650
27.917
These numbers, like the last, approach closely to the theory 3PbO 4. 2C02 + Aq,
— the exact numbers, by calculation from the oxide, being 3.06 of carbonic, and
0.62 of water.
In a third trial with 23.935 grains, the results were —
Oxide of lead, ..... 20.870
Carbonic acid (5.285 cubic in.), . . . 2.497
Water, . . . . . . 0.547
23.914
Theory applies here exactly so far as regards the water, but the acid is somewhat
deficient, the correct numbers, by calculation from the oxide, being 2.635 acid,
and 0.540 water.
I have also examined the proportion of carbonic acid in other differently pre-
pared specimens, by wrapping the powder in filtering paper, and introducing this
into a jar filled with mercury and a little strong muriatic acid previously charged
with carbonic acid gas. The results have been conformable with those stated above.
When the water was freely exposed to the atmosphere, I have never found that
the proportions differed more than a small fraction from the theoretical numbers
just assigned.
The substance in question is therefore a definite compound of two lead salts.
Other analogous examples have been for some time known to exist among the
oxides and salts of this metal. Though of a brilliant whiteness while in water,
it is rather gray when dry. It is permanent in the air ; for a specimen exposed
for many months gave the usual proportion of carbonic acid, when decomposed
with muriatic acid. When suspended in water and treated with a stream of car-
bonic acid, the water of the hydrated oxide is displaced, and a neutral carbonate
is formed, which is more dense, and of a pure white colour when dry.
On first ascertaining the nature of this substance, I imagined it was a new
276 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD.
body, not previously recognised by chemists. I have since found that MULDER
conceives the common carbonate of lead, the white lead of commerce, to be of the
same nature. He has recently discovered it to consist sometimes of two, and
sometimes of three, equivalents of neutral carbonate, united with one of hydrated
oxide ; and he states that the whitest and finest varieties contain most carbonic
acid. I find the white lead of this city, which is usually of fine quality, to be a
compound of four equivalents of carbonate and one equivalent of hydrate. MULDER
adds, that he could not succeed in displacing the whole water by means of car-
bonic acid. This may be so ; but the compound formed by the action of distilled
water on lead is not similarly constituted. When agitated for two hours in water
with a brisk stream of carbonic acid gas, 27.93 grains of the dry product gave, by
analysis, —
Oxide of lead, ..... 23.44 grains.
Carbonic acid (9.27 cubic in.), . . . 4.38 . . .
Water, ...... 0.15 . . .
27.97 grains.
The carbonic acid obtained is only 0.06 of a grain short of what is required to
neutralize the oxide.
( 277 )
XVII. — On the Parasitic Vegetable Structures found growing in Living Animals.
By JOHN HUGHES BENNETT, M.D., Edinburgh. (Communicated by Dr GRAHAM.)
(Read 17th January and 7th February 1842.)
THAT the eggs of numerous parasitic animals may be deposited in the tex-
tures of living beings, and that these develop themselves in such textures, and
draw thence their nourishment, has been long known. But that, under particular
circumstances, certain cryptogamic plants are capable of germinating and fructi-
fying in the living tissues of animals, and especially in man himself, is a discovery
of recent date.
As these growths are not only interesting to the naturalist, but, inasmuch as
they are connected with disease in animals, ought to arouse the attention of the
pathologist, I was induced to make them a subject of observation, and have now
the honour of laying the results before the Society.
The following are the objects of the present memoir.
1st, To confirm and extend the observations and experiments of M. GRUBY
concerning the mycodermatous vegetations found in the crusts of the
disease named Tinea fawsa, or Porrigo lupinosa of BATEMAN.
2d, To announce the occasional existence, and describe a plant found grow-
ing on the lining membrane or cheesy matter of tubercular cavities in
the lungs of man.
3d, To describe the structure of a plant found growing on the skin of the
gold-fish.
And, 4th, From a review of all the facts hitherto recorded in connexion with
this subject, to draw certain conclusions respecting the pathological state
which furnishes the conditions necessary for the growth of fungi in living
animals.
I.
Observations on the Mycodermatous Vegetations constituting the crusts of the Tinea favosa, or
Porrigo lupinosa of BATEMAN.
In the Comptes Rendus des Seances de 1' Academic des Sciences for July and
August 1841, there will be found abstracts of observations made by M. GRUBY on
the crusts of the disease named Tinea fawsa, or Porrigo lupinosa, according to
VOL. XV. PART II. 4 F
278 DR BENNETT ON THE PARASITIC1 VEGETABLE STUCTURES
BATEMAN. He shews, 1st, That this disease consists in the aggregation of millions
of mycodermatous plants. They are formed of articulated filaments of a diameter
from j^og to gfo of a millimetre ; they spring from an amorphous mass of which
the periphery of each capsule of Tinea is composed, and give off towards its centre
oblong or round homogeneous corpuscles, which are the reproductive spores. The
longitudinal diameter of the sporules is from 555 to jgg of a millimetre, and the
transverse is from ^ to ^ The cells of the tubes sometimes contain small
round transparent molecules, of a diameter varying from jg^g to j^g °f a milli-
metre. "2dly, The seat of these vegetations is in the cells of the epidermis. The
true skin is compressed, not destroyed ; and the bulbs and roots of the hairs are
only secondarily affected. Sdly, The disc of the capsule, which is not at the com-
mencement perforated, opens by a small hole in the centre. This enlarges, and
the plants push through it, so that, at a more advanced period, instead of there
being a central depression in the capsule, there is a convexity, and its edges dis-
appear. 4thly, He inoculated 30 phanerogamous plants, 24 silk- worms, G reptiles,
4 birds, and 8 mammifera, but only induced the disease once, and then in a plant.
The human arm was inoculated five times, but, independent of a slight inflamma-
tion and suppuration, no effect was produced.
On reading the above observations last autumn, I examined the crusts on the
head of a boy who laboured under the disease, and immediately detected the
cylindrical and ramified appearances described by M. GBUBY. With a view of de-
termining the real nature of this affection, and observing the manner in which
the fungi germinated, I was desirous of making a few observations on this case,
and Dr HENDERSON, who had charge of it, obligingly consented to suspend for a
time all active treatment.
Observation 1st. All the crusts were removed from the head by the applica-
tion of poultices. In a few days the scalp was quite clean, presenting here and
there anteriorly patches about the size of half-a-crown deprived of hah1. In these
bald portions of the scalp the skin looked somewhat injected and glossy on the
surface ; but there was no pain on pressure, no abrasion in the skin, or other
symptom of inflammation or local lesion. The disease was now allowed to take
its natural course, and I watched its development daily. In two days, minute
pustules were observed to be thinly scattered over the surface, the contents of
which, when examined under the microscope, were found to consist of normal
pus. In two days more, the number of pustules had considerably increased, and
those formerly observed had become larger. I surrounded several of the latter
with a ring of ink, in order that there might be no difficulty in following the
changes they underwent, and distinguishing them from others. In another day
two of them broke, and the matter exuded formed a scab, which, under the mi-
croscope, was found to be composed of epidermic scales and irregular amorphous
masses, without any trace of vegetable structure. In the interstices of these scabs,
FOUND GROWING IN LIVING ANIMALS. 279
the scalp was covered with a furfuraceous desquamation, consisting only, as
shewn by the microscope, of epidermic scales. On the sixth day, the scabs were
of a dirty yellow colour, but not of the peculiar tint or form of the porrigo crust.
Only a few pustules remained, and the injected appearance of the skin was gone.
On the tenth day, the head was covered with irregular agglomerated scabs, simi-
lar to those produced from impetigo. The separation of numerous epidermic
scales, constituting a furfuraceous desquamation, also continued. On the twelfth
day, I detected for the first time, at the posterior part of the scalp where the hair
was most abundant, small bright yellow spots, the size of a pin's head, somewhat
depressed below the surface. On removing one of these spots with the point of a
lancet, and examining it by means of a biconvex lens of an inch focus, I found a
smooth, cupped-shaped, bright yellow capsule, the diameter of which was about
55 of an inch. Its margin was continuous with several epidermic scales, which it
was necessary to cut or tear through before the capsule could be removed. Hav-
ing done this, it was readily separated from the parts below, except where the
hair which usually perforates these crusts connected it inferiorly with the dermis.
On pulling this out, or cutting it through, the capsule could be removed entire,
leaving behind it a reddened inflamed concave depression, corresponding to the
convexity of its inferior surface. Its removal gave rise to the effusion of a thin
greyish looking serum, which soon concreted on the surface. On placing this
capsule in a drop of water, pressing it between two slips of glass, and examining
it with a magnifying power of 300 diameters, it was found to be composed of an
amorphous mass, in which Avere numerous long-jointed filamentous tubes. These
were seen coming from the edge of the capsule, as M. GHUBY has described.
(Plate VI. fig. 3.) At this time there was no appearance of beaded filaments, com-
posed of round or oval globules. These did not appear until three days later,
at first isolated, and then in groups and chains. (Plate VI. figs. 5 and 6.) The
further development of the plants, and of the disease, appeared to be exactly as
M. GRUBY has described it.
Observation 2d. In a boy of well marked scrofulous habit, labouring under the
Porrigo lupinosa in its most characteristic form, the crusts over the two anterior
thirds of the scalp, where it was for the most part bald, were numerous, round,
and isolated, but matted together posteriorly where the hah* was still abundant.
When examined microscopically the mycodermatous vegetations were immediately
detected as in the last case. All the crusts were removed by the application of
poultices, and the head rendered perfectly smooth and clean. In three days, a
furfuraceous desquamation of the cuticle appeared, which became more and more
abundant until the eighth day, when the small bright yellow spots of the porrigo
made their appearance, not having been preceded by the formation of any pus-
tules. The crusts were removed several times in succession, and the disease
again allowed to appear ; but in this case the appearance of the peculiar porrigo
crusts was never preceded by that of pustules.
280 DR BENNETT ON THE PARASITIC VEGETABLE STRUCTURES
In several other cases which have come under my observation, I have satis-
fied myself that the formation of pustules is not essential to the disease, although
they are often present. Hence the mistake of those pathologists who classified
Porrigo lupinosa amongst the Pustulse. M. GRUBY says that pustules are never
present, which is equally erroneous, although they appear to be a secondary re-
sult, attributable to the irritation the disease produces in some individuals. On
the other hand, I have never seen the disease produced without having been pre-
ceded by desquamation of the cuticle, an observation which appears to me of some
importance, inasmuch as, if true, the disease ought to be classed amongst the
Squamce.
According to M. GRUBY, the plants grow in the substance of the epidermis. I
have made observations to determine the correctness of this statement, and found
that the whole inferior surface of the capsule is formed of epidermic scales, thickly
matted together. These are lined by an amorphous, finely granulated matter, from
which the plants appear to spring, and which unites the branches and sporules to-
gether en masse. Superiorly, however, the epidermic scales are not so dense ; and I
have always found them more or less broken up, and not continuous. The observa-
tions just described are here valuable, as indicating the probable mode in which these
plants, or the sporules producing them, are deposited on the scalp. It will be seen
that the appearance of the peculiar porrigo capsule was invariably preceded by a
desquamation of the cuticle, that is, a separation or splitting up of the numerous
external epidermic scales which constitute its outermost layer. Hence, it is more
probable that the sporules or matters from which the vegetations are developed
insinuate themselves between the crevices, and under the portion of epidermis
thus partially separated, than that they spring up originally below, or in the
thickness of the cuticle.
M. GRUBY accurately describes the mode in which the capsule is formed by
the continual growth of the mycodermatous plants, but he says little regarding
the manner in which the plants themselves are developed. According to my ob-
servations, as soon as the small yellow crust becomes visible, it consists of the
outer capsule, formed by epidermic scales, with a layer of amorphous, very finely
granulated matter within it, from which spring numerous jointed tubes. Sporules
do not appear until later, varying from two to four days ; and their presence in
any quantity may be detected by the eye, from their presenting a whitish colour,
as M. GRUBY pointed out. In order to examine the development of these vegeta-
tions microscopically, it is necessary to make a very thin section of the capsule,
completely through, embracing the outer layer of epidermis, amorphous mass,
and light friable matter found in the centre. It will then be found, on pressing
this slightly between glasses, that the cylindrical tubes spring from the sides of
the capsule, proceed inwards, give off branches which in turn terminate in round
FOUND GROWING IN LIVING ANIMALS. 281
or oval globules. Fig. 1, plate VI. represents a portion of such a section, and fig. 7
shews how these globules or sporules are given off in various ways. I have seen
some oval bodies about twice the size of the others, and some round, both dis-
tinctly nucleated. (Fig. 6, a.) The long diameter of the former measured ^ of
a millimetre. The sporules agglomerated in masses are always more abundant,
and highly developed in the centre of the crust. The cylindrical tubes, on the
other hand, are more readily found near the external layer. I have occasionally
seen swellings on the sides of the jointed tubes, but whether these are sporules,
or the commencement of branches, remains still undetermined.
Remembering the ill success of M. GEUBY'S inoculations, I thought it right
to try whether the disease could be propagated in another part of the individual
already affected ; because, if not susceptible of extending in a person already pre-
disposed, it was not likely to be caught by one in perfect health. I accordingly
made a small puncture in the neck of the boy first spoken of, about an inch below
the occipital protuberance, and an inch and a half from the large masses of crusts
connected with the scalp. I introduced through this puncture, under the cuticle,
some of the broken down yellowish -white friable matter found in the centre of
the capsules, which consists principally of the sporules of the plant. The wound
healed up in a few days without presenting any thing abnormal. I also inocu-
lated my own arm in the same manner, but without any result. I repeated these
inoculations twice on the boy and on myself with the matter of the pustules,
instead of that of the crusts, but in every case without success.
It then occurred to me that, as the disease usually appeared in the hairy
scalp, it might be more readily produced in that part of the integuments. I
therefore had my own scalp inoculated in two places with the pus taken from
one of the pustules. It excited inflammation, suppuration, and ulceration. The
matter discharged formed hard scabs, which, however, in no way resembled those
of the porrigo, or exhibited vegetations when examined with the microscope.
After continuing three weeks, during which period one of the sores extended to
the size of a shilling, and both ulcerations still spreading, they were destroyed by
the frequent application of caustic. I subsequently had my head inoculated with
the sporules of the mycodermata, but the wound healed up completely without
producing any appreciable result.
I subsequently rubbed a mass of the white friable matter, constituted of the
sporules, upon the arm, so as to separate several of the epidermic scales, and
induce erythematous redness. Slight superficial abrasions were produced, which
healed in a few days, without presenting any evidence of the mycodermata hav-
ing germinated. I also sprinkled the sporules over an extensive accidental abra-
sion on the leg, which, however, healed up- in the usual manner.
Thus, in none of these experiments, performed in various ways, on different
portions of the surface, and frequently repeated so as to avoid fallacy, could I
VOL. XV. PART II. 4 G
282 DR BENNETT ON THE PARASITIC VEGETABLE STRUCTURES
succeed in causing the plant to germinate on parts different from those which
originally produced it. In other words, I could not communicate the disease to
other individuals, or from one part of the same individual to another, although it
is generally conceived to be of a highly contagious nature.
I am not aware that this peculiar disease has ever been shewn to exist on
any other animal than man, and we shall hereafter see, that whilst parasitic vege-
table growths have been described as occurring on insects, fishes, reptiles, and birds,
their occurrence in the inferior mammals has, with one exception, escaped notice.
It is important, therefore, to mention, that I have observed crusts upon the face of
a living common house-mouse, similar in every respect to those which constitute
the Porrigo favosa in man. The crusts were of a more irregular form, prominent
in the centre, not forming distinct capsules or perforated by a hair. They formed
a prominent whitish friable mass on the left side of the face of the animal, about
the size of a small bean. Examined microscopically, they presented the cylindrical
tubes and sporules en masse, in every respect identical to those which grow on the
scalp of man.
It has been noticed by every writer on the subject, that the odour of the
crusts of Porrigo favosa is similar to that of mice, and this is so peculiar as not
readily to be mistaken. It is singular, then, that the mycodermatous plant, con-
stituting this disease, should be found growing on these animals. Whether the
disease be peculiar to Man and the Rodentia ? whether it be communicable from
one to the other, or among the latter class of animals ? are questions only to be
answered by future researches.
II.
Description of a Cryptogamic Plant found growing in the sputa and lungs of a man who
laboured under Pneumothorax.
In numerous microscopic examinations of tubercle, tuberculous sputa, and
the lining membrane of tubercular cavities in the lungs of man, I had often ob-
served long filaments, which were evidently the softened shreds of the cellular
tissue constituting the natural texture of the lung. On some occasions, however,
I observed fragments of tubes, somewhat larger, more or less matted together,
which appeared distinctly jointed, and which led me to suppose that a vegetable
structure must occasionally be developed in the matter of tubercle found in the
lungs. I am now enabled to put the truth of this supposition beyond doubt,
whilst circumstances render it highly probable, if not certain, that in the indivi-
dual to whom I am about to refer, these fungi were developed before death.
In examining the sputa of a man in the Royal Infirmary, the most beautiful
and regular vegetable structure was observed. The individual laboured under
phthisis in its last stage, with pneumothorax. On simply placing a drop of the
inspissated purulent-looking matter, discharged by expectoration, between two
FOUND GROWING IN LIVING ANIMALS. 283
slips of glass, and examining it with a magnifying power of 300 diameters, long
tubes, jointed at regular intervals, and giving off several branches, could be seen.
They varied in diameter from jgg to 355 of a millimetre, and appeared to spring,
without any root, from an amorphous soft mass. Their edges were distinctly de-
fined, and the joints composed of distinct partitions, the tubes being in that part
constricted somewhat like certain kinds of bamboo. They were very transparent,
and some management with the diaphragm of the instrument was necessary to
shew them distinctly. They did not appear to contain granules or nuclei. (Plate
VH. fig. 1.)
Interspersed amidst these tubes were numerous round and oval globules,
often 7*5 but generally jgg of a millimetre in diameter, which here and there as-
sumed the form of bead-like rows. (Fig. 5.) On one occasion I found a perfect
branch of the jointed tubes connected with a bunch of these, but this was evi-
dently accidental.
Both the jointed filaments and sporules were developed in great abundance
on the sides of the spit-box containing the man's sputa, which, in this situation,
was inspissated, and presented a yellowish coherent and viscous layer. Here they
were often matted together, and presented the appearance drawn, Plate VII.
fig. 2.
Two days afterwards the man died, and the left lung was found studded
with cavities of different sizes, some of which communicated, by fistulous open-
ings, with the cavity of the pleura. Several of the smaller cavities were partly
filled with soft tuberculous matter, readily separable from the lining membrane.
On examining this matter microscopically thirty-six hours after death, exactly the
same appearances presented themselves as have been described. Numerous
jointed transparent tubes, here matted together, there isolated, were readily ob-
served, mingled with round or oval corpuscles, which, however, were larger and
more developed. Some of these were of an oblong or truncated shape, and ap-
peared to be separated joints of the tubes. (Fig. 6.)
I have no doubt that these vegetations existed in the man's lungs during
life ; first, Because they were apparent in sputa freshly expectorated, and, secondly,
Because they could not have reached such a state of development, as has been
described, hi thirty-six hours. They continued to grow and develop themselves
in the tubercular matter, after the removal of the lungs from the body, as well as
in the matter discharged before death, by expectoration. They appeared to me
somewhat analogous to the Penicilium glaucum of LINK, or those fungi so often
found covering disorganized animal matter ; although the form of the plant, and
the mode in which the branches are given off, shew that they are not identical.
284 DR BENNETT UPON PARASITIC VEGETABLE STRUCTURES
III.
On the Structure of a Cryptogamous Plant found growing on the Skin of the Gold-Fish,
(Cyprinus auratus.)
For such notices as have already been published connected with the growth
of vegetations on living fishes, I must refer to a subsequent part of this memoir.
As in no case, however, are details entered into, I am ignorant whether the vege-
tations or confervse alluded to are the same as those which I have myself perso-
nally examined.
Mr GOODSIR was the first who examined microscopically the vegetations found
growing on the gold-fish. The fish he examined was observed to be in a lan-
guishing state for some time before death, and to be covered with a white efflo-
rescence, of considerable length, which sprung principally from the dorsal fins and
tail, and floated in the water. The animal was dead before being put into his pos-
session. Some days afterwards, he kindly placed at my disposal some of these
filaments, which I examined microscopically, and the following are the results.
Viewed with a power of 300 diameters, two very distinct structures were ob-
served. One of these might be called Cellular, the other Non-cellular.
The cellular structure was composed of elongated cells, which varied in thick-
ness ijjo to ^ of a millimetre, presenting the appearance of long jointed tubes,
which often extended twice across the field of the microscope. They were fre-
quently branched, generally in a dichotomous manner, although sometimes three
branches were given off from one joint. Some of the cells were empty, and ap-
peared very transparent ; others were full of granules, which varied in size from
§55 to ilo °f a millimetre in diameter. Every possible degree of variation ex-
isted in the quantity of the cellular contents, some being full of granules and
opaque, others being partially so, and others again empty and very transparent.
In most of the cells, a distinct nucleus existed, which appeared as a transparent
vesicle about ^ of a millimetre in diameter. Some contained two nuclei.
(Plate VII. fig. 10.) The nuclei were generally (not always) placed at the'proxi-
mal end of the cell, from which came off sometimes two other cells, more rarely
three, giving a branched appearance to these vegetations. (Fig. 12.) On applying
pressure, and by means of a little manipulation, the granular matter Avithin any
particular cell could readily be made to flow from one end to the other, or forced
out by rupturing its walls. These jointed cellular tubes Avere often grouped to-
gether, forming a mesh-work, in which the cells filled with granules ; and those
Avhich were empty could readily be distinguished from each other by their opaque
and transparent appearance. (Plate VII. fig. 8.)
As regards the substance from which this jointed structure arose, it appeared
to be an amorphous mass, composed of very minute granules almost identical with
the matter found in the capsules of the Porrigo, and tubercular cavities formerly
described. It appeared very abundant below the scales from Avhence the tubes
FOUND GROWING IN LIVING ANIMALS. 285
appeared to spring, and push through the crevices between them. No roots could
be observed, and the cells appeared to come out directly from the above granular
mass. I could not satisfy myself in what manner these filaments terminated,
whether they bore sporules, or ended in bulbous extremities similar to those de-
scribed by HANNOVER in the confervse growing on the salamander. The specimen
I examined was already so putrid, and the tubes broke so readily, that this point
could not be determined.
Intermixed with these vegetations, were numerous long finer filaments, from
55o to 5Qo of a millimetre in diameter, and uniform in their size throughout. They
were very long, sometimes curved, and sometimes matted together so as to form
a mesh more or less dense. (Figs. 11 and 12.) Some of these filaments appeared
broken or interrupted, although, on pressing the glasses, the interrupted portion
moved simultaneously with the other. On increasing the magnifying power to
650 diameters, these portions were found connected by a very delicate sheath,
which invested them externally. (Plate VII. fig. 13.)
It was some time before I could make out the origin of these filaments. I at
length satisfied myself that they sprang from the sides of the cellular tubes.
IV.
Facts observed by various Authors connected with the growth of Parasitic Vegetables in
Living Animals.
Before we can draw any conclusions regarding the origin or mode of growth
of fungi in living animals, it will be necessary to inquire into what is at present
known on this subject, and see how far the facts already detailed are analogous
with the observations of others.
Parasitic vegetables have been found growing in numerous animals, and I
shall arrange the facts respecting them according to the class of animals in which
they have been found.
Mottusca. — LAURENT1 has observed cryptogamous vegetations in the eggs of
the Limax agrestis, which more or less impede the development of the embryo.
He has noticed, 1. That the vegetations arise most often from the walls of the in-
ternal tunic of the egg, ramify in the albumen, and form in it a net- work, which
is sometimes checked and compressed by a vigorous embryo, and sometimes they
entwine the embryo in such a way that there is a struggle between the vegetable
and animal development. 2. That the vegetable filaments may also be seen to
arise from the body of a dead embryo, or of a non-developed vitellus. After hav-
ing filled the albumen with then* ramifications, the vegetations throw out new
filaments, which pierce the internal tunic and shell, and prolong themselves from
1 L'Institut, torn. vii. p. 229.
VOL. XV. PART II. 4 H
286 DR BENNETT ON THE PARASITIC VEGETABLE STRUCTUEES
the egg placed in water, under the form of simple or ramified branches, which are
extended to the surface and a little beyond the water. They terminate en masse.
VALENTIN1 also saw confervse in a state of active growth, for several days,
upon the ova of (probably) Limnius stagnalis, during which period the embryo
was in lively motion, and which did not die till later.2
Insects. — LEDERMULLER3 noticed the fact, that on leaving dead flies in water
for a certain time, plants spring from the surface of their bodies. Similar observa-
tions have been made by WRISBERG/ SPALLANZANI,S OTTO FRIEDERICH MULLER/
liYNGBYE,7 GlLL,8 GoTHE,9 NEES VON ESENBECK,10 and MEYEN."
Parasitic vegetables have also been observed on living insects. On this sub-
ject KIRBY and SpENCE12 justly remark, " that as insects often pass no small
portion of their lives in a state of torpidity, in which they remain chiefly without
motion, it will not seem strange, should any partial moisture accidentally accumu-
late upon them, that it affords a seed-plot for certain minute fungi to come up and
grow in." Hence, probably, may be explained the phenomenon of the mwm plant,
described by PE'RE PARRENIN and REAUMUR," and of the vegetable fly found in
Dominica, described by NEWMAN.U To this circumstance, also, it seems most
rational to attribute the growth on insects of certain species of Clavaria, as men-
tioned by HlLL,15 FOUGEREAUX DE BONDAROY,16 BuCHNER,17 and WESTWOOD ;18 of
certain species of Isaria, noticed by PERSOONI!) and SCHWEINITZ ;20 of the Peni-
cillium Fieberi, figured to exist on the Pentatoma prasina, by CoRDA,21 and of the
Spharia entomorhiza, noticed by DICKSON, MADIANNA, and HALSEY,22 and seen by
them growing on the vegetable wasp of Guadaloupe.
1 Repertorium, vol. v. p. 44.
2 See also GRUITHUISEN, Nova Acta, vol. x. p. 445 ; who gives a description of, and figures con-
fervae growing from, a dead Valvata branchiata.
3 Mikroskopische Ergbtzungen, 1760 ; pp. 1-90, tab. xlix. fig. 2.
* Obs. de Animalculis Infusoriis Satura. Goettingse, 1765 ; p. 31, fig. 9-2.
5 Opuscules de Physique Animate et Vegetale, torn. i. p. 157.
6 Neue Samml. d. Schriften der Kbnigl. Danischen. Ges. d. Wiss. Copenhagen, 1788 ; iii. p. 13.
And Nova Acta, vol. iv. p. 215.
7 Hydrophylotogia Danica, p. 79, tab. xxii. See also Flora Danica, tab. 896.
8 Technological Repository, vol. iv. p. 331. ° Heften zur Morphologic, i. p. 292.
10 Nova Acta Physico-Medica, &c. 1831, vol. xv. Pars post. p. 375, tab. 79 and 80.
11 Idem, p. 381, and WIEGMANN'S Archives, 1840, p. 62. I2 Entomology, vol. iv. p. 207.
13 Mem. de 1'Acad. Roy. des Sciences, 1726, p. 426.
14 Philosophical Transactions, 1764, p. 271. 15 Idem, p. 272.
16 Mem. de 1'Acad. Roy. 1769, p. 591.
17 Nova Acta, vol. iii. p. 437, tab. 7.
18 Annals of Nat. History, Nov. 1841, vol. viii. p. 217-
19 Synops. Meth. Fung. 687. g. 63, s. 12.
20 Annals of the Lyceum Nat. Hist, of New York, vol. i. pp. 125-6.
21 Icones Fungorum hucusque cognitorum, Pragse, 1837, 1840.
22 Annals of Lyceum, Nat. Hist. Soc. New York, vol. i. p. 126.
FOUND GROWING IN LIVING ANIMALS. 287
On some occasions, it would appear, that the so called fungi observed on
insects are, in point of fact, constituted of the stolen parts of flowers or plants.
Thus BROWN' has determined apparent fungi on certain bees, to be composed of
the stamina of orchidise, and detected the stamen of aristolochia in a beetle shewn
to him by Mr M'LAY. SCHLECHTENDAHL and SiEBOLD2 have recognised an appa-
rent fungus formation on Eucera Druriella, Zygcena lonicer\ ) \2irpe b\ ' AIRY'S Tracts, p. 324.
Hence the total intensity, or the quantity of light on the screen is
sn sn
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT. 317
g = x' =y' '' dp~~dx' &C'
64 a2 e2/2 l>2 A2 J
-- dx-
st^acosmxdx TT —ma
N°W> Jo ~
/
"I l-cos2ar
. , ° — 2a
= — [ - J ; a being equal to 0.
7T 2« + &C. / n\
= — - I 0 = 0 1
4 « V /
•7T
4£
total quantity of light =
= area of parallelogram x — ^
Now, it ought to be, area of parallelogram x a2 ;
PROB. II. — A series of equal parallelograms are placed before a lens, to find the whole
quantity of light received on a screen placed perpendicular to the axis of the lens
at its focus.
Let e, 2/be the breadth and length of one of the openings, g the breadth of
one of the opaque sides of one of the parallelograms ; p, q the co-ordinates of a
point on the screen, measured from the focus of the lens, q being parallel to the
sides of the parallelograms, b the focal length of the lens, or the perpendicular
distance between the screen and the lens ; m the number of openings.
The intensity of the light at the point p, q is given by AIKY (Tracts, p. 328) as
4a2e2/2 / X6 . 2-7ry/\2 / \b . -rr p e\
D2 \2 TT qf S1 X b ) \irp e S ' \ 6 )
— m
\ A 6 /
~ being introduced as the coefficient of vibration, and the divisor which we seek
to determine respectively.
The whole quantity of light received on the screen is the integral of this
pression with respect to p and q, each between the limits of + oo and - oo . i
ex-
oo. Call
318 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
it w, and let
f g
d
r» rf /rinjr Y /sin_V
J0 y\ y ) \ z )
o Jo \ y J \ * J \ sin r *
Now, / dyr~} = TT (lastProb.)
4a2e
T u Jo \ x I \ sm
Now, it was proved in my Memoir in the Transactions of the Cambridge Philo-
sophical Society, vol. vii. p. 163, that the value of the integral
r/sin a;\ 2 /sin rm x\2 . TT
dxt - ) (- _) is
\ x J \ mart J 2
2 A2 62
v, — - gg - = j)g~ • a x area ot the aperture left uncovered.
Now, it ought to be a2 x same aperture.
D = 6 X.
PBOB. III. — Let evw*y thing remain as in the last Problem, except that the aperture
is an isosceles triangle.
The vibration at the point whose co-ordinates are p, g, is
the limits being y-—x tan a,y-x tan a ; #=0, x=c cos a : where « is the half
of the angle included by the equal sides of the triangle. Integrating with respect
to y, we get
^6a/jf 2 TT / px qx tan a\ 2 '
A 6 a /\ f 2 TT / -n Px y£tana\ 2 TT / JBJ
If M, N denote the coefficients respectively of
cos - (» *— B) and sin -,— - (» /-B) in this integral,
M= . -^ ; r-^pr sin A . (p cos a—a sin a)
2-7T7 STT (p— q tan a) D \b ^
A6 A6a ,27Tc. .,
— s • -o — / — — ^TT sin ^ , ( » cos a + q sm a)
27ry 2 -7T (/> + y tan a) D A6
27TC ,
_ . ^ , — 1 + cos tr-j- (»cos a— o sm a)
A b \ba Afi
2 Try 27rD j»— y tan a
2-7TC.
J . - . 1 — cos -^-r- ( p cos a + o sin a;
\b \ba A o ^
^ '2irq 2 TT D p + q tan a
>. 2.
/•>./ I.'*
B
A
®
11 ])
C m
B
A
" J)
S
B
A C
D B
1)
1) B
'"' '•' A
B
B
444
-3 If*
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT.
By developing the sines and cosines, these expressions become,
319
M =
«-«• tan «
P
a
cos
2%
sm
27T
27T
p . /27T \ 72^ \
+ — sm I ^— , p c cos a ) sin ( ^-7 q c sin a 1
? \X ? / \A6 /
- -
Abbreviate -j pccosa by a:, and -^- y c sin a by y ; then - = - tan a ;
!f !?
M2 + N2, or the intensity at the point whose co-ordinates are jt>, q, is
4 a2 c4 .. 2
4 a2 c4 f .. 2 # . ir2 . )
na „ - ^ sm 2acos 2a 1 1 — 2 cos x cos y -- smzsiny + cos 2y + -^ sm2^ J-
U (* — y j i y y '
If then M = total intensity, we have
4o2c2\2.62sinacosa
- ST-RP -
7r2 D2
2 a; .
5 - %r<>^l — 2cos;rcosw -- smarsin y4-
2— 22 y
y
We proceed now to find the value of this integral. To eifect this we assume the
- f^acosqxdz TT __„ ,, ^
following as proved,^ q2+a.2 =-3 e
Dividing by a, and then differentiating with respect to a, we get,
/" COS §'#«?#_ TTya + l— ja .. .
a? + 3? ~~ T ~^^
Differentiating this with respect to q
/'axsmqxdx_'7rg a
«2 -~
ty ty o
Now 1 + cos 2y + -g sin 2y—2 + —3*- sin 2y.
_
Put a=V-l.y,?=Oi
TK.J. , -i 0 'n
VOL. XV. PART II.
/JJ-
4 K
320 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
r> , 7 - , ,. /ON /"" COS X d X IT . — — ,.— 2/ V— 1
Put a = J-ly,q=Im(2).: _ , - (J-ly + I)e
*00 x sin x d x IT
Put « = V-l^=l
so that we get
4aaca Aa68sinacosa/'°c J f 1 1 . 2 !T »+ta
w = - = - / dy \ — fr- , + 0- •» sin y + <717i lv— •» y+ l; cos y
TrD2 ,/-! •/• I 2y3 2>* "f
_ 2 a2 c2 \2 d? sin a cos a r<*> r cos2y 1 — 1
- -5- sin y (cos y - J~^T sin y ) j-
^
_ 2 a2 c2 X2 ft2 sin a cos a /"* f J. _ siny cosy"!
From (1), by putting y=0, a=0, we getyo ^= «^, «=0 . •• yo -f = ~ •
rx sin y cosy dy 1 f™ sin 2 y , P* sin x ,
Also / „» = o / ~dy=2 I — r rf«,
o/» y3 2^/0 y3 J o x*
/OO • 0t
L- ^ — ^ rf^r= ^ - from (3.), q being equal to 1,
and a to 0.
TJ /^°° /^y ^^ siny cosy\ 7T/1 e a\ tr . n
Hence / I —a- -*- - =:prl — — — =« since a = 0.
»/•» VJr y3 / 2 \ a a / 2
a2 c2 \2 62 sin a cos a X2 6s
.•. M = - =rg - = — ^2- x a15 x «r sm a cos a
X2 &
= p2 x a2 x area of aperture.
Now it ought to be a2 x area of aperture
.-. D = \b.
Remark. — The intensity at the point p, q is expressed by
(sin * " ~y sin
But this is not the problem as it is most frequently presented to us. We must
therefore solve another case.
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT. 321
CASE 2. When the centre of gravity of the triangle falls in the line with the
focus of the lens.
TT T M. / 2ccosa\ / 2ccosa\ ,
Here our limits are y = — ( x+ — ^ — 1 tan a, y = ( * + — „- — j tan a ;
2 c cos a _c cos a
3 '* 3~'
Integrating with respect to y we get
\ba C f 27T/ _ p x q 2, c \
~ rr / dx - cos -^— I v t— B + -T T tan a x + -~- cos a 1
2-7T/ »# o 2~c \ 1
— cos— c- I v t — B + -T- + I tan a a; + -5- cos a )
A V b b 3 / J
\ 6 \ba f . 2 <7T c /« cos a \ 2 'TT c 2 » cos a "I
.-. M = ~ pr . s — j— N \ sm-^-r I e— s 9 sm a ) + sm -=— r -^-5 — f
27ryD 2 TT ( j» — y tan a)^ A.o\ — q tan o) l.A6v3 / A6 3J
If we adopt the notation previously used, this gives
f . (x \ . 2x .
A b a c cos r
{. /x \ . 2x . (x \ . 2x\
sm^g-^j +sm-g- sm (g + yj +sm~3- I
x—y x+y )
27TO _
x—y x+y
2 a c2 sin a cos a f x x . 2x
3 C°S y~* °°S 3 Sm 3
2 a c2 sin a cos a f * x . 2x \
N= (# -y") y D 1 y cos 3 cos y + * sm 3 sm y-y cos T J
4 a2 c4 sin2 a cosz a f n 2* a^ .
-y sm a? sm y + -^ sm2 y
4 sin2 a cos2 a f . x . \
(x2_y^ { (^s *- cos y)2 + (sm x -- sm y)2 j
_4o2c
As this expression is precisely the same as that in the last case, it is unnecessary
to integrate it.
PROB. IV. Every thing the same, except that the aperture is a circle concentric
rvith the lens.
The vibration at the point M, whose distance from the focus of the lens is p, due
to an element of the front of the wave at P, whose distance from the centre is r,
322 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
and angular distance from a plane passing through the axis of the lens and the
point M is 6, is
Now
a r d rd (9 sin 2~(v t-PM).
P M = B— -|-cos Q nearly ; and the vibration becomes
-=r d r d 6 sin -j- ( v t— B + -£- cos 6 ) •
a re /*2 * /27T ro .\
jj/ jo rdrddsm^ -j-cos6\ =M
«-•)-*
then the intensity at the point M is M2 + N2.
o /»2»
Now M^^
27TOC /j
where t0 r+ rtepm8
H &c)
J
.
1 2' "(/I)2 3
(-l)r f r + l r+l (r + iy (r + l)r (r + l)(r)(r-l)
~(fr+T)2{ ~T~ ~T~ ~T72~ 1.2 1.2.3 C'
(— l)r
= 7/r + 1)* x coefficient of the products two and two of the consecutive terms
of the expansion of (1 + *) , i. e. 1st coefficient x 2d + 2* x 3d + &c.
VOL. XV. PART II. 4 S
324 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
f _ ]\r •
= (,r+i)8 x coefficient of xr in the expansion of (1 + *)
(2r + 2)(2r + l).. . . (r + 8)
1-2 .......... r
(-I)
A/r + 2
/r/r + 2
0-4.0
2r
2.4.6...(2r + 2) /r /r-
= 42(-l)r l.3...(2r + l) „«•
2.4...(2r +
/OD
27T J rfj N2
27T
_
-7TC/ D o 2.4...(2r + 2) /r/r+2
_2Tra2 c2 \a 62/>* .r 1 . 3 . . . (2 r + 1) m?r+i
~~D* Jo "lj 2.4...(2r + 2)/777+
-n-o2c2\262 r 1.3... (2 r + 1) OT2^ +2
D2 2.4...(2r + 2) /r + 1 /r+2'
the smallest value of r being 0.
xr .- «"»y * .
Now =2(— 1)
beginning with r = 0.
Hence thatpart of y*~ ^" e~^ which does not contain -V is
(/ — z* m t z* mi
»/m + 7T72 + /2/3
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT.
325
J-—
or, that part of
beginning with r= - 1 .
1 1 m
which does not contain y is — 2 '/,-'+ i'/r+2
,r+l 1.3...(2r+l)
= 2(-l)" -J
l>eginning with r= — 1.
.-. that part of the product
(y + L)
which contains neither ^ nor 2, is
2 C- X)
beginning with r=-l,OT (since the first term
is — 1) ; that part of the product which does not contain y or z in
....
^4 ^ 2.4...(2r +
beginning with r = 0.
But this is precisely one of the factors of the expression for the total intensity.
•TT a2 c2 \a b~
.-. total intensity = - ^ *
r ( -M
z in 1+ y— - v
(that term which contains neither y nor
Now, the actual value of m is infinity, since the integral has to be taken between
the limits 0 and oo , and has been expanded in such a form as to vanish for the
former limit. But in order that the expression which we have just determined
may also vanish when m=0, which it must do if it be the proper formula for ex-
pansion, we must add to it some function which does not contain a term inde-
pendent of y or z. We may add any such term we please. For our present
object it is not necessary to add any at all ; but it may be thought fit to do so.
We observe, then, that -
~y
-, which always involves y, will suffice.
326 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
TT «2 e2 X2 bz
.: total intensity = -- — - x
_vm j t/ + - _ -IN
(that term which contains neither y nor 2 in 1 +^A£ — _ _ _ y — — I) when m= oo)
But y — — =0, whatever be y or z, when m — oo . Hence the part
x-
of it which does not contain y or z is 0 also.
•TT a2 c2 \2 62 X2 62
.-. total intensity = - -^ = -ga- «2 x area of aperture.
Hence we obtain D = \ 6.
PROB. V. — A series of plane waves are reflected at each of two equal mirrors in-
clined by an angle to each other, and are brought by a lens to a screen ; to
find the total intensity of light at the screen.
Let x, y, z, be the co-ordinates of a point in the front of the wave ; p, q, those
of the point in the screen ; the origin being that point of the screen which lies in
the centre of the line joining the foci, whose distance is 2f, the axis of x being in
this line, and the plane of x y the screen.
.: PM2 =(»-s
P M = B — b — — nearly, for the upper mirror.
Similarly Q M = B + (/*""/) ( +f)-iy for tne gecon^ yt being measured down-
wards in this case.
.-. the whole vibration due to the two mirrors is
^ ffdx dy sin ?5 (vt. - B
D J J A
*
b
vt- B - (p~f} (*--n~
Let 2 1 be the length of the mirrors, g their breadth, measured perpendicular
to the axis of z ; then the limits are ir=g, x=0, tf=g, ^=0, y=l, y= —I.
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT. 327
Integrating for y we obtain,
ab\ fff , ( 27T / . n
Vlbratlon = ^9 d* { cos ^ (vt. - B
_ cos Yt _B + + cos (vt. -B -
Integrating for x, it gives
o> 6s X2 f 1 F" . 2 TT / „
47T2Dy IJO + /L ~X"VV
^
-.
2 TT- D
f^^
< X
t,_-
,_
7T2 Dq X 6 < X Z> _ X V 26
sm ^-v~— ^-^ sin
X o
/a 62 X2 . . (
intensity = (^ «m ^- sm - cos
sn Cos
sn
X 6 > + X b X 6
/»-/ J P+f
VOL. XV. PART II.
328 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF
^01*. 2 ( . „ ir(p + f)g .
T> 7 \ sm — \, s
) I
~~yV (/» +/)2
. .
1.2^2 sm T> 7 sm — sm
= I O 62 A2
2* vi i 'u — / iu • '/i i // ~r / i v •" *7T P ' 9 i ^y ) I
sm =;- ^f- — J Jy sin -•f— i« cos -=r- ^ • , — —
X b X 6 X o >
Now the total intensity is the double integral of this expression between the
limits oo and — oo of p and q.
But
Z 7T
b
..,, T (/>-/)
and total intensity = - -^^ J^ dp - 0+2
/-,
total intensity = - —353
a.
and it remains only that we find the value of this integral
We have 4 sin -IftQ* sin !L£#* cos
THE ABSOLUTE INTENSITY OF INTERFERING LIGHT. 329
Now, by formula (1.) Prob. Ill, we can obtain the value of each of the integrals of
these expressions by writing/ v^ for a, and putting for q its corresponding va-
lue: thus,
TT e
/
« co__ ,____
—
r co
/
X
sin sn cos
A 6 A
{_^ 2ir(y + 2/)/V— 1 4 7rfff —e - e * *
A6
/v-
^ f« 27T/ff/ 2-7T , - T
= — == J 2 cos , y, ( cos -- v"? . y x— — V— 1 sin
f,J-l\
, -- .
b \ \b
,. — , 4-7T/2 4-7r(^+/)/ 4 TT(^ + /•)/•-!
- cos ^ •; + V — 1 sin -=T-T -- cos - ^ ,J'J + V - 1 sin - ^ •' ' }
Ao A6 A6 A6J
•7T
cos - > A + cos ^T7 -- V — sm
> A ^T7 -- — - -\ L
A 6 A 6 A 6
4-7T/2 4lT/2 ,— 5 . 4-7T/2
- V-l sm -^- — cos ^ ; + V — 1 sin ^ ; - cos
^ — ^ - -- .
A6 Ao Ao
\ Q
-sm -^4-- } '
jjo^ig 27 / " ~\ '' 2
Hence the expression for the total intensity is reduced to - — a ff= - ^-£- x
sum of areas of the mirrors estimated perpendicularly to the line which bisects
the angle between ; or which is the same thing,
£2 ^2 a2
total intensity = — jp — x effective aperture.
But it ought to be, «2 x effective aperture
330 PROFESSOR KELLAND ON THE THEORETICAL INVESTIGATION OF, &c.
CONCLUSION. — It appears that in all the Problems, the result is one and the
same, that the divisor is b \. Hence, we enunciate Huyghens' principle as fol-
lows : — The vibration at a given point, caused by a given wave, is found by taking the
front of the wave, dividing it into an indefinite number of small parts, considering the agi-
tation of each of these parts as the origin of a wave whose maximum of vibration, on
reaching the point, is equal to the quotient of that at the disturbing point, divided by the
product oftlie length of the wave, and the perpendicular from the disturbed point on the
front of the wave.
( 331 )
XXI. — Analysis of Caporcianite and Phakolite, two nerc Minerals of the Zeolite
Family. By THOMAS ANDERSON, M.D. Communicated by Dr CHRIS-
TI80N.
(Read, April 18. 1842).
THE minerals of the zeolite family have for many years attracted the espe-
cial attention of men of science, and the class has been rapidly extended in pro-
portion to the progress made in its study in a crystallographic as well as chemical
point of view. The first characteristic difference, originally observed long since
by CRONSTEDT, and by him considered to be the distinguishing mark of one single
mineral species, which he designated Zeolite, — namely, the property of swelling
out by heat previous to fusion, — has since been found to belong to a great
number of other combinations. These, although materially different from each
other in crystallographic form, have proved to be closely allied in chemical con-
stitution, in so far as they consist, without exception, of a silicate of an alkali
or alkaline earth, in combination with a silicate of alumina and water. It is
evident, then, that the relation of the silicic acid to the base, in both terms, as
well as the quantity of water, is capable of considerable variation, so that the ge-
neral mineralogical formula which should embrace all the members of the zeolite
family would be
u r S" + x A Sy + « A q.
Where r represents the monatomic alkaline or earthy basis, and the terms u, v, x,
y, and z, are capable of varying within certain limits.
The minerals Caporcianite and Phakolite form two new members of the above
general formula. Their analysis was conducted in the following manner : —
The finely pulverized mineral was dried for several days over sulphuric
acid in an exsiccator, at the ordinary temperature of the atmosphere. A certain
quantity of the dry powder was then weighed in a small tube retort, and heated
to moderate redness for the space of half an hour. The water thus driven off was
absorbed in a counterpoised tube of chloride of calcium and weighed. Another
portion of the dry powder was then dissolved in hydrochloric acid, and evapo-
rated to dryness for the separation of the silicic acid. The dry mass was then mois-
tened with hydrochloric acid, digested for several hours, and dissolved in water,
and the silicic acid filtered off. The purity of the silicic acid was then tested by
solution in a boiling solution of carbonate of soda ; the undissolved matter, which
VOL. xv. PART u. 4 u
332 MR ANDERSON ON THE ANALYSIS OF CAPORCIANITE AND PHAKOLITE.
consisted chiefly of silicate of lime, reproduced by the strong drying necessary for
the separation of the silicic acid, was then heated to redness with carbonate of
soda; and alumina and lime were precipitated respectively by ammonia and oxalate
ammonia. The precipitates thus obtained, weighed and subtracted from the first
weight, gave that of the pure silicic acid. The solution, after the filtration of the
silicic acid, was precipitated by caustic ammonia ; the precipitate, after being fil-
tered, washed, dried, and weighed, was dissolved in hydrochloric acid, and the
silicic acid left undissolved was weighed ; to the filtered solution potassa was
added in sufficient quantity to redissolve the alumina at first precipitated. By
this means iron and magnesia were left undissolved, which were again precipi-
tated from a solution in hydrochloric acid, the first by succinate, and the second
by phosphate, of soda. The weights of the silicic acid, peroxide of iron, and mag-
nesia, contained in the phosphate, being subtracted from the first weight of the
ammoniacal precipitate, gave that of the pure alumina. The solution filtered
from the ammoniacal precipitate was then treated with a solution of oxalate of
ammonia ; and the precipitate of oxalate of lime, after filtration and washing, was
heated to strong redness, and treated several times in succession with a solution
of carbonate of ammonia at a gentle heat as long as it continued to gain weight ;
and the lime was then weighed in the state of carbonate. The solution which
was left affer the separation of the oxalate of lime, was then evaporated to dry-
ness in a counterpoised platinum crucible, and the ammoniacal salts driven off
by a moderate heat ; after which a higher temperature was given for the purpose
of melting the remaining salts. These, which consisted of chloride of potas-
sium, chloride of sodium, and magnesia, were weighed together. By solution in
water the magnesia remained undissolved, and was filtered off, washed and
weighed ; to the solution, chloride of platinum and spirit were added, when the
double chloride of platinum and potassium fell, which was collected on a weighed
filter, and from which the quantity of chloride of potassium, and thence that
of the potassa, were determined. By subtraction of the weights of magnesia and
chloride of potassium from the first weight, that of the chloride of sodium was
obtained from which the soda was reckoned.
CAPORCIANITE.
This mineral was kindly presented to me for analysis by Professor BERZELIUS.
It was first observed by Dr PAOLO SAVI at Caporciani, in the valley of the Caecino.
where it occurs in a copper mine worked by two Englishmen of the names of
HALL and SLOANE, and has been described by its discoverer in his Memorie per
servire allo studio della costituzione fisica della Toscana, parte 2da, § 53.
Caporcianite conducts itself before the blowpipe in a manner perfectly simi-
lar to the other zeolites, in so far as its fusibility and relation to the fluxes are
MR ANDERSON ON THE ANALYSIS OF CAPORCIANITE AND PHAKOLITE. 333
concerned ; but it differs from them in this much, that, previous to melting, it
swells out only to a very inconsiderable degree ; for it melts almost at the same
instant that the swelling manifests itself.
The analysis yielded the following results : —
Silicic acid, . 52.8 oxygen contained 27.43 8.
Alumina, -. 21.7 10.15 1
Peroxide of iron, 0.1 >. 0.03 J
3.65—1.
Lime, . 11.3 3.23
Magnesia, . 0.4 0.15
Potassa, . 1.1 0.22
Soda, . 0.2 0.05
Water, ., 13.1 11.64 3.
100.7
If we here express by r the monatomic bases, then the quantities of oxygen in
r, A, S, and Aq are to each other as 1 : 3 : 8 : 3, which evidently determine the
mineralogical formula to be r S2 + 3 A S2 + 3 A q. This when transformed to the
chemical formula, becomes r3 Si2 + 3 Kl S«'2 + 9 H.
It thus appears that Caporcianite stands chemically in near relation with the
minerals, Analcime, Ledererite, Potash-Harmotome, Chabasie, and Levyne, from
which it is separated merely by the difference in the quantity of water which it
contains. All these minerals consist of a bisilicate of the first as well as of the
second term ; and the quantity of oxygen in the alumina is in all of them three
times that contained in the monatomic basis. The formulae of these minerals are
as follows : —
Analcime, "| ( r — N.
rS2 + 3AS2+2Atf{
Ledererite, J • I r = C.N.
Caporcianite, . r & + 3 A. S2 + 3 A.y r = C.
Potash-Harmotome, rS2 + 3AS2 + 5Ay r= K.C.
Chabasie, -| . r r - C.N.
r S2 + 3 A S2 + 6 A q \ ^ ... T
Levyne, J I r = C.K.N.
The formula r S2 + 3 A S2 is thus, then, known to exist in no less than four diffe-
rent combinations with water, namely, with 2, 3, 5, and 6 atoms, the second of
which results from the foregoing analysis.
PHAKOLITE.
This mineral occurs in small crystals in the Bohemian Mittelgebirge, and
was from crystallographic investigation believed to be nearly related to Chabasie.
But the following analysis shews that this supposition is not confirmed by its
chemical constitution.
4.442.
334 MR ANDERSON ON THE ANALYSIS OF CAPORCIANITE AND PHAKOLITE.
Phakolite, which, in its relations before the blowpipe, agrees in all respects
with the other zeolites, was analyzed after the foregoing method, with this ex-
ception, that the quantity of water was determined simply by the loss of weight
sustained at a red heat. The composition was found to be as follows : —
Silicic acid, . 45.628 oxygen contained 23.708.
Alumina, . 19.480 9'077 1 9 <>21
Peroxide of iron, 0.431 0.144)
Lime, . . 13.304 3.737
Magnesia, . 0.143 0.053
Potassa, . . 1.314 0.222
Soda, . . 1.684 0.430
Water, . . 17.976 15.982.
99.960
This constitution has little resemblance to that of chabasie ; for the quantities of
oxygen in r, A S and A q, are to each other in chabasie, whose mineralogical
formula is r S2 + 3 A S2 + 6 A q, as 1 : 3 : 8 : 6, whereas those quantities in pha-
kolite are in the relation of 1 : 2 : 5 : 3^. If we assume that the quantity of water
has come out too high, which is generally the case when it is determined by the
simple loss of weight at a red heat, then the constitution of phakolite would be
represented by the mineralogical formula r S3 + 2AS + 3 A.q, which transformed
to the chemical, is 3 r Si + 2 Al Si + 9 H.
It appears, then, that phakolite belongs to that class of minerals which in
the first term contain a tersilicate, and in the second, a simple silicate of the
base, along with water. The minerals belonging to this class at present made
out are : —
Gigantolite, . . r S3 + A S + A q r = fe, mg, K.N.
Harringtonite, i §3 A S + 2 A , f ' = C.N.
Mesotype, J • ' \r = N.C.
Lehuntite, . . r S" + AS + 3 Ag r = (N.)C.
Phakolite, . . rSs + 2AS + 3A? r = (C.)K.N.
Mezolite ,, . . r Ss + 3 A s + 3 A , f ^ N + 2 C.
Scolezite, J . I r = C.
Pyrargillite, . . r S" + 3 A S + 4 A q r = fe, my, K.N.
Antrimolite, . . rSs + 5AS + 5Ay r = C.(K.)
From this table it will be seen that phakolite forms a middle term between le-
huntite and mezolite, and differs from them only in the second or alumina term,
which in the three minerals stand to each other in the ration of 1, 2, and 3, while
the quantities of silicate of the monatomic bases and water are the same in all
three.
( 335 )
XXII. — On the Property belonging to Charcoal and Plumbago, in fine Plates and Par-
tides, of Transmitting Light. By JOHN DAVY, M.D., F.R.S. L. & E., Inspector-
General of Army Hospitals, L. R.
(Read 9th January 1843.)
I AM not aware that this property has yet been known to belong to these sub-
stances ; they are commonly considered and spoken of as opaque, without any
qualification.
It was in examining the charcoal of the pith of the elder, that I was first led
to entertain doubt of the accuracy of the current opinion.
The pith of the elder consists of polyhedral cells, commonly pentagonal, of
from about ggg^h to soo^h mcn m diameter, formed of woody matter of extraor-
dinary fineness, as may be inferred from their transparency when seen under the
microscope, and their great lightness. They are unaltered in form, when converted
into charcoal. The charcoal obtained (that which I examined was from a shoot
of this year gathered in December) was brilliant, as might be expected, from its
consisting of plates, and very soft and brittle ; in other respects, in mass, it was
nowise peculiar, having the ordinary colour and opacity of charcoal. When
broken up, however, and seen with a high magnifying power, the detached plates
were found to be transparent in different degrees (allowing lines drawn on the
glass-support to be seen under them), and of different shades of brown — passing
into black on one hand, and into almost white on the other, especially as seen
by reflected light. In general appearance they were not unlike mica viewed with
the naked eye. No pores were visible in them ; but in some there were foramina,
circular, or oval, varying in diameter from about jg^oo^h °f an mcn *° 4o^oth. The
plates themselves varied in size from about gggth to lo^gth of an inch, estimating
their width, and selecting the most entire. So thin were they, that, under a glass
magnifying 800 diameters, the most transparent had no apparent thickness ; the
darker, less transparent, may have had a thickness of from about goioooth *°
3o*oooth of an inch, judging from one, the edge of which, when floating in water,
was so inclined as to offer a tolerable view of it.
That these plates consisted of charcoal, and were not composed of foreign
adventitious matter, such as silica, potassa, or carbonate of lime, I satisfied myself
by a few simple experiments. They were unaltered in the dilute mineral acids,
took fire when heated, and left hardly a perceptible ash : they deflagrated with
chlorate of potash, like common charcoal, and, in brief, did not appear to possess
any chemical qualities connected with their attenuated state, different from those
VOL. xv. PART m. 4 x
336 DR DAVY ON THE PROPERTY OF CHARCOAL AND PLUMBAGO
of common charcoal. I may add, they were found in mass to conduct electricity.
I may observe, further, in confirmation of what has just been stated, that I could
detect no material difference in the charcoal, as regards the translucency of its
plates, after it had been subjected to boiling in distilled water and in dilute mu-
riatic acid ; nor, in a specimen prepared from the pith of the elder similarly treated,
and boiled also in alcohol previously to charring, nor after the charcoal had been
ignited a second time ; if any difference existed, it was in favour of the purified
portions.
Inferring that the charcoal of the pith of the elder owes its transparency
under the microscope to the thinness of its plates, I expected to find the same pro-
perty exhibited by charcoal generally, in a finely divided state ; and the trials I
have made of different specimens have not disappointed me. The notice of a few
examples may suffice.
The pith of the annual shoot of the sycamore, is very similar in structure to
that of the elder ; and the plates of which it consists, when reduced to charcoal,
exhibit, under the microscope, a similar appearance, though not quite so distinct.
The pith of the rush is formed of radiating fibres, ^ooth mcn m diameter and
under, five or six of which commonly proceed from a common centre, and which
are occasionally connected by a membrane or plate of extreme thinness. When
charred, the fibres, by transmitted light, appear of a brownish hue, and some of
them allow lines on the glass-support to be seen obscurely. The plates, by re-
flected light, appear almost white ; by transmitted light brown or grey ; through
them, lines on the glass may be seen distinctly.
The charcoal of cotton shews the fibre of this substance in a very clear
manner, varying in diameter from jgogth to ^ooo^h mcn> flattened, ribbon-like, and
twisted at intervals.* The finer fibres, and the flat part of the larger, free from
torsion, exhibit a certain degree of transparency under the microscope, although
they do not allow lines to be seen through them, unless they have been wasted
in a certain degree in the fire during the process of carbonization ; the larger
fibres, especially when twisted, are almost black, and nearly, if not quite, opaque.
The charcoal of linen-thread, and flax, equally well shew the form of the
fibre of this substance, which is so characteristic. Smaller than the fibre of the
cotton, varying in thickness from ggggth to zmfi*- °f an inch» cylindrical, without
any twist, it appears to be more dense than the fibre of the cotton, and is in a less
degree translucent, — indeed, it is difficult to find a fibre of the charcoal made
from the finest cambric, that transmits light with tolerable distinctness.
* Mr BAUER, in the account he has given of the microscopical appearance of cotton, appended to the
" History of the Cotton Manufacture in Great Britain," by E. BAINES jun., Esq., describes the twisted
appearance of the fibres as being often owing to the junction and torsion of two fibres : this I have never
witnessed, and I am induced in consequence to question the correctness of the observation ; Mr BAUER
may have been deceived by using a microscope of indifferent construction.
OF TRANSMITTING LIGHT. 337
It occurred to me as probable, that the very thin and delicate flower-leaves
of plants might yield charcoal of marked transparency. The petals, probably from
being more heterogeneous in composition than the substances before mentioned,
contract more when subjected to heat, and are more changed, than they are in
form. This may be in a great measure prevented, by confining them in the
process of carbonization between two surfaces of platina or silver-foil. Charcoal
thus obtained from the petal of the pansy, adhering to the foil, was sufficiently
translucent to allow the metallic splendour of the platinum to be seen beneath it.
Examined with a high magnifying power, it displayed no pores ; it appeared of a
bright brown colour, where most translucent, evidently the effect of transmitted
light reflected from the metal.
I shall make mention of only one other variety of vegetable charcoal, that
made from oak-wood. This, when reduced by trituration to the most subtle
powder, spread on glass, and held between the eye and a bright light, obscures
the light in a certain degree, like soot, the matter of smoke from flame, and im-
parts to it a brownish red hue ; and under the microscope, like soot, each minute
particle appears to transmit a reddish light : the smallest particles barely within
the limit of distinct vision, using a glass with a magnifying power of nearly four
hundred diameters and a strong light, have a peculiar splendour, not unlike that
of the dust of the diamond.*
As most animal substances enter into fusion in the process of carbonization,
it is not easy to obtain animal charcoal, fit for trial, of the kind under considera-
tion. However, such as I have tried, has exhibited pretty distinctly the same
property as that from vegetables, as regards the translucency of its minute parts.
I may mention particularly that from gold-beaters' skin, and that from silk.
The charcoal of gold-beaters' skin displays with great clearness the texture
of this substance, provided it is prepared with care, so as to prevent the running
together of its parts in fusion under the action of heat — which may be effected by
charring it, spread on glass or metallic foil. The structure it exhibits under a
high magnifying power, is, as it were, of two layers, very like that of gold leaf;
one composed of fibres forming an irregular open net-work, almost, if not quite
opaque ; — the other, of a close tissue, either apparently homogeneous, or consist-
ing of extremely minute fibres, transmitting a brownish light, about equal in
strength to the green light transmitted by the finer tissue of the gold-leaf, the
coarser fibre of which reflects yellow light.f
* It may be remarked that this powder, by reflected light under the microscope, appears white, but
by transmitted, highly coloured ; and when not in exact focus, almost black. This applies to the finest
powder, viz. that just within the limits of distinct vision, using a lens magnifying about 400 diameters, as
well as to powder somewhat coarser.
t Some parts of gold leaf, which, under a feeble illumination, reflect yellow light, with a stronger
transmit green.
338 DR DAVY ON THE PROPERTY OF CHARCOAL AND PLUMBAGO
Silk, eveii when charred, compressed between pieces of silver-foil, in conse-
quence of fusion, loses entirely its fibrous structure, affording a hard, brittle, char-
coal.* A single fibre of silk, however, may be preserved in its filamentous form,
if charred with a graduated heat on a plate of glass ; when it appears as a glassy
thread, expanded at intervals into globules, of different degrees of transparency,
and of different shades of brown, according to their thinness.
Plumbago, in a very attenuated state, like charcoal, appears to be translucent.
The powder of it, rubbed on glass so as to render dim its surface, like smoke, im-
parts to light transmitted through it a certain colour, a brownish hue ; and seen
with a high magnifying power, exhibits much the same appearance as the fine pow-
der of the charcoal of oak-wood already mentioned ; its minute particles transmit a
reddish light, and are very brilliant when seen with a strong light. The streak of
plumbago on glass, when very light, exhibits the same colour, and admits of a
line underneath it being pretty distinctly seen. The specimens I have examined
have been a foliated kind, which occurs in small quantity, disseminated through
the dolomite rock of Ceylon, associated with ceylanite, — the common plumbago of
commerce, sold in the state of powder, — and two pieces of the foliated kind from
Cumberland. The Ceylon specimen appears to be very pure ; it admits of exten-
sion under pressure, or, in other words, of a certain degree of malleability,! and,
also, of having its minute fragments united by pressure, as it were by a process of
welding.
Coke and anthracite, reduced to a very fine powder, I find, in regard to the
transmission of light, resemble the powder of charcoal of oak-wood ; the minute
particles have the same brilliant appearance under the microscope. Two speci-
mens of the former were tried, one obtained from bituminous coal, the other from
compact lignite ; these substances themselves differ very little from the coke they
yield in the degree of transparency of their minute particles. One specimen only
of anthracite was made the subject of experiment. Strong illumination was re-
quired to shew the translucency of its minute particles ; many of the minute
fragments, having flat surfaces, reflected white light.
* So very different in appearance is the charcoal of cotton, linen, and silk under the microscope, that
the admixture of either in a fabric is more easily recognised after charring than before, especially in tho
instance of a mixed fabric of silk and linen that has been in use, — the coarser fibres of both being of nearly
the same diameter, and, after wearing, the jointed appearance of the fibre of linen becoming very indistinct.
The process of charring, I may add, may probably be employed with advantage in examining the minute
structure of many of the lower vegetables, such as the byssi, confervas, and others of the cryptogamia ;
one species that I have thus tried (Byssus globosd) displays its structure in a very distinct manner,
composed of beaded fibres of about y^gg inch in diameter.
t It is right to remark, that I first heard of this property belonging to the purer forms of plumbago
from Professor JAMESON. Is it not owing to this quality that plumbago exhibits a metallic lustre when
rubbed ? The compact kind, when broken by main force, is without this lustre, is of a dull opaque black,
not unlike fractured basalt, but on the slightest friction it acquires the lustre of a metal.
OF TRANSMITTING LIGHT. 339
t
I shall offer, before concluding, a few remarks on carbon, considered in its
varieties. How paradoxical are these ! The diamond — most remote in its cha-
racter from a metal, perfectly transparent — a nen-conductor of electricity — placed
at the head of the class of gems, and resembling not a little, in its general cha-
racter, those oriental ones, of which a metallic oxide, alumine, is the chief consti-
tuent part. What a contrast is there between it and charcoal, a conductor of elec-
tricity, possessed of peculiar properties, especially in regard to absorption, differ-
ing in this respect from almost every other substance, excepting, indeed, the hy-
drate of alumine — a resemblance the more remarkable, considering their similarity
in their crystalline state ! And, farther, what a contrast is there between both
these substances and plumbago, which possesses the perfect metallic lustre, is
sectile, slightly malleable, admits of incorporation, as it were, by welding, and, in
brief, has very much the character of a metal !
To what the marked differences of these substances are owing remains to be
ascertained. It may be to the presence of minute portions of foreign matters,
which have hitherto escaped detection, although diligently sought after. The dif-
ference in their specific gravities is in favour of this view.* Or, it may be, that
* Whilst the diamond is comparatively of the high specific gravity 3.5, I find that of charcoal, coke,
and anthracite (making allowance for the ash yielded by the latter) is only about 1.5. This is the result
of some trials made with considerable care. The method employed was briefly the following. In the
instance of the charcoal, whilst hot from the crucible in which it had been prepared, it was weighed in
air; then, with distilled water, it was subjected to the air-pump, till it sunk and ceased to give out any
air, when it was weighed in water ; after which it was dried, ignited, and again weighed in air.
A piece of charcoal of the oak, weighing 12 grs., thus treated, appeared to be of sp. gr. 1.519 at
53° F. ; a piece of charcoal of deal, weighing 5.67 grs., of sp. gr. 1.54, and reduced to powder of the sp.
gr. 1.45.
In the instances of anthracite and coke, the same method was used, omitting the weighing in air the
second time, after the weighing in water, as they yielded nothing soluble in water, and ascertaining the
quantity of ash, or foreign fixed matter, which each afforded on incineration.
A portion of a specimen of anthracite, for which I was indebted to Professor JAMESON, weighing
65.2 grs., appeared to be of the sp. gr. 1.57 ; it contained 4.7 per cent, of ash. A portion of coke, weigh-
ing 18.02 grs., obtained from bituminous coal, appeared to be of the sp. gr. 1.70; it contained 6.8 per
cent, of ash. The ash of the anthracite consisted chiefly of silica, with a little alumina, coloured light red
by peroxide of iron ; the ash of the coke, of silica, with only a trace of alumine and peroxide of iron, of the
latter not sufficient to colour it ; both were without lime or alkali. The difficulty of extracting the whole of
the air from the anthracite, charcoal, and coke, was considerable, especially from the coke. After three days'
exposure to the action of the air-pump, the effect was produced on the anthracite ; in about the same time
on the charcoal ; but not in less than eleven on the coke ; it floated eight days, — and this notwithstanding
that the pump was frequently worked — the mercury in the gauge standing steadily, after the first day, at
.25 inch, and although the total quantity of air to be disengaged was equal only to the volume of 4.48 grs.
of water. In one instance, the charcoal was boiled in distilled water, after it had ceased to give out air
under the exhausted reservoir ; but without effect in increasing its specific gravity.
The
VOL. XV. PABT III. 4 Y
340 DR DAVY ON THE PROPERTY OF CHARCOAL AND PLUMBAGO
they are connected solely with difference of mechanical arrangement. The trans-
parency of the minute portions of charcoal and plumbago, assimilating them to
the diamond, may be considered as not unfavourable to this latter view, which is,
I believe, the one now commonly adopted, especially taking into account the dif-
ference of magnitude between the plates and particles described, possessing the
property of translucency, and the atoms, or ultimate particles, the subject of che-
mical action, and probably of crystalline aggregation. A piece of goldbeater's
skin, an inch square, before it was reduced to charcoal, weighed .36 grain, and,
when reduced, only .03 grain ; and yet a portion of this, not exceeding in size a
single red particle of the blood of man, might be seen under the microscope to
consist of several parts : a cylindrical piece of the charcoal of the pith of the elder,
A of an inch long, and .2 of an inch in its transverse diameter, weighed only ^th
of a grain, and yet it was composed of a vast number of plates of large dimen-
sions, microscopically considered, one of them being capable of covering more than
a hundred of the smaller particles which abound in and seem to form the basis of
chyle.
The translucency of charcoal or carbon, in a very finely divided state, and its
effect on light, may help to account for the colour of flame and of luminous bodies
seen through the medium of smoke, and also for the colour (different tints of
brown) exhibited by fluids in which carbonaceous matter is suspended, as when
sulphuric acid is heated with alcohol ; or charcoal in impalpable powder, such as
lamp-black, is mixed with a solution of gum. In the former instance, it is not
improbable that the brown colour of the fluid may be owing chiefly to particles
of carbon suspended in it, so small as to be invisible even when the eye is aided
by the highest power of the microscope. This conjecture is in accordance with
the fact, and indeed was suggested by it, that the coloured fluid, which, seen by
The specific gravity of plumbago is stated to range between 1.987 and 2.456. A specimen of the
compact kind, from Borrowdale, I found of sp. gr. 2.264, and after the exhaustion of adhering air, by the
air-pump, 2.316. A specimen of the foliated kind, I found of the sp. gr. 2.22, and after having been sub-
jected to the action of the air-pump, 2.26. The former yielded, on incineration, 11.48 per cent, of ash,
retaining the form of the mass, of a light ochre yellow, which was found to consist chiefly of silica, with a
little peroxide of iron, and a very little alumine, with a trace of lime and magnesia. The latter being
incinerated with great difficulty, was deflagrated in red hot nitre ; it yielded 4 per cent, of ash, which
was found to consist chiefly of silica and peroxide of iron, with a little lime and magnesia. The ash was
in the form of a powder of fine scales. If the iron and silicon exist in plumbago uncombined with oxygen,
their presence may account for the specific gravity of the mineral exceeding that of charcoal and anthra-
cite ; but, if combined with oxygen, then it must be admitted that the carbon in plumbago is in a denser
state than in charcoal. The circumstance that plumbago is slightly magnetic is in favour of the first idea,
and also the fact, as I have ascertained, that it yields air (which it may be presumed is hydrogen) when
acted on by dilute sulphuric acid previously purged of air by the air-pump, and after which iron may be
detected in solution.
OF TRANSMITTING LIGHT. 341
the naked eye, is apparently a perfect solution, under the microscope, with a high
power, exhibits particles of carbon, many of them so small as to be barely within
the limits of distinct vision, and what these are to a lower power, others may be
to the power which brings these into view.
It may be conjectured that other substances, at present considered as opaque,
if examined in the same manner as that which I have applied to charcoal and
plumbago, may also be found to be translucent. Hitherto, I have succeeded only
with one, viz. iodine. When it is viewed in a very finely divided state, as in
the smallest crystals in which it can be obtained, and these allowed to be
attenuated by evaporation, and so reduced to extreme thinness, it appears by
transmitted light of a bright purple colour, very like the colour of iodine in its
gaseous state.
EDINBURGH, December 21. 1842.
( 343 )
XXIII. — On the Growth of Grilse and Salmon. By Mr ANDREW YOUNG, Inver-
shin, Sutherlandshire. In a Letter addressed to JAMES WILSON, Esq.,' F.R.S.E.
Communicated by Mr WILSON.
(Bead 9th January 1843.)
THE history of the habits and development of the salmon has been for ages a
subject of dispute, even among men of science and experience. The general theory
which prevailed regarding its earlier stage of existence was, that the spawn depo-
sited in the autumn or beginning of winter, produced by development the smolts
which were seen descending to the sea in the course of the next ensuing spring.
In regard to its after state, some supposed that the smolts which descended
the rivers in spring or early summer returned as grilses that same season. Manjr
doubted this theory, and maintained that it was impossible, or very improbable,
that they should return so speedily in that greatly enlarged condition ; their only
argument, however, being founded on the unlikelihood of such a rapid growth.
Others, again, have maintained the opinion that the grilse is a distinct species
of fish, closely allied to, but not identical with, the true salmon, and that in the
so-called condition of grilse it has attained to its ultimate state. In fact, this has
been asserted not only by naturalists, viewing the subject somewhat vaguely as
one with which they had no great acquaintance, but also by practical, that is,
professional fishermen, whose opinions, from their more enlarged experience, were
supposed to carry greater weight. But till recently all these various opinions were
uncertain and unsatisfactory, in so far as they were founded upon supposition,
without proof or trustworthy experiment.
But in regard to the first, or, as I may call it, fresh-water state of the fry of
salmon, Mr JOHN SHAW of Drumlanrig, several years ago commenced, and some
time ago concluded, a series of most sagacious and well known practical expe-
riments, which settled that part of the subject. I lately visited Mr SHAW'S expe-
rimental ponds, and carefully examined his various specimens, from the ova to
the smolts, and I am perfectly convinced of the accuracy of the results, and of the
correctness of the general conclusions which he has drawn. This I believe would
have been my opinion, judging simply from Mr SHAW'S explanations ; but I am
happy to say (and think it my duty so to do), that my own more recent experi-
ments, undertaken upon similar principles, though not for such a length of time,
have led to the same results. I have as yet gone no further than to a period cor-
responding to Mr SHAW'S first season ; but this decidedly confirms Mr SHAW'S
principal discovery, by confuting the idea entertained by our ancestors, that the
fry became smolts during the first spring after the ova were spawned. All my
confined specimens are still in the state of parr, exactly as described by Mr SHAW,
with this difference, that their dimensions are somewhat greater ; and I therefore
VOL. XV. PART III. 4 Z
344 MB YOUNG ON THE GROWTH OF GRILSE AND SALMON.
anticipate that a larger number will become smolts in about a twelvemonth after
then* first spring, than was the case with those observed in Dumfriesshire. This
may possibly arise from then- being with me so much nearer the salt-water, of
which I find the influence on salmon, in all its stages, to be most remarkable. I
conceive, however, that the question of the true history of this important species,
from the egg to the smolt, has been set at rest. To connect that early state with
the grilse, and the latter link with the adult salmon, is therefore the object of the
present communication. My long continued superintendence and control of some
of the finest and most productive salmon fisheries in Scotland, and the peculiar
position I occupy, as residing almost within a few yards of the cruives upon the
noted river Shin, afford me advantages which I trust I have not altogether ne-
glected.
I have now made many experiments on these fish, taking up the subject
where it was necessarily left off by Mr SHAW ; and I find, that, notwithstanding the
slow growth of the parr in fresh water, such is the influence of the sea, as a more
enlarged and salubrious sphere of life, that the very smolts which descend into it
from the rivers in spring, ascend into the fresh waters in the course of the imme-
diate summer as grilses, varying in size in proportion to the length of then- stay
in salt water.
Thus, in the months of April and May ef the year 1837, I marked a great
number of the descending smolts by making a peculiar perforation in the caudal
fin with a pair of small nipping irons constructed for the purpose ; and in the
months of June and July I caught a considerable number on their return to the
rivers, all in the state of grilse, and varying from 3 Ib. to 8 lb., according to the tune
which had elapsed since their first departure from the fresh water, or, in other
words, the length of their sojourn in the sea.
Again, in April and May of the present season (1842), I marked a number of
descending smolts, by clipping off the dead or adipose fin upon the back, and care-
fully replacing them in the river. In the course of June and July following, I
caught them returning up the river, bearing my peculiar mark, and agreeing with
those of 1837, both in respect to size, and the relation which that size bore to the
lapse of time. Two of these smolts, as marked last spring, and which I caught
again as grilse, I have transmitted to the care of Mr GOODSIR, College of Surgeons,
in whose hands they may be seen for the satisfaction of the curious or the scep-
tical.
I have no doubt that many who argue on supposition, not on facts, may ask,
how, when salmon from the ovum to the smolt are so slow of growth, their ad-
vance from the smolt to the grilse should be so rapid ? In regard to this, I can
only state the fact as I have repeatedly ascertained it ; and it is not the less a
fact, although some of the final causes which produce it may be uncertain or
obscure. My own opinion is, that it is owing to their change of domicile from
MR YOUNG ON THE GROWTH OF GRILSE AND SALMON. 345
fresh to salt ; and in proof of this I may refer to the following fact, that, with the
exception of the early state of parr, in which the growth is admitted to be slow,
salmon actually never do grow in fresh water at all, either as grilse, or in the
adult state. All their growth in these two most important later stages takes
place during their sojourn in the sea. Not only is this the case, but I have also
ascertained that they actually decrease in dimensions after entering the river, and
that the higher they ascend the more they deteriorate, both in weight and quality.
In corroboration of this I may refer to the extensive fisheries of the Duke of
Sutherland, where the fish of each station of the same river are kept distinct from
those of another station, and where we have had ample proof that salmon habi-
tually decrease in weight in proportion to their time and distance from the sea.
I have also instituted another series of experiments for the purpose of shew-
ing the relationship of the grilse and adult salmon, and connecting, as it were,
these two final stages with each other. In the spring of 1841 I marked a number
of spawned grilses soon after the termination of the spawning season. I took a
net and coble, and fished the rivers for the purpose ; and all the spawned grilse of
4 Ib. weight were marked, by putting a peculiarly twisted piece of wire through
the back fin. They were immediately thrown into the river, and of course disap-
peared, making their way downwards with the other spawned fishes to the sea.
In the course of the next summer we again caught several of these fish which we
had thus marked with wire as 4 Ib. grilse, grown, in the short period of four or five
months, into beautiful full-formed salmon, ranging from 9 Ib. to 14 Ib. in weight,
the difference still depending on the length of their sojourn in the sea.
Again, in January 1842, I repeated the same process of marking 4 Ib. grilses
which had spawned, and were therefore about to seek the sea ; but, instead of
placing the wire in the back fin, I this year put it in the upper lobe of the tail or
caudal fin. On their return from the sea we caught them, salmon as before.
Two of these fish, marked as grilse on the 29th of January, and weighing at that
time 4 Ib., were caught as salmon on the 4th and 14th of July, weighing respec-
tively 8 Ib. and 9 Ib. They were transmitted, at your request, to the care of Mr
GOODSIE of the College of Surgeons, for preservation by that gentleman, in whose
hands they may now be seen, in confirmation of my statements on the subject of
the salmon's growth.*
I may here state, that the motive which first induced me to mark both grilse
and salmon was the desire to ascertain whether the fish of a river were a breed
peculiar to that river alone ; that is, whether the same individuals, after descend-
ing to the sea, returned to their original spawning grounds, or whether, as many
supposed, the main body returning shorewards from their feeding grounds in dis-
tant parts of the ocean, and progressing southwards along the coasts of Scotland,
were thrown into, or encouraged to enter, estuaries and rivers by various acci-
dental circumstances, and thus, that the numbers obtained in these estuaries and
* The specimens above referred to are now in the Museum of the Royal Society.
346 MR YOUNG ON THE GROWTH OF GRILSE AND SALMON.
rivers depended mainly on wind and weather being suitable to their upward
entrance at the time of their nearing the mouths of the fresher waters.
To settle this point I commenced, in 1836, to catch and mark all the spawned
fish I could obtain in the course of the winter months during their sojourn in the
rivers. We frequently fished all the pools of a river with net and coble ; and,
as soon as we drew the fish ashore, we made a peculiar perforation in their tails
with the nipping-irons, and threw them back into the water. In the course of
the following fishing season we caught great numbers of them after their return
from the sea, each in its own river with its distinctive mark.
We have also another proof of the fact, that the different breeds or races of
salmon continue to revisit their native streams. You are aware that the river
Shin falls into the Oykel at Invershin, and that the conjoined waters of these
rivers, with the Carron and other streams, form the estuary of the Oykel, which
flows into the more open sea beyond or eastwards of the bar, below the Gizzen
Brigs. Now, were the salmon which enter the mouth of the estuary at the bar
thrown in merely by accident or chance, we should expect to find the salmon of
all the various rivers which form the estuary of the same average weight, for, if
it were a mere matter of chance, then a mixture of small and great would occur
indifferently in each of the interior streams. But the reverse of this is the case.
The salmon in the Shin will average from 17 lb. to 18 Ib. in weight, while those of
the Oykel scarcely attain an average of half that weight. I am therefore quite
satisfied, as well by having marked spawned fish descending to the sea, and
caught them ascending the same river, and bearing that river's mark, as by a
long continued general observation of the weight, size, and even something of the
form, that every river has its own breed, and that that breed continues, till cap-
tured and killed, to return from year to year into its native stream.
I may now mention that I commenced marking grilses, with a view to ascer-
tain that they became salmon, so far back as 1837, and have continued to do so
ever since, though never two years with the same mark. The result in respect to
growth in each of these earlier years corresponded exactly with what I have given
in more detail regarding the years 1841 and 1842.
The following lists are extracted from the note-book in which I have care-
fully recorded the peculiar marks, the periods of marking, the weight at each
period, the time of the recapture, and the increased weight.
List of Smolts marked in the River, and recaptured as Grilse, on their first ascent from the Sea.
Period of Harking. Period of Recapture. Weight when Retaken.
1842, April and May. 1842, June 28. 4 lb.
... ... July 15. 6 lb.
15. 5 lb.
25. 7 lb.
25. 6 lb.
... 30. S^lb.
Period of Recapture.
Weight when Marked.
Weight when Retaken.
1841, June 23.
41b.
91b.
26.
41b.
11 lb.
26.
41b.
91b.
26.
41b.
10 lb.
... July 27.
4Ib.
13 lb.
28.
41b.
10 lb.
1.
41b.
12 lb.
1.
41b.
14 lb.
27.
41b.
12 lb.
1842, July 4.
41b.
81b.
14.
41b.
91b.
14.
41b.
81b.
23.
41b.
91b.
29.
-41b.
11 lb.
... Aug. 4.
41b.
10 lb.
11.
41b.
12 lb.
ME YOUNG ON THE GROWTH OF GRILSE AND SALMON. 347
List of Grilse marked after having Spawned, and recaptured as Salmon, on their second ascent
from the Sea.
Period of Marking.
1041, February 18.
18.
18.
18.
18.
18.
March 4.
4.
4.
1842, January 29.
29.
29.
March 8.
January 29.
... March 8.
January 29.
In the year 1841, we marked a few spawned salmon along with the grilse.
We marked both kinds in the back fin, but the salmon with copper wire, and the
grilse with brass wire. I perceive by my lists, that a salmon marked on the 4th
of March, returned and was captured on the 10th of July, with an increase of
6 lb., having grown in that time from 12 to 18 Ib. In 1842, however, we marked
no salmon ; all were grilse of 4 lb., and were marked in the caudal fin. In the
course of both seasons we caught far more marked grilse returning with the form
and attributes of perfect salmon than are recorded in my lists. 'In many speci-
mens the wires had been torn from the fins, either by the action of the nets or
other casualties ; and although I could myself recognise distinctly that they were
the fish I had marked, I kept no note of them. All those recorded in my lists
returned, and were captured with the twisted wires complete, — the same as the
specimens transmitted for your examination.
I think that the preceding facts, viewed in connection with Mr SHAW'S obser-
vations, entitle us to say that we are now well acquainted with the history and
habits of the salmon, and its rate of growth from the ovum to the adult state.
The young are hatched during a period which admits of considerable range, ac-
cording to the temperature of the season, and the character of special places.
Their growth in the early state of parr is extremely slow, and the silvery aspect
of the smolt is not assumed till at least the lapse of a year from the time of
hatching. The great mass of smolts descend to the sea during the months of
April and May, but not the whole, because the varying range of the spawning
season carries with it a somewhat corresponding range in the assumption of the
VOL. XV. PART III. 5 A
348 MR YOUNG ON THE GROWTH OF GRILSE AND SALMON.
first change, and the migration of the smolts towards the sea. They return
as grilse during the summer and autumn of the same season, their increase of
size depending on the length of time which has elapsed between their departure
from and return towards the river water. Such of these grilse as escape the
snares of the fishermen and other enemies, spawn that same season in common
with the salmon, and after spawning, both the one and the other redescend into
the sea in the course of the winter or ensuing spring. They all return again to
the rivers sooner or later, according as they had previously left it, after having
spawned, early or late. The grilse have now become salmon by the time of their
second ascent from the sea All these changes and conditions I have verified by
special experiment, as well as by general observation, from the egg to the smolt
(the parr inclusive), from the smolt to the grilse, from the grilse to the salmon ;
and I am perfectly satisfied with the accuracy of the conclusions come to, and
which I have here endeavoured to explain.
XXIV. — Ow £/i<2 Z«w <2/" Visible Position in Single and Binocular Vision, and on
the representation of Solid Figures by the union of dissimilar Plane Pictures
on the Retina. By SIR DAVID BREWSTER, K. H. D. C. L., F. R. S., and
V. P. R. S. Edin.
(Read 23d Jan. and 6th Feb. 1843.)
IN the course of an examination of Bishop BERKELEY'S " New Theory of Vision,"
the foundation of the Ideal Philosophy, I have found it necessary to repeat many
old experiments, and to make many new ones, in reference to the functions of the
eye as an optical instrument. I had imagined that many points in the physio-
logy of vision were irrevocably fixed, and placed beyond the reach of controversy ;
but though this supposition may still be true in the estimation of that very limited
class of philosophers who have really studied the subject, yet it is mortifying to
find that the laws of vision, as established by experiment and observation, are as
little understood as they were in the days of LOCKE and BERKELEY. Metaphysi-
cians and physiologists have combined their efforts in substituting unfounded spe-
culation for physical truth ; and even substantial discoveries have been prema-
turely placed in opposition to opinions of which they are the necessary result.
In prosecuting this subject, my attention has been particularly fixed upon
the interesting paper of my distinguished friend Professor WHEATSTONE, " On
some remarkable and hitherto unobserved phenomena of binocular vision." * It is
impossible to over-estimate the importance of this paper, or to admire too highly
the value and beauty of the leading discovery which it describes, namely, the
perception of an object of three dimensions by the union of the two dissimilar
pictures formed on the retinse : — but, in seeking an explanation of this curious
phenomenon, and in applying it to explain phenomena previously known, Mr
WHEATSTONE has adduced experimental results, and drawn conclusions which
stand in direct opposition to what was best established in our previous knowledge.
Before entering, however, upon this branch of the subject, I must first explain the
law of visible direction, and the phenomena of ocular parallaxes.
1. On the Law of Visible Direction in Monocular Vision.
Several philosophers had hazarded the opinion, that every external visible
point is seen in the direction of a line passing from its picture on the retina
through the centre of the eye considered as a sphere ; while others maintained
that every such point was seen in the direction of the refracted ray by which its
image was formed.
* Phil. Trans. 1838, p. 371.
VOL. XV. PAR? III. 5 B
350 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
The celebrated D'ALEMBERT, in his Doutes sur differents questions d'Optique,
maintains that the action of light upon the retina is conformable to the laws of me-
chanics ; and he adds, that it is difficult to conceive how an object could be seen in
any other direction than that of a line perpendicular to the curvature of the retina
at the point where it is really excited. He then investigates, mathematically,
how the apparent magnitudes of objects would be affected, on the two supposi-
tions that the line of visible direction coincides either with the refracted ray, or
with a line perpendicular to the retina at the point of excitement. On the first
of these suppositions, he finds that the apparent magnitude of small objects would
be increased about j^th, and on the second supposition, a little more than g, or
TJjjfi. This last result is, as D'ALEMBERT justly remarks, so contrary to expe-
rience, that we cannot suppose vision to be thus performed, however natural the
supposition may appear. " In the direction of what line, then," he adds, " do we
perceive objects, or visible points, which are not placed in the optical axis ? This
is a point which it appears very difficult to determine exactly and rigorously. As
experience, however, proves that objects of small extent, which are within the
range of our eyes, do not appear sensibly greater than they are in reality, it fol-
lows, that the visible point which sends a ray to the cornea, is seen sensibly in
its place, and consequently in the direction of a line joining the point itself and
its image on the retina. But why," D'ALEMBERT adds, " is this the case ? It is
a fact which I will not undertake to explain."*
When we consider the data from which D'ALEMBERT has deduced the pre-
ceding results, it is not easy to account for his having abandoned the inquiry as
a hopeless one. He employs the dimensions of the eye as given by PETIT and
JURIN, and he assumes JURIN'S index of refraction for the human crystalline lens,
though it is almost exactly the same as that of an ox, as given by HAWKSBEE.
These, indeed, were the best data he could procure ; but he should have inquired
if the most probable law of visible direction was compatible with any other di-
mensions of the eye, and any other refractive powers of the humours which were
within the limits of probability ; and above all, he ought to have examined expe-
rimentally the truth of his fundamental assumption, that visible points are really
seen in their true places when they are not in the axis of vision.
Now it is quite certain that these points are not seen in their true direction,
and that there is an ocular parallax* which is the measure of the deviation of the
visible from the true direction of objects. This parallax is nothing in the axis of
the eye, and it increases as the visible point is more and more distant from that
axis ; and hence it follows, that, during the motion of the eyeball, when the head
is immoveable, visible objects not only change their place, but also their form.
Had the eye consisted of only two concentric coats, a cornea and a retina,
filled with a homogeneous fluid, vision would have been performed by centrical
* Opuscules Mathematiques, Tom. I. Mem. ix. p. 266.
IN SINGLE AND BINOCULAR VISION. 351
pencils ; — the visible and the true direction of points would have coincided, and
objects would have changed neither their form nor their position during the mo-
tion of this hypothetical eyeball round the common centre of the two coats. But
as such an eye could not have afforded sufficiently distinct vision, the introduc-
tion of the crystalline lens became necessary ; and it is owing to the secondary
refractions at its surfaces and within its mass of variable density, that the paral-
lax of visible direction is produced.
The following experiment will establish the existence, and explain the nature
of this parallax. Let MN, Fig. 1, be the eyeball, C the centre of curvature of the
retina, and also the centre of motion of the eyeball. Having placed an opaque
screen S several inches from the eye, till its inner edge just eclipses a luminous ob-
ject A, look away from the screen, and the object A will appear. Keeping the head
steady, place another screen S'* so that, when viewed directly, it does not eclipse
another luminous object B, the line CS'B just grazing the outer edge of B. When
the screens and luminous objects, therefore, are so arranged that A is invisible
when the axis of the eye is directed to S or to A, and B visible when the axis of
the eye is directed to S' or B, — then by turning the eye from A to B, A will appear,
and B will disappear, exhibiting the curious effect of an invisible body appearing
by looking away from it, and of a visible body disappearing by looking at it!
Had the eyeball MN been our hypothetical one, these effects would not have
been produced. All objects, near and remote, would have retained their relative
positions and magnitudes during its rotation.
Hence it follows, that we are not entitled to reject any law of visible direc-
tion, because it gives a position to visible objects different from their real posi-
tion.
Having removed this difficulty, I proceeded to examine the other data of
D'ALEMBERT. Making the eyeball and the retina spherical, he assumes that the
centre of the latter is equidistant from the foramen centrale of the retina, and the
centre of the crystalline lens. This, however, is far from being the case. M. Du-
TOUE, and Dr THOMAS YOUNG, have made the centre of curvature of the retina
coincident with the centre of curvature of the spherical surface of the cornea, as
in our hypothetical eye ; and this centre, in place of being almost half-way be-
tween the apex of the posterior surface of the lens and the foramen centrale, is
actually almost in contact with the latter ! The dissections of Dr KNOX and Mr
CLAY WALLACE, of New York, give similar results. When we add to these con-
siderations the fact that the refractive power of the crystalline lens assumed by
D'ALEMBERT is nearly triple of what it really is, we are entitled to reject the re-
sults of his calculations.
Assuming, then, the most correct anatomy of the eye, namely, that according
* The two screens S, S' may be the opposite edges fo a triangular notch in a card held in the hand.
352 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
to which the cornea and the retina are concentric, it is obvious that if there was
no crystalline lens, pencils, incident perpendicularly on the cornea, would pass
through the common centre, and fall perpendicularly upon the retina. Hence, in
this case, the line of risible direction would coincide with the line of real direc-
tion, and also with the incident and intromitted ray. Now, the refractions at the
crystalline are exceedingly small, and, at moderate inclinations to the axis, the
deviations from the preceding law are very minute. At an inclination of 25° or
30°, a line perpendicular to the point of impression on the retina passes through
the common centre already referred to, and does not deviate from the line of real
visible direction more than half a degree, a quantity too small to interfere with
the purposes of vision. The deviation, of course, increases with the inclination ;
but as there is no such thing as distinct vision out of the axis, and as the indis-
tinctness increases with the inclination, it is impossible to ascertain, by ordi-
nary observation, that any deviation exists. Hence the mechanical principle of
D'ALEMBERT, which he himself has rejected, and the law of visible direction,
which I have established, are substantially true. As the Almighty has not made
the eye achromatic, because it was unnecessary, so He has, in the same wise eco-
nomy of His power, not given it the property of seeing visible points in their real
direction.
Had it been necessary to make the visible ray coincident in direction with
the incident ray, it might have been effected by giving such a form and variable
density to the crystalline lens as to make the ray which it refracted cross the axis
of vision at the centre of curvature of the retina ; and if the crystalline lens were
such that this crossing point was variable, this variation might have been compen-
sated by making the retina spheroidal, with a variable centre of curvature.
That a visible point is seen in the direction of a line perpendicular to the sur-
face of the retina at which the image of the point is formed, may be established ex-
perimentally in the following manner. Having expanded the pupil by belladonna,
look directly at a point in the axis of the eye. Its image will be formed by a cone
of rays variously inclined from 85° to 90° to the surface of the retina. While the
point is distinctly seen, intercept all these different rays in succession, and it will
be found that each ray gives vision in the same direction, the visible point retain-
ing its position. Hence it follows, that on the part of the retina in the axis of
vision, all rays, however obliquely incident, give the same visible direction per-
pendicular to the surface of the membrane. That the same property is possessed
by every other part of the retina cannot be doubted, and may be proved by direct
experiment.
Although D'ALEMBERT states it as unquestionable, that when the visual ray
is in the axis of vision, or the optic axis, and passes to the retina without refrac-
tion, the point which emits it will be seen in the direction of a line passing from
its image to the visible point ; yet, after he has found that his mechanical prin-
IN SINGLE AND BINOCULAR VISION. 353
ciple is not correct, he gives loose reins to his scepticism, and maintains the ex-
traordinary paradox, that objects even which are placed in the optical axis are
not always seen in this axis. The following is the argument he employs, which
I shall give in his own words.
" If we direct the two optic axes AE, BE, Fig. 2, towards a star E, it is
certain that this star appears much nearer to us than it really is : It is true that
we estimate its distance only in a very imperfect and vague manner ; but it is not
less certain that this distance perceived, whether apparent or presumed, is greatly
below the real distance. If, then, we see the star in each of the optical axes AE,
BE, we should see it in each of these axes in the points e, e, which are incompa-
rably nearer A and B than E. Thus we should see two stars e, e, and their appa-
rent distance e e would be nearly equal to AB. Observation, however, proves that
we see only one star, and this star is seen nearly at the middle point e of the line
e e in the direction of lines A e, Be, different from the optic axes. It is true that
these lines, though really different from the optic axes, deviate from them but
very little, but still they do differ from them ; and this experiment is sufficient to
prove that objects which are at a considerable distance from the eye are not seen ex-
actly in the optical axis, even when we look at them directly.
" Whence, in general, nothing is less certain than this common principle in
optics, that objects are seen in the direction of the ray which they send to the eye.'1'1 *
It is almost impossible to believe that D'ALEMBEKT is serious in maintaining
these doctrines. The major proposition of his syllogism is absolutely incorrect. It
is not true that we see the star E nearer than it is. The eye does not see distances
directly : the mind only estimates them, and, according to its means of judging, it
forms a right or a wrong opinion. The second proposition is equally incorrect. We
do not see the star along the lines A €, B e . We see it along the lines AE, BE, at
the very place where it is, and whether we consider it nearer or more remote than
it is, — whether we think that it touches our eye, or exists at the remotest verge
of space, — the position of the optical axis of each eye remains as before, and our
vision of the star is not affected by the truth or falsehood of our judgment.
2. On the Law of Visible Direction in Binocular Vision*
In admitting the correctness of the law of visible direction in monocular Vision,
which I have endeavoured to establish in the preceding section, Professor WHEAT-
STONE justly remarks, " that the result of any attempt to explain the single appear-
ance of objects to both eyes, or, in other words, the law of visible direction for
binocular vision, ought to contain nothing inconsistent with the law of visible di-
* Opuscules Mathematiques, Tokn. I. Mctn. ix. § iv. p. 273-4.
VOL. XV. PART III. 5 C
354 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
rection for monocular vision." * Properly speaking, however, there is no such
thing as a law of visible direction in binocular vision, because there is no such
thing as a centre of visible direction, or a line of visible direction in binocular vision.
When we see an object distinctly with both eyes, it is actually seen in tmo direc-
tions, and the point where these directions intersect each other determines the
visible place of the object. But if we follow Mr WHEATSTONE in considering such
a law as equivalent to the law which regulates " the single appearance of ob-
jects to both eyes," we can readily deduce it as a corollary from the law in mono-
cular vision. A visible point is seen single with two eyes only when it is at the
intersection of its lines of visible direction as given by each eye separately. It is
obvious that this law does not harmonize with the doctrine of corresponding
points, or with the binocular circle of the German physiologists. It is, however,
rigorously true ; for no philosopher can adopt the monstrous opinion that the
functions and laws of vision which belong to each eye, acting separately, are
subverted when they act in concert. Hence it is obvious that the single vision of
points with two eyes, or with tmo hundred eyes, is the necessary consequence of the
convergency of the tmo, or the two hundred, lines of visible direction to the same
point in absolute space ; and although we think that objects appear single with
both eyes, yet it is only the points to which the optic axes and the lines of visible
direction converge that are actually seen single, and the unity of the perception
is obtained by the rapid survey which the eye takes of every part of the object.
The phenomenon of an erect object from an inverted picture on the retina,
which has so unnecessarily perplexed metaphysicians and physiologists, is a demon-
strable corollary from the law of visible direction for points. The only difficulty
which I have ever experienced in studying this subject, has been to discover where
any difficulty lay. An able writer, however, in a recent number of Blackmood' s
Magazine,^ in discussing the BERKLEY AN theory of vision, has started a difficulty
of a very novel kind, and has called upon me personally to solve it. Were this
the proper place for such a discussion, I should willingly enter upon it ; but I
must content myself with stating, that the doctrine which the very ingenious
author calls the ordinary optical doctrine, was never maintained by any optical
writer whatever, and that the doctrine which he substitutes in its place is that
which all optical writers implicitly adopt, though they have thought it too ele-
mentary to require illustration. A visible point which throws out tmo separate
particles of light, an upper and an under, will be inverted on the retina, but a
smaller visible point, which throws out only one particle of light, cannot be in-
verted, because inversion implies a change in the relative position of tmo visible
points.
* Phil. Trans. 1838, p. 388. t June 1842, vol. li. p. 830.
IN SINGLE AND BINOCULAR VISION 355
3. On the Vision of Objects of Three Dimensions.
(1.) By Monocular Vision. — If we look with one eye at a solid body, for example a
six-sided pyramid with its apex directed to the eye, and uniformly illuminated, we
recognise at a single glance that it is not a drawing of the pyramid. When the eye
adjusts itself to distinct vision of its apex, all the more distant parts are seen in-
distinctly, but the eye quickly surveys the whole, adjusting itself to distinct vision
of its base and of its edges, and by these successive efforts, at one time contract-
ing the pupil and the eyebrows to see the near parts, and expanding them to see
the more remote ones, it obtains a knowledge of the relative distance of its differ-
ent parts. The vision of the pyramid thus obtained is nearly perfect. There is
no inequality of illumination produced by the act of single vision ; and there is
no flickering in the outlines of the figure. The only apparent imperfection is, that
when we see one point very distinctly we do not see the other parts with equal
distinctness ; but this imperfection is unavoidable in vision, whether with one or
two eyes ; and, in place of being a defect, is the very means by which we judge
of the relative distance of its parts. If we saw all its lines and parts with equal
distinctness, without moving the eyeball, or without altering the mechanism for
its adjustment, we should not have been able to distinguish the pyramid from its
projection upon a plane surface.
Hence we draw the conclusion that the vision of bodies of three dimensions
with one eye is perfect.
(2.) By Binocular Vision. — -If we now place the pyramid before both eyes, so
that the pictures of it on each retina are nearly similar, the one being the reflected
image of the other, we shall see the pyramid with great distinctness. It will ap-
pear more luminous with the two eyes, and if the observer wished to estimate
the distance of its apex, or any other point of it, from himself, the convergency of
both eyes to that point would enable him to form a more correct judgment than
with a single eye. These, doubtless, are advantages, but they do not in the least
degree improve our vision of the pyramid, which is independent of them. More
light may injure vision as well as improve it ; and if we could project a foot-rule
from each eye, and read upon it the distance of every part of the pyramid, the
vision of it would not in the slightest degree be affected. May we not add also,
that the intromission of scattered light through two eyes in place of one, and the
possible dissimilarity, however small, between the curvatures and densities of
their humours, which would give rise to two pictures of different magnitudes,
would entitle us to give the preference to single vision, in reference to its power
of giving us a distinct view of objects of three dimensions.
356 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
Hence, we conclude, that when the pyramid is placed in a position of sym-
metry between the two eyes, binocular is not superior to monocular vision.
But if the pyramid is so placed that the left eye sees only four faces of it,
while the right eye sees all the six, then the monocular vision of the pyramid is
more distinct than the binocular one. The vision of faces 1, 2, 3, and 4 is suffi-
ciently distinct with two eyes ; but the faces 5, 6, being seen only with one eye,
are less luminous than the other faces, and as the optic axes do not perform
their functions with the same accuracy when the object to which they are directed
is visible only to one eye, the part of the object seen by single vision will not
unite with that seen by double vision ; and, in the case of the pyramid, we shall
observe its apex actually projecting upon the faces 5, 6, of the pyramid, and de-
stroying the symmetry of the picture. When all the faces but No. 6 are seen by
the left eye, vision is still unsatisfactory with both eyes, and yet more so when
only three of the faces are seen by the left eye.
Hence we conclude that, in these cases, binocular is inferior to monocular
vision.
Let us next suppose that the object viewed is a table knife, so placed that,
when the back of it is towards the observer, the left side of the blade is seen by
the left eye, and the right side of the blade by the right eye. As the back is seen
by both eyes, the picture presented to the mind is a compound of one double and
two single sensations, and, consequently, a very unsatisfactory representation of
the object.
Hence we conclude that, in this case, binocular is still more inferior to mono-
cular vision.
These results stand in direct opposition to those given by Professor WHEAT-
STONE, who considers it an established fact, " that the most vivid belief of the soli-
dity of an object of three dimensions arises from two different perspective projections
of it being simultaneously presented to the mind.'" Before entering, however, upon
this branch of the subject, I must examine Mr WHEATSTONE'S views respecting
the binocular vision of figures of different magnitudes.
4. On the Binocular Vision of Figures of Different Magnitudes*
Mr WHEATSTONE seems to have been the first person who made experiments
on the binocular vision of unequal figures. Having drawn on separate pieces
of paper " two squares or circles, differing obviously, but not extravagantly, in
size ;" he placed them in the stereoscope, and concluded from his observations
that the two unequal pictures " coalesced, and occasioned a single resultant per-
ception ;" and that the binocular image thus perceived was apparently intermediate
IN SINGLE AND BINOCULAR VISION. 357
in size between the two unequal monocular ones. This perfect coalescence of the
two images he considers as demonstrated, and he deduces from it the important
conclusion, that, if it were otherwise, " objects would appear single only when the
optic axes converge immediately forwards." That is, we see objects single when
the optic axes converge laterally in virtue of the coincidence of two unequal
images.
These extraordinary results are obviously subversive of the established laws
of vision, but especially of the law of visible direction ; and if they are true, they
must arise from a sudden change in the properties of the humours, or in the func-
tions of the retina. The lesser image may become greater, or the greater less, by
a variation in the refractive density or the form of the cornea and the crystalline
lens, or, what would be more probable, the retina may become subject to a new
law of visible direction. Assuming this to be the case, we must suppose the
change of law to take place in each eye, so that the larger image must be seen
less, and the smaller image seen greater, than they really are. Now, this change
must take place instantaneously at the moment of coalescence, for the two images
retain their proper magnitude till their apparent union takes place ; and the eye
must recover its ordinary functions as instantaneously, for the moment we inter-
cept one of the images the other resumes its proper size.
In order to understand what the nature of this supposed change actually is,
let MN, M'N' (fig. 3, 4) be the two eyes, AB the larger image, and a b the smaller
one ; then if C be the centre of curvature of the retina, the points A,B will be seen
in the directions, An, Em intersecting at C, and the points a, b in the directions as, br
intersecting at C'. But when these separate images coalesce, in consequence of
AB becoming less and b c greater, the points A,B, a, b must be seen in the direc-
tions A.n, Bo, av, bt, intersecting at new centres of visible direction c, c', the one
farther from, and the other nearer to, the retina. If we now shift the larger picture
to the right eye, and the smaller to the left eye, the function of the retina will be
again changed : the left eye MN will have its lines of visible direction as in fig. 4,
and the right eye as in fig. 3. Such an oscillation of the binocular centre of visible
direction on each side of the monocular centre, produced solely during the attempt
to unite unequal images, would indicate a function of the retina so extraordinary,
that the most incontrovertible experiments, and the universal experience of accu-
rate observers, could alone give it credibility.
There is no doubt that the two unequal images appear to coalesce ; but if we
make the outlines of the squares and circles luminous, by pricking small holes in
their outlines, and exposing them to very strong light, we shall find it impossible
to produce a coincidence. The best way to make this experiment is to take two
lines, AB, a £, fig. 5, of unequal lengths, and with a large pin to perforate the
lines at A,B, a, b, so that when we attempt to unite them, as at fig. 6, we shall
see with perfect distinctness then- four luminous extremities. When the point a
VOL. XV. PART III. 5 D
358 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
is made to pass into A, I have never succeeded in making b pass into B. When-
ever there is an appearance of this, either turn round the paper, or the head, so
as to separate the lines as in fig. 6, and it will be invariably seen that if a springs
out of A, b will spring out of a point between A and B. The apparent coincidence,
therefore, of AB with a b, fig. 6, when it is seen, arises from the disappearance of
one or other of the extremities of the two lines.
But Mr WHEATSTONE has described another very interesting experiment, of
the same character as that which we have been examining, and he regards it as
" proving that similar pictures, falling on corresponding points of the two retinae,
may appear double and in different places." Draw a strong vertical line, AB,
fig. 7. and another CD inclined ]some degrees to it, and also a faint line m n paral-
lel to AB, and cutting CD at its centre S, then, according to Mr WHEATSTONE,
the two strong lines AB, CD, when seen with different eyes in the stereoscope, or
brought together by looking at a nearer object, " will coincide, and the resultant
perspective line (CD) will appear to occupy the same place as before ; but the
faint line (m n) which now falls on a line of the left retina, which corresponds
with the line of the right retina, on which one of the coinciding strong lines, viz.,
the vertical one (AB) falls, appears in a different place." In repeating this ex-
periment, I have occasionally observed an apparent coincidence similar to that
which is described in the preceding passage ; but after numerous and varied obser-
vations, made with lines coloured and uncoloured, opaque and transparent, similar
and dissimilar both in strength and form, I have no hesitation in affirming that
the phenomenon described by Mr WHEATSTONE is an illusion, arising from the
actual disappearance of one or more parts, or even of the whole of one of the
lines, and from the difficulty of observing the separation or superposition of images
in the circumstances under which the experiment is made.
The following are a few of the variations of the experiment which I have
found the best calculated to exhibit the real place of the combined images.
1. In Mr WIIEATSTONE'S form of the lines shewn in fig. 7, the strong line A B
assumes more readily the appearance of uniting with the similarly strong line C D ;
but if m n is a strong line and CD a weak one (fig. 11), or an interrupted one, AB
will unite with m n, and not even apparently with CD. In like manner, if AB be a
weakline, it will unite with the weak line m n rather than with CD. (See fig. 12.)
Now, the apparent coalescence of similar lines arises from the fact, that when
corresponding, or nearly corresponding, parts of the retinas are impressed with
similar images, one of the two more readily vanishes, independent of its liability
to vanish from its being out of the axis of vision. Whenever two images inter-
fere with one another so as to impede vision, one of them disappears — or rather,
is not taken cognisance of by the eye. Hence it is, that many sportsmen shoot
IN SINGLE AND BINOCULAR VISION. 359
with both eyes open ; and hence it is that, in very oblique vision, one of the eyes
resigns its office, and leaves the other to view the object distinctly and singly.*
But, in point of fact, AB, fig. 7, does not coalesce with CD. If the eye strives
to see distinctly any object at the point S', then AB coalesces with m n. If the eye
looks fixedly at C when A is united with C, AS' will unite with CS' and S'B with
S'n ; and if the eye is fixed intently on D when B and D are united, S'B will coa-
lesce with S'D and AS with m S'. In these two last cases, the coalescence arises
from the same cause as the coalescence of dissimilar forms in Mr WHEATSTONE'S
fundamental experiment, as I shall now shew.
2. If we join C m, D n, fig. 7 (as is done in fig. 8), we may regard AB and
C m S' n D as dissimilar images of a solid, consisting of two triangles C m S', D n S',
united at their apex. In this case, AS, fig. 8, will coincide with OS' and S'B with
Sw. If the two dissimilar images are, as in figs. 9, 10, 11, and 12, AB will not
appear to coalesce with CD. In fig. 13, the coalescence is not complete ; but it
becomes so by removing the portion a b of the line AB the part A a coalescing
with C, and b B with D. In fig. 14, the line AB will not coalesce with CD ; but
each separate portion of AB will, when the other two portions are concealed or
removed, coalesce with the corresponding portion of CD.
The ocular equivocation, as it may be called, which is produced by the capri-
cious disappearance and reappearance of images formed on nearly corresponding
parts of the retina of each eye, is placed beyond a doubt by Mr WIIEATSTONE'S
own experiments. f Having inscribed the letters A, S, fig. 15, in two equal cir-
cles, he unites the circles, and finds, that, while the common border remains
constant, " the letter within it will change alternately" from A to S. At the
instant of change, the letter " breaks into fragments ; while fragments of the
letter which is about to appear, mingle with them, and are immediately re-
placed by the entire letter." I have long agot described an affection of the re-
tina, of an analogous kind, which illustrates the subject under consideration.
" If we look very steadily and continuously with both eyes at a double pattern
— such as one of those on a carpet — composed of two single patterns of different
colours, suppose red and green ; and if we direct the mind particularly to the con-
templation of the red one, the green pattern will sometimes vanish entirely, leav-
ing the red one alone visible ; and, by the same process, the red one may be made
to disappear." When we join to these various facts the remarkable phenomena
of the disappearance of objects seen out of the axis of vision by one or by both
* The fact of objects seen obliquely not being double, is ascribed by Mr WHEATSTONE to the coa-
lescence of the images of different magnitudes given by each eye.
t Phil. Trans. 1838, p.386, § 14.
} Letters on Natural Magic, p. 54.
360 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
eyes,* we shall find it difficult to believe that two similar unequal figures can
coalesce ; or that " similar pictures, falling upon corresponding points of the two
retinae, may appear double, and in different places."
5. On the Cause of the Perception of Objects in Relief by the Coalescence of Dissimilar
Pictures,
Mr WHEATSTONE concludes his interesting paper with an inquiry into the
cause " mhy two dissimilar pictures, projected on the two retinae, give rise to the
perception of an object in relief." " I will not attempt," he adds, " at present, to
give the complete solution of this question, which is far from being so easy as at
a first glance it may appear to be, and is, indeed, one of great complexity. I
shall, in this place, merely consider the most obvious explanations which might
be offered, and shew their insufficiency to explain the whole of the phenomena."
Mr WHEATSTONE then proceeds to describe the process of vision in the same
manner as we have done in \ 3 ; but impressed with the conviction that his previous
results are correct, he adds, " All this is in some degree true ; but were it entirely
so, no appearance of relief should present itself when the eyes remain intently
fixed on one point of a binocular image in the stereoscope." He then gives the
following experiment as decisive on the subject : — " Draw two lines, about two
inches long, and inclined towards each other as in fig. 7, on a sheet of paper ; and
having caused them to coincide by converging the optic axes to a point nearer
than the paper, look intently on the upper end of the resultant line, without al-
lowing the eyes to wander from it for a moment. The entire line mitt appear
single, and in its proper relief," &c. After making this experiment with the greatest
care, we admit that it may appear single, without being single. To us it does
not appear single, but exactly the same as a line having the same length and the
same position appears in ordinary vision. Now, though this latter line appears
single to most eyes, yet it is certain that every point of it is double and indistinct,
excepting the point on Avhich the attention is fixed, and to which the optic axes con-
verge. The vision of objects in relief from the union of dissimilar pictures, is per-
formed by the very same process as the vision of real objects in relief by the or-
dinary agency of our two eyes ; and in establishing this principle, the true cause
of the phenomenon discovered by Mr WHEATSTONE will be readily obtained.
Mr WHEATSTONE considers it as experimentally established, " that the most
vivid belief of the solidity of an object of three dimensions arises from two diffe-
rent perspective projections of it being simultaneously presented to the mind ;"
and that " the simultaneous vision of two dissimilar pictures suggests the relief of
* See Letters on Natural Magic. Lett. III., p. 54.
IN SINGLE AND BINOCULAR VISION. 36]
objects in the most vivid manner." Having already explained, in § 3, the true
process by which solid bodies are seen in relief, I shall now endeavour to shew,
that, in the vivid relief produced by the union of two dissimilar plane pictures, this
union is merely a necessary accessory, and not the cause of the phenomenon in
question.
When two of the images of two perfectly similar objects are united either by
looking at a nearer or a remote object, the compound image, thus formed, is
seen at the place where the two optic axes converge, and is larger and more re-
mote than the single image if we look at a more distant object, and smaller and
nearer if we look at a nearer object.* The best mode of conducting this class of
experiments is to suspend two equal rings by invisible fibres, or to cement them
upon a large plate of glass, whose surface and figure are not visible to the ob-
server. The object of this arrangement is to prevent the observer from having
any knowledge of their distance from the eye. When the rings, thus placed, are
doubled, interpose an aperture, so as to permit only the united rings to be seen ;
and it will be found that they appear at the place to which the optic axes con-
verge, appearing smaller and nearer, or larger and more remote, according as the
optic axes are converged to a point nearer or more distant than the actual rings.
In both these cases, the similar rings are seen in identically the same manner,
having the same apparent magnitude and position as if a similar real ring were
placed as an object at the spot to which the optic axes converge. Let us now
apply these facts to the vision of the apparent solid produced in consequence of
the union of two dissimilar plane pictures of it. For this purpose, I shall take
the case of the frustum of a cone, after having considered the process by which we
see a real frustum of a cone by both eyes — the nature of the compound picture
which we do see — and the cause of the apparent single picture of which the mind
takes cognizance.
When we look at the real frustum of a cone (ABCD, placed as in fig. 16), the
right eye R sees a solid, whose projection is a! V CD, or abed, fig, 17 ; and the
left eye to a solid, whose projection is A'B'CD, or ABCD, fig. 17. The smaller
circle CD appears nearer to the observer than the base AB, because the eye cannot
see it distinctly without adjusting itself to the distance RC, LD, and converging
its optic axes to that distance. Each eye, acting alone, sees the cone single, and
the various points of its outline are seen more or less distinct, according as they
are more or less remote from the point to which the eye is for the instant adjusted.
But so rapid is the motion of the eye, and so quickly does it survey the whole of
the solid, that it obtains a most distinct perception of its form, its surface, and its
* Several curious facts establishing this result have been given by Dr SMITH in his Compleat System
of Optics, vol. ii. 387-389 ; and Remarks, § 526-527.
VOL. XV. PART III. 5 E
362 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
solidity. When we view the cone with both eyes, we have the same indistinct-
ness of outline when the optic axes are converged to a single point : but in addi-
tion to this, we have the greater indistinctness arising from every point of the
figure being seen double, except the single point to which the axes are converged.
But this imperfection, too, is scarcely visible, from the rapid view which the eyes
take of the whole solid, converging their axes upon every point of it, and thus
seeing each point in succession single and distinct. Hence, we must draw a
marked distinction between the vision, of the solid (as an optical fact) when the
eyes are fixed upon one point of it, and the resultant perception of its figure ari-
sing from the union of all the separate sensations received by the two eyes.
Let ABCD, fig. 16, be the solid frustum of a cone, having its axis MN pro-
duced, bisecting at 0 the distance LR between the two eyes L,R. Draw AL, AR,
BL, BR ; and also CL, CR, and DL,DR. Then, if we look at this solid with the
left eye L only, the projection of it will be as shewn in fig. 17 at ABCD, and in
fig. 16 at A'B'CD ; AC being much greater than DB, and the summit-plane CD
appearing on the right-hand side of the centre of the base AB. The reason of
this is obvious from fig. 16, where the left eye L sees the side AC under the angle
ALC, Avhile it sees the other side DB under the much smaller angle BLD ; the
apparent magnitude being in the one case A'C, and in the other DB'. In like
manner, the right eye R sees DB under the large angle BUD, and with an appa-
rent magnitude D V ; Avhile it sees AC under the smaller angle ARC, and with an
apparent magnitude C a'. Hence it follows, that, with both eyes,, we shall see the
solid in perfect symmetry, with its summit CD concentric with AB ; and hence
the reason is obvious why the two dissimilar pictures in the retina give a resultant
picture corresponding with the solid itself.
Quitting our solid frustum of a cone, let us now suppose that its two dissimi-
lar projections ABCD, abed, fig. 17, are united by the two eyes L,R, converging
their axes to a point nearer the observer. By drawing lines from A,B,C,D, a, b, c, d,
to L and R, the centres of visible direction, it will be seen that the circles AB, a b at
the base, can be united only by converging the optical axes to M, and the summit
circles CD, c D only by converging the axes to N. Hence, mnop will represent
the solid frustum of a cone, whose axis is MN. Now. all the rays which flow from
any point of the two projections AB, a b, cross each other at the figure mnop;
and, consequently, this figure is seen by both eyes in identically the same manner
as if the rays which really emanate from the plane figures had emanated from
their points of intersection, that is, from the outlines of the solid figure mnop.
In order to see the base m n, the optic axes must be converged to M, or any
other point of the base ; and in order to see the summit op distinctly, the axes
must be converged to N. But the distance MN is so very small, that the whole
outline mnop will be seen with great distinctness ; though it is certain that
every point of it, but one, is seen double.
IN SINGLE AND BINOCULAR VISION. 36:3
The height MN of the cone, fig. 18, is =col ^ A-cot\A', A,A' being the an-
gles of the optic axes LMB, LNR, and OL or OR radius. But as these angles are
not known, we may find MN thus : — Let D= distance OP ; d=8s, the distance of
the two points united at M ; e?,=SY, the distance of the two points united at N ;
C=LR=2i inches. Then MP=—,< NP=~~,; and MN=-^. When the two
-
figures are united by converging the axes beyond P, the base mn of the line will
be nearest the eye ; and, consequently, the cone will appear hollow. In this case,
M'N' = - — - — ^ — - ; and the cone will be much larger than in the other case. If
v/ — & o — d
we make
D = 9.24 inches,
C = 2.50 ; then
d = 2.42 ;
d' = 2-14; and
MN = 0.283, the height of the cone. Whereas, in the se-
cond case, M'N = 18.9 feet !
Considering that the summit-plane op rises above the base m n, in conse-
quence of the convergency of the optic axes at N, it may be asked, how it happens
that the frustum still appears a solid, and the plane op, where it is, when the op-
tic .axes are converged to another point M, so as to see the base m n distinctly ?
Should not the relief disappear, when the condition on which it depends is not
fulfilled ? But, instead of the relief disappearing, the summit-plane op maintains
its position there as fixedly as if it belonged to the real solid ; and it ought to do
so, for the rays emanate from it in exactly the same manner, and form identi-
cally the same image on the retina as if it were a real solid. Now, by the mere
advance of the intersection of the optic axes from M to N, the rays from the
circles AB, CD, &c. still produce the same picture on the retina of each eye, and
the only effect of the advance of the point of convergence from N to M, is to throw
that picture a little to the right side of the optic axis of the left eye, and a little
to the left of the optic axis of the right eye ; so that the summit op still retains its
place, and is merely seen double.
6. On ike Doctrine of Corresponding Points.
Our celebrated countryman, Dr REID, calls those points in the retina of each
eye corresponding, which are similarly situated with respect to the foramen centrale,
or centre of each retina; and he maintains that objects painted on those points have
the same visible position. He observes " that the most plausible attempts to
364 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
account for this property of the eyes have been unsuccessful, and that it must be
either a primary law of our constitution, or the consequence of some more general
law which is not yet discovered." This doctrine has been very generally admitted ;
and if great names could have given it currency, those of NEWTON and WOLLAS-
TON, supported by a number of anatomists and metaphysicians, might have placed
it, both optically and metaphysically, beyond the reach of challenge. The doc-
trine of the semidecussation of the fibres of the optic nerve, as explained by NEW-
TON, gave great support to the theory of corresponding points. The idea that
each fibre of the nerve divided itself into two, one of which went to a given point
in the retina of one eye, while the other went to the corresponding point in the
retina of the other eye, seemed to be at once an explanation and a proof of the
doctrine.
Whether the anatomical supposition be true or false is a matter of little con-
sequence at present, as the doctrine which it supports is not true excepting in the
single case where the optic axes are parallel, and in this case it is true only be-
cause it is a necessary consequence of the general law of visible direction.
Along with the theory of corresponding points, we must rank the binocular
circle of the Germans in which it is embodied. Let R, L, fig. 18, be the right and
left eyes whose centres of visible direction are C, C', and whose optic axes CA, C'A,
converge to any point A. Through the three points A, C, C', describe the circle
ABCC'. This circle is called the Binocular Circle, because if we take any point
B in its circumference, and draw BCE, BC'E', the points E, E' on the retinse will
be corresponding points, that is, points equidistant from D (because the angles
ACB, AC'B being equal, DC'E' and DCE are also equal), and consequently when
the optic axes are directed to A, an object at B will have its image formed upon
the corresponding points E, E', and will be seen single.
Now, when the optic axes are directed to A, a ray from B will fall upon the
left eye at L with a greater angle of incidence than on the right eye at R ; and
consequently it will strike the retina at a point farther from D in the left eye
than in the right eye ; that is, if the ray BR is refracted to E, the ray BL will
be refracted to some point e, and consequently the lines of visible direction EC, e C
will meet in a point without the circle ABC. The real binocular curve, therefore,
is everywhere without the circle. Hence the doctrine of corresponding points is
not true ; and if it had been true, it would have been so because it was a neces-
sary consequence of a law of visible direction.
7. On the Vision of Cameos and Intaglios.
The beautiful experiment of converting a cameo into an intaglio, and an in-
taglio into a cameo, by monocular vision, is well known. In 1825 I had occasion
IN SINGLE AND BINOCULAR VISION. 365
to investigate this subject, and in January 1826 I published an account of my ob-
servations, with an ample notice of the previous labours of other authors.*
Mr WHEATSTONE has ingeniously connected this optical fallacy with the union
of dissimilar images on the retina, though he does not refer it to this union as its
cause. After quoting my previous explanation of the illusion, he makes the fol-
lowing observations upon it. " These considerations do not fully explain the phe-
nomenon, for they suppose that the image must be inverted, and that the light
must fall in a particular direction ; but the conversion of relief will still take
place when the object is viewed through an open tube without any lenses to in-
vert it, and also when it is equally illuminated in all parts."-j- In thus objecting
to the fulness of my explanation, Mr WHEATSTONE has overlooked the great num-
ber of experiments by which I have supported it ; and especially those facts in
which I observed the fallacy when the object is viewed without even an open tube, —
without inversion ; — with both eyes open, and when it is placed in broad daylight. Mr
WHEATSTONE then gives his own opinion as follows. " If we suppose a cameo
and an intaglio of the same object, the elevations of the one corresponding exactly
to the depressions of the other, it is easy to shew that the projection of either on
the retina is sensibly the same4 When the cameo or the intaglio is seen with
both eyes, it is impossible to mistake an elevation for a depression ; but when
either is seen by one eye only, the most certain guide of our judgment, viz., the
presentation of a different picture to each eye, is wanting ; the imagination there-
fore supplies the deficiency, and we conceive the object to be raised or depressed
according to the dictates of this faculty. No doubt, in such cases our judgment
is in a great degree influenced by accessory circumstances, and the intaglio or the
relief may sometimes present itself according to our previous knowledge of the
direction in which the shadows ought to appear ; but the real cause of the pheno-
menon is to be found in the indetermination of the judgment, arising from our more
perfect means of judging being absent." $
Now, what Mr WHEATSTONE calls the real cause of the illusion is no cause at
all, — it is merely a previous state of the mind which is favourable to the opera-
tion of the real cause. Two eyes, like two witnesses, must always bear a better
testimony to truth, than one ; and, in the present case, the want of the conver-
gency of the optic axes to estimate the distance of the highest and lowest points
of the cameo and the intaglio, undoubtedly favours the illusion, and allows the
real cause to influence the judgment ; but even here this admission has its limits,
* This account was published anonymously in the Edinburgh Journal of Science for January 1826,
No. VII. vol iv. p. 97 ; and a popular abstract of it afterwards appeared in my Letters on Natural
Magic, Letter V. p. 98.
f Phil. Trans. 1838, p. 383.
t This is true only when they are not seen obliquely. — D. B.
§ Phil. Trans. 1838, p. 384.
VOL. XV. PART III. 5 F
366 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION
for in very shallow cameos and intaglios the illusion takes place with both
eyes.*
Without repeating in this place the various facts respecting mother-of-pearl
and other phenomena in which I observed the illusion when both eyes were used,
I shall content myself with quoting the following observation, made in Egypt by
Lady GEORGIANA WOLFF. " Lady GEORGIANA," says the Rev. Mr WOLFF, " ob-
served a curious optical deception in the sand about the middle of the day, when
the sun was strong ; all the foot-prints, and other marks that are indented in the
sand, had the appearance of being raised out of it ; and at those times there was such
a glare that it was unpleasant for the eye."f
8. On the Change in the Apparent Position of the Drawings of Solid Bodies.
Although this illusion may have been previously observed, yet I believe Pro-
fessor NECKEB of Geneva is the first person who has described and explained it.
He mentioned it to me in conversation in 1832 ; and afterwards sent me a notice
of it, which I published in the London and Edinburgh Philosophical Journal.:):
Mr NECKER describes the illusion in the following manner. " The rhomboid AX,
fig. 19, is drawn so that the solid angle A should be seen the nearest to the spec-
tator, and the solid angle X the farthest from him, and that the face ACBD
should be the foremost while the face XDC is behind. But in looking repeatedly
at the same figure, you will perceive that at times the apparent position of the
rhomboid is so changed that the solid angle X will appear the nearest, and the
solid angle A the farthest, and that the face ACDB will recede behind the face XDC,
which will come forward ; which effect gives to the whole solid a quite contrary
apparent inclination." Professor NECKER observed this change " as well with one
as with both eyes," and he considered it as owing " to an involuntary change in
the adjustment of the eye for obtaining distinct vision. And that whenever the
point of distinct vision on the retina was directed on the angle A, for instance,
this angle seen more distinctly than the others, was naturally supposed to be
nearer and foremost ; while the other angles seen indistinctly were supposed to be
farther away and behind. The reverse took place when the point of distinct vision
was brought to bear upon the angle X." Upon this explanation Mr WHEATSTONE
makes the following observations : " That this is not the true explanation is evi-
* When the cameo and intaglio are viewed very obliquely, one of the causes of deception disappears.
In the case of a cameo appearing depressed, the depression disappears the instant that the shadow of
the cameo encroaches distinctly upon the plane surface from which it is raised, because an intaglio never
can, however obliquely viewed, throw a shadow upon the plane surface out of which it is excavated. For
the same reason, an intaglio seen very obliquely will not rise into a cameo, because the shadow on the
plane surface is wanting.
t -Journal of the Eev. Joseph Wolff, 1839, p. 189. | Vol. i. p. 334.
IN SINGLE AND BINOCULAR VISION. 307
dent from three circumstances : in the first place, the two points A and X being
both at the same distance from the eyes, the same alteration of adjustment which
would make one of them indistinct would make the other so ; secondly, the figure
will undergo the same changes whether the eye be adjusted to a point before
or behind the plane in which the figure is drawn ; and, thirdly, the change of
figure frequently occurs while the eye continues to look at the same angle. The
effect seems entirely to depend on our mental contemplation of the figure, or of
its converse. By following the lines with the eye, with a clear idea of the solid
figure we are describing, it may be fixed for any length of time ; but it requires
practice to do this, or to change the figure at will. As I have observed before,
these effects are far more obvious when the figures are regarded with one eye
only."
In a case of this kind, where one eminent individual assures us that he has
proved his explanation to be true in three different ways, and another maintains
that this explanation is evidently not the true one from three different circum-
stances, there must be a misapprehension to be removed, as well as a difficulty to
be solved. It is impossible to read Mr NECKER'S paper without discovering that
Mr WHEATSTONE has entirely mistaken his meaning, though the mistake is partly
owing to Mr NECKER'S use of the phrase, " adjustment of the eye for obtaining dis-
tinct vision." Mr WHEATSTONE understands this to mean the adjustment of the
eye to A or X, as if they were at different distances from the observer ; Avhereas
Mr NECKER clearly refers to that indistinctness of vision which arises from dis-
tance on the retina from the foramen centrale, or point of distinct vision. When
the eyes are converged upon A, X is seen indistinctly, and vice versa; and that his
is Mr NECKER'S meaning is obvious from the following conclusion of his letter :
" What I have said of the solid angles is equally true of the edges, — those edges
upon which the axis of the eye, or the central hole of the retina, are directed, will
always appear forward ; so that now it appears to me certain that this little, at
first so puzzling, phenomenon, depends upon the law of distinct vision." That
this is the true cause of the phenomenon I have no hesitation in affirming. By
hiding A with the finger, or making it indistinct with a piece of dimmed glass, or
throwing a slight shadow over it, X appears forward, and continues so when these
obscurations are removed ; and the same effect is produced by hiding X, A be-
coming then nearest to the eye. This experiment may be still more satisfactorily
made by holding above the rhomboid a piece of ground glass (the ground side
being farthest from the eye), and bringing one edge of it gradually down till it
touches the point A, the other edge being kept at a distance from the paper. In
this way AX, and all the lines diverging from A, become dimmer as they recede
from A, and consequently A becomes the most forward point. A deep plano-
convex lens, with its convex side ground, will answer the purpose still better, the
apex of the lens being laid upon A or X ; or the effect may be still farther improved
368 SIR DAVID BREWSTER ON THE LAW OF VISIBLE POSITION, &c.
by making the roughness increase either from the apex of a convex surface, or
any fixed point of a plane one.
Following out his general opinion of the superiority of binocular vision, Mr
WHEATSTONE remarks, that the illusion which we have been examining is most
obvious with one eye. It is not so with my eyes ; and I conceive it should not be
so, as the convergency of the optic axes can have no efficacy in preventing illu-
sion when the figure occupies a plane surface.
In the course of the investigation which I have now brought to a close, I
have had occasion to observe many very interesting phenomena, which it would
be out of place to describe at present. They relate partly to the effects produced
by uniting unequal and dissimilar pictures which have a tendency to represent in-
compatible solids ; — to the union of dissimilar pictures, when the parts of the solid
which they tend to produce lie wholly or principally in a plane perpendicular to
the line joining the eyes and to the plane of the optic axes ;* — to the union of pic-
tures, one of which is more or less turned round in its own plane ; — to the pheno-
mena exhibited by uniting the images of two similar real solids, the one elevated
and the other depressed ; — to the union of dissimilar plane figures which should
at the same time give a solid in relief, and in the converse of relief ;f — and to the
union of portions of dissimilar figures, those which are wanting in the one figure
existing in the other. Among the singular effects produced under these various
conditions, nothing is more remarkable than the tendency or desire, as it were,
of the eyes, to unite and fix the two pictures hovering before them, to convert
them into some figure of three dimensions (sometimes in relief, sometimes in the
converse, and sometimes in both at the same time) ; and the suddenness with
which the two images start into union, give birth to a solid figure on which the
optic axes are converged, and release the eyes from that unnatural condition in
which they had previously been placed.
ST LEONAKD'S COLLEGE, ST ANDREWS,
January 1843.
* Such as the magnified teeth of a saw, as in fig. 14, or a thin section of a hexagonal prism whose
axis is parallel to a line joining the eyes.
f In order to produce simultaneously this double effect, the lines of the pyramid, for example,
which are to give the converse of relief, should be fainter than the other lines, or in different and feebler
colours.
( 369 )
XXV. — On theGromth and Migrations of the Sea-Trout oftheSolrcay (Salmo trutta).
By Mr JOHN SHAW, Drumlanrig. Communicated by JAMES WILSON, Esq.,
F.R.S.E.
(Read 27th March 1843.)
ALTHOUGH the sea-trout (Salmo trutta} cannot be considered either of so much
importance to the community as an article of food, or so interesting in its habits
and economy to the naturalist as the true salmon, nevertheless, it is universally
allowed to rank next in value to that species. It holds a high place in the esti-
mation of the public as an article of diet, and is, consequently, an object of great
commercial value to our fisheries. Its history being still almost as involved and
obscure as was that of the salmon some seasons back, I am induced to offer the
following remarks with a view to its elucidation.
From the circumstance of the sea-trout fry, in its earlier stages, bearing such
a marked resemblance to the young of the common river-trout (Salmo far io), en-
quirers, even of the closest habits of observation, have had much difficulty in
assigning to it any other place among our British Salmonidse than that of a mere
variety of the last named species. However, by proceeding on the mode of arti-
ficial or mechanical impregnation, the exact species of the parent fishes being pre-
viously ascertained, there can remain no doubt as to the identity of the progeny,
under whatever diversity of colour and markings they may shew themselves, in
then1 progress to the adult state.
It being a question among naturalists whether the so-called herling (Salmo
albus of Dr Fleming) is actually a distinct species, or only a certain progressive
state of the young of the sea-trout, I have taken every opportunity of determining
the question by marking the fins, &c., of a considerable number of these fishes for
several years, according as the seasons and conditions of the river enabled me to
obtain them ; and many specimens, as the details of my experiments will shew,
were taken and retaken, for several successive seasons, as common sea-trout, in-
creasing in dimensions from year to year. But as I now know the herling to be
only one of the links in the progressive chain, it will be better, instead of referring
separately to that state of the fish, to narrate the details of the several experi-
ments in the order in which the species advances in size, rather than that in
which the experiments upon their several stages were conducted.
In consequence of experiencing much difficulty in capturing the parent sea-
trouts in the act of depositing then- spawn in the tributaries, I had recourse for
many years to the plan of taking them from the cruive on the river, during the
VOL. XV. PART III. 5 G
370 MR SHAW ON THE GROWTH AND MIGRATIONS
summer months, when the real species to which they belonged was less difficult
to determine. I then placed them in ponds, with a good supply of wholesome
water, and spawned them artificially when the due season arrived. This method,
however, I never considered as a very legitimate mode of procedure, from the cir-
cumstance of a possibility of error from an improper selection and combination of
the parent fishes, and I therefore watched every opportunity of capturing them
in the act of depositing their spawn in the natural bed of the streams or tribu-
taries, each fish accompanied by a mate of its own selection. It was not, how-
ever, until the autumn of 1839 that I had the good fortune to capture the parent
fishes under these circumstances, and this I effected by the aid of my fowling-
piece.
On the 1st of November 1839, having discovered a pan* of sea-trouts (See
parent specimens A) engaged in depositing their spawn in the gravel of one of the
small tributaries of the river Nith, and being unprovided at the moment with the
necessary apparatus for their capture, I had recourse to shooting, as the only mode
within my power of insuring instant possession of them. However, the vigilance
exercised by both parents in protecting the ova from being devoured by multi-
tudes of smaller fishes which surrounded them, rendered it exceedingly difficult
to seize the precise moment at which both might be disabled by one discharge of
the piece. This, however, was at length effected by shooting immediately across
the heads of the pair as they lay parallel to each other, but more by the influence
of concussion, than the actual effects of the shot, they being at the time in about
six inches depth of water. Having taken them ashore, I proceeded to spawn
them by pressing the ova from the body of the female into a little water by the
side of the stream, and afterwards, by the same process, I caused the milt from the
body of the male to mingle with it. I then removed the impregnated ova in a
copper-wire gauze bag, in which some fine gravel had been placed, to a little stream
connected with my experimental ponds. The temperature of the water was at
this time 47°, but during the winter it ranged a few degrees lower. By the 40th
day after impregnation, the embryo fish were visible to the naked eye, and on the
14th January 1840 (75 days after impregnation) the fish were excluded from the
egg-
The specimen No. 1 exhibits the young as it existed the day on which it was
hatched, with a single specimen of the ovum to shew the condition the day before
hatching. The brood at this, the earliest period, exhibit no perceptible difference
from the young of the salmon of a corresponding age, except that they are some-
what smaller in size, and of a paler blue upon the body, the vitelline bag being
likewise of a lighter red.
The specimen No. 2 is the young sea-trout of two months old, taken from
the ponds on 17th March 1840. It is about 1 inch in length, and has assumed
those lateral markings which seem to characterize the earlier stages of all the
OF THE SEA-TROUT OF THE SOL WAY.
species of this family, but its progressive growth, the lapse of time considered, has
been extremely small.
No. 3 shews the state of the young sea-trout when four months old, taken in
May. It measures about 2 inches in length, and by its considerably enlarged
size, and improved condition, exhibits the effects of an increase of food and tem-
perature.
No. 4 is a specimen of young sea-trout 6 months old, taken in July. It
measures 2^ inches in length, and exhibits a corresponding progressive improve-
ment in size and condition.
No. 5 is a specimen 0 months old, taken in October. It measures about
3 inches in length, and also exhibits an improved aspect.
No. 6 is the same species when 12 months old, taken in January 1841. It
measures about 3| inches in length, and presents an example of the average size,
and somewhat defective condition, of the brood during the winter months.
No. 7 is a specimen of young sea-trout 21 months old, taken in October 1841.
It measures about 6 inches in length, and has now lost all the lateral bars or
transverse markings which are so characteristic of the younger stages of the Bri-
tish Salmonidae. It forms one of the most interesting specimens of the series ex-
hibited. It bears a very marked resemblance to some of the varieties of the com-
mon river- trout, and it has also now attained that age (from 18 to 20 months) at
which it appears that the whole of the males of the migratory species of our Sal-
monidae are capable of procreation, — none of the females, however, of a corre-
sponding age, in any of my broods, having ever been observed to mature their roes.
But, from the experiments which I have repeatedly made with the milt from the
young males of other broods of this age (18 months or upwards), I find them quite
capable of reproducing their kind with the adult females.
No. 8 is a specimen of the young sea-trout upwards of 2 years old, taken in
May. It measures about 7£ inches in length, and has now, along with three-
fourths of the brood, assumed the migratory dress. As the young of this species,
in the migratory state, are not unfrequently mistaken by ordinary observers for
that of the real salmon, it may be proper here to endeavour to give some general
description of the colour and markings which they exhibit when first taken from
the ponds. The whole brood, at the age of 2 years, average about 7 inches in
length, and are of a dark brown on the back, passing gradually into a white silvery
appearance on the sides and belly ; the pectoral fins are white, with one-third
part (the extremities) orange ; the ventral fins are pure white ; the anal fin is
also white, with a faint marking of dusky on each side ; the dorsal fin is of a
lightish brown, inclining to black at the extreme points of the anterior rays, which
are tipped with a very little white ; the posterior portion of the rays of the same
fin have a faint tint of orange, and the whole fin is very much spotted ; the adi-
372 MR SHAW ON THE GROWTH AND MIGRATIONS
pose fin is dark brown, margined with red ; the caudal rays are of a light colour
near the base, running into dark orange, terminated by a faintly marked double
margin of black. The spots on the back and sides vary much in individuals of
the same brood, but the specimens produced exhibit a pretty correct example of
the general markings of the brood. The spots prevail principally along the back,
with a few below the lateral line. Each spot is surrounded by a circle of a lighter
colour than the general surface of the body, and this appears to be a prevailing
character of the trout species, and one which the sea-trout fry exhibits even after
having assumed the migratory dress, when every other feature of resemblance to
the common trout has disappeared. The spots on the gill-covers are also more
numerous than those of the salmon, generally amounting to 5 or 6.
From the ovum up to the migratory state, the natural economy of the sea-
trout appears to bear a resemblance to that of the real salmon. However, from
the latter stage to that of the herling (which, as I have said, is beyond all doubt
the young of the sea-trout), there is certainly a singular departure from the uni-
form progress of that species. It appears from experiments very carefully con-
ducted, that there is always a certain number of individuals of both sexes (pro-
bably about one-fourth of each brood) that never assume the silvery exterior, or
migratory dress; and even if those which have assumed that appearance be detained
in fresh water for a month or two, they will reassume the dusky coating ; and
by the beginning of the ensuing autumn, the females mature the roe sufficiently
to reproduce their species with young males of corresponding age. As an evi-
dence of this fact, I may here detail the particulars of an experiment made upon
individuals in the condition alluded to. Having discovered, on the 25th of No-
vember last, that the whole of the females of the brood, as well those which had
been silvery as those which had not, were exhibiting signs of being in the breeding
state, I took six individuals (three males and three females, the latter having
matured their roe for the first time at the age of 2^ years, the former being
milters for the second time), and commingling the milt and roe, I placed the im-
pregnated ova in wire bags in a stream connected with the ponds, and in 76 days
thereafter they were hatched, and the brood now exhibits as healthy a condition
in every respect as those produced by adult parents from the sea.
From these facts, it may perhaps be inferred that the sea-trout bears, in some
respects, a closer affinity to the common trout than it does to the real salmon ;
and that that portion of each brood which does not assume the migratory dress,
but matures healthy roe and milt, and is capable of reproduction at the proper
season without going to sea, forms one of the supposed varieties observable in all
rivers to which migratory trout have access. It is then by no means improbable,
that portions of each brood are permanent residents in fresh water, as they are
never observed to migrate in a dusky state, along with the shoals of silvery fry,
OF THE SEA-TROUT OF THE SOL WAY. 373
at the usual season of migration. In support of such views, we have the autho-
rity of Dr M'CuLLOcn, who states, that sea-trout are now permanent inhabitants
of a fresh- water loch in the island of Lismore.
Having detailed the several particulars relating to my experiments on the
ova of the sea-trout up to the migratory stage of the brood, it will now be ne-
cessary to recur to the results of experiments made on the fry while migrating to
the sea.
On the 9th of May 1836, having observed the salmon fry descending towards
the sea, I took the opportunity of capturing a number of them, by admitting them
into the salmon cruive, and, on examination, I found about one-fifth of each
shoal to be what I regarded as sea-trout ; and conceiving this to be a favourable
opportunity of ascertaining the fact by actual experiment, I proceeded to mark
every individual of that species which entered the cruive in the course of the day.
They amounted to about 90. A fresh, however, taking place in the river in the
evening, prevented my following out the experiment any farther that season. In
experimenting on migratory fishes at 25 miles distance from the sea, windings in-
cluded, the chances of recapturing the individuals marked is comparatively small,
and I therefore did not calculate upon retaking more than an individual or two
out of the 90. My expectations were not agreeably disappointed by any better
success than I had anticipated. However, on the 1 6th July, just 80 days after-
wards, I recaptured a herling in the cruive, with the mai'k which I had put upon
the young sea-trout of the previous May, viz., the whole of the adipose fin being
taken off, and three-fourths of the posterior rays of the dorsal fin removed. It
measured about 12 inches in length, and weighed 10 ounces. The average weight
of the sea-trout fry, at the age at which they migrate to the sea, is about
3^ ounces, so that the specimen referred to exhibited an increase of weight of
6|r ounces in about 80 days' residence in salt water. It was my intention to have
retained specimens of the several individuals on their return from the sea, as they
were successively retaken, with the view of exhibiting more correctly the deve-
lopment and growth of the species in salt water. This single specimen, however,
of that year having been injured in the cruive, was deemed unfit for the object in
view, and was therefore set at liberty, in the hope of obtaining one in a more per-
fect state. In this, however, I was disappointed, no other having presented itself
during the remainder of that season. But No. 9 is a specimen of the herling of
the Nith, taken from the river in July, and is exhibited as an example of the next
progressive stage ensuing that of the silvery condition of the smolt or fry (No. 8).
It may also be considered as a correct representative both of the specimen alluded
to, and of the general state of the species at that age. These herlings enter our
rivers in most abundance in the months of July and August.
No. 10 is a specimen exhibiting the next state of advance beyond the her-
VOL. XV. PART III. 5 H
374 MR SHAW ON THE GROWTH AND MIGRATIONS
ling, and is actually one of the 90 individuals marked as fry in May 1836, though not
captured on its first return. It was retaken on the 1st of August 1837, — fifteen
months after being marked as a fry on its way to the sea. It weighed about two
pounds and a half, and represents pretty correctly the average size of sea-trout
on their second migration from the sea. These older fish usually make their ap-
peai'ance in our rivers in greatest abundance in the months of May and June. In
consequence of the specimen now before you having been in fresh water for a
considerable time, it has acquired a dusky exterior. To shew the better and
brighter aspect of the species, I have placed beside it a specimen of corresponding
size taken from the river in May.
In consequence of the herling having greatly abounded in the river Nith in the
summer of 1834, 1 took the opportunity of marking a great number of them (524),
by taking off the adipose fin, and returning them into the river. During the fol-
lowing summer (1835), I recaptured 68 of the above number as sea-trout, weigh-
ing on an average about 2^ pounds. On these 1 put a second distinct mark, and
again returned them to the river; and on the next ensuing summer (1836) I re-
captured a portion of them, about 1 in 20, averaging a weight of 4 pounds. I
now marked them distinctively for the third time, and once more returned them
to the river, also for the third time. On the following summer (23d day of Au-
gust 1837), I recaptured the individual now exhibited (No. 11) for the fourth
time. It then weighed 6 pounds. This fish exhibits the nature of the several
different marks put upon itself and the other individuals, as they were succes-
sively recaptured, from year to year, on their return to the river. These marks
were as follows : 1st, The absence of the adipose fin (herlings in 1834) ; 2d, One-
third part of the dorsal fin removed (sea-trout in 1835) ; 3d, One-half of the anal
fin taken off (large sea-trout in 1836). Captured and killed in 1837.*
I also marked, in the summer of 1835, about 120 sea-trout, by putting cop-
per-wire into the dorsal fin of one-half of that number, while I marked the other
half by twisting a small portion of the copper- wire round the right maxillary
bone. Of the latter group I recaptured five individuals the following summer,
and found that they also had gained an average increase in weight of 1^ pound.
None were recaptured with the wire in the dorsal fin* which I attribute to the
circumstance of that part being of too fragile a nature to retain the wire for a
sufficient length of time ; and therefore, though they no doubt returned, they
could not be recognised.
From the numerous and long-continued experiments which I have thus been
conducting for many years on this species of migratory trout, I have come to the
* Where only the cartilaginous portion of the fins is taken off, they frequently prove defective
marks, as nature always makes an effort to heal and restore those important organs of locomotion, when
injured. But when taken off close to where they articulate with the body, the parts are never restored.
See, as examules, the dorsal and anal fins of No. 11.
i
OF THE SEA-TEOUT OF THE SOL WAY.
375
conclusion that the small fry called Orange Fins, which are found journeying to
the sea, with the true salmon fry, are the young of the sea-trout of the age of two
years ; that the same individuals, after 9 or 10 weeks' residence in the sea, ascend
our rivers for the first time as herlings, weighing about 9 or 10 ounces, and on
the approach of autumn pass into our smaller tributaries, for the purpose of con-
tinuing their kind ; that having spawned, they soon again make their way to the
sea, during their residence in which, they almost wholly acquire their increase of
weight, viz. about 1^ pound per annum ; and that they return annually, with an
accession of size each season, to the same river in which their parents gave them
birth*
* Among innumerable authentic and well-known instances of the migratory Salmonidse returning to
their own rivers, I may state, that, of the many hundreds of this species which I have marked, I am not
aware that even one of them has ever found its way into any of the tributaries of the Solway, saving that
of the river Nith.
I may here note, in reference to the change of colour in fishes in relation to the bed on which they
rest, that if the head alone is placed upon a peculiar shade, whether light or dark, the whole body of the
fish will immediately assume a corresponding shade, entirely independent of the colour of the ground on
which the body itself may bappen to rest.
( 377 )
XXVI. — On the Optical Phenomena, Nature, and Locality of Muscce Volitantes;
with Observations on the Structure of the Vitreous Humour, and on the Vision
of Objects placed tvithin the Eye. By Sir DAVID BKEWSTEE, K.H.D. C.L., F.R. S.,
and V.P.R.S. Edin. *****
(Read, 6th March 1843.)
ALTHOUGH some of the phenomena of Muscce wlitantes may be seen by per-
sons of all ages, and with the best eyes ; and though those which are more pecu-
liarly entitled to the name are exceedingly common beyond the middle period of
life ; yet no account has been given of them that has even the slightest pretension
to accuracy. M. DE LA HIRE, in his Differens accidens de la Vv«e, describes these
Muscce as of two kinds ; some permanent and fixed, which he ascribes to small
drops of extravasated blood upon the retina; and others, as flying about, and
changing their place, even though the eye be fixed. The first kind, he describes
as like a dark spot upon a white ground ; and the second, as like the knots of a
deal board. Some parts of them, he says, are very clear, and surrounded with
dark threads, and are accompanied with long fillets of irregular shapes, which are
bright in the middle, and terminated on each side by parallel black threads.
In order to account for these knots and irregular fillets, BE LA HIRE sup-
poses that " the aqueous humour is sometimes troubled with some little mothery
ropy substance, some parts of which, by the figures of their little surfaces, or by
refractive powers different from the humour itself, may cast then" distinct images
upon the retina. He supposes them in the aqueous humour rather than in the
vitreous, because of its greater fluidity for a freedom of descent, and because they
will then appear to descend, as being situated before the pupil, or, at least, before
the place of intersection of the pencils." *
Dr PORTERFIELD, who has given a very inaccurate drawing of the filamentous
musc(B, considers them as produced by diaphanous particles and filaments, that
swim in the aqueous humour before the crystalline ; and he regards the distinct
pictures of them upon the retina of long-sighted persons, as produced by the rays
which pass through the dense particles, having suffered a greater refraction than
those which pass by them, so as to be converged to foci upon the retina.f
The latest writer on this subject, Mr MACKENZIE of Glasgow, describes the
muscte as resembling minute, twisted, semi-transparent tubes, partially filled with
* Smith's Optics, vol. ii. Rcm. p. 5. t Treatise on the Eye, vol. ii. p. 74-80.
VOL. XV. PART III. 5 I
378 SIR DAVID BREWSTER ON THE OPTICAL PHENOMENA, NATURE,
globules, which sometimes appear in motion ; while another set are more opaque,
or perfectly dark, and follow the motions of the eye. The latter he considers as
" of a more dangerous character than the former, and as occasioned, generally, by
a partial insensibility of the retina," either from the pressure of some " irregular
projecting point or points of the choroid, or from some other cause." Mr MAC-
KENZIE regards the globules within the semi-transparent tubes, as probably "blood
passing through the vessels of the retina, or of the vitreous humour ;" and he re-
marks, " that neither these semi-transparent tubes themselves, nor any of the fila-
mentous muscse, or black spots (which are so frequently complained of), possess
any real motion, independent of the general motion of the eyeball ;" and hence
he concludes that they " must be referred either to the retina itself — including,
of course, the three laminse of which it is composed, — or to the choroid coat."
" The probability is," he adds, " that the semi-transparent muscce, of a tubular
form, are owing to a dilatation of the branches of the arteria centralis retina.*'1'1
Such was the state of our information on the subject of Muscce volitantes,
when my attention was specially directed to it, in consequence of finding in my
own eye a good example of the phenomenon ; and, having carefully investigated
the facts as observed by other persons in their own eyes, I trust I shall be able
to lay before the Society a correct description, and a satisfactory explanation, of
the general phenomena.
Although the bodies which are within the eyeball, and give rise to the phe-
nomena under consideration, are often seen under ordinary circumstances, yet, in
order to see them with distinctness, we must look at the sky, or a luminous ob-
ject, either through a very minute aperture, or, Avhen the light is limited or feeble,
through a lens or microscopic doublet, of very short focus, held close to the eye.
By this means, we shall observe a luminous ground, covered, more or less, with
transparent filaments or tubes, transparent circles, exceedingly minute, and (when
they do exist) with Musca;, or black spots like flies.
In examining the transparent filaments, I have observed them of four or five
different sizes, the smallest of which are the most distinct. These distinct fila-
ments are bounded by two sharp black lines, and the space between them is more
luminous than the general ground on which they are seen. In the larger fila-
ments, the black lines are coloured at their edges, and, on the outside of each of
them, are one or more coloured fringes.
The minute transparent circles, when smallest, have a luminous centre, with
a sharp black circle round it. In the larger ones, this circle is coloured at its
edges ; and, on the outside of it, are one or more circular coloured fringes. These
spherical bodies sometimes exist singly, and sometimes in groups, partly connected
by small filaments, and partly by an invisible film, to which they seem attached.
* Practical Treatise on the Diseases of the Eye, 1830, pp. 748, 750.
AND LOCALITY OF MUSCLE VOLITANTES. 379
They sometimes adhere to the outside of the filaments, and very frequently oc-
cur mithin the filaments, so as to prove that these filaments are tubular. These
spherical bodies have, like the filaments, four or five different sizes.
In making observations on these spherical bodies, the observer will sometimes
see luminous spots pass through the field ; but as these arise from the state of
the lubricating fluid on the outside of the cornea, they have no connection with
the phenomena under our consideration.
The transparent filaments, already described, are seldom seen single. Two
or three are united, like threads crossing one another ; and sometimes a great
number are united, like a loose heap of thread, in which case, obscure spots ap-
pear at the places where the crossings of the filaments are most numerous.
In some cases, a single long filament is once or twice doubled up upon itself,
and sometimes a knot is, or appears to be, tied upon it, consisting of several folds,
as it were, of the filament. This knot has several very dark spots at the places
where the different portions of the filament are in contact ; and this accumula-
tion, as it were, of black specks, constitutes the real muscce. In many, indeed in
almost all of these muscte, when distinct, a little bright yellow light accompanies
the black specks.
All the bodies which we have now described have two different motions ; one
arising from the motion of the head or eyeball, and the other when the eyeball
is absolutely fixed. By a toss of the head, they are thrown into different abso-
lute and relative positions, sometimes ascending and descending in succession,
sometimes oscillating between two limits, and generally with different velocities.
When the eye is first applied to the lens or aperture, the field of view is tolerably
free of these moving bodies ; but the light seems to stir them up, as it were, and,
to a certain extent, the longer we view them, the more numerous do they
become.
If the centre of motion of the eyeball coincides with the centre of visible
direction, the Muscce will ascend when the eye looks upward, and vice versa,
whether they are placed before or behind that common centre. If the eyeball
remains fixed, the Musca; in front of the above centre will have the direction of
their real and apparent motions the same, and those behind that centre will have
these two directions different. Hence the appearance of two opposite currents
when the eyeball is turned quickly from one extreme of its range, either verti-
cally or horizontally, to its mean position ; and so rapid is their motion through
the luminous field, that it seems covered with continuous lines parallel to the
direction in which the eyeball has been moved, — an effect arising from the du-
ration of the impression of light upon the retina.
If we mark individual filaments, or groups, or knots, we shall find that they
change their shapes, one part of a filament doubling itself over another, and again
resuming its elongated form. The minute spherical bodies separate and approach
380
SIR DAVID BREWSTER ON THE OPTICAL PHENOMENA, NATURE,
one another ; but I have not been able to satisfy myself that those within the
tubular filaments change their place. They often appear to do so ; but as this
may arise from the bending of the filament, or from the varying obliquity of diffe-
rent parts of it arising from its change of form or place, we are not entitled to
consider them as moveable within the tube. It is certain, however, that they
have no progressive motion, as supposed by Mr Mackenzie.
In order to obtain a correct knowledge of the phenomena of the real Miiscte,
I confined my attention to one in my own eye, of which I first made a drawing
in October 1838. It is represented in the annexed figure, and consists of four fila-
ments, ABC, BDE, FGH, and AK. Between BC and BDE there is a sort of
transparent web containing a great number of minute spherical specks, and some-
thing similar, though less extensive, below FGH. The real Musca exists at A,
and has obviously been produced by the accidental overlapping of the different
filaments which are united with it. In four and a half years, the Musca at N has
perceptibly increased in size, and the length of the associated filaments has di-
minished. It is distinctly seen without any of its accompaniments in ordinary
light, but is, in no respects, injurious to vision, as it is never stationary in the
axis of the eye. When seen by means of the lens, the long branch FGH takes
various positions, sometimes falling below the knot or musca A, and sometimes
crossing the main branch AB, below B. The branch BDE has often a loop at D,
and FGH another at G.
Having had occasion to study the phenomena of the diffraction of light, as pro-
duced by transparent fibres and films of different forms, I could not fail to observe
that the phenomena above described were the shadows formed on the retina by
divergent light passing by and through transparent filaments and particles placed
within the eyeball. They are indeed perfectly identical, and may be accurately
imitated in various ways. If we crush a crystalline lens in distilled water, or
AND LOCALITY OF MUSCLE VOLITANTES. 381
macerate some very thin laminae of it, and dry a drop of the fluid on a piece of
glass, we shall perceive, with a fine microscope a little out of focus, or with an ill
adjusted illuminating apparatus, a number of minute fibres, single and in groups,
and knots, with minute spherical particles, which display the very same phenomena
as the analogous bodies within the eyeball.
Hence it follows, that the filaments and spherical particles, whose diffracted
shadows have four or five different sizes, have the same magnitude, and are placed
at four or five different distances from the retina ; those which give the sharp,
black, and minute shadows, being placed near the retina, and those which are large
and ill defined at a distance from it. These various bodies, though they change
their place, still preserve their general distance from the retina, thus clearly indi-
cating that the vitreous humour is composed of cells within which the filaments
and muscce are lodged. That they do not exist in the aqueous humour is
very obvious, because if they did, they would either rise to the top or sink
to the bottom of the aqueous chamber when the eyeball was at rest, and thus
withdraw themselves entirely from the field of view, which they never do.
In order to obtain farther information respecting these muscte, I fixed the eyeball
in different positions, and looking at a sheet of white paper, I marked upon it the va-
rious positions on the paper where the Musca rested. It never withdrew itself from
the field of view, and suffered no sensible change in its size ; but it rested in posi-
tions at different distances from the axis of vision. In one position of the head,
I could bring the musca into the optic axis so as to obtain the most perfect vision
of it, but in all other positions of the head, it rested at a distance from the optic
axis ; though in these it could, by a toss of the head, be made to cross the axis
of vision. In making these experiments, we must recollect that, as the musca is
generally seen by oblique vision, it will very frequently disappear, though it has
not withdrawn itself from the field of view. In all positions of the head, the
musca, appears to descend, so that it must actually ascend in the vitreous humour,
and be specifically lighter.
Now, it is obvious, that, if we determine the visible position of the Musca
when at rest in different positions of the head, we determine the direction of lines
passing from the centre of visible direction through the points in the vitreous hu-
mour where the musca rested, and thus obtain a general notion of the form of the
cell in which it is contained. But Ave may go still farther, and determine with
considerable accuracy the diameter of the Musca or its filaments, and also then-
distance from the retina, and thus obtain a knowledge of its locality, and of the
form of the cavity by which its excursions are limited.
In order to do this, I place before the eye two bright sources of light, so as
to obtain from them, by the method already described, two divergent beams of
light, and I thus obtain double images on the retina of all objects placed within
the eyeball. The filaments or Musccs in the anterior part of the vitreous humour
VOL. XV. PART III. 5 K
;jg2 SIR DAVID BREWSTER ON THE OPTICAL PHENOMENA, NATURE,
will have their double images very distant : those in the middle of it will have
their double images much nearer : those near the retina will have their two images
close or perhaps overlapping each other ; while any object on the retina itself, any
black spot arising from defective sensibility, will have only one image, as it were.
Now, if we measure the distance of the two sources of light from each other, and
also their distance from the centre of visible direction, when the two images of
the filaments, &c., are just in contact, we may determine the size of the filament
and its exact position, as well as its distance from the retina. In making this
experiment, I first found that the angle of apparent magnitude of the shadoAv
of the filament ABC was eight minutes, and consequently [that it subtended
this angle at the centre of visible direction.* Now, if we take the radius of the
retina as 0.524 of an inch, the diameter of the shadow of the filament will be
0.0122, or g|gth of an inch, and its distance from the retina 0.018, or g^th part of
an inch.
When we use a small aperture alone for producing a divergent pencil, the
centre of divergency must necessarily be without the eyeball ; but we may throw
the centre of divergency within the eyeball, and place it at any distance from the
retina, by using a lens of the proper focus. If we wish to place this centre near
the retina, a lens of considerable focal length must be used, and as the light col-
lected by it will be powerful, it will extinguish all the smaller filaments and mi-
nute spheres, and allow only the larger Muscte to be seen. We must therefore
reduce its aperture by looking through a pin-hole or other minute opening. When
we wish to have a clear field of view for examining the larger Muscte, we may ex-
tinguish all the smaller ones by increasing the luminosity of the field. If we
wish to study the filaments or Muscce that may be placed about the middle of the
vitreous humour, we must use a lens of such an aperture as will obliterate all
those more remote from the retina.
It is very obvious, from the preceding observations that objectsplaced within the
eyeball are not seen, as Dr PORTERFIELD believes, by rays which pass THROUGH dense
particles having suffered a greater refraction than those which pass BY them. A fibre
or particle of glass of nearly the same refractive power as the vitreous humour will
be seen distinctly by means of its image formed on the retina by diffracted pencils.
If the light is not sufficiently divergent, or is too intense to produce and exhibit
the diffracted image, the object will be invisible, unless it be of such a size, and so
near the retina, as to shew itself by its ordinary shadow. But in whatever way
the image of the object is formed, the mind takes cognizance of it, or gives it an
external locality, by means of the same law of visible direction which regulates
the vision of objects placed without the eyeball.
* This may be done by projecting it upon a luminous surface, and marking its apparent size ; or by
comparing it with the images of objects of known dimensions seen with a fine microscope.
AND LOCALITY OF MUSCLE VOLITANTES. 333
While these results exhibit the true physical cause of all the optical pheno-
mena and limited movements of the filaments and Muscce, they lead also to some
important and useful conclusions of a more general nature. It had been conjec-
tured that the vitreous humour of animals was enclosed in separate bags or cells
connected with the hyaloid membrane by which the vitreous mass is enveloped.
The preceding experiments not only appear to demonstrate that this is the struc-
ture of the vitreous humour in man, but to shew that there are at least four or
five cells between the retina and the posterior surface of the crystalline lens. The
limited motion of the Muscce indicates that the cell in which they float is
of very limited extent. When the vertical diameter of the eyeball, in its
natural position, is placed, by the inclination of the head, 30° to the right hand
of a vertical line, and the optic axis of the eye directed 20° below a horizontal
line, the Musca is seen along the optic axis, and consequently in the most perfect
manner. One point of its cell must therefore touch the optical axis.
I have endeavoured, with the assistance of my eminent colleague Dr REID,
to discover cells in the vitreous humour of quadrupeds and fishes by the aid of
the microscope and other means, but we have not succeeded : and unless some
chemical substance shall be found which acts differently upon the albuminous
fluid and the membranous septa, it is not likely that they will be otherwise ren-
dered visible.*
Mr Ware, in a paper on the Muscce Volitanles of nervous persons,^ describes
some as "• globules twisted together, and others as like the flue that is swept
from bedrooms," and he considers it " probable that they depend on a steady
pressure on one or more minute points of the retina which are situated near the
axis of vision .":):• In the cases described by Mr Ware, the Muscce were liable to
great and sudden changes in intensity and number, particularly from causes
affecting the nervous system, and hence they cannot be regarded as of the same
character as the Muscce described in this paper, unless we suppose that Muscce,
invisible under ordinary circumstances, become visible in consequence of an in-
creased sensibility of the retina.
This supposition, however, is by no means probable, because the Muscce are
not visible by any light of their own, and an increase of sensibility in the retina
would affect equally the luminous field on which they are seen. But, as this
point is of some importance both in a physiological and a medical aspect, I have
submitted it to direct experiment. With this view, I examined the MUSCCE
* The vitreous humour, when slowly dried, either by itself, or along with parts of the septa in which
it may be contained, shoots into beautiful crystalline ramifications proceeding from the four angles of a
quadrilateral crystal. Thin six-sided plates frequently occur, but they seem to exercise no action upon
polarised light, probably on account of their thinness. The same effects were produced when the vitreous
humour from a fresh eye was well washed in distilled water.
t Medico-Chirui-gical Trans., 1814, vol. v., p. 255. J Id. Id., p. 266.
384 SIR DAVID BREWSTER ON THE OPTICAL PHENOMENA, NATURE,
in the morning before the sensibility of the retina had been diminished by ex-
posure to daylight, and found that they were neither increased in number or in-
tensity. I varied this experiment by diminishing the sensibility of the retina.
This was done by holding a bright gas flame close to the eye, and near the axis
of vision, till the retina lost its sensibility to all the rays of the spectrum, except
a few of the more refrangible ones.* In this case, too, the MUSCCE were as nu-
merous and distinct as before, and we may therefore consider it as certain, that
the Musav described by Mr Ware, in so far as they were of the same character
as those in the healthy eye, are not affected by any variation in the sensibility of
the retina. I am disposed to think that they consisted of the ordinary Muscce
seen simultaneously with others produced by the pressure of the bloodvessels on
the retina, and that it was the latter only which underwent the variations which
he describes.
It is not easy to form any rational conjecture respecting the cause and pur-
pose of the numerous filaments by which the Muscce are produced ; for as they
exist in all eyes, whether young or old, they are neither the result of disease, nor
do they indicate its approach. Were they fixed or regularly distributed, we might
regard them as transparent vessels which supply the vitreous humour ; but ex-
isting, as they do, in detached and floating portions, they resemble more the
remains of some organic structure whose functions are no longer necessary. But
though these filaments have no morbid character, they may nevertheless obstruct
and even destroy vision. They certainly interfere with nice microscopical observa-
tions, and in observing the minute and almost imperceptible lines in the solar spec-
trum, I have found them to be occasionally injurious. It is quite possible that some
of the cells near the retina and around the optic axis might be filled up with accu-
mulated Muscce, and produce a considerable degree of blindness ; but this is an
effect of them which there is little occasion to apprehend.
Mr MACKENZIE! informs us, " that few symptoms prove so alarming to per-
sons of a nervous habit or constitution as Muscce wlitantes, and they immediately
suppose that they are about to lose their sight by cataract or amaurosis." Pro-
fessor PLATEAU of Ghent, to whom I had communicated, at his own request, some
of the preceding results, mentions to me, that few physicians are able to distin-
guish between the Muscce described above, and those appearances which indicate
amaurosis, and that they often, without cause, alarm patients who consult them
for the first time respecting such affections of the eye. He assures me that he
has already been the means of freeing from alarm many persons with Musca;
wlitantes, and that he had even done this to a distinguished physician. {
* Lond. and Edin. Phil. Mag., 1832, vol. i., p. 172, vol. ii., p. 168
t Practical Treatise, &c., p. 751.
J Professor PLATEAU mentions that he had been led to suppose that the Muscce had their seat in
7
AND LOCALITY OF MUSC.& VOLITANTES. 385
The details in the preceding pages may, therefore, be considered as establish-
ing the important fact, that Musca wlitantes have no connection whatever either
with Cataract or Amaurosis, and that they are nearly altogether harmless. This
result has been deduced by the aid of a recondite property of divergent light,
which has only been developed in our own day, and which seems to have no
bearing whatever of an utilitarian character. And this is but one of numerous
proofs which the progress of knowledge is daily accumulating, that the most ab-
stract and apparently transcendental truths in physical science will sooner or
later add their tribute to supply human wants, and alleviate human sufferings.
Nor has science performed one of the least important of her functions when she
enables us, either in our own case, or in that of others, to dispel those anxieties
and fears which are the necessary offspring of ignorance and error.
ST LEONARD'S COLLEGE, ST ANDREWS,
March 4. 1843.
the vitreous humour rather than in the aqueous ; but that he had been stopped by the difficulty of recon-
ciling this opinion with the viscosity of the vitreous humour. As the vitreous humour is perfectly fluid
within each cell, the viscosity here supposed being only apparent, no longer presents any difficulty.
VOL. XV. PART HI. 5 L
( 387 )
XXVII. — On the Specific Gravity of certain Substances commonly considered lighter
than Water. By JOHN DAVY, M.D., F.R.S., L. and E., Inspector-General of
Army Hospitals, L.R.
(Head, 3d April 1843.)
THAT the common varieties of wood which float in water, owe their apparent
lightness to air contained in their structure, is generally admitted by those who
have paid any attention to the subject. By means of the air-pump, the fact is
clearly demonstrated. Under the exhausted receiver, after a certain time, the
time varying with the quality of wood, all the different specimens which I have
tried have sunk ; I may mention two or three in particular, as examples. A
piece of oak, weighing 29.7 grs., sank in distilled water, after having been sub-
jected to the air-pump three days ; — a piece of deal, weighing 16.3 grs., similarly
acted on, floated ten days ; — and a portion of the pith of the elder, weighing only
.133 grain, floated seven days. The temperature of the room in which the expe-
riments were made, was about 50° F. ; the air-pump was frequently worked in
the course of each day, and was in perfect order. After the exhaustion of the
air was carried as far as it well could be, the specific gravity of each wood, ex-
clusive of hygrometric moisture,* was found to be as follows : oak, 1.58 ; deal,
1.18 ; pith of the elder, 1.45.f
The remark made on the common woods is applicable also to pumice and all
vesicular minerals, and admits of proof in the same manner. The specific gravity
of pumice is stated to be, according to BRISSON, .914 ; according to HOFFMAN,
.752 and .770 ; that is, in its ordinary condition, when its cavities are full of air.
But, when acted on by the air-pump, I find it is as high as 1.94. The subject of
the experiment was a portion of a specimen from Lipari, that weighed 31.8 grs.,
* The oak-wood lost by thorough drying, at a temperature a little below the scorching point (in-
cluding a small loss from the action of cold water), 18.3 per cent. ; the deal, 14.2 ; and the pith of the
elder, 13.3.
t According to COUNT RUMFORD (Nicholson's Journal, vol. xxxiv., p. 322), the specific gravity of
oak is 15,344 ; of fir, 14,621, to water as 10,000. He arrived at these results, not by means of the air-
pump, but by the expulsion of air by boiling in water. The specific gravity of deal or fir-wood, as given
by him, is nearer the truth than that in the text, which is too low, for a reason which will afterwards be
assigned. I find, that when air is entirely, or nearly entirely expressed from it by compression in water,
that it sinks in a fluid of specific gravity 1.5 ; and that the pith of the elder, similarly treated, sinks in
the same fluid.
The number 1.45, given in the text, as the specific gravity of the pith of the elder, was determined
hydrostatically, using a very delicate balance, affected by the one thousandth of a grain, when loaded with
500.
VOL. XV. PART III. 5 M
388 DR DAVY ON THE SPECIFIC GRAVITY OF SUBSTANCES
thoroughly dried. It floated on water, in the exhausted receiver, about thirty
hours ; and continued to give off air — extremely little indeed in quantity — until
about the thirtieth day, reckoning from the commencement of the exhaustion.*
There is a small number of other substances generally believed to be lighter
than water, respecting which doubt may be entertained, such as cork, caoutchouc,
camphor, wax, spermaceti, cholesterine, stearine, — which, like the preceding, may
owe their apparent lightness to entangled air.
To endeavour to determine this question, I have made some experiments, the
results of which I shall noAV have the honour of submitting to the Society, — be-
lieving the subject to be deserving of some attention, practically considered, espe-
cially in connexion with the examination and analysis of certain vegetable and
animal compounds, the oily and fatty contents of which are daily becoming more
interesting, in connexion with theoretical views respecting elementary cells and
their nuclei.
The great buoyancy and apparent extreme lightness of cork is well known :
its specific gravity is stated to be as low as .2400.1 When subjected to the air-
pump, much air is disengaged from it ; it subsides a certain way in the water,
but does not sink. A portion of cork weighing 12.4 grains, was kept under the
exhausted receiver from the 23d of January until the 3d of April, when it conti-
nued to float ; and even minute portions of this substance, not exceeding one
tenth of a grain in weight, appear incapable of being sunk by the action of the
air-pump.:]: This, it may be conjectured, is owing to the elastic cellular structure
* Reduced to powder, after having been subjected to the air-pump, and weighed hydrostatically, it
was found to be of the specific gravity 2.41, which is about that of obsidian, — the mineral substance
from which, it would appear, that pumice is formed by the action of volcanic fire. As no air was disen-
gaged when the pumice was crushed under water, it seems probable, from the circumstance of its specific
gravity being increased by its cells having been broken, that some of them may be destitute even of
air. This brings to my recollection the result of an experiment made many years ago, on exposing
obsidian to a high temperature in a gun-barrel, in which I assisted a distinguished member of this
Society, Sir GEORGE MACKENZIE. The air disengaged from the obsidian had a distinct smell of nitrous
acid gas. Now, supposing that this acid is always set free in the production of pumice from obsidian,
part of it may be re-absorbed, and tend perhaps, with steam, to form the minute vacua which I have
supposed may exist in pumice, — vacua, the existence of which it is easy to imagine, considering the na-
ture of the substance, in reality a vesicular glass, and differing chiefly from obsidian, or, as it has been
significantly called, volcanic glass, in its vesicular condition. This is well displayed by the microscope,
under which, with a high power, its minute fragments appear as transparent glass, in some of which
cavities are distinguishable.
f Henry's Chemistry, vol. ii., p. 506.
J Whether cork kept in water unaided by pressure, would ever sink, seems very doubtful ; probably
it would continue to float so long as the plates constituting its cells retained their integrity and elasti-
city,— that is, so long as its substance resisted decomposition. The portion of cork, the subject of the
experiment described in the text, which weighed in air 12.4 grains, after having been in water, under
CONSIDERED LIGHTEE THAN WATER. 38.Q
of cork offering resistance to the escape of air, when highly rarified, similar to
that presented by a strong solution of gum-arabic, or any other viscid fluid acted
on by the air-pump, when we see, after the pump has been worked some time,
and the exhaustion is as complete as it can well be made, that bubbles rise, on
which the farther working of the pump seems to have little effect, and which ap-
pear to break rather in consequence of evaporation than of exhaustion. In accord-
ance with this view, when the cells of the cork are forcibly compressed and bro-
ken down, then their substance ceases to be buoyant, and the cork sinks readily in
water. The effect is easily shewn by compressing and breaking up small portions,
as by forcibly crushing them in a mortar under water. I find, after this has been
done, that cork sinks not only in water, but also in a saturated solution of common
salt, which is of the specific gravity 1.148, and in sulphuric acid of specific gra-
vity 1.5, at which strength the acid has no immediate charring effect. This last
result would seem to indicate that its specific gravity exceeds 1.5. If the base of
cork be considered as wood (a conclusion I am disposed to adopt, rather than the
idea that it is a distinct substance, suberine), it is probable that its specific-
gravity is as high even as 1.6, which I believe to be that of the matter wood or
lignin in its purest form, being, as I find, that of cotton and of linen.*
The specific gravity of caoutchouc, according to BRISSON, is .93. I have
found it, when its outer black pellicle has been removed, even lower, viz. .91.
Under the microscope, using a high power, this specimen appeared to have within
its substance minute cavities, which, from the transparency of the mass, were
sufficiently distinct. From the properties of caoutchouc, it could not be expected
that any air contained in it, in closed cavities, could be extracted, either entirely
or even in considerable part, by the air-pump, or by boiling, or by compression.
Solution in ether, and precipitation by alcohol and the addition of water purged
of air, seemed to afford a probable means of determining the question, whether
or not the presence of ah* in this substance is connected with its lightness.
To a hot saturated solution of caoutchouc in sulphuric ether, alcohol was
added ; the caoutchouc thrown down, resembling in appearance a mass of fibrin
separated from the blood by stirring, was taken up by a forceps and transferred
to water that had ceased to give out air under the exhausted receiver, and was
immediately acted on by the air-pump. The effect of the removal of the atmo-
spheric pressure on it was remarkable, owing, no doubt, to the ether adhering to its
the exhausted receiver 33 days, had increased in weight, from the absorption of the water, to 20.5 grains ;
and after 22 days more, its farther increase was only 1 grain.
* I have found the specific gravity of cambric carefully freed from air 1.600 ; of hemp cord, 1.560 ;
of fine cotton cloth, 1.605; and of cotton thread, 1.61, at 50° F. The cambric and cotton thread were
first boiled in distilled water, and then subjected to the air-pump before weighing in water ; they were
thoroughly dried before being weighed in air, and weighed whilst still warm. The cord and thread were
treated in the same manner, excepting that they were not previously boiled.
390 ER DAVY ON THE SPECIFIC GRAVITY OF SUBSTANCES
substance. When the exhaustion was nearly complete, the little mass of caoutchouc
was thrown into violent motion, resembling in its movements a piece of potassium
on the surface of water, being driven from side to side with strong effervescence or
ebullition. Even after many hours, bubbles continued to be disengaged : on their
cessation, I found its specific gravity .93. But as, on examining this caoutchouc
with the microscope, it also was found to contain minute cavities, which might be
filled with the vapour of ether or of alcohol, if not vacua, the specific gravity, as
ascertained, was liable to the same objection as in the case first referred to of
common caoutchouc.
To endeavour to obviate the interfering circumstances in this experiment,
another was made. To an etherial solution not saturated, alcohol in considerable
quantity was added, in a manner to prevent the particles of caoutchouc, as they
were precipitated, from cohering and forming a mass. After the addition of a
portion of water, the mixture was subjected to the air-pump, and was kept under
the exhausted receiver till the greater part of the spirit had evaporated. The
fluid was turbid from particles of caoutchouc suspended in it. Transferred to a
tube and carefully watched, some of them, chiefly the largest, were seen to ascend ;
others were seen to descend. The specific gravity of the fluid was found to be
•97. This result seems to be in favour of the conclusion that the true specific
gravity of caoutchouc differs but little from that of water, as in all probability
even the smallest visible particles contained cavities in which might be included
the lighter substance either of ether or of alcohol.
The specific gravity of camphor, according to BRISSON, is -9887. Subjected
to the air-pump, floating on distilled water, air is disengaged from it, and the
mass of camphor gradually sinks in the water ; but unless very small, not entirely.
On close inspection it may be seen commonly to be buoyed up by minute globules
of air, either adhering to it or included in its substance. Now, if the mass be
broken in the water and reduced to a coarse powder, and again submitted to the
pump, after the exhaustion, many of the little fragments will be seen to have sub-
sided, and some will be seen at the bottom. If, however, the warm hand be ap-
plied to the bottom of the vessel, then the bits of camphor will be found to rise
and fall with the ascending and descending currents produced in the fluid. The
inference from this experiment obviously is, that the specific gravity of camphor
exceeds that of water, but only in a very slight degree. Adding salt, I find the
particles free from air ascend and descend with the currents, excited by the par-
tial application of heat, when the water has acquired the specific gravity 1'005,
at about the temperature 50° ; which therefore may be concluded to be about that
of the substance itself. And confirmation of this was obtained by dissolving a
portion of camphor in alcohol, precipitating by water deprived as much as pos-
sible of air, and adding a portion containing particles of the precipitated camphor
to the salt and water. Many of them remained stationary below the surface,
CONSIDERED LIGHTER THAN WATER. 391
when the temperature of the water was steady, or followed its currents when its
temperature was disturbed. Further, it may be remarked, that when the preci-
pitated camphor is thrown into a large quantity of water, even at the temperature
40°, part of it subsides to the bottom. That the whole does not subside is no more
than might be expected, considering that the smallest globule of air attached may
suffice to render a particle, or congeries of particles, buoyant. Examined with
the microscope, the particles that had subsided, or were suspended, appeared to
be quite homogeneous, of a globular form, or an approach to that form ; none of
them were crystallized.
The specific gravity of unbleached wax, according to FABRONI, varies from
•9600 to -9650, and of white wax from -8203 to -9662. Owing to the peculiar
properties of this substance — either impervious or little pervious to air in its
solid state — the rapid manner in which, when melted, on reduction of tempera-
ture it congeals at the surface, and its great degree of contraction on cooling —
owing to these properties, the ascertaining of its specific gravity as a solid mass
is peculiarly difficult.
In its liquid state, at the boiling temperature of water, I have found the spe-
cific gravity of yellow wax to be 0.856, distilled water of the same temperature
being considered as 1.000. This is the mean of two experiments; according
to one of which it was -854 ; according to the other, -858. At 100°, its specific
gravity appeared to be to water of the same temperature as '952 ; and at 52°, as
•989. The specific gravity of white wax, at the boiling point of water, was found
to be '861 ; and at 50°, it appeared to be -988. The manner of conducting the ex-
periments which gave these results was the following. The melted wax, in the
first instance, was poured into a bottle fitted for ascertaining the specific gravity
of liquids, immersed in boiling water, and the stopper heated was then introduced
into the bottle. Thus filled, the bottle weighed, of course gave the specific gra-
vity of wax at the boiling temperature of water — its weight, filled with boiling
water, having been previously determined. For the lower temperatures, the
bottle, charged with melted wax, reduced as near to its congealing point as was
compatible with its liquidity, was immersed immediately after the introduc-
tion of the grooved stopper, into water purged of air by the air-pump, and then
allowed to cool previous to weighing. By this method I had hoped to exclude
air, and obtain satisfactory results. But the examination of the congealed wax
satisfied me that I was mistaken. On slicing the mass of wax, cavities were
found in its substance — some of large size, containing water, others of small size,
many of them extremely small, requiring the aid of the microscope to be seen
distinctly — apparently dry and empty — it may be, they were filled with air. The
general appearance, I may remark, called forcibly to recollection the condition of
certain minerals and rocks, containing cavities, supposed to be formed during
VOL. XV. PART III. 5 N
392 DR DAVY ON THE SPECIFIC GRAVITY OF SUBSTANCES
consolidation from a state of fusion, and the contents of which have been found
to be so various, and in their theoretical bearings so instructive.
It appearing impracticable to ascertain the true specific gravity of wax in its
solid state in mass, recourse was had to another method. The wax was dis-
solved in hot alcohol, and then poured into distilled water, deprived of air by the
air-pump. The precipitated wax, in a flocculent state, sank in the mixture of
water and spirits. It was divided into three portions, to which a solution of com-
mon salt was added in different proportions. In the lightest of specific gravity
.992, at 50°, the 'greater part of the flocculi sank to the bottom, or were sus-
pended midway; in another, of specific gravity 1.005, a considerable portion was
suspended midway, a little sank; and, in the third of specific gravity 1.014, the
greater portion rose to, or towards the surface ; a few flakes were suspended, and
a very few subsided. These results induce me to believe, that the specific gravity
of wax, free from ah*, exceeds very little that of water ; and the results of the
trials on the specific gravity of bleached and unbleached wax at the boiling tem-
perature of water, seem to show, that the former is rather the heaviest of the
two.
Wax, as is now well known, is composed of two substances, cerine and my-
ricine. I have not examined them apart in regard to their specific gravity ; — I
have thought it the less necessary, as the latter in bees'-wax is in small propor-
tion, and its specific gravity is stated to be the same as that of water, whilst the
specific gravity of cerine is made as low as .969.*
Spermaceti is stated to be of the specific gravity .9433. f In connection with
the properties of this substance, analogous to those referred to when treating of
wax, there is not less difficulty in determining accurately its specific gravity in
mass. At the boiling point of water, I find its specific gravity to be .839 ; at 100°,
which is about 12° below its point of congelation, it appears to be about .910 ; and
at 50°, apparently .96, using the same method as that employed with wax. This
last number, as in the parallel instance of wax, and for the same reasons, is, I be-
lieve, too low. I find, that when spermaceti is dissolved in hot alcohol, and is pre-
cipitated by admixture with water freed of air, that the flocculi thrown down
are suspended when a solution of common salt is added in just sufficient quantity
to make the specific gravity of the mixture that of distilled water ; and which,
therefore, probably, apart from entangled ah*, is the true specific gravity of this
substance, and also of cerine, of which the purified crystalline spermaceti, the sub-
ject of trial, almost entirely consists.
The specific gravity of cholesterine is commonly considered inferior to that of
* Noveau Syst&me, de Chimie Organique, par F. V. RASPAIL, iii. 406.
t HENRY'S Chemistry, 6th edit. ii. 505.
7
CONSIDERED LIGHTER THAN WATER. 393
water ; but I am not acquainted with any author who states the difference nu-
merically, excepting in the instance of biliary calculi, of that kind which is com-
posed almost entirely of this substance : GREN found the specific gravity of one
so low as .803. From the trials, I have made, it would appear, that the specific
gravity of cholesterine, in its pure state, is greater than that of water. Crystals
formed in alcohol on cooling, well washed with distilled water, are, I find, sus-
pended in a solution of salt of specific gravity 1.0102 at 50°, and which, therefore,
may be considered as the specific gravity of the cholesterine itself. The apparent
greater lightness of biliary calculi formed of cholesterine, is clearly owing to the
air which they contain ; and to the same cause must be referred the circumstance,
that when crystals of this substance procured by the cooling of an alcoholic solu-
tion are thrown into water, most of them float, being buoyed up by the minute
air-bubbles disengaged on the admixture of the water and alcohol. If the crys-
tals are minutely examined, none will be seen to float excepting those to which
air-globules are adhering, — and some of the larger size will be seen to sink, al-
though each of them may have attached to it a very minute air-globule.*
Stearine, it is stated by M. RASP AIL, is of the specific gravity .795. From the
trials I have made on stearine, obtained from the suet of beef and of mutton by
boiling alcohol, I am disposed to infer, that, in its solid state, at ordinary tempera-
tures, its specific gravity differs but little from that of water. Alcohol, contain-
ing a sediment of stearine, which had separated and subsided on cooling, after
the addition of a portion of water purged of air, was submitted to the air-pump,
and was left under the exhausted receiver several hours without agitation. The
greater part of the stearine was found suspended midway ; a smaller portion had
reached the bottom, and a smaller still was at the surface. This admixture of
spirit and water was of specific gravity .98. Another mixture, which was turbid
throughout, from particles of stearine diffused through it, after rest of many hours
under the exhausted receiver, was of specific gravity .991. In this instance, there
was a thin stratum at the surface more opaque than the mixture generally, from
containing a larger quantity of stearine ; — an excess which may have been owing
to the entanglement of a little air (for a small quantity was disengaged on ex-
haustion), or to those particles not being free from oleine ; or, it may be, they
contained included in them a little alcohol. In favour of this latter conjecture, it
may be mentioned, that when stearine, deposited from alcohol, has been a consider-
able time in water, its specific gravity seems to increase, its particles are carried up
and down in the ascending and descending currents of the fluid, or when these
* Since the above was written, I find that Dr J. LAWRENCE SMITH, in a short article on Cholei-
terine, published in SILLIMAN'S Journal for January 1843, has pointed out the common error relative to
the specific gravity of this substance, but without endeavouring to determine it exactly. His conclusion
was drawn from finding it sink when fused and thrown into water.
394 DR DAVY ON THE SPECIFIC GRAVITY OF SUBSTANCES
are not excited, remain stationary, or almost so, showing only a very slight ten-
dency to ascend.
The result of these experiments admits of some practical applications, and
may aid to explain some phenomena of an obscure kind, in certain processes.
Were the substances treated of lighter than water, it might be expected that
in every instance, when mixed with water, whether precipitated from an alco-
holic, or obtained from an etherial solution, or mechanically detached, as in the
operation of boiling, that they would of necessity find their place of rest, and be
collected at the surface. But, on the contrary, if their specific gravity is either
the same, or in the smallest degree superior to that of water, then the same could
not be expected ; — all that could be expected would be, that no more of each
substance would rise to the surface on admixture with water, than is buoyed up
by the adhering particles of air : and no confidence would be placed in the cir-
cumstance of specific gravity in an operation of analysis, for collecting the whole
of the substance sought. In illustration, cholesterine may be specially mentioned
— a substance of common occurrence in animal concretions and morbid deposi-
tions ; indeed, as I have satisfied myself by recent inquiry, much more common
than is generally supposed. If a concretion containing cholesterine be digested
in hot alcohol, and the alcoholic solution be precipitated by water, a portion of
the cholesterine will rise to the surface, and appear there as a pearly film ;*
whilst another portion, not rendered buoyant, will subside, and, on careful
inspection, will be found at the bottom. Or if the concretion be broken up, and
boiled in water, — as cholesterine is not fusible at the boiling temperature of
water, — its crystalline plates, on rest, will form a sediment, and may be separated
by decantation ; or if extremely minute, — and they are sometimes met with
not more than go^oth of an inch in width, — they may be suspended for a consi-
derable time, imparting a milky opaqueness to the fluid.
The raising the cream of milk may be mentioned as another instance of the
influence of disengaged air. It is well known, that in cold weather, cream rises
slowly. Is not this owing chiefly to the milk, at a low temperature, resisting
that change to which it is so prone in warm weather, — the fermentation of its
saccharine part, and the formation of carbonic acid ? Milk, the instant it is
drawn from the cow, is, I find, destitute of air : I have been able to obtain none
from it, when collected with proper precautions and subjected to the air-pump. f
* Oleine is a frequent accompaniment of cholesterine in animal concretions, and when present,
being considerably lighter than water, may be looked for in the film alluded to in the text. Mixed with
cholesterine and air, its appearance is very like that of cream on milk.
t Researches, Physiological and Anatomical, vol. ii. p. 221. I find that, when milk fresh from the
cow is subjected to the air-pump, a small portion of cream soon collects at the surface ; and farther, that
it may be kept many days (I have kept it twelve days) without any sensible increase in the quantity of
cream, or distinct diminution of the opaque whiteness of the milk,— seeming to indicate, that a part of
CONSIDERED LIGHTER THAN WATER. 395
But cream, whenever separated, however fresh, is found to abound in ah*. Were
it not for ah" attached to the cream globules, it seems questionable that any sepa-
ration of them would take place, as then- albuminous envelope (adopting the
inference of MULLER and HENLE, that they are so provided)* seems to give them a
specific gravity about the same as that of the medium in which they are sus-
pended.f
In pharmaceutical processes, in which it is required to suspend powders in
fluid mixtures, the efficacy is well known, of subjecting the powder to attrition
with a very little water or alcohol. This seems to be owing entirely to the
separation of air, either contained in the substance of the powders, or adhering
to their surface in minute globules, and is well illustrated by the effect of attri-
tion, as described in a preceding page, on cork.
On the contrary, whenever great lightness and buoyancy are necessary,
whether for raising bodies in the atmosphere, or floating them in water, or making
them run or press lightly on the earth's surface, air is in some way included.
The hollow bones of birds, filled with air — the swimming-bladders of fishes, dis-
tended with air — the elastic cellular structure of cork, the rigid cellular and
tubular structure of pumice, full of air — or, in the instance of the latter, nearly
so filled, — are examples of the kind, and may be deserving of being studied, par-
ticularly the last mentioned substances, with wax and caoutchouc, in relation to
the principles on which vessels, and implements, and edifices should be made,
requiring an unusual degree of buoyancy or lightness, especially if intended for
a permanency.
EDINBURGH, 3d April 1843.
the cream globules, those which rise, may be without an albuminous envelope, and that another part,
those which do not ascend, may be provided with such a membrane.
* Histoire des Tissus et de la Composition Chimique du Corps Humain, par J. HENLE, p. 165.
t Butter, I find, when as pure as it can be rendered by melting, is, at the boiling point of water, of
the sp. gr. .902 ; at 100°, apparently .913 ; and at 48°, .932, — employing the method used in the instances
of wax and spermaceti. The lightness of the substance of butter increasing with its temperature, must
necessarily expedite the raising of cream, as when the " scalding" process is employed.
VOL. XV. PART III. 5 O
( 397 )
XXVIII. — Biographical Notice of the late Sir CHARLES BELL, K.H.
By Sir JOHN M'NEILL, G.C.B,
" v*
(Read 17th April 1843).
THE pleasure which honourable and enlightened minds must feel in acknow-
ledging their obligation to the individuals who have advanced useful knowledge
in any department of science, — who have contributed to the means of promoting
human happiness, or of alleviating human suffering, has, in all times, led men
to seek an opportunity of recording their sentiments of admiration and of grati-
tude towards the distinguished instructors of mankind. They have felt, too, that
the time when one of these guiding lights has been quenched, when a contributor
to the treasury of knowledge has just terminated his labours, is peculiarly fitted
for the discharge of this duty. The whole amount of his contributions is then
presumed to be before them, and they are restrained by no fear of offending his
delicacy by their praise, or of having their own feelings hurt by a misconstruction
of their motives. They know, that what might have been regarded as adulation
of the living, is often admitted to be but justice to the dead.
To this Society, whose express object is the advancement of science, — whose
especial care it therefore must be to watch over the reputation of every one to
whom science is indebted, and which is not only entitled, but required, to take a
leading part in determining the measure of praise that each labourer in the
various fields of its own domain may have merited, no apology can be necessary
for laying before it a short sketch of the late Sir CHARLES BELL'S claims to be
ranked high amongst the men who have established a title to its admiration.
But I may perhaps owe it to you, as well as to myself, to say, that having been
so long a stranger to the subjects with which I shall chiefly have to deal, I should
not have ventured to undertake this task, had I not been led to set aside all such
considerations by a desire to comply with the wishes of persons whose sentiments
are at all times, and especially on this occasion, entitled to respect and deference
from me. At the same time, I did not doubt but that I should experience your
indulgence while I endeavoured to do what I have thought it my duty to attempt.
Sir CHARLES BELL, the youngest son of the Rev. WILLIAM BELL, a clergyman
of the Episcopal Church of Scotland, was born at Edinburgh, in the month of
November 1774. Having studied at the High School and the University of this
city, he devoted himself, at an early age, to the medical profession, and especially
to the study of anatomy, under his brother, the late Mr JOHN BELL, who was
twelve years older, and who had already laid the foundation of his fame as an
anatomist and as a surgeon. But Mr JOHN BELL was not merely an anatomist
VOL. XV. PART III. 6 P
398 NOTICE OF THE LATE SIR CHARLES BELL.
and a surgeon second to none in his time ; he was a man of enlarged mind, of
extensive acquirements, of elegant accomplishments, and of refined taste ; and
those who remember his powers of conversation, and the keenness of his wit,
will probably acknowledge that they have rarely seen them surpassed. If in the
later period of his life he was so unfortunate as to have " fallen on evil days and
evil tongues," we can only lament that prudence and discretion should not always
accompany genius such as his.
Under the guidance of this enlightened teacher, CHARLES BELL soon began
to give evidence of the talents which seem to have been inherited by every
member of his family. JOHN BELL found in his younger brother a distinguished
pupil, an able coadjutor, and then a worthy rival in the race of usefulness and
of fame. In the preface to the third edition of his work on the Nervous System,
Sir CHARLES acknowledges how greatly he was indebted to his first instructor.
" The author," he says, " began his public labours as an assistant lecturer to his
brother JOHN BELL, who gave up to him that part of the course of anatomy
which treats of the nerves, and he advised him to demonstrate the relations of
the brain to the base and spinal marrow, instead of cutting it into horizontal
sections. The intelligent student will at once perceive, that much of what is
contained in this volume may be traced to the aspect in which the author was
accustomed, during all his after labours, to look upon the relations of the brain
to the rest of the nervous system."
While yet a pupil, Sir CHARLES BELL had published the first volume of his
System of Dissections, illustrated by engravings from his own drawings, — a work
which exhibited some originality, and which was regarded as a valuable guide to
the student of practical anatomy. On the 1st of August 1799, he was admitted
a member of the College of Surgeons, and his admission to that body brought
him at once into a situation which tested his practical proficiency and skill ; for
the whole surgeons of Edinburgh were then, in rotation, Surgeons of the Royal
Infirmary. His knowledge of anatomy, and the admirable use of his hands,
exhibited both in his dissections and in his drawings, Avere already conspicuous ;
and in the hospital, he distinguished himself by the dexterity and the simplicity
of his operations. He also eagerly availed himself of the opportunities which his
attendance there afforded him, to improve his knowledge of pathology; and
having now been associated with Mr JOHN BELL in his lectures on anatomy and
surgery, he was assiduous in making preparations, drawings, and models, for the
use of the class, from the dissections at the hospital. He even invented a method
of representing morbid parts in models, of which some specimens were long after-
wards purchased by the Royal College of Surgeons, in whose museum they are
still preserved.
But a controversy arose respecting the arrangement of medical attendance
in the Infirmary. This contest, which was carried on with great ardour, some
NOTICE OF THE LATE SIR CHARLES BELL. 399
wit, and much asperity on both sides, by the late distinguished and respected Dr
GREGORY and Mr JOHN BELL, ended in a new arrangement, which excluded many
of the surgeons from the only hospital within their reach. Sir CHARLES BELL
happened to be of this number ; and so highly did he prize the advantages he had
lost, that in a printed memorial, presented to the Managers of the Infirmary, he
offered to pay L.I 00 a-year, and to transfer to them, for the use of the students,
the Museum he had collected, on condition that he should be " allowed to stand
by the bodies when dissected in the theatre of the Infirmary, and to make notes
and drawings of the diseased appearances."
This proposal, which was made in October 1804, was rejected ; and per-
ceiving that he had so many difficulties to contend with in Edinburgh, he went
in the course of the following year to London, to inquire into the expediency of
removing thither. The prospect there could not have been very encouraging ;
but he had relinquished all hope of being able to surmount the numerous impedi-
ments which stood in his way here ; and in 1806 he went to the capital.
It is impossible not to admire the courage with which Sir CHARLES BELL, then
a solitary and unsupported stranger in London, trusted to his own resources for
success in a field which was already occupied by CLINE, ABERNETHY, COOPER, and
other eminent surgeons, supported by the great hospitals with which they were
connected, and then lecturing daily to large audiences. To have failed in such
an enterprize, would have been no disgrace ; but to have succeeded and to have
established a high reputation as a teacher, in a department of science so preoccu-
pied, is unquestionable evidence of the highest merit.
He immediately commenced a course of lectures on anatomy and surgery,
and rapidly rose to distinction. " In the lecture-room," says one of his able suc-
cessors in the Middlesex Hospital, " in the lecture-room he shone almost without
a rival. His views were nearly always solid, — they were always ingenious, — and
his manner and language enchained the attention of his audience. Dull indeed
must have been the pupil who could have slumbered when CHARLES BELL was in
the professorial chair. In short, Sir CHARLES BELL made his pupils think ; and
interesting as anatomy is, even if considered as a mere branch of natural history,
he taught them to value it most of all as a guide to the art of healing." *
Previous to his departure from Edinburgh, he had written his work on the
" Anatomy of Expression," which was published shortly after his arrival in Lon-
don, and immediately attracted public attention. He had felt as a physiologist,
as an artist, the want of some philosophical and systematic explanation of the
rationale of expression ; of those muscular movements which are the natural ex-
ternal indications of the passions and emotions of the mind. He had observed
that many works of art, otherwise excellent, exhibited anatomical inconsistencies,
* ARNOT'S Hunterian Oration, 1843.
400 NOTICE OF THE LATE SIR CHARLES BELL.
which he attributed to the want of some competent guide to a knowledge of the
principles on which these movements are regulated ; and, perhaps, no other man
was so well qualified, by his profound knowledge of anatomy, and his practical
acquaintance with art, to supply the want. But he did not confine himself to
the illustration of what was useful to the artist ; he also explained how an ac-
quaintance with the anatomy of expression might be available to the surgeon or
to the physician, in distinguishing the nature or the extent of some important
diseases.
Independent of its intrinsic merit, this work has another interest, for there is
reason to suspect that his inquiries into the functions of the nerves in connection
with the anatomy of expression led him to prosecute those investigations which
terminated in the most remarkable anatomical discovery of our times.
But before attempting to give an account of Sir CHARLES BELL'S discovery of
the different functions of the nerves, corresponding with their relations to different
portions of the brain, I must beg your indulgence while I state shortly the opinions
upon this subject, which were taught in anatomical schools prior to the announce-
ment of his views. This is the more necessary, because these views have now
been so generally adopted, both in Great Britain and on the Continent, that we
are apt to forget what the previous state of our knowledge really was. And I
may perhaps be permitted to make a few preliminary observations, not imme-
diately connected with the subject, but which may serve to make it more intel-
ligible to such of you as may not have attended to the history of anatomy, and
which may also assist us in appreciating the comparative value of the truths
which Sir CHARLES was the first to explain.
In the higher classes of animals, there are three great ramified systems which
are distributed to every part of the body. The arteries and veins ; the lacteals
and lymphatics ; and the nerves. It is little more than two centuries since we
have obtained a tolerably accurate knowledge of the true functions of any of these
systems. The earliest anatomists believed, that the arteries in their healthy state
contained nothing but ah*, as the name which they still retain denotes ; and the
veins were then believed to be the only blood-vessels. In the second century of
our era, GALEN is said to have discovered that the arteries also were blood-vessels ;
but it was still believed, that there was* a flux and reflux of the blood in the ar-
teries and veins, — that the blood which flowed through these vessels from the
heart or the liver to the extremities, flowed back through the same vessels to the
heart and the liver ; and various theories were devised to reconcile this belief,
with the natural phenomena which presented themselves. At length in 1628,
HARVEY set the question at rest, by publishing his discovery of the circulation of
the blood, propelled through the arteries to the extreme parts, and returning
through the veins, in two great circles from the right and the left cavities of the
heart.
NOTICE OF THE LATE SIR CHARLES BELL. 401
The more obscure vessels called lacteals and lymphatics, altogether eluded
the observation of ancient anatomists. The existence of the lacteals was dis-
covered accidentally, and their functions were partly conjectured by ASELIUS of
Pavia, a cotemporary of HARVEY ; and their office, that of conveying the nutritive
part of the food from the intestines to mingle with the blood, and thus to be
distributed to all parts of the body, was demonstrated by PECQUET, a French
anatomist, who had also the candour to acknowledge that his discovery was ac-
cidental. The lymphatics were shortly afterwards discovered by RUDBECK and
by BAETOLINE, the one a Swede, the other a Dane, who shrewdly suspected what
their functions were ; and the subject was further illustrated, and the functions
of these vessels fully explained, by the late Mr HUNTER and the late Dr MONRO,
who proved them to be absorbents, that is, the vessels by which the waste of the
body, which the lacteals supplied new matter to replace, was carried off.
It is worthy of remark, that both these offices had been assigned to the veins,
which, as we have seen, were also, at one time, regarded as the only blood-ves-
sels ; and although the manner in which the work of absorption is divided be-
tween the lymphatics and the veins is still somewhat obscure, yet the constant
result of these successive discoveries has been to shew, that the function of each
portion of these vessels is simpler than it had been supposed to be ; and that na-
ture perfects the performance of the animal functions, by multiplying the organs
and simplifying the duties of each, rather than by simplifying the general struc-
ture, and complicating the functions of its parts; and we shall find that the
nerves afford a further illustration of this principle.*
The nerves had been noticed from the earliest times, and their functions were
long known to be to transmit the mandates of the will from the brain, which has
always been regarded as the sensorium, to all the parts which are under the con-
trol of the will ; and to communicate to the sensorium, intelligence of the condi-
tion of their own extremities, which we call sensation. They were divided by
anatomists into cranial and spinal or vertebral nerves, with reference to their
origin from the brain or the spinal marrow.
In the same manner as it had been taught before the discoveries of HARVEY,
that there was a flux and reflux of the blood in the arteries and the veins ; that
it flowed " backwards and forwards like the tide of Euripus ;" so it was taught in
our own days, that the same nerves transmitted the mandate of the will from the
sensorium to the organs of voluntary motion, and likeAvise carried to the senso-
* Another general fact, which seems to be well ascertained, may be referred to the operation of the
same principle, and, in this respect, has also some analogy to the great discovery of Sir CHARLES BELL
in regard to the nerves, viz., that different portions of the small arteries, which are similar in size, struc-
ture, and degree of subdivision, have nevertheless very different relations to the blood which they carry,
and suffer very different portions of that blood to transude through their coats, so as to maintain the
functions of secretion and nutrition ; thus affording another instance of the natural subdivision of labour.
VOL. XV. PART III. J5 Q
402 NOTICE OF THE LATE SIR CHARLES BELL.
rium intelligence of the condition of their extremities, or sensation. It was
taught that, in some mysterious manner which no one could explain, these two
impulses might be simultaneously communicated along the same cord, in oppo-
site directions, without impairing the efficiency of either. This proposition was
certainly startling ; but so long as each spinal or vertebral nerve was regarded as
a simple cord, composed of one bundle of similar filaments, the inference was in-
evitable ; for if we divide the trunk of one of these nerves, at any point, we leave
unimpaired the power of motion, and the sensation of the parts which intervene
between the point of section and the brain ; but we paralyze at once both motion
and sensation in the parts over which its remoter ramifications are distributed.
The cord thus divided was, therefore, necessarily and truly inferred to be the
channel through which volition acted to move the muscles, and through which
sensation was communicated from other parts of the body to the sensorium.
It is nevertheless true, that physiologists had not been uniformly satisfied
with this theory. The fact that a limb, which had lost the power of voluntary
motion, often retained sensation, had led some discerning men, at an early time,
to question whether there might not be different nerves for motion and for sen-
sation. GALEN asserted this opinion in a part of his writings ; but he elsewhere
maintains that one nerve may minister to both offices ; that motion is active, and
sensation passive ; and that a nerve may retain this passive power after it has
lost that which is active.
BOEMIAAVE, following GALEN, asserted that there were two kinds of spinal
nerves — the one serving for motion, the other for the use of the senses. Speak-
ing of the spinal marrow, he uses these remarkable expressions : " Ex hac me-
dulla exit duplex genus nervorum, unum motui, alterum sensuum inserviens, nee
unquam inter se communicans ;" and then he adds the inquiry, " Quis dicet hie,
hoc movet hoc sentit ? " This was certainly a striking and ingenious specula-
tion ; but BOERHAAVE did nothing towards solving the question he had put, or the
doubts he seemed desirous to raise ; accordingly, these speculations produced no
change in the opinions of anatomists and physiologists, and the old theory not
only maintained its ground, but appeared to be confirmed by further investi-
gations.
The renowned HALLER, who carefully investigated this subject, and who
must have been well acquainted with the writings both of GALEN and of BOER-
HAAVE, rejects a theory which neither of these distinguished authors had supported
by any evidence, and which they had not even uniformly maintained. " But I
know not," says HALLER, " a nerve which has sensation without also producing
motion ; the nerve which gives feeling to the finger, is also that which moves the
muscles ; and the fifth nerve of the brain branches to the papillae of the tongue,
and also to the muscles."
Dr ALEXANDER MONEO maintained similar opinions ; and he combated the
NOTICE OF THE LATE SIR CHARLES BELL. 403
theory that ganglia were for the purpose of cutting off sensation, on the express
ground, that they were to be found on the posterior half of all the spinal nerves of
the voluntary muscles ; thus shewing that, to be a nerve of voluntary motion, was
by him regarded as conclusive evidence that it must also be a nerve of sensation,
and that he believed all those spinal nerves which passed through ganglia to be
motor nerves. On this Sir CHARLES BELL justly remarks, " If I had ascertained
nothing more than that no motor nerve passes through a ganglion, the observa-
tion would have been important towards the true doctrine of the nerves."
BICHAT (a distinguished name in modern anatomy and physiology) distinctly
asserts that there are not nervous cords appropriated to sensation, and others to
motion.
BARON CUVIER maintained, that the difference in the functions of the nerves
depends rather on the different organization of the parts to Avhich they are dis-
tributed, than on any essential difference between themselves ;* and M. SEREES,
in his work on Comparative Anatomy, published as late as 1824, quotes with ap-
probation this opinion of CUVIER'S, even maintaining, in conformity with it, that
in certain animals a part of the fifth nerve answers the purpose of the optic
nerve ; and without making allusion to Sir CHARLES BELL'S experiments and ob-
servations. But he admits, at the same time, that it is doubtful whether these
animals are realty endowed with the sense of sight.
Dr BARCLAY of Edinburgh, a learned man and an eminent anatomist, who
communicated the history of Anatomy to the Edinburgh Encyclopedia published
in 1810 or 1811, not only makes no allusion to any discovery of the varied func-
tions of the nerves, but, having related the discovery of the lymphatics, and de-
scribed their functions, referring to the conflicting claims of HUNTER and of MONRO,
he expressly tell us, that this system of absorbents is the last great and leading
discovery made in anatomy by means of dissection.
In short, that which has already been stated to have been the doctrine of the
Anatomical Schools, viz. that the same nerves ministered at once to motion and
sensation, that the impulses of volition and of sensation were transmitted back-
* " On pourrait penser d'apres cela qu'au fond toutes les parties du systeme nerveux sont homogenes
et susceptibles d'un certain nombre do fonctions semblables, a pou pres comme les fragmens d'un grand
aimant que 1'on brise deviennent chacun un aimant plus petit, qui a ses poles et son courant ; et que ce
sont des circonstances accessoires seulement, et la complication des fonctions que ces parties ont a rem-
plir dans les animaux tres eleves, qui rendent leur concours necessaire, et qui font que chacune d'elles a
une destination particuliere — II paroit, en effet, quant a ce dernier point, que si certains nerfs ne nous
procurent que des sensations determinees, et que si d'autres ne remplissent egalement que des fonctions
particulieres, cela est du a la nature des organes exterieurs dans lesquels les premiers se terminent, et a
la quantite de vaisseaux sanguins que recoivent les autres, a lours divisions, a leurs reunions, en un mot,
a toute sorte de circonstances accessoires, plutot qu'a leur nature intime." — Lemons d' Anatomie Com-
pare.e de CUVIER, torn, ii., p. 95.
404 NOTICE OF THE LATE SIR CHARLES BELL.
wards and forwards along the same cord, continued to be taught, or was left to
be inferred, by all the teachers of Europe, for at least a year after Sir CHARLES
BELL had announced to his friends his ideas on the nervous system.
To the genius and to the patient and laborious investigations of Sir CHARLES
BELL we owe the discovery, that no one nerve serves the double purpose of minis-
tering to motion and to sensation ; — that the spinal nerves and the fifth nerve of
the brain, which had been regarded each as one nerve, consisted each of two dis-
tinct nerves, connected with different portions of the brain, enclosed in one sheath
for the convenience of distribution, but performing different functions in the ani-
mal economy, corresponding with the different portions or tracts of the brain to
which they could be traced ; the one conveying the mandates of the will to the
muscles of voluntary motion from the sensorium, the other conveying to the sen-
sorium intelligence of the condition of distant parts, or sensation. That, to use
the illustration I have already employed, as the arteries carry the blood from the
heart and the veins carry it to the heart, so one set of nerves carry the impulses
of volition from the brain, and another set of nerves carry the impulses of sensa-
tion to the brain ; — that the brain is divided, together with the spinal marrow
Avhich is prolonged from it, into separate parts, ministering to the distinct func-
tions of motion and sensation ; — and that the origin of the nerves, from one or
other of these sources, seems to endow them with the particular property of the
division whence they spring. Such were the leading features of BELL'S great
discovery, one of the most remarkable that the history of anatomy will now have
to record.
Let us not forget that the steps by which human knowledge has advanced
have at all times been short and slow. It has rarely or never been permitted to
the same mind to originate the idea, and to perfect the development of any of the
great truths of nature. The greatest discoveries in science have either been dimly
seen at a distance and imperfectly shadowed forth, or coniectured as matters of
speculation, or the minor truths on which they are founded have been divulged
by those who went before, but who failed to arrive at the conclusion which opens
up to our view what till then had been hidden, and which expounds to us one of
the great laws of nature. But it is to him who, pressing on in advance of his
fellows, takes this last and greatest step, and establishes the truth on a sure foun-
dation, making it practically available to other men, — a permanent contribution
to human knowledge, and a fresh illustration of the perfection of created things, —
that we justly attribute the glory of a discovery ; and to that glory Sir CHARLES
BELL is justly entitled.
The circulation of the blood through the lungs was known to GALEN and to
many of his successors ; and it was demonstrated by COLUMBUS, the disciple of
VESALIUS. CJESALPINUS not only knew the circulation through the lungs, but he
also discovered that there was a communication between the extreme branches of
NOTICE OF THE LATE SIR CHARLES BELL. 405
the arteries and the veins in other parts of the body ; and FABIUCIUS pointed out
the valves in the veins, which prevent the reflux of blood in these vessels ; yet
they did not deduce from these facts the theory of the circulation, though, now
that it is known, we wonder how they could have failed to discover it. But in
the progress of knowledge, the mind has much to unlearn as well as much to ac-
quire ; and when our opinions have been sanctioned by the concurrent belief of
successive generations, the former is often the more difficult task of the two.
When HARVEY announced his great discovery, almost every physician of his time
denied its truth, and none of them who were above forty years of age ever, it is
said, admitted it. When its truth could no longer be disputed, eiforts were made
to deprive its author of the merit and the glory of the discovery. Some searched
the works of previous writers for evidence that it had been known before his
time ; and others who followed him, sought to appropriate the honour that be-
longed only to him. Somewhat similar was the reception Sir CHARLES BELL'S
discovery encountered on its first announcement to the world in 1811 and 1821.
But as the name of HARVEY is inseparably connected with the great truths which
he was the first to ascertain, so will the name of BELL for ever be united in the
records of science with his discovery of the varied functions of the nerves.
Insulated facts and unsupported speculations are forgotten and lost, but great
discoveries never perish ; for they become fixed and established portions of know-
ledge on which the mind reposes in security. Their leading facts become familiar
to all educated men — a part of every man's ordinary information; and the light
with which genius illuminated the high places of science is not only shed on the
paths which lead up to them, but pierces far into the darkness beyond, and
lights on successive generations in their ascent to the loftier heights of a more
exalted knowledge.
Confidence in the perfection of the works of creation, and a conviction that
the nervous system appeared to be utter confusion, only because of our own igno-
rance, was BELL'S leading principle in all his investigations ; and to this confi-
dence we must attribute the unwearied perseverance with which he prosecuted
his enquiries, without any other support or encouragement during so many years
of his life.
It would detain you too long were I to trace, step by step, the progress of
these inquiries, till he caught a glimpse of the truth in 1807 ; — but the letter in
which, with joy and exultation, he communicated the intelligence to his brother,
Professor GEORGE JOSEPH BELL, is too remarkable to be omitted, although it has
already been made public ; and as it bears the post-mark of London, December 5,
and Edinburgh, December 8, 1807, it puts an end to all question, if there ever
could have been a reasonable question, as to the originality of his views, and the
priority of his discoveries.
VOL. XV. PART III. 5 R
406 NOTICE OF THE LATE SIR CHARLES BELL.
" My anatomy of the brain is a thing that occupies my head almost entirely.
I hinted to you formerly that I was ' burning,' or on the eve of a grand discovery.
I consider the organs of the outward senses as forming a distinct class of nerves
from the others. I trace them to corresponding parts of the brain totally distinct
from the origin of the others. My object is not to publish this, but to lecture it,
* * * as it is really the only new thing that has appeared in anatomy
since the days of HUNTER ; and, if I make it out, as interesting as the circulation,
or the doctrine of absorption. But I must still have time. Now is the end of a
week, and I shall be at it again."
In" another letter, bearing the post-marks March 28 and 31, 1808, is the fol-
lowing passage : — '• I have been thinking of having a room five or six miles from
town, and pursuing there my physiology of the brain — that which is to make me, I
am convinced."
Others have followed in the same track, and walking by the lights which he
had furnished, and in the path which he had pointed out, have advanced our
knowledge and confirmed the truth of his opinions. Amongst these, his relative
pupil, and coadjutor, Mr JOHN SHAW, has been conspicuous ; and to him Sir
CHARLES BELL was indebted for some important experiments. Mr HERBERT
MAYO, another of his pupils, has prosecuted similar inquiries. In France, in Italy,
and in Germany, the method of investigation first employed by Sir CHARLES BELL
to determine the functions of the nerves, by attending to their roots, and not to
their trunks, has been followed by MAJENDIE, LONJET, BELLINGERI, and the most
distinguished physiologists of those countries. They have instituted experiments
in imitation of Sir CHARLES BELL'S ; and the practical precepts which were first
deduced from his discoveries, by himself and by Mr JOHN SHAW, have thus been
extended and multiplied.
Mr ARNOT, of the Middlesex Hospital, has stated with so much discrimina-
tion and distinctness the precise nature of Sir CHARLES BELL'S discoveries in the
physiology of the nerves, that I shall take the liberty of concluding my observa-
tions on this part of the subject in his words. After acknowledging whatever he
thought incomplete or imperfect in BELL'S writings on the Nervous System, and
especially that his views in respect to certain nerves being superadded in the
higher animals, for the purposes of respiration, had not been fully proven, he goes
on to say —
" But after all these acknowledgments, there remains to BELL, clearly and
unequivocally, the merit of having first shewn—
" That in investigating the functions of the nervous system, we must direct
our attention to the roots and not to the trunks of the nerves.
" That the nervous trunks, conveying motion and sensation, consist of two
distinct sets of filaments in the same sheath.
" That the filaments for motion form a distinct root from those for sensation,
NOTICE OF THE LATE SIR CHARLES BELL. 407
and that the anterior roots are for motion ; leaving it to be inferred that the pos-
terior are for sensation.
" That the portio dura is a nerve of motion, and the fifth a nerve of motion
and sensation.
" And, lastly, of having been the first who, dissatisfied with the observation
and study of the mere form of the various parts of the nervous system, applied
the method of experiment to aid him in determining their functions.
" In a word, there belongs to BELL the great discovery, — the greatest in the
physiology of the nervous system for twenty centuries, — that distinct portions of
that system are appropriated to the exercise of different functions."
The Royal Society of London acknowledged his merit by assigning to him,
in the year 1839, the first annual medal of that year, given by his Majesty
GEORGE IV. for discoveries in science ; and when a new order of knighthood for
men of science and literature was instituted, on the accession of the late King
to the throne, Sir CHARLES BELL was amongst the first who were invested. But
this was the only public reward he received for his labours, — a reward which he
would have merited for the services he rendered to the wounded after the battles
of Corunna and Waterloo, if he had never rendered any other either to his coun-
try or mankind.
In 1812, he was appointed Surgeon to the Middlesex Hospital, and a few
years afterwards Professor of Anatomy, Physiology, and Surgery to the College
of Surgeons of London. In the hall of that noble institution he delivered a course
of lectures which was attended by a very numerous audience, including men of
high professional and literary reputation. On the institution of the London Uni-
versity College, he was solicited to place himself at the head of the medical de-
partment,— an office which he afterwards resigned, in consequence of dissensions
which arose in the establishment. In 1836 he was appointed to the Chair of Sur-
gery in our own University.
It is not my intention to say more of his various writings on the practice of
different branches of his profession, than that they place him in the highest class
amongst our writers on surgery.
But there is another series of his works which must interest every reader,
and which, of all his labours, were perhaps the most congenial to his feelings, and
afforded him the greatest pleasure.
In his treatise on Animal Mechanics, written at the desire of the Society for
Diffusing Useful Knowledge, he embodied the substance of some of his lectures,
which had been so much admired in the College of Surgeons, on the evidences of
creative design to be found in the anatomy of the human body. These views had
long been deeply impressed upon his mind, and the manner in which he illustrated
them probably pointed him out to the executors of the late Earl of BRIDGEWATER as
408 NOTICE OF THE LATE SIR CHARLES BELL.
a fit person to maintain the great argument which it was the purpose of that no-
bleman's bequest to have published. The part which Sir CHARLES himself select-
ed was " The Hand," that which seemed chiefly to have been in the mind of the
testator ; and we all know how admirably he executed the task.
Still following out this favourite subject of his contemplation, he associated
himself with Lord BROUGHAM in the illustration of Dr PALEY'S Natural Theology,
published in 1836 ; and every one who has looked into that publication must ac-
knowledge the high additional interest which these illustrations derive from his
delightful contributions.
Of his private character this may not be the place to speak ; but the highest
eminence in science receives so great an additional lustre from being associated
with the most amiable and estimable social virtues, that it would be unjust not
to remind you how largely he was endowed with these. It was in the exercise
and the indulgence of the friendship and the affection of social and domestic life,
and in the contemplation of still higher objects, that he found the reward of his .
labours and a solace in his difficulties and disappointments ; and if he was but ill
requited by his country, for devoting his life so successfully to the advancement
of science, instead of employing it, as he might have done with equal success, in
improving his own circumstances, he enjoyed while he lived a happiness which
wealth alone could not have bestowed, in the devoted attachment of one who was
in every way worthy of the undivided affection with which he regarded her.
After a cheerful and peaceful day of calm contemplation and tranquil enjoy-
ment, he was suddenly seized with a spasmodic affection duringt he night, and
died, after an hour's illness, on the 29th of April 1842, at Hollow Park, in Worces-
tershire ; and if he left behind him none of the wealth which a more sordid mind
might, with his genius, have accumulated, he left an enduring and unsullied repu-
tation, of which the most ambitious of his surviving friends may well be proud,
and with which the most virtuous must be more than satisfied.
( 409 )
XXIX. — On the Determination of Heights by the Boiling Point of Water. By
JAMES D. FORBES, Esq., F.R.S., Sec.R.S.Ed., Inst. Reg. Sc. Paris. Corresp.,
and Professor of Natural Philosophy in the+University of Edinburgh.
(Read 6th March 1843.)
IT was observed by FAHRENHEIT, that the boiling point of water depends on
the height of the barometer, the pressure of the air hindering the conversion of
water into steam by a resistance which must be overcome by an increase of heat.
DELUC* and DE SAUSSUREJ contrived apparatuses for making the observation in
the open air, and at great heights, and appear to have contemplated the substi-
tution of the thermometer for the barometer upon occasion. They, as well as
Dr HoRSLEY,t Sir GEORGE SCHUCKBUEGH,§ and Mr CAVENDISH, || seem to have
regarded the question as one which concerned the fixity of the point used in gra-
duating thermometers, and its requisite corrections, rather than as applicable to
barometric purposes generally. Several of them have given empirical tables for
correcting the boiling point within the limits of the usual barometric variations,
but one only, M. DELUC, has given a formula for connecting the indications of the
barometer with the boiling point of water throughout the range which the baro-
meter has been observed to vary on the earth's surface. This is the only formula
immediately deduced from direct observations of the boiling point ; and having
been verified by DE SAUSSURE at a height greater than the limits for which it was
constructed, and having elsewhere been declared by him to be so accurate as to
supersede farther experiment on the subject, it might have been expected to be
generally adopted, or at least known. We find, however, that though it has been
occasionally copied into the formal articles of Encyclopaedias, as a correction in
graduating thermometers, observers who have used the boiling point for the
determination of heights, have always preferred the ordinary tables which give
the elasticity of steam in terms of its temperature, determined from experiments
of quite a different kind from the boiling of water.
Dr DALTON, indeed, has given a table from observation under the air-pump
of the boiling point,^[ and that table shews a manifest deviation from the elasti-
cities and temperatures of vapour determined by himself, and now generally
accepted as the most accurate below 212°. In boiling, the temperature requires
* Modifications de 1' Atmosphere, torn. ii. t Voyages, § 1275, 2011.
J Phil. Trans, vol. Ixiv. § Ibid. vol. Ixix. || Ibid. vol. Ixvii. p. 816.
*[ Meteorological Essays, 2d edit. p. 127.
VOL. XV. PART III. 5 8
410
PROFESSOR FORBES ON THE DETERMINATION OF HEIGHTS
to be higher, under a given pressure, than the temperature of steam which has
the same tension. Thus, comparing DALTON'S two tables —
Temperature.
Pressure
under which
Water boils.
Tension of
Vapour.
Difference.
212
30-0
30-0
o-oo
200
22-8
23.64:
+ 0-84
190
18-6
19-00
+ O-iO
180
15-2
15-15
— 0-05
it is exactly at the part of the scale where the difference is most practically im-
portant that it is most conspicuous, namely, between 190° and 212°. The method
of observation used by Dr DALTON, does not admit of any great accuracy in ob-
serving the boiling points, and the numbers he has given are evidently only ap-
proximate. Still, from observations made under naturally low pressures (the only
ones worthy of much confidence in this case), I have found the same nonconfor-
mity of the theoretical tension of steam and the atmospheric pressure.
In 1817, Archdeacon WOLLASTON described a thermometer destined particu-
larly for the purpose of determining heights.* But he seems not to have been
aware of the progress which the subject had already made in the hands of DE-
LUC and DE SAUSSUKE. The latter used a thermometer indicating jggg of a de-
gree of REAUMUR. WOLLASTON'S instrument, though a neat laboratory one, has
almost every fault which a travelling instrument can have, excepting only its
small dimensions, to which everything is sacrificed. It is apt to break, and still
more apt to be deranged, the contrivance for extending the scale being excessively
incommodious ; finally, it is impossible to use it in windy weather, and its indi-
cations are in an arbitrary scale. No was the method of calculating the heights
more happy. At first he contented himself with assuming the progression of
height to be proportional to the fall of the boiling point, near 212°;f but he
afterwards \ extended his calculation from Dr URE'S table of tensions of vapour,
expressly stating, that he had used the proportionality of 1° of FAHRENHEIT to
0.589 inches of the barometer, or 530 feet, merely as an approximation for small
heights.
A reference in BOUE'S Guide du Geologue Voyageur, directed me to a paper
by Mr PRINSEP, in the Journal of the Asiatic Society of Bengal for April 1833.
I hoped there to have found a table of boiling temperatures observed at great
heights in India. But it only contains a modification of TREDGOLD'S Formula of
* Phil. Trans, vol. cxx. p. 183.
t Ibid. p. 192.
1 Ibid. vol. ex. p. 295.
/ 'LA n: .n.Jioiial &v. trans. Edin
Fig. 5.
1 I'.ll,'. !':,!
Pic,. 3.
_
Relation behrefti Boilin<> /'<>/'/// .1,1, f /;/- i -///.-//
fi+s>. 5 feet for l" Ftihr.
•
' >i°
2*7" 1W
»,.
BY THE BOILING POINT OF WATER. 411
the Elasticities of Steam adapted to the measurement of heights by the thermo-
meter, and no original observations.
During a late journey in Switzerland (in 1842), I made several observations
on the boiling point of water at great heights. Having long since abandoned
WOLLASTON'S thermometrical barometer as practically useless, I was led to re-
sume the method in consequence of a very ingenious and compact apparatus for
chemical or culinary purposes having been shewn to me the preceding winter, by
Mr STEVENSON, instrument maker, under the name of a Russian furnace, and
which was, I believe, introduced into the country from Russia by Dr SAMUEL
BROWN. It consists of a very thin cylindrical copper-pan for holding water, Fig.
1, Plate XL, with three moveable wire-legs. The bottom is flat, so that the flame
of a spirit-lamp plays fully upon it. This lamp or furnace consists of two parts ;
a flat dish or saucer, Fig. 4, containing a little alcohol, which is set on fire,
and then covered by the double dome-shaped vessel, Fig. 5, also of thin copper,
with an air-tight plug a, by which a certain quantity of spirit of wine is intro-
duced, and the lower part communicating with a bent tube or nozzle b, by which
alcohol in ebullition is violently projected by the pressure of its own vapour,
when heated by the flame in the saucer. The jet of burning spirit thus thrown
up like a volcanic explosion through the aperture of the dome, has such force as
to resist the blast of a hurricane, and plays right upon the bottom of the cylin-
dric boiler or pan. Two fluid ounces of spirit of wine, will thus boil above a pint
of water in still air in four minutes ; and I have frequently first melted snow, and
then brought it to boil to the amount of a pint, with little more alcohol, but, of
course, in a longer time.
The furnace and boiling apparatus, together with a reservoir of alcohol, packs
into the copper-pan, and that into a cylindrical leather case 4 inches high, and
6 in diameter. The thermometer, Fig. 2, is carried separately. It is 15 inches
long and the degrees measure fg inch, which is quite sufficient in practice. Paral-
lax is avoided, by having the scale repeated on each side of the tube on two
pieces of copper not in the same plane.
Fig. 6 represents the spirit measure, Fig. 7 a reservoir for spirits, Fig. 8 a
water measure or cup, Fig. 9 a handle which opens all the plugs, and serves also
for lifting the lamp and pan when heated.
I immediately saw the value of the apparatus for determining the boiling
point, and directed Mr ADIE to adapt a thermometer to it, graduated from 185° to
214° of FAHRENHEIT'S scale, divided to lOths of a degree, the divisions admit-
ting an estimation to 1 OOths. I am well assured, however, that in no circum-
stances, even the most favourable, is the observation true to less than go of a
degree. But this quantity corresponds to only 25 feet of elevation, and is there-
fore accurate enough for most purposes. The minute subdivisions of DELUC'S,
DE SAUSSUKE'S, and WOLLASTON'S instruments, are quite unavailing, as I have
found by using the instrument of the latter with every precaution.
412
PROFESSOR FORBES ON THE DETERMINATION OF HEIGHTS
My barometer having been broken in the course of my journeys, I was glad to
have recourse to the boiling point as a means of estimating (only roughly as I ex-
pected) some remarkable elevations not before measured. In several cases I had
the advantage of comparing my thermometric boiling point with a barometer, and
lately I resolved to discuss these observations empirically, without reference to
any theory or tables, or previous observations.
I first projected the barometric pressures in terms of the corresponding ther-
mometric observations. These were the following : —
DATE.
PLACE.
BOILING POINT.
Barometer re-
duced to English
inches, and to
32°
1842.
August 4
Tacul
200°-10
23-154
6, 7i A. M.
Tacul
200°'6
23-353
13, 8 A.M.
St Bernard
199°-08
22-674
16, 8 P.M.
Prarayon
201°-58
23-893
17, 9 A.M.
Col Collon
195°-15
20-77
29, 11 A.M.
Gressonay
204°-20
25-143
September 5, 7 P.M.
Martigny
210°-12
28-489
I obtained a curve, which resembled a flattish logarithmic, the barometric
numbers appearing to be in geometrical progression, whilst the temperatures
varied uniformly. This recalled to me an idea which I had entertained some
years ago, that the boiling point would be found to vary simply Avith the height
to which I was led from knowing DELUC'S formula; but the idea had since es-
caped me, or been postponed to other occupations. Now, however, I projected
the simple elevations of the points of observation (derived from the barometric
pressures from the common tables for computing heights uncorrected for the tem-
perature), in terms of the boiling points, as in the Plate XL, Fig. 3, and I was gratified
to find, that a straight line passed almost quite through the whole of them, shew-
ing that the temperature of the boiling point varies in a simple arithmetical pro-
portion with the height, namely, 549 -5 feet for every degree of FAHRENHEIT;
so that the calculation of height becomes one of simple arithmetic, without the
use of logarithms, or of any table whatsoever.
When I had ascertained this fact, I looked back to DELUC'S formula, and
found my old conjecture entirely confirmed. Its form is
a log p + C = h,
h being the height of a thermometer plunged in boiling water under a pressure p ;
BY THE BOILING POINT OF WATER. 413
a and C constants. But the first side of this equation is the very form which gives
elevations in terms of the barometric pressure. Hence the boiling temperature
varies as the height. In other words, the pressure varies in a geometrical ratio,
when the temperature of boiling, water varies uniformly ; but the pressure varies
geometrically when the heights above the sea vary uniformly : hence the heights
vary uniformly with the boiling temperatures.
It is very singular that so elegant and simple a result should have escaped
every writer on the subject (so far as I know) ; even DELUC himself who proposed
the logarithmic law, and WOLLASTON, who unawares adopted the true law as a
first approximation, and then took a wrong one.*
It is not to be supposed that the coincidence appears close, because the obser-
vations are not accurate enough to test it. Of seven observations between 195°
and 210°, no one differs 20 feet of elevation from the mean line, — a quantity cor-
responding to 23g of a degree, an amount which can by no means be considered as
being beyond the errors of observations ; and the small errors ± are well distri-
buted throughout. On the contrary, when the tensions of vapour, from DALTON'S
Table, are projected beside them, as in the dotted curve of the figure, not only do
they lie wholly above the line, but these tensions cannot be represented (when
treated as representing barometric heights) as a straight line at all. They have
a manifest curvature convex upwards. In short, as is well known, the tensions
of steam cannot be represented by a geometrical progression in terms of the tem-
perature ; but when water boils in the free air, the pressures are then exactly in
geometrical progression.
I never saw any ground for believing that the two laws must be the same. Our
theory of vapours is not sufficiently perfect to admit of our drawing any such con-
clusion. Indeed I cannot help thinking that the influence of the pressure of the air
upon the elasticity of nascent steam, is a fact not easily reconciled with DALTON'S
theory of the pressure of elastic fluids. It is one thing to ascertain the elasticity of
steam of maximum density which water of a given temperature can yield, and it is
another to ascertain under what pressure of air water will yield steam of a given
temperature. In practice I have observed the temperature of the boiling water,
and not of the steam. The construction of the apparatus required this. But by
moving the furnace to a side, so as to prevent the flame from disengaging the
steam immediately under the thermometer, I have found the indications as steady
* He says, — " Having occasion last summer of visiting Caernarvon, which would afford an oppor-
tunity of trying the instrument on the known height of Snowdon, and being aware that in 3550 feet the
variations of the boiling temperature were not to be considered uniform, as they might in small ele-
vations, on which alone I had before tried the experiment, I wished to provide myself previously with a
table for making the necessary correction, and from Dr UBE'S paper was supplied with data for calcula-
tion."— Phil. Trans. 1820, p. 295. The table given from URE'S law of tensions gives a gradually in-
creasing number of feet, corresponding to every degree that the thermometer falls.
VOL. XV. PAET III. 5 T
4]4 PROFESSOR FORBES ON THE DETERMINATION OF HEIGHTS
as I believe can be got in any other way. The mass of the water and also of the
thermometer favours this.
But I had a farther test of the exactness of the arithmetical progression
above established, and that as severe as could well be proposed. It was to com-
pare DE SAUSSURE'S observations on Mont Blanc and the pressure there ob-
served with the result of my formula. But first, it was necessary to correct the
zero point of his instrument, and to render it comparable to mine. DE SAUS-
SURE'S boiling point, 80° of REAUMUR, or 212° of FAHRENHEIT, was adjusted at 27
French inches, or 2H.777 English.
At that pressure my thermometer (AciE) shews 210.58 F. DE SAUSSURE'S
stood, therefore, 1°.42 F. higher than mine. Now, on the top of Mont Blanc, the
barometer stood at 17.133 English inches.
The boiling temperature by DE SAUSSURE was . . 187°.234 Fahr.
Reduced to ADIE 185°.814 ...
But the boiling point of ADIE'S thermometer, with the baro-
meter at 30 inches, is 212°.62
Subtract 185°.81
At Mont Blanc, below boiling point at 30 inches, 26°.7l
By GALBRAITH'S Tables, .... 30.000 inches = 29228 feet.
27.133 — = 14593
Height unconnected for temperature, 14635
Now, by the proportion found empirically above,
Height uncorrected for temperature = 26.71 x 549.5 = 14677 feet, — a coin-
cidence really surprising.
I have already stated, that DE SAUSSURE found DELUC'S formula to conform
accurately to his observation on Mont Blanc. It may therefore be concluded,
that DELUC'S formula and mine agree closely. In fact, if we take its conversion
into English measures, as given by Dr HORSLEY,*
99
899^ log z — 92.804,
which gives the boiling point, in degrees of Fahrenheit, reckoned from 32°, z
being the height of the barometer in tenths of an English inch, we find that this
gives
544.7 English feet of ascent for 1° Fahr.
Practically, I consider it sufficient to find the difference of height, in feet, be-
tween two stations, to multiply the difference of the boiling points by 550, and
then correct as in barometric observations for the temperature of the air.
* Phil. Trans., vol. Ixiv., p. 226.
BY THE BOILING POINT OF WATER. 415
If the barometer at one station is to be compared with the boiling point at
another, the simplest way is to find what elevation the barometer expresses, com-
pared to an imaginary station, where the barometer stands at 30 inches, the boiling
point at 212°. Then the height of the station, where the thermometer has been
observed, above the imaginary station, is found by the preceding rule.
For example : The corrected boiling point on the Col d'Erin between Evolena
and Zermatt, in the Vallais, on the 19th August 1842, was 19F.93, the external
thermometer 34°., the barometer (English) at Geneva was 28.73, ^and the tempera-
ture 72°, required the height.
Then, by GALBRAITH'S table, for 30 inches, . . . 29228 feet.
28.73 28098
Difference, . . 1130
Consequently, supposing the atmospheric temperature 32°, the barometer stood at
30 inches, at a level 1130 feet below Geneva. The boiling point at the upper
station was 20°.07 below 212°. TheCold'Erin was, therefore, 20.07 x 549.5 = 11028
feet above that imaginary sattion, or 9898 feet above Geneva. Corrected for
temperature, this gives 10377 ; and Geneva being 1343 feet above the sea, the
height of the Col d'Erin is 11720 feet.
This is purposely given as a complex case ; but let us suppose that the boil-
ing point, at the level of the sea, is assumed to be 212°, then the approximate
height of the Col d'Erin is 549.5 x 20°.07 = 11028 feet; and supposing the mean
temperature of the column 54°, the height will be 11586 feet above the sea.
( 417 )
XXX. — On the Presence of Organic Matter in the Purest Waters from Terrestrial
Sources. By ARTHUR CONNELL, Esq., Professor of Chemistry in the University
of St Andrews.
(Read 17th April 1843.)
EVER since the discovery by BERZELIUS of crenic acid in the iron ochre of the
water of Porla, in Sweden, chemists have admitted the usual presence of that acid
in mineral waters, or those springs containing notable quantities of dissolved in-
organic constituents. In such natural waters, also, as are visibly coloured, orga-
nic matter is usually understood to be present. Any ideas, however, which may
have been entertained respecting the occurrence of organic matter in the per-
fectly colourless, transparent, and comparatively pure water of ordinary springs,
wells, and rivers, have been merely vague and conjectural.*
There is a simple experiment, which must have been familiar to most che-
mists, viz., that when a solution of acetate of lead is added to the water of springs,
wells, and rivers, a more or less dense white cloud is almost invariably formed.
This reaction, so far as I know, has been commonly attributed to the presence of
inorganic salts, such as carbonates, sulphates, and muriates. No doubt, where
these salts are present, in sufficient quantity to affect the lead solution, they will
produce their proper agency ; but, having often been struck with the much more
marked effect caused by this reagent in such waters, than by the other ordinary
tests of the common impurities in such sources, I was led to suspect that the
effect must be usually due, in whole or in part, to some other cause ; and a very
little investigation soon satisfied me that this was the case. The ordinary cir-
cumstances attending the reaction, I find to be as follows : The precipitate by
acetate of lead is formed even after the water has been boiled for some time, and
is then soluble without sensible effervescence, if a drop or two of an acid is added
immediately. The absence of effervescence may be noticed with a lens in a large
test-tube ; or by allowing the precipitate to subside in a well corked vessel, and then
acting on it by acid. These facts shew that it cannot be due, in such cases, to the
presence of carbonates or sulphates ; and its ready solubility, on the immediate ad-
dition of a drop or two of acetic acid, proves that it is not a phosphate. Farther,
* Since this paper was read, my attention has been directed to a passage in Dr CHRISTISON'S Dis-
pensatory, p. 155, in which he states that all pure spring-waters contain " some vegeto-animal impreg-
nation," the presence of which is shewn by the discoloration of the residual salts, obtained by evaporation,
when farther heated. I do not know of any other chemical writer who expresses himself in equally
broad terms.
VOL. XV. PART III. 5 U
418 PROFESSOR CONNELL ON THE PRESENCE OF ORGANIC MATTER
the circumstances that nitrate of silver seldom shews an equal, and generally a
much less, degree of muddiness, and that that reagent, in no case of such waters
which I have tried, ever produces a dense, curdy precipitate, establish that the
effect is not due to any muriate ; for a solution containing such a constituent,
and giving even a curdy precipitate with nitrate of silver, may, nevertheless, be
too weak to be affected by acetate of lead. The most probable view, therefore,
which occurred was, that the reaction is due to the presence of organic matter ;
and this became the more likely, when it was observed that rain-water is scarce-
ly affected by acetate of lead, although some of the other reagents are not with-
out action on it.* Of course, as already stated, where the water contains a suf-
ficient quantity of inorganic salts to produce their proper reactions with the lead
solution, the above appearances will be modified accordingly.
I made several attempts to insulate the matter in combination with oxide of
lead, by subjecting the precipitate to the action of sulphuretted hydrogen. The
water employed for this purpose was the town water of St Andrews, which pro-
ceeds from springs in the rising ground to the south side of the town, and is con-
veyed into the houses in pipes. In its ordinary state it is transparent and colour-
less. It contains from 7^00 *° Woo °f solid inorganic constituents, which are
sulphate of magnesia, carbonate, sulphate, and muriate of lime, with a trace of
muriate of potash. When fresh drawn from the pipes, it deposits a very little
ochreous matter ; and, on the whole, if it may not be ranked amongst the purest
of spring waters, it at least is of greater purity than the ordinary colourless water
of wells and running streams. This St Andrews water gives a pretty copious
white precipitate with acetate of lead, which is easily dissolved by a drop or two
of nitric or acetic acid, without visible effervescence ; and previous boiling scarcely
diminishes the amount of this precipitate. It is equally formed if the lead-salt
is added to the water after the latter has been allowed to stand some weeks
in a glass jar, so as to separate every thing which is capable of subsidence.
If, after adding the acetate of lead, the water is allowed to remain at rest
for about a quarter of an hour, a farther precipitation then begins, which is
no longer soluble in weak acids, and which is now sulphate of lead. Barytic
salts immediately indicate the presence of sulphates, but the muddiness is
* It will be found, that if the solution of acetate of lead is prepared by dissolving sugar of lead in
any well or spring water, which gives a considerable cloud with that salt, and is then filtered, it is less
readily affected by carbonic acid in any liquid to which.it may be added, than when it has been prepared by
solution in distilled water. Itwas a solution of the former kind that was employed in the above experiments.
Of all tests for free carbonic acid in solution, the most delicate is a solution of basic acetate of lead. It
instantly indicates traces of carbonic acid in distilled water, on which lime-water has no action, and ba-
rytic water a comparatively feeble one. It seems to be for carbonic acid in solution what silver salts are
for muriatic acid, or barytic salts for sulphuric.
IN THE PUREST WATERS FROM TERRESTRIAL SOURCES. 419
less than that afforded by acetate of lead. Silver salts produce merely a decided
opalescence, not a trace of any dense precipitate.
To a large stoppered bottle containing several quarts of this water, acetate of
lead was added as long as a precipitate was produced. The stopper was then re-
placed, and the bottle left twenty-four hours undisturbed, when the precipitate was
found to have entirely subsided to the bottom. The clear liquid was then cautiously
decanted by a glass syphon, 2 or 3 ounces of liquid only being left. A current of
sulphuretted hydrogen was then conducted through a long tube into this liquid,
and the precipitate well stirred up. The liquid was then filtered and heated, to
drive off the excess of sulphuretted hydrogen. A colourless solution was thus
obtained, which reddened litmus powerfully, and of course [contained sulphuric
acid, proceeding from the decomposition of the sulphate of lead precipitated from
the water, after a certain interval. When a portion of it was evaporated to dry-
ness in vacuo over sulphuric acid, the residual matter was deliquescent, from the
presence of sulphuric acid. This residue, when redissolved, left some flocky
matter, and when ignited a little oxide of iron remained. That the liquid ob-
tained, however, also contained some organic matter, was evident from the fol-
lowing circumstances. Saturated with potash, and evaporated in vacuo, it yielded
a white crystalline mass, mixed with darker matter ; and when this saline sub-
stance was heated to redness in a tube retort, it yielded vapour having a strong
empyreumatic smell, and left a black coaly mass ; and turmeric paper was occa-
sionally made brown by its vapour, although this reaction could not always be
distinctly observed, perhaps from the small quantity of matter heated. The acid
liquid itself scarcely affected solution of acetate of copper ; but when the acetate
was made neutral by ammonia, or when the potash salt was used, although there
was no immediate change, a greyish- white precipitate formed in a day or two.
With persulphate of iron, made as neutral as possible by ammonia, the potash
salt gave no precipitate at first ; but a little was formed after a day or two.
Nitrate of silver was scarcely affected by the liquid. Both the neutral and the
basic acetate of lead were abundantly precipitated by it, and the precipitate shewed
no trace of effervescence when acted on in mass by acids. The liquid evidently
contained the same matter which originally affected the lead salt in the water em-
ployed ; for when the potash salt was diluted with five bulks of distilled water,
and acetate of lead added, a cloud was produced as in the original water, dissolved
by acetic acid ; soon after which, a precipitation of sulphate of lead commenced.
It appears to me that the legitimate conclusion from all these experiments is,
that the original action on the lead salt was due to organic matter in the water
employed. The precise nature of that organic matter they are hardly sufficient
to determine, although it would rather appear to be an azotised substance, ana-
logous, perhaps, to the crenic acid ; and the flocky matter which I always observed
to separate when the solutions were evaporated and redissolved, was in all like-
420 PROFESSOR CONNELL ON THE PRESENCE OF ORGANIC MATTER
lihood allied to the apocrenic acid. It did not seem that the whole of this matter
was procured by the process followed ; for when the potash salt was farther diluted
than above stated, but to an extent much short of the original bulk of the water,
it ceased to be acted on by the lead salt.
My attempts to obtain larger quantities of this substance, by precipitating
successive portions of the water in the same vessel, and allowing the several
precipitates to accumulate together, were unsuccessful, when the process was
continued for a week or two, — the precipitate, by standing, apparently suffering
some degree of decomposition, or otherwise escaping the subsequent agency of
the sulphuretted hydrogen ; for in this way I ultimately obtained considerably
less matter than by a single operation concluded without delay, as above
described. It was found by BEKZELIUS that the salts of crenic acid are extremely
liable to decomposition ; and to the same cause was probably due the partial loss
in the single operation.
I could have wished to try the decomposition of the precipitate from a purer
water, and therefore less liable to give an intermixture of inorganic salts ; but at
the time, I had not access to a sufficient quantity of any of those purer spring
waters which I examined on a smaller scale.
Having thus, as I trust, shewn that some degree of confidence may be placed
in the reactions to which I have alluded as indicative of the pi'esence of organic
matter in water, I shall proceed to mention those instances in which I have
convinced myself, by such indications, of the presence of this matter.
Besides the town water of St Andrews, I have found it in the town waters
of Edinburgh and Glasgow. Edinburgh, as is well known to its inhabitants, is
chiefly supplied from a celebrated spring in the vicinity of the Pentland Hills.
The water, as it comes into the town, contains only from lygggth to j^ooth of its
weight of inorganic salts, which are chiefly carbonate and sulphate of lime, and
a little sulphate of magnesia. In this water, by the reactions already detailed, I
fully satisfied myself of the presence of this organic matter. Its quantity was
greater during dry weather in summer than after rains in winter, a result quite
to be anticipated. The town of Glasgow is supplied from the river Clyde ; and
at the time I examined its water, which was in winter, the river was in high
flood from heavy rains, and so muddy, that I could not employ the water taken
directly from the channel ; but in the water brought from the river into the
houses, which has been cleared by subsidence and filtration through sand and
gravel, I found this organic matter, although to a less extent than in the St An-
drew's and Edinburgh waters, a circumstance which was probably due more or
less to the large quantity of rain-water present at the time. I have farther found
this matter abundantly in all the running streams and wells which I have ex-
amined around St Andrew's ; and likewise in such well-waters about Edinburgh
as have come under my notice.
IN THE PUREST WATERS FROM TERRESTRIAL SOURCES. 42]
An excellent illustration was afforded by the well-known spring of St An-
thony's well, at the foot of Arthur's Seat, near Edinburgh. The water of this well
may be considered as a very pure spring- water, as respects inorganic constituents ;
the ordinary tests shewing very feeble reactions with it. On the other hand,
acetate of lead produces in it, whether before or after being boiled, a dense white
cloud, dissolved without effervescence, by a drop or two of nitric or acetic acid,
and no farther precipitate, insoluble in acetic acid, is afterwards formed ; in short,
whilst in comparison with many other waters, its inorganic purities are insigni-
ficant, its proportion of organic matter is notable.
There could be little doubt, that the origin of this organic matter in pure
water was to be referred to the decomposition of vegetable matter contained in the
strata and soil through which the water had infiltrated, or otherwise had its pas-
sage. I therefore could have wished to examine some spring at a considerable
elevation, and having as rocky a source as possible, with the view of ascertaining
to what extent it might still contain such a constituent ; but during the course of
these investigations, I had not an opportunity of visiting any more elevated spring
than one about two-thirds of the way up the hill of Arthur's Seat, or, by barome-
tric measurement, 522 feet above the level of the sea. This spring issues from
the trap-rocks on the NW. face of the hill ; but, of course, there is vegetation scat-
tered on their surface. Accordingly I found the organic matter in its water, al-
though to a less extent than in St Anthony's spring at the foot of the hill.
We may anticipate, that if a spring were examined on any elevated moun-
tain, at a height entirely above the limits of any vegetation, we should cease to
find this substance. A similar observation may be made respecting the water
directly issuing from snow and glaciers. I have already stated, that in rain-water
it does not exist. Such water, if collected with ordinary care and boiled a few
minutes, is entirely unaffected by the acetates of lead.
It will readily occur, that on the supposition that this matter exists to a
greater or less extent in all waters which have infiltrated through strata be-
low the limits of vegetation, it must necessarily perform a part of considerable
importance in the economy of nature. Being in solution in water, it is evidently
in that state which is best adapted for being taken up by the roots and fibres of
plants, and so contributing to their nourishment, in so far as that nourishment
has access by these channels. May not a part of the beneficial effects of irriga-
tion be due to such dissolved organic matter ? Even as regards the animal eco-
nomy, we cannot suppose that it will not contribute, in proportion to its amount,
to the nourishment of man and other animals partaking of such waters ; and this
will more particularly be true, if it really be an azotized body.
ST ANDREW'S, 8th March 1843.
VOL. XV. PART III. 5 X
( 423 )
XXXI. — On the Bebeeru Tree of British Guiana. By DOUGLAS MACLAGAN,
M.D., F.R.S.E.
(Read 17th April 1843.)
ABOUT three years ago, I received from my friend l)r WATT of West Coast,
Demerara, specimens of the bark of a tree, native of British Guiana, which had
been found by Mr RODIE, late surgeon R.N., to contain a vegetable alkali, and to
possess some value as a remedy in the intermittent fevers of that colony. Mr
RODIE made known his discovery by means of a letter which he published in the
year 1834. I made some experiments with the piece of bark, at that time in my
possession ; but the conclusions at which I then arrived did not appear to be wor-
thy of being published. It was obvious to me, however, from the results which
I obtained, that Mr ROME'S statement was so far correct, that the bark did con-
tain a bitter matter, having all the general characters of a vegetable alkali, and
capable of forming neutral compounds with acids. The exhaustion of my original
little store of materials prevented me from proceeding farther, till last year, when,
through the kindness of Dr WATT, I received a barrel of the bark, and likewise of
the fruit of the plant.
The bark as I have received it, now from several sources, occurs in large Hat
pieces, from one to two feet long, and varying in breadth from two to six inches.
It is about four lines thick ; heavy, and with a rough fibrous fracture ; dark cin-
namon brown, and rather smooth within ; and covered externally by a splinter-
ing greyish-brown epidermis. It has little or no aroma, no pungency or acrimony,
but a strong persistent, bitter taste, with considerable astringency.
The fruit sent to me is a nut, of an obovate form, slightly compressed. The
pericarp is greyish-brown, hard and brittle, half a line thick, rather rough exter-
nally, except at the part surrounding the point of its attachment to the footstalk,
where it is smooth, and has probably been embedded in the calyx. The cotyle-
dons are plano-convex ; and when in apposition, are of the size and general figure
of a walnut. A section of the cotyledons, when moist and fresh, was pale-yel-
low, speedily becoming brown by exposure to the air. The juice had an acid re-
action, and was intensely bitter. I suspect that those sent to me were unripe,
both from their appearance, and from the fact that all the attempts made to grow
them have proved abortive.
The plant yielding these productions is still unknown to me. According to
the information which I have received from my Demerara correspondent, it is
known in the colony by the Indian name of Bebeeru ; whilst by the Dutch colo-
nists it is called Sipeeri, under which name, Dr WATT informs, it is known to
VOL. XV. PART III. 5 Y
424 DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA.
SCHOMBURGH ; but I have been unable to trace any reference to such a plant in
his catalogues of British Guiana Plants, hitherto published in the Botanical Ma-
gazine.
The timber of the tree is well known to wood merchants by the name of
Greenheart ; and I find that several loads of it are imported annually into the
Clyde, for the use of carpenters and shipbuilders. There can be no doubt, that
this timber is the produce of the tree yielding the bebeeru bark ; for 1 have re-
ceived from Greenock specimens of the wood with the bark attached, and find the
latter identical in characters with that sent to me directly from Demerara. The
appearance of the wood justifies the English name. It is of a pale yellowish-
green colour, very hard, and heavier than water, — its density, when its pores
are full of air, being 1080. It polishes readily ; is said to be durable, and an-
swers well for shipbuilding, and for making dock-gates, &c. ; but it is difficult to
work, and apt to split in driving bolts through it.
The plant appears, both from its use as timber and from the appearance of
its bark, to be a large tree. Mr RODIE describes it as a " magnificent variety of
laurel ;" but beyond this, I possess no information as to its botanical history. I
sent specimens of the fruit to Sir WILLIAM HOOKER and Dr LINDLEY, both of whom
considered it to be a lauraceous plant, the latter regarding it as allied to the genus
Ocotea. SCHOMBURGH, who saw a decayed flower of it, also referred it to the Lau-
rinese, and he considered it as having some affinity to the genus Persea. I must
own, however, notwithstanding these authorities, that I have in vain searched
through NEES VON ESENBECK'S Systema Laurinarum for any genus, or even sub-
order of Lauraceae, at all corresponding in character with this fruit.
The bebeeru bark has been made the subject of chemical experiment by the
original discoverer of its properties, Mr RODIE. He prepared from it a solution of
the sulphate of its alkali, some of which was sent to me, but it is obviously mixed
with impurities. He does not state what process he followed in preparing it. Mr
RODIE had likewise put samples of the bark into the hands of some of the manu-
facturing chemists of London, including Messrs HERRING and Mr BATTLEY ; and
more lately, Dr BLAIR, of the Seaman's Hospital, Georgetown, Demerara, had
operated upon the seeds, following the London Pharmacopoeia process for Sul-
phate of Quinine. None of these trials, however, seem to have led to any very
satisfactory result as to its chemical history. Most of the experimenters seem to
have directed their attention too exclusively towards procuring a crystallizable
salt of the alkali, which, as the sequel will shew, is not attainable. I received
from Dr BLAIR specimens of crystalline matter, which he obtained in his expe-
riments ; but these I find to be only sulphate of lime, with a little adhering orga-
nic matter. I soon satisfied myself, that any attempt to procure crystalline
salts was out of the question, — neither the alkaline matter, nor any of its com-
pounds with acids, evincing any tendency to assume the form of crystals. It is
DR MACLAGAN ON THE BEBEERTJ TREE OF BRITISH GUIANA. 425
unnecessary to say anything as to the various unsuccessful attempts which I
made to obtain a product presenting any appearance of purity. The following is
the method by which I have arrived at the results, which I now venture to sub-
mit to the Society.
The bark is boiled in water acidulated with sulphuric acid, as in the ordi-
nary process for sulphate of quinine. The fluid so obtained, which speedily be-
comes very turbid, is concentrated and allowed to cool. A copious deposit takes
place of a light-brown matter, which is a variety of tannin ; and along with it a
notable quantity of sulphate of lime, in a crystalline state, is likewise deposited.
These are got rid of by nitration ; and to the fluid, which is of a yellowish-green
colour, ammonia is added, which lets fall a dark-grey precipitate. This being
collected on a filter and washed, is to be dried over the vapour-bath, being at the
same time freely exposed to the air, during which process it gradually darkens in
colour, from changes induced in tannin adhering to it, until it becomes of a deep-
brown, or almost black tint. It is then suspended in distilled water, and sulphu-
ric acid in slight excess added, which dissolves the alkaline matter ; the liquid
is treated with animal charcoal, and on filtration, is found to be of a clear yellow
colour, and strong bitter taste. From this fluid ammonia throws down a precipi-
tate, which, when washed and dried, is nearly white, and does not in the least
darken by exposure to the air. This is the alkaline matter in the form of a hy-
drate. If this precipitate is treated with rectified spirit, it readily dissolves, leav-
ing only a little brown flocculent matter, and forming a clear solution of a tint
intermediate between yellow and orange. It has a powerful alkaline action on
reddened litmus paper, and an intense durable bitter taste. The alcoholic fluid,
when evaporated, leaves a shining totally uncrystalline matter, a good deal re-
sembling a resin in external appearance, and when in thin layers, quite translu-
cent. It is obvious, however, that this is not a homogeneous product, for in some
parts it is pale-yellow, in others orange-brown. It is, however, separable into
two distinct portions by the action of ether, which, for this purpose, must be
anhydrous, and perfectly free from alcohol. That which I used was of density
.735, and had been rectified by distillation from caustic potash.
The ether eventually dissolves by far the larger portion of the alkaline matter :
but as the solubility of the alkali in this menstruum is not great, the treatment
with ether must be frequently repeated, and ought to be continued, until a portion
of the fluid, on being evaporated, leaves no residuum. The ether being recovered
by distillation leaves a strongly alkaline and bitter resinous-looking matter, to in-
sure the purity of which it should be dissolved in alcohol, treated again with ani-
mal charcoal, and evaporated. As thus prepared it should have an uniform homo-
geneous appearance, and be, when thoroughly dried, nearly of a canary-yellow
colour. In mass it is opaque, and forms a pale yellow powder ; but when evapo-
426 DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA.
rated in very thin layers it is clear and transparent, separating from the evapo-
rating basin in small glittering yellow scales.
The portion not dissolved by the ether is now to be taken up by alcohol,
treated with animal charcoal and filtered, and, on evaporation, is obtained in the
form of shining reddish-brown scales, not crystalline. This matter likewise pos-
sesses all the characters of a vegetable alkali.
To the former of these alkaline bodies I apply the name of Bebeerine, origi-
nally used by Mr RODIE : to distinguish the second, I would give it the provisional
name of Sipeerine, from the Dutch name applied to the tree in Demerara.
The difficulty of procuring these products uniform, and the consequent un-
certainty as to their purity, arises from their being uncrystallizable, and being at
the same time associated with a substance so troublesome to the chemist as tannin.
I have succeeded in obtaining the same results by another process which is some-
what more expeditious, but not so economical. It consists in heating the original
grey precipitate in water containing about 6 or 7 per cent, of caustic potash, which
forms a deep orange-red fluid, and leaves the greater portion of the alkalies, in
the form of hydrate, nearly white, which is to be dissolved in alcohol and treated
with anhydrous ether in the manner just detailed. A large proportion of the
alkaline matter is dissolved, along with the tannin, &c., in the potash ley, but
may in great measure be recovered from it, though in an impure state, by adding
muriate of ammonia to the liquid.
Results of a precisely similar character were obtained from the seeds ; the
process of extraction, however, requiring some modification. As the seeds con-
tain starch, cold water is the proper menstruum for exhausting them, which can
be accomplished readily by the method of percolation. For this purpose the seeds
should only be coarsely bruised, otherwise the starchy matter is apt to form a
dense layer which impedes the passage of the fluid. The percolation should be
continued till the water passes without bitterness. The fluid is then concentrated
by boiling, during which a quantity of vegetable albumen separates, along with a
considerable amount of tannin, and a peculiar reddish-brown substance allied to
fatty matter. The fluid, when cooled and filtered, is precipitated by ammonia.
The precipitate is of a pale pink colour, but becomes brown on drying. The alka-
lies can most readily be obtained from it by treating it while still moist with
caustic potash, and subsequently by alcohol and ether in the manner formerly
described.
There thus appear to exist, both in the bark and seeds, two bodies of an
alkaline nature distinct in their properties. It seemed likely that there should
be, besides the tannin, a vegetable acid of some kind present where so much or-
ganic matter of a basic kind existed, and to this my attention was also directed.
I succeeded in separating an organic acid by the following process.
DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA. 427
To the concentrated mother liquid, from which, in operating on the seeds,
the alkalies had been separated, nitrate of baryta is added. A copious dirty-
white precipitate falls, which is to be slightly washed with cold water to free it
from the brown fluid. It is now to be dissolved in boiling distilled water, filtered
and evaporated till a crystalline pellicle forms on the surface. The crystals are
best got by skimming them off as they form during the evaporation ; and by repeat-
ing the crystallization once or twice, a nearly white product may be obtained.
This may be decomposed by sulphuric acid in the usual way ; but I have succeeded
better by decomposing a solution of the barytic salt by acetate of lead, and sub-
sequently decomposing the precipitate so formed, by sulphuretted hydrogen. The
acid liquor thus obtained is to be evaporated to a syrupy consistence, and then
placed in vacuo over sulphuric acid to crystallize. It is not, hoAvever, pure, be-
ing generally of a brown tint, but it may be purified by dissolving it in ether, and
again evaporating in vacuo. I have thus succeeded in procuring it in small quan-
tity, in the form of a white crystalline mass with a waxy lustre. The process,
however, has not always succeeded well, and I have not yet been able to satisfy
myself as to the causes of this difficulty. The acid does not correspond in charac-
ter with any hitherto described by chemists. I have therefore called it Bebeeric
acid.
The properties of these several products may now be shortly considered in
detail.
Bebeerine. — The process for obtaining and purifying it has been already de-
scribed. When its solution in alcohol or ether is evaporated in small quantities,
so as to leave a thin layer of residue, it remains in the form of a translucent
shining yellow film, but when in mass or in powder it is dull and opaque. It is
not at all crystalline. Its alcoholic solution has a strong alkaline reaction on
reddened litmus paper. Its taste is strongly and permanently bitter, with a slight
resinous flavour, and it evolves feebly a corresponding odour when dissolved in
water by the aid of sulphuric acid. This does not seem to arise from any adhe-
rent impurity, but appears to be characteristic of the substance. Bebeerine is
soluble in five times its weight of absolute alcohol, and it is likewise dissolved with
great facility by rectified and by proof spirit. Ether takes up a thirteenth of its
weight. It is very sparingly soluble in water, requiring 1766 parts of hot, and
6650 of cold water for its solution.
It will be impossible to maintain with certainty that this substance is chemi-
cally pure, until it shall have been subjected to the more rigorous examination of
ultimate analysis ; but the uniformity of the product which I have obtained, on
many separate trials, both from the bark and seeds, and by processes varying
slightly from each other, leads me to believe that it may be regarded as such. An
unfortunate accident which occurred in my laboratory deprived me of almost the
whole store of what I had prepared for the purpose of analysis ; I have, therefore,
VOL. xv. PART in. 5 z
428 DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA.
as yet had only one opportunity of testing its purity by determining its combining
proportion. The results obtained, so far as this trial goes, are of a satisfactory
nature.
I found, on analysing a portion of its sulphate dried at 240°, that its compo-
sition per cent, was, Bebeerine 86.30, sulphuric acid 13.61, which, supposing it to
contain one atom of each of its constituents, would indicate for its atomic weight
254.536, or according to the scale now generally in use on the Continent, 3181.19.
Again, 0.1995 dry bebeerine absorbed 0.0295 dry muriatic acid gas ; which is
equivalent to the following per centage : Bebeerine, 87.56 ; Muriatic acid, 12.44 ;
numbers which indicate for its atomic weight, 256.506 or 3203.47. These two
results are sufficiently approximative to entitle us to suppose that the difference
may depend merely on errors of "manipulation.
The combination of bebeerine with dry muriatic acid gas takes place rapidly
and without fusion. The salt so formed is very soluble in water, forming a clear
yellow solution, on evaporating which, it is obtained in the form of transparent
yellow scales. The sulphate of bebeerine is equally soluble in water ; it has a
bright yellow colour and glistening aspect like the muriate ; both are intensely
and durably bitter, with a slight feeling of astringency on the tongue. I have
likewise prepared an acetate of bebeerine, of the same general appearance, and,
like the others, uncrystallizable.*
The action of nitric acid on bebeerine is peculiar. My attention was accident-
ally directed to this, when, in the course of many attempts to purify my alkali, I
on one occasion essayed to apply to this purpose M. COUERBE'S process for veratria,
where nitric acid is the agent employed to precipitate a peculiar resinous matter.
(Ann. de Chimie et de Physique, torn. 52.) I found on adding nitric acid to a cold
dilute solution of bebeerine in sulphuric acid, that the greater part of the alkali
was precipitated in an altered state. Still more is it altered when it is boiled with
nitric acid a little diluted with water. In this case it undergoes complete con-
version, with evolution of nitrous acid fumes, into a yellow pulverulent substance,
readily dissolved by hot but sparingly by cold water, and having, so far as I have
examined it, a great resemblance in many of its properties to carbazotic acid.
Sipeerine. — This alkaline matter, which is insoluble in ether, I have obtained
in quantities too small to enable me to do more than briefly describe its general
properties.
When its solution in alcohol is evaporated, it is obtained in the form of a
translucent dark reddish-brown resinous-looking matter, in thin glittering scales,
* To procure these salts of the translucent shining aspect, their solution should be evaporated in
thin layers in a smooth porcelain basin. The thin layer of fluid dries up into a transparent yellow pel-
licle, which is easily detached from the basin. It splinters, however, in every direction, and thus assumes
the form of brilliant scales, which give it, when in this condition, a pseudo-crystalline appearance. In
mass, the salts are opaque and dull yellow.
DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA. 429
but without the least appearance of crystallization. It is readily dissolved by
alcohol, and also by proof spirit. It is sparingly soluble in water, and insoluble
in ether. It combines with and neutralizes acids, forming uncrystallizable salts
of an olive-brown tint, having, when in thin scales, a glistening appearance, which
gives them the same false appearance of crystallization as in the case of the salts
of bebeerine. Though I have not examined it further, I have little doubt, from
its appearance and general properties, that it is a distinct substance.
Bebeeric acid. — When pure, it is white and beautifully crystalline. It deli-
quesces rapidly, assuming the syrupy form, especially in an atmosphere at all
moist. At a temperature of 300° it fuses ; and a little above 400° it sublimes,
apparently unchanged, and condenses in tufts of acicular crystals. It forms
with baryta, lime, and magnesia, salts which are sparingly soluble in water ; with
potash and soda, salts which are deliquescent, and soluble in rectified spirit ; and
with lead, a salt which is very sparingly dissolved even by boiling water.
The tannin ofbebeeru bark has attracted my attention, chiefly from its marked
resemblance in general characters to that variety which exists in the cinchona
barks. It strikes a green tint with persalts of iron. It becomes slowly altered by
exposure to the air, becoming sparingly soluble in cold water, and giving rise to
a deposit which presents the general characters of the well known cinchom'c red.
Besides these more important constituents, the bark contains brown resinous
matter, gum, woody fibre, and a large proportion of calcareous salts. I have not
detected any starch in the bark.
The seeds contain a little sugar, abound in starch, and contain likewise a red
fatty matter, which obstinately adheres to the alkalies during precipitation, giv-
ing them a pink or reddish tint.
The general composition of the bark and seeds will appear from the follow-
ing analysis : —
Bark. Seeds.*
Alkalies (not quite pure), .... 2.56 2.20
Tannin and resinous matter, .... 2.53
Soluble matter (gum, sugar, and salts), . . 4.34
Starch, . . . . . . ....
Fibre and vegetable albumen, . . ••,'''•• . 62.92
Ashes, chiefly calcareous, '••.'•::. . . 7.13
Moisture, . . , • , . . . . 14.07
Loss, ...... !„.. . 6.45
100.00 100.00
The interest which attaches itself to this plant, is not limited to the fact of its
adding to the already formidable list of our vegetable alkalies and acids, but arises
* The seeds which I analyzed had dried very much by keeping.
430 DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA.
more particularly from the statements made by Mr RODIE as to its power of act-
ing as a febrifuge remedy.
In his printed letter he states, that the solution of the alkali in the state of
sulphate of bebeerine was concentrated, and exhibited in intermittent fever, and
proved to possess the medicinal qualities of quinine, apparently in a very eminent
degree, whilst he conceives it to have less tendency to produce determination to
the head, or irritation of the stomach. He further says, — " Reasoning from ana-
logy, we see that quinine is more febrifuge than cinchonine in the proportion in
which it is less crystallizable ; and therefore bebeerine, being still less crystalliz-
able than the latter substance, might be expected, by that rule, to be still more
febrifuge ; and the result of the experience we have had of bebeerine, seems to
warrant the conclusion."
I am not at all disposed to agree with the analogical conclusions to whicli
Mr RODIE has come, and which were adopted by Sir ANDREW HALLIDAY, in a
short notice which he published of Mr RODIE' s discovery. (Edinburgh Medical and
Surgical Journal, vol. xliv.). Neither am I sanguine enough to expect, that this
is ever likely to take the place of sulphate of quinine as an antiperiodic remedy.
At the same time, however, I think that I am in possession of sufficient evidence
that bebeerine is endowed with powerful febrifuge virtues ; and, considering that
the tree is large, and a native of one of our own colonies, it may yet be found a
good substitute for quinine, when dear or not easily procurable.
One object which I have constantly had in view in my experiments has been
to make out a good process for preparing salts of the alkalies, and I have already
obtained results which encourage me to make further trials. It is unnecessary
to detail the variety of attempts which I have made to accomplish this object
and at the same time get rid of the employment of alcohol in the manufac-
ture, which, in Great Britain at least, would much tend to increase the expense.
Through the zeal of Mr BROWN, superintendent of the chemical establishment of
Mr J. F. MACFARLANE of this city, I have been enabled to procure, by a modifica-
tion of the process for sulphate of quinine in the Edinburgh Pharmacopoeia, a
sulphate containing both the alkalies in a state of considerable purity, though not
altogether free from traces of tannin. The best product, in point of quantity, ob-
tained in one trial, was two and a half ounces of this mixed sulphate from ten
pounds of the bark. My own experiments have likewise indicated, as an average
product, about two and a half ounces, or a little more, from this quantity of
bark.
Compared with the productiveness of yellow cinchona in the manufacture of
sulphate of quinine, which may be said to yield on an average from two and a
half to three per cent, of the salt in crystals, the productiveness of the bebeeru
bark is much less, being at most about one and a half of sulphate per cent. I
have no doubt, however, that the amount of product may be increased by future
DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA. 431
improvements in the process ; for I have found, from subsequent trials, that a
considerable loss was sustained from portions of the alkalies remaining dissolved
in the mother liquor of precipitation. Further, it must be remembered that
sulphate of quinine in crystals contains 10 per cent, of water of crystallization,
whilst the bebeerine salts are anhydrous, or contain at most only a small per-
centage of hygroscopic moisture.
It is impossible to arrive at any precise estimate as to how far, in point of
cheapness, this substance will realize the expectations of my Demerara corre-
spondents, until we know what price will be sought for the bark. I should esteem
one shilling a pound the most that it is likely to cost, considering the fact men-
tioned, on Mr RODIE'S authority, by Sir ANDREW HALLIDAY, that " at present the
tree is felled only for its timber, and thousands of tons of the bark are destroyed
annually." I have in my possession samples of the bark which were thrown out
as refuse from a' ship-building yard. At this price, then, which I look upon as
more than should be asked, and even with a productiveness of not greater than
one and a half per cent., I find that it may be prepared at a cost of 6s. an ounce ;
and, of course, it might be greatly cheaper, were the productiveness increased
only fractionally, or the price of the bark were lower. The above price would be
but little cheaper than the sulphate of quinine at its present cost, which I find to
be 7s. 6d. an ounce ; but not long ago, from an enactment of the governments of
South America regarding cinchona barks, the price was as high as 11s. and 12s. ;
and under these circumstances, bebeerine might prove a useful succedaneum.
As to the comparative productiveness of the bark and seeds, I have no hesi-
tation in giving a decided preference to the former, both in point of amount and
purity of product. This arises from the difficulty of freeing the alkalies from the
red fatty matter by any process applicable to the purposes of the manufacturer.
I shall not detain the Society with entering into details as to the evidence in
favour of the antiperiodic powers of bebeerine, but shall avail myself of some
other opportunity of submitting this to the attention of my professional brethren.
I may mention, however, that last autumn, I sent out a small quantity of the sul-
phate prepared for me by Mr BROWN, to my friend Dr WATT, and he has sent me
the details of several causes of intermittent fever, in which he used it with marked
success. I have likewise had an opportunity of trying it myself in three cases of
ague ; and, in all, the arrestment of the disease was rapid and complete. I haAre
likewise made trial of it in periodic headache, and the effects were such as to
leave no doubt in my mind of its activity as an antiperiodic remedy. Both Dr
WATT and myself administered it in the doses in which sulphate of quinine would
have been employed.
Some time ago a secret medicine, absurdly purporting to be a cure for all
fevers, made its appearance under the name of " Warburg's Vegetable Fever
Drops." This has been found to be possessed of antiperiodic virtues ; and I was
VOL. XV. PART III. 6 A
432 DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA.
recently informed by Dr GERGENS of Wisbaden, that he and other practitioners had
used it with success in Germany. Both Dr WATT and myself were led to suspect,
from the history of this substance, that it was a preparation from the bebeeru
tree ; and chemical examination has decided me in this opinion. On evaporating
the fluid, which is alcoholic, treating the residue with water acidulated with sul-
phuric acid, and precipitating by ammonia, I got from it a pink precipitate, be-
coming darker on drying, from which, by the action of ether, I extracted bebee-
rine of its characteristic appearance. I infer from the colour of the precipitate,
that the fluid is a tincture of the seeds. It contains but little of the alkali, and
abounds in a yellow colouring matter and other ingredients which I did not
examine.
I feel that this paper requires some apology, as it is wanting in those points
of minute research into the ultimate constitution of the alkalies, &c. which alone
can render it of interest in a chemical point of view. These investigations I hope
to be enabled to make in the course of the summer. In the mean time I was de-
sirous of making known the results I had already obtained, as it is my intention
to have the sulphate prepared in quantity, that its supposed virtues as a medi-
cine may be fairly tested. Should the expectations which have been formed of
it be in any measure realized, the original discoverer, Mr RODIE, will be entitled
to our grateful consideration.
/'/-//, A7/ Royal Soc. Trans. Edin.VolXVp.433.\
OKO LOGICAL MAP
of tie
COUNTY or ROXBURGH,
in Illustration of
M? MILNE'S
PAPER
in Transactions of
HOYAI, SOCIETY
K D 1 Sf
Seal* of JKlts.
tic Trap Recks
1 ISafaltf Greenstones tc I
4 K «
( 433 )
XXXII. — Geological Account of Roxburghshire. By DAVID MILNE, Esq ., F.R.S.E.
[Read 5th December 1842 and 9th January 1845.]
IT seems extraordinary, that no one should have undertaken a geological sur-
vey of Roxburghshire, more especially as the counties to the east and west of it
have been examined, and accounts of their formations were published some
years ago. It cannot be from its uninteresting character, that the intervening dis-
trict has been neglected ; for it presents as great a variety of apparently distinct
formations, as there are in the adjoining counties of Dumfries and Berwick ; and
some of these have long been the special subjects of speculation and controversy
among geologists. The British Association, in the Report of its Meeting held at
Cambridge in 1833, propounded the following questions for geological inquiry.
" 1. Is the red sandstone of Kelso contemporaneous with that of Salisbury
Crags ; and what relation do they respectively bear to the adjacent coal-fields ?
" 2. What is the exact northern boundary of the coal-field of the River
Liddettf
" 3. What are the relations as to age of the two series of whin-rocks, one
running north-east along the Liddell in Roxburghshire, the other south-east in the
neighbourhood of Melrose and Jedburgh ?"
These questions show the opinion entertained by the Geological Section of the
Association, as to the interesting geological character of Roxburghshire. But the
questions which they propounded have never received an answer ; a result not
surprising in regard to the last of these questions, as it calls for an explanation of
facts which really have no existence. A stronger proof could scarcely be adduced
of the ignorance prevailing among our best geologists, of Roxburgh geology.
In describing the different formations existing in this county, I shall treat of
ihem,Jirst, with reference to the state in which they now are ; and, second, with
reference to the causes which have apparently produced that state.
I shall describe the formations in the following order : —
I. The Stratified or aqueous rocks.
II. The Unstratified or igneous rocks.
III. The Diluvial or post-tertiary deposits.
I shall not attempt by words, to define the geographical limits of these seve-
ral formations, but content myself with referring to the accompanying map (Plate
XII.), the colours on which represent the several classes of rocks I am now about
to describe, and will at once shew the extent of each.
VOL. XV. PART III. 6 B
434 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
I. — Stratified or Aqueous Rocks.
1. The first of these which I shall describe, and which is by far the most
abundant, is the Greywacke. Almost all those hills which occur in elongated
ridges, are composed of this rock.
It has, in most places, the usual colour of bluish grey, though occasionally
the colour is red, as in the Leader near Carolside, in the Jed near Kersheugh, and in
the Kale near Oxnam. Its strata vary much in thickness ; some being almost as
thin as paper, and others several feet in thickness ; — but its ordinary charac-
ter is slaty, a character for which it is indebted to the presence of mica. On this
account, the greywacke rocks very generally exfoliate by the varying influence of
the atmosphere, and produce a soil, wet but by no means ungenial. I am not
aware that the thin strata are found anywhere in this county so hard as to pro-
duce roofing-slate; but the thicker strata afford tolerably good building ma-
terials.
The texture of the greywacke is, generally speaking, what is termed " fine
granular." A coarser variety (amounting almost to conglomerate) sometimes
occurs, as a few miles west of Galashiels, on the turnpike road, where it is
quarried.
The greywacke strata are in this county, as in the rest of the British islands,
almost every where vertical. Any deviations from this rule observed by me,
were very rare. At the Miller's Knowe, near Hawick, they dip at an angle of 80°
to the south ; at Kirkton, 80° to the south ; at Rinkfair, about 75° to north ; at
Southdean Manse and at Abbotrule, they dip south at an angle of about 50° ; above
Jedburgh, the dip is to south at an angle of 65° ; at Carolside Bridge, about 40° to
the north ; west of Edgerstone Rig, they make an angle of only 20° with the hori-
zon, dipping south.
In several places, the foldings or contortions of the greywacke strata are well
exhibited. On Jed water, about a mile west of Edgerstone, there is a good example,
in consequence of the great height of the west bank. The greywacke strata are
there bent, forming a very acute angle, opening vertically downwards. The same
individual strata which, at the top of the bank, form this rapid curvature, may
be seen at a little distance, forming an opposite bending at the bottom of the
bank. On Oxnam water, a similar fracture of the greywacke strata may be seen,
and on a much larger scale ; but on that account it is not so obvious, as the whole
contortions cannot be easily taken into one view. Near Crailing house, they dip
north at an angle of 85°., whilst near Upper Crailing mill (about two miles higher
up the river), they dip south at an angle of 80° ; and in the intervening parts of the
river, they present extraordinary bendings and twistings. Near South Dean and
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 435
near Abbotrule, the strata may be seen dipping in opposite directions, not far
from each other, affording indications of contortions on a still more gigantic scale.
It is an interesting fact, as tending to indicate the direction of the forces
which produced these contortions, that the greywacke strata in Roxburghshire,
as elsewhere, crop out in lines which run nearly due east and west by compass.
One place where I observed the greywacke strata cropping out in a different
direction was in Liddesdale, above Hermitage Castle, at a place called the Grains.
Its strike there is north-east by east; but this was a mere local aberration,
which was the more obvious, from the strata there dipping at the small angle of
40° to the horizon. In the burn behind Melrose, which flows from the Eildons,
the greywacke strata run north-west by west, and rise to these hills. This is the
strike of the beds also on the Jed, ^ mile from Cleslipeel, and on the Carter burn
at Sykehead.
It is a consequence of these gigantic foldings of the greywacke strata, in an
east and west direction, that all the principal valleys in that formation run in
the same direction, as is well shewn by the course of the rivers Ewes, Teviot,
Ale, and Borthwick, which are the principal rivers in the district.
No fossils, except some morsels of black vegetable matter, have been dis-
covered in the greywacke strata of Roxburghshire. Sometimes they exhibit on
their surface a curious concretionary structure, which has been by some, though
I think quite erroneously, attributed to organic causes.
The only metallic veins I have observed in this formation consist of hematite
or red oxide of iron. They are in some places very abundant, as below Cowden-
knows (on the Leader river), where they may be seen in the channel, from half an
inch to an inch in thickness, filling up the natural joints of the rocks. In some
places, these hematitic veins form, at their out-cropping on the surface of the
greywacke strata, fantastic figures, as on the Jed at Cleslipeel. There is no doubt
that this red oxide is largely distributed through the greywacke rocks.
I understand that small portions of galena were formerly found in the grey-
wacke strata, at Langholm Bridge.
2. The next class of rocks to be described is the Old Red Sandstone formation,
though I am unwilling to assert, that they form a class independent of, and dis-
tinct from, the one which I am next to describe, viz., the Coal Measures. On the
contrary, there are strong reasons for believing, that both these sets of rocks,
though their outward and visible characters are very different, belong to the same
epoch, and have only been made to assume distinct appearances by local causes,
to be afterwards alluded to. At all events, there is no grand line of demarcation
between them, such as, in other cases, is indicated by the interposition of beds of
conglomerate, or by strik ing differences of dip.
For the sake of distinctness, I will here treat of these two sets of rocks sepa-
rately, and in the order generally followed.
436 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
The Old Red Sandstone rocks are most generally of a dull brick-red colour,
[n a few localities, there are strata nearly pure white, and, still more rarely,
there are strata of a yellow colour.
The texture of the stone is soft, and seldom compact. The picturesque charac-
ter of the valley of the Jed, enclosed within steep and lofty cliffs, for many miles
of its course, is mainly attributable to the facility with which that river and its
tributaries cut through the old red sandstone strata. But, though this is the
general character of these rocks, they in many places become hard enough to
form good building stone.
The lowest member of this formation, when visible, is almost every where
seen to be a conglomerate, or bed of pebbles cemented by sand and clay, highly
impregnated and reddened, by oxide of iron. This conglomerate is found in very
many places on the upturned edges of the greywacke, as may be seen at Jedburgh,
both above and below the town, in the river ; in Hassendean burn, a few hundred
yards below the village of that name ; in the Wauchope and Catlie burns, and
other places.* It was the first of the places just mentioned, which furnished to
Dr HUTTON the strongest of his proofs in support of his views as to the elevation
and disruption of rocks by volcanic action, and the formation of new rocks out of
the ruins of the former set. As Dr BUTTON'S description of the section is still
perfectly applicable, I cannot do better than quote the following passage from his
celebrated work on the Theory of the Earth.f In describing the vertical and the
horizontal strata of the Jed, he refers to " a certain pudding-stone, which is inter-
posed between the two, lying immediately upon the one and under the other.
This pudding-stone (he adds) is a confused mass of stones, gravel, and sand, with
red marly earth. These are consolidated or cemented in a considerable degree,
and thus form a stratum extremely unlike any thing which is to be found either
above or below.
" When we examine the stones and gravel of which it is composed, these
appear to have belonged to the vertical strata or schistus mountains. They are
in general the hard and solid parts of those indurated strata, worn and rounded
by attrition ; particularly sand or marl-stone consolidated and veined with quartz,
and many fragments of quartz, all rounded by attrition. In this pudding-stone
of the Jed, I find also rounded lumps of porphyry, but have not perceived any of
granite. This, however, is not the case in the pudding-stone of the schistus moun-
tains, for, where there is granite in the neighbourhood, there is also granite in the
pudding-stone. From this it will appear, that the schistus mountains or the ver-
tical strata of indurated bodies had been formed, and had been wasted and worn
in the natural operations of the globe, before the horizontal strata were begun to
* These places are indicated on the map by red dots.
t Vol. i. p. 436.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
437
be deposited in those places : the gravel formed of those indurated broken bodies
worn round by attrition, evince that fact."
At every place where I have examined the conglomerate of this formation —
whether in contact with the greywacke or not — I have found that Dr BUTTON'S
remark is true, viz. that the pebbles composing it consist chiefly of greywacke
strata, and partly of other rocks, such as porphyries, which will be afterwards
shown, from other evidence, to have been previously existing. In the Catlie Burn,
the pebbles consist chiefly of grey wacke, quartz, and porphyries.
The place where I observed the conglomerate in the largest masses, is near
Earlston. There are escarpments of it there, several hundred feet thick. The
lowest parts of the county are, generally speaking, those in which the conglome-
rate beds are thickest and coarsest.
In some places, the red sandstone formation is seen resting on the greywacke
rocks Avithout any conglomerate interposed, as, for example, at South-dean manse.
The lowest stratum there is a dark red clay, with streaks of yellow in it ; and a
little farther off, this turns into a soft yellow sandstone. The following woodcut
represents an interesting junction of the old red sandstone rocks and the grey-
wacke strata, on the river Jed, about half a mile below the North Lodge of Edger-
stone.
North
South
AB and CD are strata of Old Red Sandstone, resting on the nearly vertical
strata of greywacke. The length of the section is about 300 yards, and the height
25 yards.
At a few places in the county, I have seen the Old Red sandstone rocks, if not
resting contiguously on the porphyritic or felspathic rocks, to be afterwards de-
scribed, at all events lying so close to the latter, as to leave no doubt that they
have been deposited upon the latter. In these cases, however, which all occur in
the higher parts of the county, near the Cheviot Hills, there was no conglomerate.
The white strata of sandstone are peculiar, not only for their perfect white-
ness, but also for that quality which geologists have termed saccharine. Yet they
are not very crystalline in then- texture, but are soft and fine-grained. These white
sandstones are worked at the top of a hill between Minto and Belshaes (where it
rises a little towards a trap-hill west-north-west of it), and on the north side of
VOL. xv. PART in. 6 c
438 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
Ruberslaw (where the stratum is 12 feet thick), and rising towards the hill at an
angle of 15°. At both of these places, there are the usual red strata, lying over as
well as under the white beds. I understand that beds of similar white sandstone
have been quarried at Pinnacle on the Ale- water, in South-dean parish, and also
in Jedburgh parish, at Tudhope and Ferniehirst.*
The yellow variety of sandstone, existing at least among the old red rocks,
occurs at only two places known to me, viz. at St Boswell's Green and Kirklands.
At the former place it is quarried. I understand it occurs also at Bedrule.
These red rocks, which prevail so extensively through Roxburghshire, are
almost everywhere horizontal. They preserve their horizon tality even at the sides
of trap hills, some of which (as, for example, the Dunion, Ruberslaw, Peniel Heugh)
being entirely surrounded by them, look like black rocky islets in a red sea.
There are few places where the strata in this formation exhibit any consider-
able dip. On Jed-water below Edgerston, the strata dip towards the north at an
angle of 25° ; on the south side of Lilliard's Edge, they dip to the south-west at
an angle of 30° ; at Plewlands quarry, in the parish of St Boswell's, they dip south
at an angle of about 20° ; to the north of Hunthill, they are nearly vertical — owing
to a local dislocation.
There are sometimes on these red sandstone rocks curious spots and blotches
of a white and bluish- white colour. The spots are generally spherical, the spheres
being an inch or two in diameter, or less. Sometimes the blotches are of no determi-
nate form, and occupy a number of square feet in their sectional area. The origin
of these white spots and patches is not very obvious. It is not in the least probable,
that the red sandstones could have been deposited with spheres of white sand in
the heart of them. The colour has more probably been discharged by chemical
action, subsequently generated at these places ; a conclusion confirmed by the oc-
currence, in the very centre of many of these spheres, of a small pea of metallic
oxide, to which the iron originally diffused through the stone seems to have been
transferred.
The spherical white spots now referred to, must be familiar to every one ac-
quainted with the old red sandstone formation in other parts of Scotland. I be-
lieve that they are not confined to this class of rocks, and in particular, that
they occur likewise in the new red sandstone. But though the phenomenon is
common, I do not think the cause of it has ever been distinctly explained. I
shall therefore venture, in the second part of this memoir, to throw out some sug-
gestions on that point.
* Tudhope quarry is three-fourths of a mile north of Jedburgh, whilst Ferniehirst quarry is on the
south side of the same valley. The rocks are, at both places, nearly horizontal ; and being on the same
level, as well as of the same colour, which is not a common one in the district, it is not improbable that
they are portions of the same stratum, which originally stretched across the valley, before it was scooped
out.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 439
In September or October 1840, 1 had the good fortune to discover in these
red rocks, at two places pretty far apart, bones and scales of fossil fish, — that
kind which has been found in such abundance at Clashbennie in Perthshire. The
place where I first found them (in company with the Rev. Mr Aitken of Minto)
is at the head of Wauchope Burn, on the east side Windburgh Hill. The next
place was at Plewlands, in the parish of St BoswelTs. Those found at the former
place I submitted to the inspection of AGASSIZ, who pronounced them to belong
to the species Holoptichius nobilissimus, and considered them clearly to indicate
that the rocks containing them belonged to the Old Red Sandstone formation.
I discovered scales of the same fish also on the banks of the Jed, about a mile to
the east of Southdean manse, and traces of them in Sunlaws quarry, on the
Tweed, opposite to Roxburgh.
Since this discovery in 1840, more remains of Holoptichius have been dis-
covered, and in rather an interesting situation. They occur about f mile to the
north of Jedburgh, at the place called Tudhope, where, as already noticed, a
quarry of white sandstone was formerly worked. No scales have yet been found
in the quarry itself. They were observed in one of the stones of which a dyke
in the immediate neighbourhood was built, but the stones of which were taken
from this quarry. This discovery of Holoptichius in rocks, apparently not near
the bottom of the series, but among their highest members, and in a rock which
has not the prevailing red colour, furnishes strong additional evidence, in confir-
mation of the opinion, that the whole of these rocks in the vale of the Jed, of the
Ale, and of the Teviot, belong to the old red sandstone formation.
There have been also sent to me, by Mr OLIVER of Langraw, a few specimens
of fish-scales, found by him in the Wauchope Burn, in the course of last year.
Some of these scales are of a much smaller size than any which I had fallen in
with, and the markings on them are quite different from those on the larger scales.
I observe that Mr DUFF, in his Sketch of the Geology of Moray, mentions
(page 29) that, besides the large scales of the Holoptichius, which abound in the
red sandstones there, — " smaller scales often occur : but they have not as yet re-
ceived much attention." Both the larger and smaller scales figured by Mr DUFF,
correspond in size and markings with those which occur in Roxburghshire.
It is proper to add here, that small portions of lead (sulphuret of galena) have
been found near Abbotrule, in a mottled red and white sandstone, which is among
the lowest of the old red sandstone formation. I do not know whether the metal
occurs in veins or in concretions, having searched the place for it unsuccessfully.
But Mr Oliver of Langraw has lately sent to me some small nodules which are
apparently in their natural form. He states that they are found in the channel
of the burn, which cuts through the sandstone in question, and which, from its
friable character, easily decomposes. It will be observed, that this locality is not
far from the trap of Bonchester Hill, and a basaltic dyke, to be afterwards parti-
cularly noticed.
440 MJR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
3. The rocks to be next described are those which, for distinction sake, may
receive the well known term of Coal-Measures. They consist chiefly of sandstones
— grey, white, and red ; of earthy marls — green, grey, and light-brown ; of black
shales ; and of limestones — grey, reddish-brown, lilac, and black. It is among
these rocks that seams of coal are occasionally found.
It will be seen from the map, that it is on the eastern and western extremi-
ties of the county, that this class of rocks exists in any abundance ; though, as
will be afterwards explained, patches of them do occur in intermediate spots. In
these intermediate spots, much money has been fruitlessly expended in searching
for coal. Trials have also been made in other places, where there was no ap-
pearance whatever to justify such attempts ; as, for instance, close to Maxton
Manse, on the west of it, where there is nothing but old red sandstone.
It has been stated, that the rocks now referred to appear generally to lie
over the red rocks already described. It should be added, that in some places
1 have observed red rocks, of similar appearance, also lying above them. For
instance, in Dinlee Burn (one of the feeders of Hermitage Water in Liddes-
dale), a yellow coal sandstone grit may be traced within two or three feet of a
greywacke hill, from which it slopes or dips at an angle of about 8° or 10°. Over
these, are strata of red sandstones and shales, very soft and friable, and not ex-
actly conformable with the subjacent coal-measures. But the exact line of junc-
tion is indiscernible. So also in Laidlehope Burn, above Winshiel-Know (in Lid-
desdale), the soft red rocks may be seen lying above black coal shales, and con-
forming with them. On the Ale also, close to Kirklands House, a yellow coal
sandstone may be seen at the river side, overtopped by the red rocks.
Though, in most places, the coal-measures of Roxburghshire lie over and
rest upon the soft red rocks, they, in a few places, may be seen resting directly
on or very near greywacke. Thus, in the Black Burn (a tributary of the Jed), I
found the grey gritty sandstone of the coal-measures lying on the vertical edges
of the greywacke formation. In the Carter Burn, at Sykehead, as well as in the
Edgerston burn (about a mile north of the Carter toll-bar), the coal sandstones of
Northumberland may be seen within 100 yards of the greywacke, and exhibiting
a southern dip.
That the rocks which I have designated Coal-Measures really deserve that
name, is evident from the fact, that they contain all the fossils which are charac-
teristic of that formation ; and, in some places, very valuable seams of coal, which
are worked. In Liddesdale, coal is now worked very extensively at Rowan
Burn. Four seams exist there, which are respectively in width 5^ feet, 9 feet, 6
feet, and 2 feet. Coal was worked, also, formerly at Byre Burn, on the Esk, about
two miles below Langholm, where the principal seams were two in number — one
2 feet 7 inches thick, the other 5 feet 10 inches thick. Coal was formerly worked
also at Lawston, on the river Liddel (where, however, the seams do not exceed
14 inches thick) ; and several thin seams have been proved by borings to run
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 441
along the south margin of the county, from Castleton eastward to the Carter.
At the Rowan Burn colliery, a beautiful set of drawings has been made by Mr
GIBSON, manager there, of the vegetables, fish-scales and teeth, as well as of
shells,* which are frequently found in the shales and fire-clays immediately above
and below the coal seams. At Maxwell-heugh, near Kelso, a great abundance
of fossil vegetables, peculiar to the coal-sandstones, have been found, of which
specimens nay be seen in the Kelso Museum. At Hunthill, where there is abun-
dance of black coal-shales, though surrounded by red rocks, I found the teeth and
spines of fish, which appear the same as those of the Berwick and Edinburgh
coal-fields, and which are generally considered to be the Megalychthis. I have
found there also the well known bivalve shell Spirifer, which abounds in carbo-
niferous strata. At this last place, trials have been made at different times dur-
ing the last fifty years, for coal ; and Mr BELL, the present proprietor, renewed
these attempts some years ago, though without success. In the sinkings made
for this purpose, a series of black shales, thin limestones, and grey sandstones,
were gone through, clearly indicative of the coal-formation. In the shales, no-
dules of clay-ironstone occur, filled with coal vegetables.! At the Forrester's
house, near Hilton hill, about two miles north of Ancrum, a coal-seam, 6 inches
thick, was found in sinking a well ; and the portions excavated for that purpose
burnt well in the fire4
F
* I saw some specimens of Lingula at Rowanburn in the fire-clay and shale lying about the pit-
mouth. This shell is very common in the Mid-Lothian coal-shales.
t As great doubts are still entertained by many persons of the relative age of the dark-coloured
strata of Hunthill, and the red rocks which surround this spot, I may mention, that the two sets of rocks
may be seen, if not in junction, at all events within a few yards of each other, in the glen on the west
side of Hunthill House. In 1839, I examined the place, at the request of some of the principal inha-
bitants of Jedburgh, who, on public grounds, were desirous of learning the probability of coal being found
there, with the laudable view of starting a subscription to assist the proprietor in boring and sink-
ing for it. It was then that I discovered the fossils above mentioned, which left no doubt in my mind
as to the class of rocks prevailing at Hunthill, though, as they appeared to underlie the Carter limestone,
I discouraged any expectation of finding a workable coal-seam. On this occasion, also, I observed that
the red rocks in the glen just referred to, appeared to dip under the shales and limestones ; though, from
the quantity of grass and brushwood then covering the ground, no line of junction was discernible. I
have been informed that last autumn (1842) Mr ADAM MATHESON, millwright, Jedburgh, and who pos-
sesses an ardent taste for Geological researches, made a minute inspection of the spot, for the purpose of
clearing up the above point, and traced the red rocks up to the coal-measures, beneath which he and Mr
JEFFREY, writer in Jedburgh (who accompanied him), distinctly saw that they dipped. He informs me,
that only about 4 feet above the red sandstone strata, there is a bed of limestone about 2 feet thick, in
three layers, in quality exactly resembling the limestone worked on the Carter at Meadowcleugh. About
300 feet above this limestone bed at Hunthill, a coal-seam 3 inches thick occurs.
J Sir W. SCOTT of Ancrum informed me (in 1840), that he ascertained this from the person who
had dug through the coal in sinking the well.
VOL. XV. PAKT III. 6 D
442 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
The general dip of these coal-measures is, near Kelso, towards the east, and at a
small angle ; on the Carter (in Liddesdale) ; and at Hunthill, towards the south.
The Rowan burn coal-seams lie a great way above the beds of workable limestone
to be afterwards described, which crop out a couple of miles to the north and east
of that colliery, — the whole strata there having a general dip to the south and west.
Even at Byreburn (where coal was formerly worked), and which is situated
about a mile north of Rowanburn, the seams are still many fathoms above the
limestone. In the west part of Liddesdale, however, the whole strata take a bend,
which accounts for the non-appearance of any workable seams of coal farther east
than Lawston : For, a little to the east of Rowanburn, the strata change from a
southerly to a westerly dip, and thus strike across the river Liddell into Cumber-
land, where they again resume their southerly dip, and preserve it, with some in-
considerable exceptions, eastward along the English border, all the way to Wooler,
at the east end of the Cheviots. Indeed, I consider that the coal-measures near
Berwick, and which run along the south bank of the river Tweed for about 10 miles,
dipping to the south, belong to the same class of rocks, and to the same epoch, as
those just described prevailing in Liddesdale. In the Berwick coal-field, as in
Liddesdale, there is a large body of workable limestone, consisting of exactly the
same number of workable beds, viz. eight, and of pretty much the same thickness.
Above that deposit there are also, in both coal-fields, workable coal-seams. It is
true that, in the Berwick coal-field, there are below the limestone beds other
seams of coal, which, though they have their equivalents in Liddesdale, are not
the same either in number or thickness ; a variation, however, which is not to be
wondered at, considering the distance between the two districts.
I consider, then, that no workable seams of coal will be found in Liddesdale
west of Lawston — a remark which I offer with reference to the attempts now pro-
posed to be made for discovering coal in Liddesdale. The thick limestone beds
which lie below all the workable coal-seams, run chiefly on the south bank of the
Liddell, from Penton Linns eastward. They do come a little farther north at the
junction of the Liddell and Hermitage ; and, in consequence of this, some thin
coal-seams are brought within the borders of Scotland, at the head of Tweeden-
burn and Harden-burn. Near Windburgh, it is true, there is a thick bed of lime-
stone worked, which is eight or ten miles within the Scotch border, so that there
might be supposed to be space enough for the existence of coal-seams lying
over it, — but of which there is only one known, a few inches thick, a good distance
above the limestone. However, it is, in the first place, uncertain whether this
bed of limestone belongs to the series just referred to ; and, in the second place,
even though it were, there is not cover enough upon it to include or " bring on"
the coal-seams in question. In the third place, a large portion of the district inter-
vening between Windburgh and the English border, is occupied by a range of grey-
wacke hills.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 443
The following is a section of the strata at the Carter Lime- Works, as given
to me by the overseer there.
Ft. In.
Limestone, ...... 18
Sandstone in two or three beds (of unknown thickness),
Shale, (Do.)
Coal-seam, ...... 14
Various beds of shale and sandstone, about . 600 0
Limestone (now worked), .... 14 0
Shale, sometimes containing a thin coal-seam, . 30
Limestone, ...... 30
Beds of shale and sandstone, . . . 14 0
Limestone, ...... 20
Sandstone and thin beds of limestone, . . ?
The coal-seam mentioned in the preceding section, is now worked near the
Carter Lime- Works. On one of the coal-pits there, I found a slab of sandstone
covered with marine fossil shells, such as spirifer, productus, &c. The same seam
was formerly worked at Kerryburn, not far to the west. It was about 12 or 14
inches thick.
As the connection between the Liddesdale and the Berwick coal-fields is, for
several reasons, important to be determined, I may here mention the places
nearest to the border, where coal-seams are or have been worked. At Lewisburn
in Northumberland, there are two seams, one said to be 1 ft. 5 in., and the other
2 ft. 2 in. thick, separated by C fathoms of shale, sandstone, and thin beds of lime-
stone. Over these coal-seams, at a distance of about 10 or 12 fathoms, there is
a thick bed of limestone, which crops out near Keildor Castle. At Plashets (still
farther east) there is a seam said to be 6 feet thick. At Blackhope there are two
seams, one 4 feet, and the other 2 feet thick, each having a stone in the middle.
At Whitelee, about a mile to the east of the Carter Lime- Works, there is a bed
of limestone 6 feet thick, which lies 17 or 18 fathoms above the Carter coal. Be-
tween this limestone bed and another of equal thickness which crops out at Ruken,
there are two coal-seams, the one 2 feet, and the other 3 feet thick. This last-
mentioned limestone is about 50 fathoms above these seams.
The coal-seams now described continue eastwards by Rothbury, Eglingham,
Chillingham, and Doddington, to Belford and Berwick.
In confirmation of the opinion, that the same set of rocks extends from the
east coast of Northumberland to the neighbourhood of Liddesdale, two other facts
may be mentioned. The limestone beds which crop out at Falstone (fifteen miles
south of the Carter) run eastward, parallel with the coal-seams. One of these
limestone beds at Falstone contains galena, and to such an extent that it was
once worked.* Between Belford and North Sunderland there is a limestone bed
* At Roanfells, on the north, side of Liddesdale, a quantity of lead was found, and a company was
formed to work it. In ancient times some metal must have been smelted there, as heaps of slag and
cinders are met with on the muirs.
444 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
on the same strike or outcrop, which in like manner contains galena. It is pro-
bably a prolongation of this bed still farther westward which, near Alstone
Moor, affords so large a supply of lead. The other fact is, that the same vermi-
cular looking fossils, indicating an animal two or three feet in length, found
in the slaty sandstones of Halt whistle,* have been found by me in a sandstone
rock of precisely the same character, on the sea-coast at Scremerston, between
Holy Island and Berwick.
Some more special notice is deserving of the limestones found in the class of
rocks now under consideration. There are three kinds, viz., carbonate of lime or
ordinary lime-rock, Chert limestone, and magnesian limestone.
(1.) The first kind is that worked at Meadow-cleugh on the Carter, at Lime-
kiln Edge, between Hawick and Castleton, at Lariston, at Harelaw Hill, and at
Gilnockie Tower on the Esk.
At Harelaw Hill the rock is about 14 feet thick. It is compact, and of a bluish
colour. There are, however, several other beds of limestone, one of which is said
to be above 20 feet thick.
At Lariston the rock is of a bluish-grey colour, and several yards in thickness,
divided, however, by one or two beds of shale or fire-clay. It abounds with marine
shells, such as the productus and the modiola, which last shell I have also seen
in the old Greenholm quarry. This bed of limestone is thought to lie above the
Carter limestone.
The limestone at the places just mentioned, and most of the others where it
is worked, contains numerous casts of the productus, orthoceras, encrinites, and
other marine mottusca. The quarries at Limekiln Edge and the Carter are, how-
ever, exceptions to this remark, which may perhaps be owing to changes produced
on their texture by large masses of trap-rocks adjoining them, to be afterwards
described.
At Limekiln Edge, the bed worked is about 12 feet thick. It presents some
remarkable undulations, which have nothing to correspond with them in the strata
above or below. These undulations are seen also in the Berwick coal-field ; and
I understand from Lord Greenock, that he has seen them near Cambo in North-
umberland, about twenty miles south of Cheviot, through which district the same
limestone beds undoubtedly run. The occurrence of these undulations between
horizontal beds have not, I believe, been explained, and I confess my inability to
offer any plausible hypothesis.
* Geological Society's Transactions.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
445
Section from Limestone quarry at Limekiln Edge. Depth 20 feet, length QQfeet.
A A, Stratum of gravel.
B B, Blue marly clay in horizontal layers, containing undulatory strata of limestone.
C C, Limestone 4 feet thick.
DD, Limestone 6i feet thick.
f
The only analysis of this class of limestones which I have obtained, is of that
worked at the Carter, made by the present Professor Gregory of Aberdeen. The
following shews the constituent elements of three specimens : —
Carbonate of lime
Magnesia,
Insoluble matter (sand),
80
3
17
100
90 90
trace. 5
7 5
97*
100
(2.) The chert limestone occurs at Robert's Linn (on west side of Windburgh),
Windshielknow, Kerchester, Bedrule, Smailholm, and Sprouston.
At all these places, the rock is accompanied by sandstones, marls, and shales,
which appear to me to belong to the coal-measures.
The rock has not much lime in it, though at Hadden and at Bedrule it has
been quarried and burnt for agricultural purposes. It is highly crystalline, con-
taining large nodules of quartz or chalcedony, generally coloured red. On an
analysis of the Hadden limestone, there was found to be (out of 100 parts) 50
• It is observed by Mr Gregory, " that this slight deficiency is probably owing to a little water,
which most limestones contain."
VOL. XV. PART II.
6E
446
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
per cent, of carbonate of lime, 44 of magnesia, 12 of peroxide of iron, and 4 of
silica.*
At all the places where I have seen this chert limestone, there is contiguous
to, or closely adjoining it, a great abundance of trap (generally a clay stone por-
phyry), containing crystals of felspar as well as of augite. This porphyry, as will be
afterwards more fully explained, occurs in beds or strata of pretty equal thickness ;
and it is a remarkable fact, that the nearer the stratified rocks are to this igneous
rock, the more perfectly are the characteristic ingredients of the chert limestone
developed. Thus, at Hadden there is a stratum of chert limestone, eight feet thick,
interposed (with other strata) between very thick and very extensive beds of a
coarse amygdaloidal felspar. The superjacent bed forms along its outcrop a pre-
cipitous cliff, which runs along the south bank of the Tweed for nearly a mile.
At a distance from the trap, the solid body of limestone ceases ; but even there,
nodules of it exist in the beds of blue marly clay which abound in that district.
At Henderside Mill, as well as above Fireburn Toll (places on the north bank of
the Tweed below Kelso), similar beds of chert limestone exist in the near vicinity
of trap.
At Bedrule Hill, there are several beds of this limestone, the position of which
is shewn in the following section.
1 and 2. Porphyry beds, from 15 to 20 feet thick.
3. Altered sandstone.
4, 5, 6. Blue shales and slaty sandstones.
7. Chert limestone, about 6 feet thick.
8. Unknown, about 20 feet.
9 and 10. Strata of chert limestone.
11. Shales and sandstones of coal-measures.
The foregoing section extends for about 200 yards. The greenstone porphyry
here, as at Sprouston and Hadden, forms beds nearly horizontal. Its outcrop at
Bedrule runs very uniformly above these carboniferous strata, for about a mile.
* Analysis by Dr R. D. THOMSON. (Mag. of Nat. History, by LOUDON, No. 29.)
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 447
At Roberts Linn, the following section illustrates the position of the chert
limestone.
A A, Bed of porphyry.
B B, Stratum of red clay, streaked with thin white lines, parallel to the porphyry.
C C, Stratum of red clay, streaked with thick blue lines, parallel to do.
D D, Bed of chert, pretty compact.
E E, Bed of chert, mixed with blue clay.
F F, Bed of gravelly red clay.
G G, Ditto.
H H, Channel of burn.
This section is about 30 feet high, and about 100 feet long.
Below Winshielknow, the trap in contact with the chert limestone is not (as
in the cases just mentioned) a plateau or horizontal flow of trap, but a dyke
30 feet wide which cuts vertically across the strata, running in a northerly direc-
tion. It has tilted the strata on each side of it.
(3.) The only place where I noticed beds of true Magnesian Limestone, is in
Tweeden Burn, on the south side of Liddesdale. There were several strata, a few
inches thick, of a buff yellow colour, and presenting cavities in the way usual in
this kind of limestone. There are thin beds, precisely similar, on the banks of
the Tweed, both above and below Coldstream.
Another rock (if rock it can be called) belonging to this class, which here
requires notice, is Gypsum. It exists in considerable abundance on the north
bank of the Tweed at Kelso ; also about a mile above Floors Castle, and near
Birgham, on the confines of Berwickshire. It has been found too on the north
bank of the Eden, about a mile above its junction with the Tweed. Both the
white and the red varieties are found at all these places. The red exists in no-
dules or concretions ; — the white is in the form of veins, more or less vertical,
and has evidently been formed subsequently to the red, for it intersects the red
gypsum. This mineral occurs only in beds of blue marly clay. Another place
where gypsum is said to have been found is Archerbeck Burn, in Liddesdale. If
this be true, it is probably in the new red sandstone formation, which will now be
noticed.
448 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
4. The formation or class of rocks just mentioned, I mean the Nero Red Sand-
stones, there are some reasons, though they are not, in my opinion, conclusive, for
supposing to exist in Roxburghshire.
At one time the whole of the red rocks of Roxburghshire were assigned to
this class, and the opinion is still entertained by some geologists ; nor is it alto-
gether devoid of plausible arguments.
(1.) In the first place, that the new red sandstone formation exists on the
western borders of the county can scarcely admit of doubt. It extends from the
plain of Carlisle, up the Esk as far as Canonby, and also up the Liddell to about
200 yards below Penton Linns, and a little way up Archerbeck Burn. At Penton
Linns, the division betwixt the coal-measures and the upper red rocks is very pal-
pable ; the former being there nearly vertical, and the latter abutting against them,
and partly covering them, but dipping westward at an angle of 30°. As the for-
mation thus reaches into Liddesdale, it was not unnatural to suppose that the same
formation existed, likewise, on the eastern borders of the county. It is well known,
however, to geologists, that the appearance of this formation in the plain of Car-
lisle, is owing to an enormous sinking of the strata, which took place in that part
of England ; and, accordingly, its eastern boundary is marked by a fault, which
divides it from the carboniferous rocks of Northumberland. This fault shews
itself on the Liddell, about 200 yards below Penton Linns, where the new sand-
stone rocks are seen with their edges tilted up against the limestones and other
beds of the Canonby coal-field, and in such a way as very clearly to indicate that
there has been a general sinking of the newer formation.
(2.) In the second place, there is a very remarkable horizontality in the red
rocks of Roxburghshire, which seems to indicate a comparatively recent period
for their deposition. And this circumstance becomes the more striking, when it
is found that, on the other hand, there are many localities bordering on this dis-
trict of country, where the coal-measures are inclined at considerable angles. Thus,
at Bedrule Hill, where, as has just been shewn, the limestones, shales, and yellow
sandstones are vertical, the red sandstones immediately adjoining in Huntly
Dell, are perfectly horizontal, and indicate no signs of disturbance. Generally
speaking, it cannot be doubted that the red rocks present fewer deviations from
the horizontal, than the coal-measures. Must they not, then, have been deposited
at a subsequent period ?
(3.) Farther, it appears that, in several parts of Liddesdale, red rocks have
actually been seen lying above coal-shales and sandstones.
These are some of the grounds on which it has been or may be maintained,
that the new red sandstone formation prevails in Roxburghshire. Nor am I in-
clined to deny, that possibly some rocks more recent than the coal-formation
may exist. That the Old Red formation exists, is clear from the discovery, in
various places, of the fossil fish characteristic of that formation, and from other
facts already alluded to. That the Coal-Measures also exist, is equally certain ;
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 449
and that occasionally red rocks are seen lying above these, I think can also be
affirmed. But there is no reason to believe, that these several classes of rocks
form separate and independent formations. They appear rather to be all mem-
bers of the same formation, deposited, however, under not exactly the same cir-
cumstances. The appearance of red sandstone strata among, and even above, the
carboniferous strata, may be explained by supposing, that the causes which had
previously led to so large and constant a deposition of red sandstones, though
diminished, had not altogether ceased. At various places in the county, the old
red formation can be seen passing into the coal-measures, by a blending and in-
termixture of the strata characteristic of both. Thus, in Mellenden Burn (two
miles south-east of Kelso), there are beds of red shales and calcareous marls and
sandstones, including beds of conglomerate which contain porphyry pebbles. In
Sunlaws quarry, on the Teviot opposite to Roxburgh, there will be seen red sand-
stone strata, overlaid by blue and brown marly strata.
II. Unstratified or Igneous Hocks.
These I divide into three classes,
1st, Felspathic rocks.
2d, Tuff or amygdaloidal rocks.
3d, Augitic and hornblende rocks.
Of these three classes, the first is by far the most extensive and remarkable ;
in proof of which, it is only necessary to mention, that the Cheviot and Eildon
Hills, as well as many others in the county, belong to it.
In each of these classes, two epochs of eruption are apparent, judging by the
effects produced on the contiguous stratified rocks.
In describing these several sets of igneous rocks, I shall endeavour to indicate
their ages by a reference to this test.
1. The Felspathic Rocks present, generally speaking, various shades of a yel-
low, and sometimes reddish-brown colour. Occasionally they present purple and
lilac hues. They form rounded and dome-shaped hills, very different from the
elongated and occasionally precipitous greywacke hills.
(1.) Following the division above explained, as to the age of these rocks, I
observe, that the Cheviot and Eildon Hills appear to have been formed at an era
prior to the deposition of the old red sandstones, as these stratified rocks are, in
many places, some of which will be immediately mentioned, seen close to the fel-
spar rocks, without exhibiting any change either of dip or of texture.
VOL. XV. PAKT III. 6 F
450 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
Cheviots. — It is impossible to describe all the varieties, they are so numerous,
and so complex in themselves, of porphyry which abound in these hills. I am
not aware of there being any greenstone or basalt among them. The rock con-
sists almost entirely of clay and felspar, exhibiting in general an earthy, seldom
a compact or crystalline structure. The latter variety seems to occur only in the
very central parts of the range, composing several entire hills near Hownam, Atton-
burn, and Yetholm. The rock of these hills has a dark resinous appearance, and
exhibits sometimes a conchoidal fracture. When struck with the hammer, it rings
like metal. It is occasionally striped with iron-shot veins of quartz, which afford
a pleasing contrast with the black resinous lustre of the rock. It does not easily
decompose, and has been used with advantage as a building stone.
The Cheviot porphyries, which present an earthy structure, are generally
filled with veins and nodules of quartz. These nodules are often reddened with
iron, and, when large, receive the popular name of jasper. Such masses are ex-
tracted on the west bank of the Jed, about a mile to the west of Edgerstone, not
far from Shaws farm-house. The colours of the earthy porphyries of Cheviot are
brown, lilac, purple, grey, and inclining to red. I have never seen any porphyries
of the brick-red colour, common in the Eildon hills.
That the Cheviots were thrown up before the deposition of the red sandstone
formation, is evident from several circumstances. (1.) At Lin ton Church, near
Morebattle, the conglomerate of the old red sandstone may be seen almost in con-
tact with the Cheviot porphyry, and perfectly horizontal. The pebbles of the
conglomerate are chiefly porphyritic. (2.) On Jed water, about two miles west of
Kdgerstone, and opposite to the farm of Shaws, there are sandstone strata which
appear to lie above the old red sandstone conglomerate existing on that farm.
These sandstone strata are within twenty yards of the Cheviot porplryry, and unaf-
fected by it. Moreover, they contain rounded pebbles of Cheviot porphyry. Be-
sides being seen so close to the igneous rock, they can, higher up the river, be traced
to within a few yards of the greywacke strata, which there run E. by S.,
dipping at an angle of 86° to the south. At this place there is little or no iron
in the greywacke, which probably explains the brownish-yellow colour of the
sandstones just referred to. The greywacke strata are here, and farther down
the river, of exactly the same yellowish colour. (3.) At Cherry trees, near Yetholm,
the old red sandstone strata are quite horizontal, and quite close to the compact
felspar porphyry, of which the hill there is composed, and seem to have been in
no way affected by it. (4.) At Blakelaw there is a thick bed of conglomerate,
composed of porphyry and greywacke pebbles, and close to a hill of claystone
porphyry, which has apparently not altered it.
Eildon Hills. — The westermost hill, on which the Cairn stands, consists of a
very hard clinkstone, having a grey basis, and small crystals of felspar inter-
spersed through it. It strikes fire with steel. On the eastmost hill, the rock,
though much the same, is not quite so hard. I have specimens of this rock, con-
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 451
taining imbedded portions of grey wacke, — a fact of itself sufficient to shew, that
these hills were thrown up after the greywacke strata were deposited.
These hills are remarkable for the columnar ribs of flesh-coloured felspar which
occur on their south-west side, opposite to Bowsden. Some of them exceed 30
feet in length. I do not know any other place in Great Britain, where this species
of trap exists in the form of such gigantic crystallization.
Bemerside Hill, which consists of a yellow or buff- coloured felspar, belongs
apparently to the same epoch. In this rock, where quarried on the south side of
the hill, I observed conchoidal fractures on a very large scale. Some of them
form elliptic figures fuUy 15 feet in diameter. It may be supposed that in igneous
rocks, such an arrangement of matter as these conchoidal surfaces indicate, may
be readily explained by the process of cooling. But similar appearances, and on
nearly as large a scale, are not uncommon in sedimentary rocks, producing what
the quarrymen call " yokes" or hard concretions.
At Easter Softlaw and Frogden, the felspar assumes the form of a compact
fine-grained clinkstone, of a purple colour. This seems to be about the northern
limit of the old felspathic rocks of Cheviot.
At Windburgh, the rock is clinkstone, and of a still darker hue. The old red
sandstone can, at several places on the east side of this hill, be seen within a few
feet of the igneous rock, and perfectly horizontal.
On the west and south-west sides of Minto Crag, which is clinkstone of a dark
colour, there is a yellow slaty sandstone within 10 yards of it, quite unaffected.
In Ancrum Park (Sir W. Scott's), a bed of claystone porphyry (containing
large crystals of felspar) may be seen in a burn below the dog-kennel, overlaid by
slaty horizontal strata, which appear to consist partly of felspar, derived probably
from the decomposition of the subjacent beds. Over these the red sandstones are
lying undisturbed and unaltered.
(2.) In regard to felspar rocks of a later date, I would, in the first place, refer
to an elevated mass or sheet of felspar porphyry, stretching across the Teviot and
the Tweed from the south by Springwood Park to Mackerston. The texture of
the rock is there coarse and friable, and not nearly so crystalline as the trap-rocks
last described. There is, however, a vein in it (to be seen in the channel of the
Teviot above Springwood Park summer-house) much more hard and fine-grained.
This vein is in one part red, and in another grey, in its colour. It is visible for
about 20 feet, running by compass west 4° north. It is from 6 to 8 inches wide.
This flow of felspar porphyry has produced remarkable effects on the strata
adjoining it, both in the Teviot and in the Tweed. The coal sandstones have evi-
dently been made to undergo great changes in their internal structure. Near the
porphyry they are highly crystalline, and the calcareous matter has separated
from the siliceous, in a way altogether unusual in this rock, except in such situa-
tions. The trap appears to have flowed among and between the stratified rocks,
and thus partakes of their dip, — as may be well seen near Roxburgh and Sprouston.
452 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
In the Tweed, about 1^ mile below Mackerston House, on the north bank,
the marls and sandstones of the coal formation are hardened in a somewhat simi-
lar, though not in so striking a manner.
These sheets of porphyry have in all probability flowed down from the Che-
viots, but at a period subsequent to the elevation of the Cheviot proper. Accord-
ingly it is found, though in a less friable state, at Hightown, about a mile to the
south of the Teviot. In a quarry of it south of this village, I noticed a vein of com-
pact red felspar running north-west, cutting through the more shivery rock. I
picked out a quantity of earthy copper-ore from the sides of this vein.
The felspar porphyry (already described) at Sprouston, Kerchester, Hadden,
and Carham, lower down the Tweed, belongs evidently to the same epoch, and has
produced effects precisely similar on the strata of sandstone and marl which oc-
cur there on both banks of the Tweed. At Hadden, near Sprouston, and at
Sucklawrig, near Mackerston, the trap has a green earthy basis, having numerous
plates of brown mica disseminated through it.
It rather appears to me, though I am by no means confident, that the Black
Hill of Earlston, sometimes called Cowdenknows Hill,* also belongs to this later
epoch. It is a felspar porphyry, the colour of the rock being, like that of the Eildons,
brick red. The red rocks reach to within about 200 feet of the top of this hill, and
dip from it at a considerable angle.
There is a small patch of felspar precisely similar to that composing Cowden-
knows Hill, on the west side of the Leader, near Clack-mae, as shown on the
map ; and there are some remarkable dykes, also of the same rock, which, in va-
rious parts of the county, may be seen traversing the old red sandstone strata.
I shall mention some of the places where I have observed these.
Just below Chappie (on the Leader), a felspar-dyke of a greyish-red colour,
and about 18 inches wide, cuts through the old red sandstone conglomerate, in a
direction east by south and west by north. It corresponds exactly with the strike
of the grey wacke strata at this place.
Below Carrolside (also on the Leader) the edges of the greywacke strata
stand up about 6 feet above the channel of the river, and are covered by the con-
glomerate of the old red sandstone, which here forms a bank not less than 200
feet high. At this place a dyke precisely similar in texture and colour to the one
above noticed, and about 6 feet wide, is seen shooting up from between the
greywacke strata, and piercing the conglomerate. The greywacke strata here
are very nearly vertical, and run east by north. The dyke runs in the same di-
rection. The following section is meant to illustrate this interesting meeting of
rocks.
* On the top of this hill are the remains of a vitrified fort, consisting of two ramparts. The rock
was well adapted for being fused, from the quantity of alkali it contains, — a quality of which the manu-
facturers of these forts seem to have been well aware, as the stones in all vitrified forts are of this
description. *-
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
453
00 "o 0
oo o 0 0
o^o 0 o °o o0
o o
AB are the greywacke strata, having the dyke CDE interposed between them.
In some places the dyke is contracted in width. It does not rise to the top of the
conglomerate, and it narrows as it rises. A vein of quartz, chlorite, and some
other minerals, runs down the centre of it, which is common enough in trap
dykes, and is supposed to have been formed in the process of cooling.
In the Dinlee Burn, one of the tributaries of Hermitage Water, there is a
similar felspathic dyke, about 15 feet wide, rising out of the greywacke, and cut-
ting across the superincumbent red sandstones. It runs, however, in a north-
north-west direction. The strike of the greywacke there, is east-by-north and
west-by-south.
The dyke at Winshielknow, already referred to, belongs to this epoch of fel-
spathic eruptions.
About a mile below Galashiels, there is a dyke of yellow felspar, which runs
east and west, following the strike of the greywacke.
At the foot of Easter Burncleuch, there is also a dyke, about 3 feet wide,
running in a north-north-west direction.* In a quarry of greywacke west of Ga-
lashiels, on the turnpike road, a dyke of porphyritic claystone, about 13 inches
wide, may be seen running east and west. Mr KEMP of Galashiels also informs
me that a porphyritic-dike. about 100 yards wide, runs from the Eildon Hills
to the hill south-east of Gledswood House. I have noticed a mass of porphyry
in the river about half a mile south of Old Melrose.
In the Allan Water, about half a mile above Fairy Dean, there are two ver-
* These two dykes I have not myself seen.
out for the DUKE of BUCCLEUCH, dated 181G.
VOL. XV. PART HI.
They are noticed in a report by Mr FAREY made
454 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
tical dykes of porphyry, both running, by compass, east \ south between the grey-
wacke strata. They are about 20 feet apart from each other. The southmost of
them is about 18 inches thick, and the other about 3 feet thick. The latter is
disposed in horizontal columns, — a phenomenon now well understood to be the
effect of a cooling process commencing at the sides. The dyke last mentioned is
a felspar-porphyry, having a dark-grey basis of clay, with large white crystals of
felspar imbedded in it. About 12 or 14 yards north of it, there is a knoll of clay-
stone-porphyry, very similar to the rock of Cowdenknows and Gledswood Hills.
Another dyke of porphyry, about 2 feet thick, similar to the above, and run-
ning in the same direction, crosses the Gala a few yards to the west of Galashiels
Bridge.
2. Tuff or Amygdaloidal Rocks, are next to be described, having an ap-
pearance as well as structure, very different from either of the two classes of
rocks just mentioned. But they contain fragments of various sizes, apparently
derived from these rocks. They are generally brown in colour, and of various
shades, sometimes lilac and lightish red. This rock derives its characteristic
structure from containing, besides the fragments just alluded to, almond-shaped
concretions, of all sizes, supposed to have been originally bubbles of gas in the
erupted lava, subsequently filled with various chemical precipitates.
Amygdaloid or tufa, apparently thrown up since the deposition of the sand-
stone formation, occurs on the north-west shoulder of the Eildon Hills (where it
is extensively quarried), — at Holm House, nearly opposite to Dryburgh, — in the
three green hills of Minto (including the one at Standhill), — at Dinlee Burn, and
above Windshielknow (where beds of amygdaloidal-porphyry are interposed be-
tween the strata of red sandstone), — in Ancrum Park (where there is a similar
bed), — and at Ancrum Craggs, where there has been a considerable outburst.
The age of the Minto Hills can be shewn pretty distinctly, in ikejirst place,
by the rapid dip from them of the stratified rocks. On the west side of the west-
most hill, and close to the amygdaloidal rock, there is a small-grained conglome-
rate, or very coarse sandstone grit, of a brown or yellowish colour (apparently a
member of the coal-measures), dipping at an angle of 60°. In the quarry behind
Minto House, the strata, even at a considerable distance from the hills, dip at an
angle of about 40°. In the second place, the sandstone strata in contact with and
adjoining these hills, are much harder than usual. In the third place, the trap
of these hills contains fragments of greywacke-slate and of Eildon porphyry.
At Ancrum Craggs, in like manner, fragments of Eildon porphyry, greywacke,
and sandstone are found in the trap.
Besides the amygdaloidal trap on the north-west shoulder of the Eildon Hills,
a breccia, or fine-grained conglomerate, occurs there, which is apparently igneous ;
the enclosed pebbles consisting of ancient porphyry, greywacke, and a variety of
other substances, probably much altered in their appearance and texture by heat.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 455
The amygdaloidal tufa of Holm House, which is about a mile to the south-
east of the Eildons, appears to be much the same sort of rock as the tufa just
described. The Holm tufa presents a wall or face, which runs north-west and
south-east, and seems to run across the Tweed, forming a rapid. It effervesces
slightly with acids. Where most compact, this rock contains white and yellow
crystals of felspar. It contains also angular fragments of clinkstone and ancient
porphyry, and probably greywacke. This tufa may be traced for a considerable
distance up the burn which here flows into the Tweed. On examining the yellow
sandstone rocks, which are close to it on the south side of it, there are appearances,
in the structure of them, which indicate that they have been acted on by heat.
At Moorhouselaw, about 2 miles south-east of Maxton, there is a sheet of
amygdaloidal porphyry, which has flowed over and among the red sandstones.
There is, in this porphyry, great abundance of chlorite and other minerals, formed
probably by chemical precipitation.
3. The Augitic and Hornblende Rocks are next to be described.
(1.) Among the oldest of this class, must be placed the well-known hills called
Ruberslaw, Bonchester, Bunion, and Peniel. The rock at Ruberslaw is greenstone,
containing steatite. That on Bonchester is basalt, containing crystals of augite.
Around the hills just named, the red rocks prevail, and, up to within a short
distance of their summits, remain on all sides pretty nearly horizontal. At
Peniel Heugh, they are to be seen within 50 feet of the summit.
There is a range of greenstone and basaltic rocks between the Fly Bridge
and Smailholm, which are to a considerable extent covered by the red rocks — also
here horizontal. They bear the name of Black-craigs and Black-dykes, derived
probably from the dark colour of the basalt. The farm-steading of Sandyknow
is built on horizontal strata of red sandstone, and within 20 yards of the green-
stone rock, which seems to have in no respect affected the sandstone. These trap
rocks appear to continue eastward by Nenthorn to Stitchell and Hume Craigs in
Berwickshire. At Stitchell the basalt occasionally exhibits red stains, whether
caused by iron or red felspar I do not know. It contains also some beautiful
crystals of black glassy hornblende ; also of several other minerals, which are
unknown to me. One of these specimens I shewed lately to my friend Mr
JAMESON TORRIE, who states that it contains a morsel of mineral pitch, having
opal imbedded in it.
To the west of Peniel Heugh, there are several protuberances of basaltic and
greenstone porphyries, which form with it a connected range. There is a patch
on the east side of the turnpike-road near Ancrum North Lodge. Another mass
occurs a little to the west of Ancrum House, at the Castle Hill, and at Scaw.
The stratified rocks are seen at the place last mentioned, within a few feet of the
trap, without being at all affected by it. To the west of Kirklands House, green-
stone again occurs ; as also about 2 or 3 miles farther west.
456 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
At Wooden Hill (Eckford parish) there is a considerable mass of basalt, full
of elongated crystals of dark glassy felspar.
Beneath Maxton Manse, there is a fine-grained greenstone, approaching to
clinkstone, which does not appear to have affected the adjoining sedimentary
rocks.
(2.) Greenstone and basaltic rocks, of a more recent epoch, occur in two
forms, viz. in dykes, and in hills, or aggregate masses. On the Carter, there is a
large mass of Greenstone lying at a considerable distance above the limestone
worked there, and which may be traced for about a mile along the top of the
hill. Windburgh Hill consists, on its west side, of fine-grained greenstone,
which has there formed itself into columns nearly vertical, and has affected the
adjoining coal strata and limestone. At Greena Hill, in Carby Hill and in
Tweeden Burn (all in Liddesdale), there are considerable masses of basaltic por-
phyry, which have upraised the coal-measures surrounding them.
Below Maxton Schoolhouse there is a fine-grained greenstone, which has
hardened as well as tilted up the sandstone strata on all sides of it. About a
mile above this, on the south side of the Tweed, opposite to Merton House, there
is a mass of basaltic greenstone (called Craigoer), which has evidently hardened
the sandstone strata. I at one time considered this a dyke, running north-east
and south-west ; but as it is composed partly of vertical columns, I am now in-
clined to think that it is an overflow. The sandstone in its immediate neigh-
bourhood has lost its red colour, and become yellow, as near the Holm, before
referred to. There is a good deal of greenstone and clinkstone along the south
bank of the Tweed, between Craigoer and Maxton, which has hardened the sand-
stone strata near it.
Dykes of basalt or greenstone are not numerous. There is one which I have
traced for about 26 miles, passing through Hawick at its north end, and a little
to the south of Edgerstone at its south end. It is, or has been, worked at the fol-
lowing places, beginning at its north end, viz. at a place 1^ miles north of Hawick,
Miller's Knowe (1| miles south of Hawick), Orchard, Ormiston, Kirkton, on muir
west of Ruberslaw, Hallrule Mill, Falside, Roughlie, Rink. It may be seen beyond
this last mentioned point crossing the Edgerstone Burn, and also the Kale Water
near Hindhope.* At this last point it enters the coal-measures of Northumber-
land ; so that even within this county, it intersects the greywacke, the porphyry,
the red sandstone, and the coal formations in its course.
Its course is not very regular, especially when within the limits of the grey-
wacke formation. Its general direction towards the north, when viewed from the
Miller's Knowe, by the line of its bearing apparent on the surface, is north 63°
west. On the muir west of Ruberslaw, its line may be traced pretty uniformly
* The best maps of the county do not, with any sort of correctness, indicate the position of the
Cheviot Hills, or even the situation of the farm-houses existing among them. I found it, therefore, very
difficult to lay down the dyke in this part of its course.
4
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
457
for about a mile, and gives a direction of north 60° west. Its more general direc-
tion, indicated on the map, is north 54° west.
I shall proceed now, however, to give a more particular account of the bear-
ing and width of this dyke, at every part of its course where it is visible, stating
at the same time the nature of the rocks which it intersects. The importance
of these details, if not here self-evident, will be seen in the second part of this
memoir.
Commencing with the south end of the dyke, where it enters the county
among the Cheviot hills, I have to mention that its course may be traced down
the face of the hill to the Kale Water, which it crosses between Upper and Nether
Hindhope. It may be distinctly followed along Eccop Hill, passing not far from
the top of it on the north side. Here the Rink quarry (to be afterwards par-
ticularly mentioned), situated on the Newcastle and Edinburgh road, where the
dyke is worked, and distant from this point about three miles, bears by compass
north 55° west. This part of the dyke exhibits on the surface of the muir, huge
horizontal columns. Proceeding about two miles west, we find the dyke crossing
in that interval several burns, and forming in most instances rocky barriers in
their channels. It has been recently quarried on the west side of Edgerstone
Burn, which is about half a mile from the Rink, and there the dyke is 36 feet
wide, its walls running in a direction north-west by west.
In the part of its course just described, the dyke traverses first the coal-
measures, which here stretch over from Northumberland, and reach nearly as far
as Eccop Hill. It then enters the porphyry formation, which continues to the
Edgerstone Burn just referred to, where it enters the greywacke formation.
At the Rink Quarry, the dyke takes several bends, which are well shewn in
the extensive workings to which it has there been subjected. The following
woodcut will explain these.
Horizontal Section, shewing course of Basaltic Dyke through Greywacke Strata.
The course of the dyke is indicated by the letters ABCDE, — the distance from
A to B being about 100 yards,— from B to C 8 yards,— from C to D 20 yards,—
from D to E 6 yards.
VOL. XV. PART III. 6 H
458 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
The dyke has been quarried from A to E, patches only being left here and
there, and especially at the angles, where the rock proved not to be good for road-
metal. It will be observed, that it runs most frequently parallel with and between
the strata of greywacke, and that it occasionally cuts across them. Its width in
the Rink Quarry varies from 16 to 30 feet.
Between the Rink Quarry and the Jed, there are several quarries on the line
of the dyke, and which, from the Rink Quarry, bear N.W. 2° N. The rock is not
perceptible in the channel of the river ; but its course up the face of the brae, on
the opposite side, is very perceptible. The progress of the dyke to the northward
I shall point out, from a very distinct account of it furnished to me in writing by
Mr OLIVER of Langraw, who. at my request, travelled along that portion of its
line to be now described. Mr OLIVER states,* that " at Roughlee Nook, the dyke
appears to be about 20 feet wide ; but where, as in this instance, there has been
no section by water or digging, it is very difficult to ascertain the width. There
appeared here to be, on each side, 4 or 5 feet of a dark-coloured mass, compact
and heavy, but not crystallized like the material of the dyke proper. This is on
the border of the porphyritic formation. At Falside, the dyke, 30 feet wide, runs
through red sandstone, which is also changed, where in contact, into a material
similar to that described above, gradually assuming its natural character as it
recedes. The adjoining strata do not seem at all deranged. From Falside, the
next point, near Abbotrule, bears nearly north-west by north. Here the dyke is
intersected by a burn, and its side exposed for 30 or 40 yards along a bank. The
material on each side of the dyke is a red and white (mottled and streaked) sand-
stone, which at some points is changed into a hard dark-coloured stone, some-
what resembling ironstone, but which gradually regains its natural features as it
recedes from the dyke. In other places, quartzy pebbles, without any other very-
considerable change in structure, indicate the action of heat. There is no dis-
cernible change in the direction of the adjacent strata, which, however, are highly
inclined, dipping to west by north, at an angle of about 20°. Width of dyke about
20 feet ; direction, as far as seen, west north-west ; but between this point and
Hallrule Mill, the direct line runs nearly west by north. At Hallrule Mill, the
dyke cuts through the sandstone, without, so far as can be seen, effecting any great
changes. From this, to the next point of view at Glen planting on Caver's estate,
the course is due west. Here the dyke is seen for 200 or 300 yards running west
north-west, and is 18 feet wide, when suddenly it changes to 30 feet for a short
distance, and then suddenly reverts to its previous dimensions (18 feet), and at
the same time changes its direction to west south-west. The dyke at Glen Quar-
ry has been quarried out to a considerable extent, and to a depth of about 30 feet
— the sides, nearly perpendicular on either hand of the dyke, being left standing.
* It is proper to premise, that the bearings given by MR OLIVER are true, and not magnetic.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 459
Here are seen to advantage, the effects on the adjacent materials, which, in imme-
diate contact, are converted into a very hard and dark-coloured stone, with some
crystals and seams of felspar. This quickly changes to a lighter colour, and, at the
distance of 5 feet, consists of a red shaley sandstone, approaching to what we call
dent, and rapidly crumbling down to red earth, where exposed to the atmosphere.
From Glen Quarry to Tofts Hill, the bearing is west ; and from that to Kirkton,
west by north. The dyke is seen nearly all the way across the Tofts Hill, which
is composed of greywacke, through which the dyke passes nearly at right angles
to the direction of the strata. The course of the dyke is jagged and irregular, the
irregularities on each side bearing a striking coincidence, and, in some places,
especially at Kirkton, when the metal is taken out, if the sides were brought to-
gether, it is evident that they would fit exactly. The greywacke does not seem
to have undergone much change beyond semifusion and distortion for a very short
distance, with now and then some of the matter of the dyke injected into its fis-
sures ; width ranging from 10 to 25 or 30 feet. At Kirkton, the dyke (15 feet)
suddenly takes a south-west direction, which it maintains whilst in view, about
100 yards."
" From Sunny side, where it is 27 feet wide, the dyke runs, for a few hundred
yards, west by north. It is again seen at a short distance, in the bottom of a
deep hollow ; and from the last point to this, the course is west, when it changes,
and runs for 200 or 300 yards west by south, width 24 feet. The next point,
perhaps 260 yards, bears west north-west. Next point, 200 yards, west north-
west, 21 feet wide. Next point, 200 yards, west by north, width about 22 feet.
From this it bears west a short distance, when it changes to west by north ; in
which direction it continues upwards of a quarter of a mile, when it abruptly
turns, and runs about 300 yards north north-east ; at least, the next point that
I can discover bears in that direction ; and I thought I could make out the angle
it formed in changing to north-west by north, in the direction of Miller's Knowes.
At Miller's Knowes, the dyke curves from north-west by north to north-west,
width from 15 to 18 feet."
" Here my survey terminates ; but I know that the dyke runs across the com-
mon haugh at Hawick, and from the old workings at Miller's Knowes, bears about
west by north. It is seen not far to the north of Wilton Lodge, — at a point some-
where between Whitehaugh and Wilton Burn, — a short distance to the north of
Mabenlaw and Whitecleughside, and at a point nearly a mile from Borthwick
Shiells."
Mr OLIVER adds, that the general strike of the greywacke strata, is south-west
by nest, by true bearings. At the Miller's Knowe, therefore, the dyke which, by
true bearings, runs north-nest by north, must cut across these strata at exactly a
right angle, — just as in the Rink quarry before described. The general course of
the dyke, however, is, as already stated and shewn, oblique to the strike of the
460 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
greywacke strata, forming, indeed, very nearly half a right angle with them. If,
therefore, it occasionally takes a course at right angles to the greywacke strata,
it must, in order to preserve its average direction, also occasionally take a course
parallel with them ; and, accordingly, it has been shewn that this is the case.
Nor is it difficult to understand, why this irregular course should have been taken,
if the dyke only fills up a rupture of the earth's crust. This rupture would
follow the lines of least resistance, — and these, it is plain, must be either parallel
with, or directly across, — and not obliquely across the strata. In the less com-
pact formation of red sandstone, there would not be the same difficulty of rup-
ture; and hence within its precincts, the course of the dyke is not so irregular as
in the greywacke formation.
This dyke varies in composition, not merely in different parts of its course,
but even at any one spot, according as the specimens are taken from the sides or
the centre. At the sides the trap is fine granular, almost approaching to clink-
stone, and occasionally it is vesicular ; whereas in the centre the texture is coarse
but compact, and highly crystalline. The crystals are sometimes pretty large, con-
sisting chiefly of quartz, and more rarely of glassy felspar. These differences of
structure can be readily explained by the difference in the rates of cooling in the
different parts of the dyke.
On the south bank of the Tweed, a little above Merton House, there is a mass
of greenstone, which has upraised and hardened the contiguous sandstone strata,
and a portion of them may be seen entirely enveloped in the trap. This rock
has all the appearance of a dyke, though of this there is (as I have already men-
tioned) no certainty, in consequence of its not being traceable for any great
distance.
A little below the Manse of Castleton, on the south bank of the Liddell, there
is a mass of greenstone about 20 or 30 yards wide, which has upraised the strata,
and appears to be a dyke, running about west-north-west. At Larriston lime quar-
ry, a similar dyke may, I understand, be seen running in the same direction. It
is marked on the map.
There is one other subject which ought here to be noticed, as common both to
stratified and unstratified rocks. I allude to the joints which intersect them.
This is a point which of late has been attracting a good deal of attention,
and not more than it seems to deserve. But it is one which can be properly
worked out, only after an immense accumulation of observations, and a careful
classification of them, which in this county I have not been able to make, and
which I regret the more, as the observations I have made are very encouraging.
At the Limekiln edge, the principal joints form fissures no less than 5 inches
in width, and are filled with a fine yellow clay. The minor joints at right angles
to these, form fissures about 4 inches wide. The former run north 55° east, the
latter north 35° west. In the limestone of Penton Linns (near Canonby), the prin-
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
cipal joints run about north-east, the others about north-west. In the coal-seams
at Rowanburn (as Mr Gibson the manager informed me), the principal joints (or
backs as the colliers term them) run about due north, and the others due west.
Mr Gibson states, that these backs and cutters are independent of several large
faults which intersect the coal-seams, and which appear to be of subsequent
origin. He thinks also, that these joints are all independent of the dip and rise of
the coal-seams.
In the greywacke, I have observed joints at only a few places. At Carolside
Bridge, there are numerous parallel joints intersecting the flesh-coloured greywacke
strata, in a north-north-west direction ; and a similar system of joints prevails in
the light blue strata at Clackmae. At Langholm Bridge, there are numerous joints
traversing obliquely the greywacke strata in a west-north-west direction, and
mostly filled with spar, which occasionally contains lead.
There is thus a remarkable uniformity in the direction of the structural joints
of the stratified rocks, — a direction apparently quite independent of their dip,
and formed at a date subsequent to their deposition.
I may here also take notice of a vein on the south bank of the Tweed, op-
posite to Birgham, intersecting horizontal strata of clay and marl, and varying in
its width according to the nature of the strata passed through. In those marly
strata which contain a good deal of lime, the vein is from 2 to 3 inches wide,
and consists of crystallized carbonate of lime. In the other beds of dark red or
brown clay, which have no appearance of lime in them, the vein becomes a mere
crack of about ^ inch in width, and has no mineral contents.
III. Lastly, I have to notice the Post-tertiary and Diluvial Phenomena, in so
far as at all remarkable in Roxburghshire.
(1.) The oldest of the post-tertiary deposits is what has been termed Boulder
clay, because characterised by containing, interspersed through it, large boulders
or rounded blocks of stone. This deposit may be seen on the banks of the Leader
at different places, and also near Sprouston. It does not appear to exist in the
higher parts of the county.
At Sprouston freestone quarry, there is a good section, shewing a bed of
boulder-clay from 2 to 8 feet thick, lying upon the sandstone, — then a bed of fine
clay or silt free from pebbles, from 1 to 2 feet thick, lying over the boulder-clay,
— and, lastly, a bed of small gravel, from 4 to 5 feet thick, immediately under the
soil. The boulders are all rounded, and consist of greywacke, porphyry, and
basalt.
In regard to the existence of boulders on the surface, there are not many
places where they are in any abundance ; though it is more than probable, that,
before agricultural improvements commenced, the whole county had been covered
with them.
VOL. xv. PART in. 6 i
402 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
Rounded blocks of grey granite occur in several parts of Liddesdale, as in the
fields and moors near Castleton Manse, where I saw several from three to four
feet in diameter. On the east bank of the Esk, about two miles below Langholm,
granite boulders, of the red as well as grey variety,* some of them very large,
are to be seen. A number also occur in the Gill Burn, which flows into the
Liddell above its junction with the Esk. These granite blocks are lying on the
greywacke-formation, as well as on the coal-measures. Now, the nearest known
hill of granite is Criffel, which consists almost entirely of a grey granite, pre-
cisely similar to that composing the boulders in question. Criffel hill is situated
about twenty miles to the west of these boulders. The next nearest place where
granite occurs in situ, is in Kirkcudbrightshire, at Loch Doun, which is at least
sixty miles distant.
A pretty large boulder of grey wacke was noticed by me, about 200 feet below
the summit of Ruberslaw. It rests on the red sandstone strata, and very near
their highest level. No greywacke rocks occur in situ nearer than three miles
to the westward, between which place and Ruberslaw there is low ground, at
least 800 feet beneath the level of this greywacke boulder. Moreover, the grey-
wacke rocks, at the place above alluded to, where they occur in situ, do not rise
to so high a level as that of the boulder in question.
To the north-eastward of Ancrum House about one mile, there is an immense
accumulation of trap-boulders. They appeared to me to be composed of the ba-
saltic porphyry, which exists at Kirklands and Castle Hill, situated about two
miles to the west-south-west.
To the east of Cowdenknowes Hill, many large blocks of felspar porphyry,
consisting of the same kind of porphyry which forms the top of that hill, are
strewed over the muirs, resting on the old red sandstone strata.
In the burn on the north side of Toft's House, about f mile east of Edgerstone, I
found several irregular blocks of greywacke, resting on a reddish-purple porphyry
rock. The nearest point where greywacke exists in situ, is about half a mile to
the west, between which, however, and these blocks, there is a porphyry hill several
hundred feet high. There is no greywacke to the south or east, which are the
only quarters from which any glacier could have descended, according to the ex-
isting levels of the country.
Near the sides of the old road which runs from Jedburgh to Crailing, a great
abundance of basaltic boulders may still be seen. There is no hill, situated to the
east or south, which could have produced them. The basaltic hills to the west and
north-west, are those from which they must have been, in all probability, derived.
Nothing is so remarkable in this county, as the uniform manner in which the
steep side of a hill faces to the nest, and the accumulation of gravel and other
* This fact is taken from FAREY'S Report before mentioned.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 4(53
loose materials exists on the east side of it. This phenomenon, which the late
Sir JAMES HALL so well denominated Crag and Tail, prevails in Liddesdale as well
as in Teviotdale, and, therefore, on both sides of the summit-level of the country.
In Liddesdale, examples are afforded in the basaltic hills of Carby, and another
up the Tweeden Burn, of which I have forgotten the name, if it has one. In
Teviotdale, there are still more remarkable examples afforded by Bonchester,
Dunion, Peniel Heugh, and Castle Hill near Ancrum ; and also, farther north,
by the Eildon Hills, Bemerside Hill, Cowdenknowes Hill, and the basaltic ranges
near Smailholm.
There are in this county a number of those remarkable accumulations of gra-
vel and sand, which have of late become objects of increasing interest, on account
of their resemblance to moraines of glaciers. These accumulations are sometimes
disposed in the form of isolated mounds, and sometimes of long ridges, which last
are called Kaims by the country people. The most distinct of these is at Liddell
Bank, between the river Liddell and the turnpike road from Castleton to Canon-
by. The ridge is about half a mile in length, about 200 feet wide at its base, and
from 50 to 60 feet in height. It forms pretty nearly a straight line, running north-
east by east. It is not quite parallel to the course of the river, its eastern extre-
mity being farther off from it than its western extremity. The ground on which
it has been deposited, slopes towards the river, and, of course, therefore, the ridge
does not form a level or horizontal line. A considerable burn, called the Mere,
joins the Liddell a little to the west of this gravelly ridge, flowing from the east-
ward ; and the ridge is situated on the high ground between the two valleys of the
Liddell and Mere. At its upper or eastern extremity, the height of the ridge above
the adjoining ground diminishes gradually, and is finally lost in the side of a pretty
high hill. The relative position of this hill and the ridge is such, that if a stream
or rush of waters had passed over the country from the north-eastward, the ridge
in question would have formed a ridge on the lee side of the hill. The situation and
direction of this ridge are indipated on the map by a blue streak.* The accom-
panying section is taken from one part of the Kahns, where it has been quarried,
apparently for sand or fine gravel, a is large gravel, b is fine gravel, c is sharp sand,
* It has been found impossible to introduce this mark into the accompanying map, on account of
the smallness of the scale.
464 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
disposed in nearly horizontal layers. Among the gravel, I observed pebbles of
red and grey granite, as well as fragments of sandstone, shale, and coal.
Another set of ridges of the same kind occurs about 1^ mile north of Kelso, on
the road to Stitchell. Their sides are steeper than the one just described, but they
are not so high, and do not form for such a distance an unbroken line. A small
stream runs along one side of the longest of these ridges. There are several other
ridges of gravel in this neighbourhood, which have given the names of Kaim-
know and Kaimflat to farm-houses near them. Several pits have been opened in
them, for the sand and fine gravel contained in them, disposed in horizontal beds,
some of which are about 15 feet long.
A similar ridge of gravel, about 50 or 60 feet high, occurs between Ormiston
and Eckford, on south side of Teviot, running nearly half a mile in a west-
north-west direction, and nearly parallel with the Teviot in this part of its course.
There is another to be seen on the south side of Jedburgh.
In the neighbourhood of Galashiels, there are a number of knolls and ridges,
which have by some persons been represented as the remains of glacial detritus.
Within the policy of Gala House, there are several of both kinds pretty distinct,
though on no great scale. Mr KEMP, in a written account of them which he sent
to me, says, " there is a quarry in one of the largest, which shews it to be com-
posed, at that part, of well rolled coarse gravel, mixed with much sand, but not
at all stratified." I visited these knolls, but unfortunately did not see the quarry
which is here alluded to. I remarked, that more than one rivulet was running
along or near the base of these gravelly knolls and ridges.
Besides these knolls and ridges in Gala park, there are others, no less re-
markable, lower down the valley. One of them, about half a mile east of Gala-
shiels, is at right angles to the course of the valley, and runs for about 200 yards.
It has already been designated the terminal moraine of the Gala (/lacier ! There
is another still longer, situated immediately to the north of Langlee House, where
Captain RUSSELL ELLIOT resides. It runs parallel to the valley, and has been dig-
nified with the title of a lateral moraine. Mr KEMP, in an account of the first of
these ridges, published by Mr BOWMAN in the London and Edinburgh Philosophi-
cal Magazine,* in reference to its internal structure, says that the greater part
" is composed of clay and boulders, many of which are quite sharp and angular,
but the greater portion are rather well rounded : and what perhaps is worthy of
notice, the top, for about 25 feet down, is composed of unstratified gravel and
coarse sand." In describing the ridge north of Langlee, Mr KEMP, in a written
account which he has sent to me, says that it " contains several beds of sand dis-
tinctly stratified, and flanked upon each side with gravel."
Whether these accumulations of sand and gravel are really the remains of
glaciers, will be considered in the second part of this Memoir.
* Vol. xvii. p. 339.
6
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 4(55
There are, in many places, indications that the rivers, in this country, flowed
formerly at a much higher level than they ever now reach. On the north side
of the Tweed, for about a mile above its confluence with the Teviot, there is an
extensive flat, about 70 feet above the ordinary level of the river, extending back
probably half a mile from the river, and there bounded by an abrupt bank, which
runs for some distance parallel with the river. On this elevation, flat, or terrace,
Floors Castle stands ; as also, a part of the town of Kelso. The terrace, at its
side nearest the river, has a steep face or front, about 15 or 20 feet high, at the
foot of which there is another and lower terrace, intervening between it and the
Tweed.
At Castleton, there is a steep bank, from 50 to 70 feet high, which runs on
the north side of the town for about two miles nearly parallel with the Liddel, and
which, at some former period, has evidently been the north bank of the river, but
which is now, for a considerable distance, more than a mile distant. The base
of this cliif is from 30 to 40 feet above the ordinary level of the river.
It is proper here to take some notice of those curiously shaped stones in the
valley of Allan Water, known by the popular name of Fairy Stones. They are most
commonly in the form of flattened spheres, and, though generally separate, they
are sometimes united together. They consist of a brownish- white clay, hard in
the mass, though easily scratched with a knife. They effervesce very briskly
with acids, and they appear from their colour also to contain a small proportion
of iron. They are found in the channel, but more frequently on the west bank of
the river, at the edge of the stream.
Various opinions have been offered, to account for these stones ; some sup-
posing that they are formed, like stalactites, by the dropping of water ; others,
that they are fragments of some hard rock, worn by aqueous attrition. My own
opinion is, that they are mere concretions in finely laminated clay, of which
there is a large bed on the west bank of the river. But deferring till next part of
this Memoir, the grounds of this opinion, I may only here mention, that the bed
of clay from which these fairy stones are derived, is overtopped by a mass of
gravel, the weight of which, aided by the infiltration of water, causes constant
slippings into the river. The clay thus exudes or is squeezed out into the stream.
The clay is extremely tough and plastic. It resembles exactly the clay found
near Berwick, on the left bank of the Tweed, where stones of the same lenticular
shape are found. In both places the clay is finely laminated, and equally tena-
cious, indicating originally deposition in still waters.
In the channel of Kale water, near Morebattle, stones, having characters in
many respects similar to those just described, occur, though of a very different shape.
They are not spherical but elongated — sometimes as long as 14 to 18 inches, and
with a transverse diameter of only 3 or 4 inches. They have precisely the same
colour as the fairy stones of Allan Water, and present like them laminae of strati-
VOL. XV. PART III. 6 K
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
tication. They seem also to be derived from a bed of clay on the west bank of
the river.
Before concluding this part of my memoir, I think it right to take notice of
some other phenomena, which have lately been brought into notice by the indus-
try of Mr KEMP of Galashiels. He was the first person who drew attention to a
number of terraces, on the sides of hills in the neighbourhood of that town ; and,
on examining the relative levels of these terraces with an instrument, he found
almost no case in which a terrace on one hill did not correspond in level with one
or more terraces on other hills. Mr KEMP considers that he has discovered no less
than fifteen or sixteen terraces, at different levels, and maintains that they have had
the same origin as the parallel roads of Glenroy. The height is represented as
being about 1300 feet, and the lowest 500 above the sea ; so that there is, on an
average, about 50 feet of perpendicular height between each terrace.
I regret not having had an opportunity of examining fully these phenomena ;
for though I am by no means convinced of the correctness of Mr KEMP'S conclu-
sion, or of the facts on which he relies, neither is there any thing, on the other
hand, which satisfies me that he is mistaken. In fact, I had myself some years
ago been much struck, when on Ruberslaw, with a terrace near its top, on the
north side, which appeared to correspond in level with one on the Dunion and
another on the Eildon Hills. But it was only with a pocket spirit-level that
I made the observation, and considering the distance of these hills from one ano-
ther, a very small error either in the instrument or in the observation would (in-
dependently of refraction) cause a considerable difference in the levels deduced.
Notwithstanding, however, the difficulty of ascertaining whether these ter-
races were exactly on the same level, it would have been a circumstance strongly
indicative of their supposed origin, had there been no abundance of such marks
on other parts of the same hills. If on twenty hills in the same district there
were terraces all very nearly on the same level, and on no other parts of these
hills, it would have been difficult to have resisted the conclusion, that they had
all been simultaneously produced by a common cause. I soon found, how-
ever, that upon almost every hill-side, there were many such marks, — an obser-
vation fully confirmed by Mr KEMP, who describes no less than fifteen or six-
teen terraces, distant from each other only forty or fifty feet. I was thus
compelled to seek for other evidence of their origin.
I proceeded to examine the ten-aces themselves ; and observed, that whilst
many of them appeared to be perfectly horizontal, several of them had a decided
slope. Indeed, I observe from an account of them by Mr KEMP, with a perusal
of which he has favoured me, that " in almost every case, whether these shelves
are of greater or less extent, their extremities are rounded over, by bending down
hill for some distance ; so that, after repeated examinations, we were at last
obliged to abandon the idea, of water alone having run out those terraces." Mr
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
KEMP then goes on to suggest, that icebergs may, by bumping on the sides of the
hills, have produced the phenomena. But I quote the above passage, as shewing
the opinion of an accurate local observer, that few or none of the terraces in ques-
tion are quite horizontal.
At the same time, it is possible to suppose, that accumulations of gravel and
sand, formed on the beach of a sea, may, by subsequent denudation, have been
worn down in some places so as now to present a surface sloping either from the
hill, or along its side. On the whole, however, the evidence derived from horizon-
tality was so doubtful, that I could not venture to place much reliance on it.
The next point to which I attended, was the nature of the materials compos-
ing these terraces. But I made little progress in this inquiry, as the interior of
them is seldom exposed. From the slight insight, however, which I did get
into the structure of some of them, it appeared to me that they were not sea-
beaches, at least of the character or comparatively modern date which has been
suggested. I found that on Ruberslaw, Dunion, Cowdenknows, and the Eildon
Hills, these terraces were composed chiefly of red soil derived from decomposed
strata of old red sandstone ; and that, in fact, they indicated the upper limits of
this formation. In the small burns and sheep-drains which intersect the terraces
on these hills, soft strata, chiefly horizontal, are to be seen, — in almost all cases
of a deep-red colour ; and, on the north side of the Eildons, containing occasion-
ally a brown-coloured and gritty-coal sandstone. It is, therefore, not improbable,
that these shelves have been formed so far back as the time when the sedi-
mentary rocks just alluded to were deposited, the land being then at least 1100 or
1200 feet lower in level than at present. On that hypothesis, but on that only,
is it possible to explain the fact, that the upper limits of this formation should be
manifested by ten-aces of its debris all nearly, if not exactly, on a level.
So far, then, I am inclined to admit that there is evidence existing on the
Roxburghshire hills, of the sea having formerly stood at a far higher level than at
present. This evidence depends, however, in my humble opinion, entirely on the
fact of the terraces in question being the upper limits of the red sandstone for-
mation ; and therefore it indicates terraces only at one particular level. I can
see no evidence to shew successive levels, at which the sea reposed so long as to
form other beaches, though of these Mr KEMP thinks he has discovered above a
dozen.
I must add, however, that even this evidence of a single sea-beach or sea-
level, is not altogether free from doubt ; for it is not yet to my mind matter of
absolute certainty, that the upper limits of the sandstone formation, as shewn on
the Roxburghshire hills, do all coincide in level. My present impression certainly
is, that they do coincide, at least so near, as to afford strong presumptive evidence
of a common origin. But it would be desirable to test more rigidly the accuracy
of this observation.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
Of course, also, if the sea stood at the height of these upper limits of the red
sandstone formation, it may be expected that, even in places where that forma-
tion was not deposited, some marks should also have been made, and should still be
visible on the hill-sides. The marks there may not be so distinct, for very obvious
reasons ; but still there should have been some abrasion of the greywacke and por-
phyritic hills, similar to what occurs in Glenroy. Mr KEMP will say that such
marks do exist in the neighbourhood of Galashiels ; and I by no means deny this.
On the contrary, it appeared to me, when visiting the locality in company with
Mr KEMP, that on Galashiels Hill, Buckholm Hill, Williarnlaw, Meigle Hill, and
Appletreeleaves Hill, there are marks of shelves, which are on nearly, if not ex-
actly, the same level with the upper limits of the red sandstone formation.
On the whole, therefore, I am strongly disposed to think, that there yet re-
main, on the hill-sides of Roxburghshire, visible marks of the sea having stood at
a level 1100 or 1200 feet higher than at present, and of its having continued at
that level for a very long period. But I see no sufficient evidence of any lower
levels at which the sea was stationary before reaching its existing level.
PART II.
Having, in the preceding parts of this Memoir, described the leading geolo-
gical features of the county of Roxburgh, I shall now advert to the inferences,
of a cosmological character, which these facts seem to authorize or render probable.
1. The first indication of important changes is afforded by the greywacke
strata, — which, after being, like other sedimentary rocks, deposited horizontally,
or nearly so, have been, as if by lateral pressure, pressed and squeezed together,
so as to become vertical, with numerous foldings upwards and downwards, in
alternating order. In consequence of having been thus compressed, they have
formed valleys and ridges, or chains of hills, all running in the same direction,
and which direction throughout the whole extent of the greywacke formation is,
with few exceptions, east and west by compass.
Now, it can scarcely be doubted, that these effects have been produced by
the operation of some force or forces of vast extent, and which could not, in its
operation, have been confined to this particular district. The greywacke rocks
of Roxburghshire form only part of the range which runs through Berwickshire
to St Abb's Head, and through Dumfriesshire and Kirkcudbrightshire to the Irish
Sea, — a range everywhere characterised by ranges and valleys, running east and
west, and by a corresponding strike of the individual beds. It is well known that
the greywacke and clay-slate system of Cumberland, as well as that of Perth-
shire, present characters precisely similar.
These greywacke strata of Roxburghshire were, therefore, in all probability,
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 45'()
elevated and squeezed into their present condition by forces, which acted over a
considerable portion of the earth's crust.
Whether they acted every where contemporaneously, so that the greywacke
hills, in the south of Scotland, were raised at the same instant, as those of Cum-
berland and Perthshire, may be doubtful. For there is no reason why the same
force might not act at different places, at several successive periods. But there
is certainly strong reason for thinking, that it was the same force which acted on
the Grampians, the Lammermuirs, and the Cumbrian chains ; (1.) Because they
consist of rocks, of apparently the same age, having been all deposited before the
epoch of the old red sandstone formation ; (2.) Because the effects on all these
greywacke chains of hills are precisely similar.
What that gigantic force was, or could have been, which produced effects so
remarkable for their extent and their uniformity, is a question too difficult and
too general to be entered on here. One theory is, that these greywacke rocks
were raised by the effects of subterranean heat. Another theory is, that the in-
ternal nucleus of the globe is, from excess of heat, in a molten and liquefied state ;
and that the temperature of this nucleus diminishes faster than the crust, so that,
as the nucleus contracts in size, or even changes in form, the external crust, in
order to accommodate itself to what it rests on, must be broken up, and occupy
smaller space than before.
Without entering upon the discussion of these two theories, I may observe,
that if, as the former implies, the greywacke strata were upturned by volcanic
action, it is reasonable to suppose that there would have been large outbursts of
volcanic rocks among these strata. But, so far from this being the case, the grey-
wacke formation in the south of Scotland, and especially in Roxburghshire, is,
generally speaking, entirely exempt from igneous rocks ; and where igneous rocks
do exist, as in Ayrshire and among the Lammermuir Hills, the adjoining grey-
wacke formation has lost many of its ordinary characters, as, for instance, the
east and west strike of its beds. Indeed, it is not easy to imagine how igneous or
volcanic action could have operated, so as to produce the remarkable parallelism
of chains and strata which distinguishes this ancient formation. The outbursts
of igneous rocks seldom or never form continuous chains, at least of any extent ;
but, according to the theory now alluded to, one would have expected to have
found a central axis of igneous rocks stretching across the island, having on each
side the greywacke strata which it had been the means of raising up.
On the other hand, if, from the refrigeration and contraction of the earth's
nucleus, its crust became rent and broken, it is easy to see how, through these
rents, portions of the molten nucleus might have squirted up, and formed those hills
of granite and other ancient igneous rocks which occasionally occur in, and on
the outskirts of, the greywacke formation. The effects, therefore, which such a
VOL. XV. PART III. 6 L
470 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
cause may be supposed to have occasioned, seem to accord well enough with the
actual phenomena.
If, then, the convulsive movements which the greywacke system has under-
gone, he attributable to changes in the earth's nucleus, these changes must have
occurred in certain lines, so as to have produced the remarkable uniformity
of direction and parallelism which prevails among the ranges and strata of grey-
wacke. But this is a question which lies still beyond the depths of modern phi-
losophy.
2. The next important change in this part of the island seems to have been
the eruption of the felspathic rocks which form the Cheviots, the Eildons, and
those other hills, shewn in the first part of this Memoir as belonging to the same
epoch with them.
It is quite manifest that these felspathic rocks, generally speaking, were
erupted long before the great mass of the greenstones and basalts appeared. The
same remark holds true in most other districts, as there cannot be a doubt that
the felspar rocks of St Abb's Head, Soutra Hill, the Pentlands, the Ochils, and of
the hills near Comrie (Perthshire), burst out long before the augite rocks of these
several districts.
Whether these felspathic rocks were erupted at the same time with, or imme-
diately after, the elevation of the greywacke strata, is uncertain. At all events,
they were not erupted previously, for in many places these felspathic rocks are
seen intersecting the greywacke strata, and in some instances containing por-
tions of greywacke rock. Moreover, those places where the strike of the grey-
wacke strata deviates from its east and west bearing, are mostly to be found near
the Cheviot and Eildon porphyries. At the same time, the outburst of these
igneous rocks seems, to a very considerable extent, to have been controlled by
pre-existing vertical strata of greywacke. Thus, most of the felspathic dykes run
east and west. Even the larger outbursts, as the Eildon Hills, exhibit, generally
speaking, an elongated shape, of which the greater axis runs in the same direc-
tion.
It would appear that felspathic rocks, after then* first great outburst, con-
tinued to be erupted, though in a gradually diminishing degree ; for we have
seen, that a number of felspathic dykes intersect the conglomerate of the old red
sandstone.
3. The next circum stance deserving of attention is, that all the geological
convulsions just described, happened when this district was under the waters of
an extensive ocean.
(1.) The depressions of the greywacke formation produced by the causes
above alluded to, as well as the hollows among the outbursts of felspathic rock,
were gradually filled up with the debris of these several rocks exposed to the
action of submarine currents. In this way beds of conglomerate, consisting of
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 471
rounded pebbles, both from the greywacke and felspathic rocks, were formed ; and
beyond, as well as above these conglomerate beds, strata of sand and mud were
deposited in greater or less abundance.
In regard to the deep red colour by which these conglomerate and other sedi-
mentary beds are characterized, it is pretty plain that it has been derived in some
way or other from the greywacke formation. That the red oxide of iron (in the
state of a peroxide) prevails largely among the greywacke strata, both in the
form of veins of hematite, and diffused through the substance of the rock, has
been already shewn. The disintegration, therefore, of these rocks, would produce
extensive beds, impregnated with iron ; and as such a sediment would be heavier
than pure sand or clay, the beds formed by it would be mostly deposited in the
immediate neighbourhood of the greywacke hills.
This last inference is proved to be correct from this circumstance, that the
red sandstone strata are most abundantly developed, and most deeply tinged along
the flanks of the hills. It is at a considerable distance from them, that we find the
yellow and white beds of sandstone beginning to make their appearance ; and it
is still farther off, before we reach the shales, marls, and sandstones of the coal-
measures, which present little or no intermixture of iron-shot strata.
This seems to be the most proper place for adverting to the probable origin
of those white spots and blotches which are occasionally seen in the old red sand-
stone formation. Dr FLEMING has suggested that they are owing to the presence
" probably of some vegetable or animal organism, the decomposition of which ex-
ercised a limited influence on the colouring matter of the surrounding rock."
Being desirous of testing, by chemical analysis, the soundness of this expla-
nation, I requested my friend Dr MADDEN of Pennicuick to do me the favour to
examine one of those white spheres, and at the same time a portion of the red
stone adjoining it. This experiment he very readily undertook, and the following
is the result.
In Spot. In Red Sandstone.
Silica, . . 67.4 .. 63.40
Alumina, . .
Carbonate of lime, . .
Iron,
Phosphate of iron and alumina,
Alkalies,
Moisture and loss,
100. 100.
Dr MADDEN, in sending this analysis to me, observes, that, " although it does
not shew the difference to be so great as I at first imagined, still I should think,
from the result, that some powerful de-oxidizing agent had been at work, as it
has so completely changed the condition of the iron. In fact, both this and the
472 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
alumina were in the spot in some curious condition, rendering them very diffi-
cult to separate, so that probably their numbers are not so correct as they
might be."
From the foregoing analysis, it appears (1.), that there is in the spot treble
the quantity of alumina which is in the adjoining red stone; (2.) that there is in
the spot, less than half the quantity of iron which is in the red stone ; (3.) that
the iron in the spot is in the state of a protoxide, whilst in the red stone it is a
peroxide ; and, (4.) that there is phosphoric acid in the spot, whilst there is none
in the stone.
There are two ways of accounting for the difference between the spot and
the red sandstone. The peroxide of iron, which prevails through the general
mass of the rock, may never have impregnated the white spot, owing to the
presence in it of some body which had the power of repelling it ; or the per-
oxide of iron may have subsequently, as Dr MADDEN suggests, become de-
oxidized.
In reference to this last theory, it may be observed, that if the abstraction of
oxygen from the iron be ascribed to the action of some body previously existing
in the heart of the stone, does the analysis above given indicate what that body
is ? Dr MADDEN infers that there has been " some powerful de-oxidizing agent at
work ;" but, as he does not surmise what this agent was, it is to be presumed
that he had been unable to discover it. Dr FLEMING, as above mentioned, suggest-
ed that the decomposition of animal or vegetable matter might have decolorized
the stone ; and, in corroboration of this opinion, I may state, that I am in posses-
sion of one specimen, where there is a scale of a Holoptichius in the middle of
the white spot. Now, as this scale consists to a great extent of phosphate of lime,
it may be supposed, that, on the decay and decomposition of part of the scale,
the phosphoric acid would combine with a portion of the iron in the peroxide,
and convert it into a protoxide, which is generally of a whitish-grey colour. But
whilst in this way the change in the state of the iron may be accounted for, what
reason can be given for the other differences between the spot and the stone,—
the larger supply of alumina in the former, and the smaller quantity of iron ?
Farther, it is deserving of observation that it is only in one case out of a
thousand, that any foreign body is discernible in the white spots. And if it is
assumed that a foreign body, such as a fish-scale, be the sole cause of the spot,
why should its form not correspond with that of the fish-scale, instead of being an
exact sphere, which is the form universally exhibited ?
I cannot help thinking that the formation of these white spots belongs to the
same class of phenomena as the blanching process which takes place along the
sides of fissures or cracks in the old red sandstane rock. On each side of the
crack there will be found, on breaking off a portion of the rock, to be a ribbon of
a greenish- white colour which fringes the red stone. It appears to me that this
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 473
is clearly a chemical process, by which the red dye has been to a certain depth
discharged,— or, in other words, the iron changed from a peroxide to a protoxide.
If this process could be discovered, we should in all probability have a clew to the
problem of the white spots.
I may observe, that along these cracks in the red sandstone, there is often a
large development of metallic incrustations, having a dendritic form. The iron
seems as if it had been withdrawn from the general mass of the stone through
which it was diffused, and that thereby the stone was restored to its original
white or greenish- white colour. Appearances similar, or at least analogous, to
these, are common in the red sandstone rocks, when in contact with or near trap
rocks, which had risen through them. The red rocks, in such a situation, acquire
a brown and sometimes even a yellow colour ;* and on examining with a micro-
scope the structure of the stone, particles of iron are found in a state of crystal-
lization, instead of being equally diffused through the whole mass.
If heat has produced these last mentioned effects, it may equally have pro-
duced the similar change which has taken place at the sides of cracks ; assuming
that these cracks were formed during the desiccation of the rocks, by the influence
of subterranean heat.
In several specimens, now before the Society, of these spherical spots,
there is a metallic-looking pea in the centre, which would seem to indicate that
the iron previously diffused through the spot, had become aggregated into the
centre. If, as in the cases just referred to, heat was capable of making the iron
separate from the general mass of the stone and form metallic incrustations, might
it not have produced the analogous effect in the spot ?f
* Two places, not far from one another, where these effects may be observed, are on the right bank
of the Tweed, one opposite to Merton House, at the Craigoer rock, and the other opposite to Dryburgh,
at the Holm House.
t When this part of my Memoir was going through the press, I wrote a note to Dr MADDEJ»T, stating
shortly the views expressed in it. From his answer I make the following extracts, as containing some
important suggestions : —
" I have just received your note, and, having considered its contents, would offer the following obser-
vations. The idea that suggested itself to me at the time of the analysis was, that the deoxidizing agent
producing the white spots, must, in all probability, have been a portion of organic matter in the act of
decomposition, — this may have been a fish bone or scale, or any other organized body ; there are, however,
certain objections to this view of the matter, which I will now state.
" 1st, If the spots were produced by the decomposition of any substance imbedded within its mass,
the effect would be produced with greatest effect in the immediate neighbourhood of the decomposing
body, and this effect would gradually diminish in intensity as the distance increased ; whereas, in the spot,
there is an abrupt transition from the deoxidized to the unaffected mineral.
" 2d, As the intensity of effect would bo proportioned to the decomposing mass, and as the distance
to which the effect was produced would likewise be proportional, the exterior of the spots should possess
a shape either exactly or nearly similar to that of the organic body inclosed ; whereas, the spots in ques-
tion are, without exception, nearly spherical.
VOL. XV. PART III. 6 M
474 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
(2.) Allusion has just been made to the coal measures, as being separated
from the greywacke formation by the old red sandstone group of rocks. I have
explained, in the former part of this Memoir, that I do not consider the coal-
measures of this district as forming, with reference to the old red sandstone, a
separate and independent formation. On the contrary, it appears to me, for the
reasons already given, that the two merge into each other by insensible grada-
tions.* It is evident indeed, that, supposing the materials of both groups of rocks
to have been derived from the same quarter, they would arrange themselves pre-
cisely as they are found to exist, viz., first the sediment loaded with peroxide of
iron, and afterwards the finely comminuted clays which afterwards constituted
the shales and limestone.
In regard to the old red sandstone rocks of this district, I may farther observe,
that they appear to present the same general characters, and even the very varieties,
" 3d, The fact of the spots being annularly stratified, the rings being in most cases distinct, and
easily separable by cleavage, militates somewhat against the hypothesis of the creating cause being placed
in the centre, because it is generally found that annularly stratified masses grow by deposition upon a
central nucleus ; whereas, when a central substance influences a surrounding mass, previously deposited,
a section generally exhibits radiations in place of rings.
" With regard to your other suggestion, it is exceedingly probable that the iron was brought in con-
tact with the calcareous sand, in the form of a solution of protoxide, and that the protoxidation was an
ulterior effect, possibly of heat. I do not, however, see exactly what state of things could exist so as to
prevent the protoxidizing of particular spots, and, at the same time, to change so materially their structure.
Some very interesting experiments have suggested themselves to me, by which I fancy we could arrive at
a somewhat satisfactory conclusion respecting1 their origin and formation. I cannot, however, as yet pro-
mise to undertake these experiments."
I had suggested, in my note to Dr MADDEN, whether clay or sand, deposited in water which held
protoxide of iron in solution, would not, on exposure to heat, acquire a red colour, like common bricks or
house-tyles when put into a kiln ? The only difficulty is, to explain how, in particular spots, the per-
oxidation of the iron was prevented or subsequently neutralized. But if organic matter of any kind, (such
as fish-bones or scales), containing phosphoric or carbonic acid, existed in these spots, then their organic
matter would become gradually decomposed, and the acid being set free, would combine with a portion of
the iron to form a protoxide, and thus discharge the red colour.
So also, in regard to the cracks and fissures, on each side of which there is a ribbon of a white or
greenish-white colour, — may the peroxide originally, in that part of the stone, not have combined with the
carbonic acid of the air and water, permeating these cracks, and produced similar effects ?
* LORD GKEENOCK, to whom, as a member of Council, this Memoir was referred for examination, has,
in reference to this point, written on the manuscript the following remarks : " According to Miller, who
quotes the opinion of Agassiz, the remains of Holoptychius are characteristic of the upper beds of the
old red sandstone, the inferior beds being distinguished by different organic fossils, viz., the midstone or
cornstone formation, by the Cephalaspis, and the lower by Ptericthys, Coccosteus, Diplopterus, &c.,
each formation having its distinct group. Therefore, the remains of Holoptychius only having been
as yet noticed in Roxburghshire, is a strong confirmation of Mr Milne's views in respect to there being
little, if any, difference in age between the two descriptions of sandstone which he has noticed as existing
in that county ; scales, &c. of Holoptychius being likewise met with in the coal formation." G.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 475
by which they are characterised in other parts of Scotland. 1°. In Fife and Moray-
shire the formation is described as consisting of yellow, grey, and dark-red beds,
the first of these being the highest, and the last the lowest in the series. It has
been seen that these varieties, and in the same order, characterize also the old
red sandstone formation of Roxburghshire. 2°. In Fife this formation is overlaid
by the coal-measures, just as in Roxburghshire. 3°. The remains of the Holopty-
chius, and of a smaller fish much akin to it, which characterize the old red sand-
stones in the North of Scotland, have been found among the red rocks of Rox-
burghshire, in several localities. It is also not a little remarkable, that these fos-
sils should be found throughout Scotland, characterizing only the red and yellow
beds,* but not the intermediate grey beds.
(3.) It has been assumed in the remarks above made, that the strata of the
coal-measures in this district have been derived from the finer debris and sedi-
ment afforded by the grey wacke and felspathic rocks. It is well known that these
ancient rocks contain, in general, all the elements which are necessary to form
beds of sandstone, shale, limestone, and magnesia. -j- The porphyritic rocks of the
Cheviot do in many places contain lime (at least they effervesce with acids^), as
also great abundance of silica and alumina. At the same tune it is difficult to
perceive how these different substances, brought simultaneously, and forming a
common sediment, could have been deposited in separate beds of pretty uniform
thickness, and of great extent. It seems more natural to suppose, that all the
particles of these different substances, mechanically suspended, were deposited
promiscuously in one common mass ; and that some movement of the particles
afterwards took place, probably according to their respective chemical affinities.
Some of the elements which now occur in the strata, of course, were held by
the water in solution, as, for instance, carbonate of lime and carbonate of mag-
nesia ; and it is not difficult to conceive how these may have been precipitated
according to circumstances.
Thus, the extensive beds of chert limestone, the thin beds of magnesian lime-
stone, and the nodules and veins of gypsum or sulphate of lime, which occur (as
was shewn in the first part of this Memoir) only near great sheets of porphyritic
trap, probably owe their origin to the great and long-continued heat in those places
where they occur. It is well known to geologists, that the frequency with which
gypsum and magnesian limestone or dolomite are associated, has long been mat-
ter of speculation, — a circumstance which, as Sir HENRY DE LA BECHE observes,
* For an account of the Fife fossils, see the Rev. Mr ANDERSON'S Memoir, published in the High-
land Society's Transactions ; and of the Moray beds, see Sketches by PATRICK DUFF, Esq.
f DE LA BECHE, Manual, p. 450.
{ The porphyry at Plewlands effervesces very briskly, and must contain a large quantity of lime.
476 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
" has not been satisfactorily accounted for." * In the work now quoted from,
Sir HENRY refersf to the opinion of VON BUCH, that the dolomite of the Alps and
some other places is an altered rock, and has been acted on by the augite por-
phyries, Avhich contain magnesia, and from which, therefore, the magnesia may
have been derived. If the magnesia has been derived only from the porphyry,
it is not easy to understand the transmission of it to beds at a distance from the
porphyry. It seems to me more natural to suppose, that the water diffused
through the sedimentary deposits held magnesia, as well as other substances, in
solution ; and that, by an excess or long continuance of heat, a precipitate was
caused, which would be diffused through the beds, and act as a cement to the
particles of silex and alumina, and other substances which had been mecha-
nically deposited. The same remark I would apply to the beds of chert at Had-
den, Bedrule, and other places, containing nodules of chalcedony and of lime,
which can scarcly be doubted to have been chemical precipitates. In like man-
ner, the nodules of red and the veins of white gypsum which occur in the marl
strata, may be easily supposed to have been thus formed.
The abundance of lime, in one form or other, existing in the sedimentary
rocks of the district, is very extraordinary ; and appears to be due to some other
cause, than the mere wearing down of the Cheviot porphyries. For though, as al-
ready mentioned, these porphyries occasionally effervesce with acids, the quantity
of lime thus indicated, bears no proportion to the quantity existing in the old red
sandstone and carboniferous formations. There are few places, where the sand-
stones of both sets of rocks do not effervesce. The red sandstone at Lochton,
about two miles east of Kelso, yielded on analysis 25 per cent, of lime.:): The well-
water at Eccles Manse, in Berwickshire, shewed, out of 100 parts, 57.75 of sul-
phate of lime, and 29.75 of common salt. It seems to me, therefore, that the
waters in which these sedimentary rocks were deposited, and which continued to
saturate the sediment out of which they were formed, must have contained in
chemical solution a large proportion of lime.
Allusion was made in the first part of this Memoir to the existence of "yokes1''
or large concretions, not merely in the igneous but also in the sedimentary rocks,
and especially the sandstones. The formation of these harder portions seems due
to chemical action of some sort, excited probably by heat.
I am disposed to ascribe to the same cause the formation, at least in many
instances, of beds of homogeneous matter. It is difficult to imagine how strata,
which sometimes extend uninterruptedly over large tracts of country, and pos-
sessing a remarkable uniformity of thickness, could have been formed by the mere
* Manual, p. 478. t Ib. p. 475.
\ Analysis by Dr THOMSON, given in London's Mag. of Nat. History.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 477
mechanical deposition of different kinds of sediment. I cannot help thinking
that substances of the same nature, and having chemical affinities, have after-
wards arranged themselves into beds. I have, however, no evidence to adduce
in support of this view, and I offer it as little better than a conjecture to account
for a problem in geology, which, it appears to me, has not yet been solved. But
it has always appeared to me that geologists have taken too little into account
the important effects which might result from chemical action continuing for a
long period to modify the arrangement and character of the sedimentary strata.
4. After the deposition of the red sandstone and carboniferous rocks, another
outburst of igneous rocks took place, — of all kinds. The amygdaloid and breccia
of the Eildon Hills, of the Minto Hills, of Bedrule, of Ancrum Crag, and Wooden
Burn, then flowed up, as well as those great coulees of porphyry already refer-
red to.
Many, indeed most, of these newer volcanic rocks are in contact with, or in
the immediate neighbourhood of, igneous rocks of a much older date. But this is
just what might have been expected, as those parts of the earth's crust, once
burst through, would continue to be weak points, and afford less resistance than
others to the expulsion of volcanic matter.
Besides those eruptions of trap, which now form hills and coulees, there be-
long to the epoch now referred to, the greenstone and basaltic dykes. It is a curi-
ous circumstance that these dykes all run very nearly parallel to one another,
viz. about west-north-west by compass ; and that this also is the direction of all
the principal dykes in Northumberland and Durham. Further, it is deserving of
remark, that the Hawick dyke, which I have traced for above 26 miles continu-
ously, and at its south end crosses the Cheviot range of hills, appears to coincide
with one or other of the basaltic dykes running into the sea on the Northumber-
land coast. Mr Wood,* in his account of the rocks on the shore between Berwick
and Newcastle, speaks of a basaltic dyke near Howick running N. 58° W.,f and
which, whilst it agrees in direction with the Hawick dv-ke, seems to cut through
the Cheviots not far from the place where the Hawick dyke runs. If the conclu-
sion to which these circumstances point, be verified by a farther examination of
the course of this dyke, it will then be found to stretch in one unbroken line for
at least 50 miles, and without at either end shewing any signs of cessation.:):
* Transactions of Newcastle Natural History Society, vol. i. p. 308.
t Mr WOOD'S statement is N. 83° W., which, it is presumed, are true bearings.
J Mr ADAM MATHESON, millwright, Jedburgh, already referred to for his geological zeal, has lately
afforded additional proof of this, by actually attempting to trace the dyke from the Scottish Border through
Northumberland to the sea. Having intimated to me his intention of setting out on this voyage of dis-
covery, and asked me for instructions, I sent him out a map, compass, and other necessary implements.
He writes me, that he hired a horse at Jedburgh, and set out from Hindhope along the line which, at that
VOL. XV. PART III. 6 N
478 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
These dykes appear to indicate the production, by some cause or other, of
very extensive cracks in the earth's crust, which were afterwards filled up by
igneous matter injected from below. But for such cracks, the whin dykes de-
scribed in the former part of this Memoir would not have existed.
I am aware that on this point there may be difference of opinion ; as in geo-
logical treatises these dykes are generally explained on the supposition that the
igneous matter, by being forced up, produced the crack. But in opposition to this
view, I submit, — (1.) That if the igneous matter was forced up through the sedi-
mentary stata, where there was no previous rupture, the edges of these strata
would, in almost all cases, have been turned upwards on each side of a dyke.
Now, this is not the case in any of the dykes of Roxburghshire ; and though I have
seen elsewhere, cases where the strata were inclined upwards to the dyke, and also
where they have dipped down towards it, these rare cases can be explained by
subsequent vertical movements of the strata on one side or other of the dyke.
(2.) I have to observe, that if igneous matter was erupted through strata, where
there was no previous fissure, it would all flow out at the place where it first got
vent, and would never form a narrow dyke only 20 feet wide (which is the average
width of the Hawick basaltic dyke), and intersecting the country in a line very
nearly straight.
On these two grounds, it seems to me perfectly clear, that at or shortly before
the eruption of the greenstones and basalts, some great convulsions took place, by
which the earth's crust was rent and ruptured, just as it had been at a former
period, and that through these rents portions of the earth's molten nucleus were
again ejected.
If the theory of ELIE DE BEAUMONT, before referred to, be well founded, that
the elevation of mountain chains, and the protrusion of the ancient trap rocks, is
caused by changes in the shape or volume of the earth's nucleus, — then the same
theory seems sufficient to explain the production of rents, and the injection of
these rents with igneous matter at a later epoch. Assuming that these last con-
vulsions may be accounted for by changes in the earth's nucleus, it is deserving
of remark, that these changes were not precisely similar to those which had pre-
viously occurred ; and, moreover, that the substance of the nucleus itself must
have undergone some alteration. At least, the matter erupted from it is ex-
tremely different, — there having been felspathic rocks in the first instance, green-
place the dyke appeared to run in. He has returned the map to me, having marked on it the places where
he recognised the dyke. From his account, it appears to run by Clennel, Borrowden, Whittle, Dibden,
Framlington, and Acklington. This last point is about seven or eight miles from the sea, — and beyond it
MATHESON did not proceed in his search. Though the dyke is reported by him to present a very variable
direction and width — its average direction and width seem to agree with its character in these respects in
Roxburghshire. The dyke at Howick, mentioned by Mr WOOD, cannot therefore be the Hawick dyke,
though it runs parallel with it, and about twelve miles to the north.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 479
stones and basalts in the second. Moreover, whilst, during the former period of
eruption, the lines of fracture were invariably east and west, on this last occasion
they were west-north-west and east-south-east. Nor is this last direction merely
that of the trap dykes ; for it has been seen that there is one set of fissures or
joints in the rocks themselves, and which pervade all the strata, from the oldest
to the newest, running in much the same direction. If any explanation of these
combined and complex phenomena is to be sought, on the hypothesis before re-
ferred to, we may suppose that the shape of the earth's nucleus changed, so as to
become, immediately below this part of its surface, more convex than before, and
to form a sort of ridge running in a west-north-west direction. The pressure of
this bone of the nucleus on the outer skin, would have a tendency to produce frac-
tures or cracks immediately above it, and in lines parallel with itself; whilst
through these cracks molten matter would gush out, and form both dykes and
coulees. At the same time, so much heat would be communicated to the whole
of the rocks, both stratified and unstratified, composing the earth's crust, that
chemical affinities would be called into action, the matter of these rocks would
begin to re-arrange itself, and thus multitudes of minor cracks in these rocks
would be produced, which would approximate to a west-north-west direction, — that
being, in the circumstances above described, the line of greatest weakness.
5. The next important epoch, in the history of those convulsions to which
this district, in common with the rest of the island, was subject, is connected with
the formation or deposition of the clay, gravels, sands, and boulders which cover
the rocks. To this class of phenomena much interest attaches, not merely from
the general and abstract difficulty of explaining them, but also from the attempt
which has recently been made, supported by great zeal and talent, to account for
them all by glacial action.
Now, I freely admit that the problem is exceedingly complex, and that, there-
fore, every attempt to solve it should receive due consideration. Nor do I pre-
tend to say, that any explanation of all the phenomena presents itself, which is
quite satisfactory even to my own mind. But, whatever the true theory may be, of
one thing I am satisfied, that glaciers could not have transported the boulders, or
produced the remarkable accumulations of gravel and sand which occur in this
part of Scotland.
(1.) What cause can be suggested for the transportation of the numerous
boulders strewed over Roxburghshire, and especially the blocks of granite which
occur in Liddesdale ?
In the previous part of this Memoir, when noticing the situation of the boul-
ders, to whatever species of rock they belong, I shewed that the parent rocks
were, in all cases, to the westward of the boulders.
In some of these cases, the situation and relative levels of the parent rocks
and the boulders are such, that there is, on that account, no impossibility in sup-
480 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
posing transport by a glacier. But in other cases, and these the most frequent,
such a hypothesis is altogether inadmissible.
Take, for instance, the case of the granite boulders of Liddesdale, which are
found strewed all over the country, between the Carter on the east and Canonby
on the west.
These blocks, it is certain, have, by some means or other, been brought from
the westward. The only places, in this part of the island, where granite, either
red or grey, is known to exist, are in Cumberland, Kirkcudbrightshire, and Gal-
loway. The nearest of these places is Criffel ; and it certainly appears to me, on
comparing the granite boulders of Liddesdale with the granite of Criifel, that they
are identical.
If this be the case, there is an end of the Glacial Theory, as affording either
a probable or possible explanation of the phenomenon. For, in the first place,
who ever heard of a glacier 40 miles long, — that being the distance of Criffel
from the upper part of Liddesdale ? Moreover this glacier, in order to have trans-
sported Criffel granite to the hills round Castleton, and near the Carter, must
have moved inconsistently with the natural levels and drainage of the country,
these being from Criffel, generally speaking, towards the south and south-west,
and not towards the east. A glacier which transported granite blocks from Crif-
fel to the hills of Liddesdale, besides having been 40 miles long, must have crossed
the valleys of the Nith, Annan, Esk, and Tarras rivers, as well as the high ridges
separating them ; — it must have done so, without having any lateral barriers to
retain and guide it ; — and, lastly, it must have moved up the valley of the Liddel
for at least 15 miles of its course.
Discarding, then, the glacial theory as quite insufficient to account for the
transportation of the granite boulders of Liddesdale, — and of several other of the
oases noticed in the first part of this Memoir, are there any other means of trans-
portation which can plausibly be assigned ?
Before offering any suggestions on this point, I beg here to allude for a moment
to another general feature of the district, as tending to throw some light on the
question, — a feature well known to prevail in many other parts of the island. I
allude to the fact, that almost all the hills present precipices of bare rock towards
the west, and tails of gravel on the east ; — a phenomenon, as already mentioned,
first prominently noticed by the late Sir JAMES HALL. This, by the way, is one
of those things which the glacial theory not only fails to explain, but which is
entirely at variance with it ; for if it is alleged that the hills were bared by gla-
ciers, the precipitous sides should always be towards the highest part of the coun-
try from which the glacier descended ; so that, in Liddesdale, they ought to be
towards the east, instead of being, as they all are, towards the west.
The phenomena now adverted to shew, I think, pretty clearly, that, at a
comparatively recent period in the history of the earth, there was some vast rush
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 431
of waters from the westward, which bared most of the hills on that side, leaving
or depositing on their opposite or lee sides, vast accumulations of sand and gravel,
containing, in many cases, large fragments of rocks.
The question, then, is, could such a rush of waters have transported from
Criffel to Liddesdale the rounded boulders, some of them 3 or 4 tons in weight,
which are now to be seen there ?
In answering this question, I refer to the Geological Manual* of Sir HENRY
DE LA BECHE, for the following facts, which are the more valuable, as not ad-
duced by him in support of any theory, but are given merely as illustrations of
the power of water to move heavy bodies. He says, that at " Plymouth, during
the severe gales of November 1824, and also of the commencement of 1829, blocks
of limestone and granite, from 2 to 5 tons in weight, were washed about on the
Breakwater like pebbles : — about 300 tons, in blocks of these dimensions, being
carried a distance of 200 feet, and up the inclined plane of the Breakwater. A
block of limestone weighing 7 tons was washed round the western extremity of
the Breakwater, and carried 150 feet. Two or three blocks of this size were
washed about." I may be permitted to add, that, having visited Plymouth a
few months ago, I was shewn by Mr STEWART, who has charge of the Break-
water, several blocks, from 7 to 10 tons in weight, which, in the storm of January
last, had been moved from 15 to 20 yards.
These effects of aqueous action become less surprising, when it is considered
that a granite block of 5 tons weight in air, weighs only about 3 tons in salt water ;
and, moreover, that the power of a current to move a solid body increases as the
square of its velocity. So that, as Mr HOPKINS has observed in a paper recently
read by him in the Geological Society, " if a current of ten miles an hour would
move a block of 5 tons, a current of twenty miles an hour might, under similar
circumstances, move one of 320 tons." Mr HOPKINS, in the paper just alluded to,
has given an account of the boulders in Yorkshire, which have been transported
from Cumberland, and has adverted to the different theories by which that trans-
port is accounted for. He gives it as his opinion that these boulders, as well as the
whole mass of diluvium with which they were associated, were transported whilst
the country was under sea ; an opinion which I had myself very confidently em-
braced and advocated, long before I had heard of Mr HOPKINS' views. He explains
in his paper, not only the efficacy of currents of a given velocity to move and
transport blocks, but the mode in which such currents may have been produced ;
and, finally, he does not " hesitate to affirm the entire adequacy of such a cause
to transport all the erratic blocks derived from the Cumbrian mountains, and
therefore to conclude, that such has been the agency by which that transport has
actually been effected."
* Page 82.
VOL. XV. PART III. . 6 O
482 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
In regard to what might have caused a current of 10 or 12 miles an hour,
Avhich seems sufficient, according to Mr HOPKINS, and according to the facts also
related by DE LA BECHE, for the transportation of boulders, various suggestions
have been offered. The most probable cause seems to be, a submarine eruption
to the west of Great Britain, of sufficient magnitude to produce a great wave. At
the time of the Lisbon earthquake in 1755, the focus of which is supposed to have
been about 100 miles to the westward, a wave was produced, which, when it
broke on the coast of Portugal, was from 40 to 60 feet high. This wave reached
the British Islands in about six hours, having travelled at the enormous rate of
about 150 miles an hour ; and on entering the different harbours in the south
shores of England and Ireland, broke the moorings of almost all the ships at
anchor.
It is related by Sir WOODBINE PARISH, that during the earthquake which de-
stroyed Callao in 1678, the sea, after first retiring, rose with such violence as to
carry " three ships, about 60 or 100 tons," — " over the town, which then stood on
a hill."
" In 1746 Callao was again destroyed by an earthquake- wave, vast heaps of
sand and gravel occupying its position. All the ships in the harbour, except four,
foundered. One of these, a man-of-war, was found in the low ground of the Up-
per Chicara, opposite to the place where she rode at anchor, and near her the St
Antonio. Another of these vessels rested on the spot where before stood the Hos-
pital of St John, and the ship Succour was thrown up towards the mountains."*
These accounts of the enormous size of the waves, which are formed during
many of the South American earthquakes, are fully corroborated by Mr CALD-
CLEUGH'S account of the earthquake, by which Talcahuano was destroyed in 1835.
There were several waves which then rolled in upon the land, apparently ex-
ceeding 40 feet in height.
With reference to these cases, however, it deserves to be remarked, that they
prove only the power of moving water to move blocks, — not to transport them, at
least for any considerable distance. The wave of translation referred to by Mr
HOPKINS, and as described in Mr SCOTT RUSSELL'S valuable papers on waves, pro-
duces only a momentary current at the place affected by the wave. There is a
forward propulsion of the aqueous particles only for a short distance, correspond-
ing with the width of the wave. The wave travels on, leaving behind it, the par-
ticles so moved. In like manner, a body immersed in the water, even of only the
same specific gravity with it, would be pushed forward but a short distance, and
left there. Of course, therefore, a block of granite, though it might readily be
moved, would not be transported more than a few feet by any single wave, how-
ever great in size or rapid in motion.
* Abstract of Geological Society's Proeecdings for December 1835.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 483
But whilst I think it fair to notice these circumstances, as creating in my
mind some difficulty in understanding how an earthquake- wave can transport
boulders, I admit that the opinion of such mathematicians as Mr HOPKINS and Mr
SCOTT RUSSELL, who concur in ascribing a transporting power to such a wave, is
deserving of all reliance. The views of the former I have already stated ; and to
shew the views of the latter gentleman, I may be allowed to quote the following
passages from a correspondence I have had with him on the subject. " The valu-
able application," says Mr RUSSELL, " which Mr HOPKINS has made of our know-
ledge of the laws of the great wave of translation, is in perfect accordance with
all the phenomena I have examined in my observations on this class of waves.
In the first place, Mr HOPKINS' mode of genesis of the wave, is identical with a
method of genesis which I have adopted in experiment, viz., the upheaval of a
considerable surface on the bottom of the channel. Suppose a depth of ocean of
400 feet : then, according to my experiments, the velocity of transmission of the
wave would be 77 miles an hour. But if the wave were of a height of 50 feet
above this level, the velocity of the wave would be increased to 84 miles an hour.
The velocity of translation of such a wave could attain a maximum of 27 miles
an hour. This represents the current of the particles of water tending to move
an obstacle at the moment when the highest part of the wave is passing." " It
is perhaps important to observe, that the transporting power of such a wave will
be greatly facilitated by encountering a gradual shallowing and contracting of
the firth or channel into which it enters, as in the case (viz. the granite boulders
of Liddesdale) which you have applied this force to explain.
" There is an additional view of this subject I may suggest to you, viz., that
on a hard or rocky surface, the chances are much in favour of the large block.
The tendency to crush an opposing obstacle, increases with the weight, or is as 26 ;
this being of a given size, both for the little and the large boulder. Further, there
is a gain of moving force, which is as the distance from the centre of gravity of
the block from the obstacle. This again gives us an increased chance in favour
of the large block as 2 : 1. Hence, on hard ground, the chances of motion, and
of continuing in motion, are greatly in favour of the large block."
On writing Mr SCOTT RUSSELL, to suggest whether his wave of translation,
though it should move the block, would not then pass and leave it behind, I re-
ceived an answer from which I quote the following passage : — " I see some diffi-
culty in getting the large boulder into motion, but little in keeping it going, after
it has set out. If you start it by a gentle slope, then the water would have no-
thing to do but give it way. A hard and tolerably even bottom, like a level strati-
fied rock, would greatly facilitate the locomotion ; and as to its being bedded in
mud or earth, why, the rushing of the waters past the boulder would soon clear
that away. Besides, the presence of a column of water, or a wave 20 feet high,
would be more than equal to the whole weight of such a boulder as you describe ;
484 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
so that the height of the impinging column would certainly be ample for its pro-
pulsion. Reckoning your granite boulder at say 5 feet diameter, a column of
water 15 feet high would give a dynamical action on it, greater than its entire
weight in air, and of course equal to its propulsion on any surface, — 2.5 is, I think,
about its specific gravity."
Mr SCOTT RUSSELL thus distinctly concurs with Mr HOPKINS as to the trans-
porting power of a wave produced in the way above supposed ; and if these opi-
nions are well founded, then there seems no difficulty in explaining how the granite
boulders of Liddesdale were brought from Criffel.
But, in addition to waves in the ocean, produced by submarine earthquakes,
there must have been currents, which, if of sufficient rapidity, must, as it appears
to me, have been still more effectual in accomplishing the results in question.
That currents, and of great force and extent, existed in the ocean which, at the
epoch of these boulders, covered the district, is proved by the bared western faces
of the hills, and the residuum of diluvial debris on their east sides ; and it will
by-and-by be shewn, that these debris could have been spread over the entire
country, by no other cause than currents of water. The origin of these currents
— all from the westward — it is certainly difficult to account for ; but the fact of
their existence seems indubitable, and also of their having had such a force and
velocity, as is quite sufficient to have transported boulders.
(2.) The next phenomena to be noticed are the accumulations of clay, gravel,
and sand.
In the former part of this paper, I mentioned that the only place where I
had observed the well-known boulder clay, which is so largely developed in Mid-
Lothian, is in the neighbourhood of Kelso. The deposit there is filled with huge
blocks of basalt, greenstone, greywacke, and porphyry rocks, of which none exist
in the neighbourhood in situ. The blocks, by their rounded forms, indicate very
plainly that they have been rolled from a distance ; and as no rocks of the same
characters exist towards the eastward, there is great probability, if not absolute
certainty, that the blocks in question, as well as the clay in which they are im-
bedded, were, by the force of water, transported from the west. The clay is not
stratified, and there are no layers of sand in it. Moreover, the imbedded boulders
are not deposited according to size or weight. Judging from these circumstances,
I should say that this boulder clay must have been deposited by waters of great
power and violence.
Above this boulder clay there is a deposit of gravel and sand, which forms a
skin, as it were, over the whole country. It is to be seen distinctly covering the
boulder-clay at Hadden. The pebbles do not generally exceed the size of the fist.
They are, in every place which is known to me, rounded and apparently water-
worn. There are occasionally extensive beds of sand, which alternate with the
layers of gravel.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 455
This accumulation of sand and gravel, is in all respects so different from the
boulder clay, that it must have been deposited under very different circumstances,
(1.) The boulder clay is almost uniformly the lowest deposit. (2.) It is never
stratified. (3.) It contains much larger fragments of rock than the superincum-
bent beds of gravel.
From these data I infer, that the boulders and clay were transported by tu-
multuous waters, whilst the gravels and sands were deposited in waters compa-
ratively tranquil, though affected by currents.
Now, here the question occurs, Whether the sands and gravel, just alluded to,
were deposited during the rush of waters which bared the west faces of the hills ?
I should be inclined to think, that they had been spread over the country pre-
viously to this event ; and that the effect of that violent and universal rush of
waters, must have been to sweep away a great proportion of these superficial
deposits, leaving undisturbed only those on the east side of hills, and, perhaps,
adding to the deposits there. In confirmation of this last remark, reference may
be made to the enormous accumulation of gravel, on the east sides of the Cheviot
hills (near Palinsburn and Wooler), of the Galashiels hills, and of Lamberton hill
in Berwickshire.
If, then, previous to the rush of waters from the westward, the country had
been overspread with sand and gravel, this would indicate that it must, at all
events, down to the date of that occurrence, have been under the waters of a sea,
which transported sand and gravel from great distances. In no other way is it
possible to account for the extensive beds of sand and gravel, often stratified, which
occur in many parts of Roxburghshire, and particularly in Liddesdale, in situ-
ations far above and beyond the reach of rivers. In some places (as at Max-
ton and Plewlands), pebbles of gneiss have been found in cutting drains, which
must have been brought at least 80 or 100 miles from the west or north-west.
We have seen, that, when the red sandstone rocks were being deposited, the waters
of an extensive ocean prevailed to a height of at least 1100 or 1200 feet above its
present level. The existence of gravel-beds as well as boulders, at much about
the same height, indicates, that, down to a very recent geological period^ there had
been no change in the relative levels of sea and land. When the sea did retire to
its present level, is quite a separate question ; the solution of which in no way af-
fects the soundness of the views above suggested.
It may, however, be asked, How it is possible, consistently with these views,
to explain the origin of the remarkable knolls and ridges described in the first part
of this Memoir, and for the production of which it has been thought necessary to
invoke the aid of glaciers ? It may be conceived how the waters of an ocean
charged with sandy sediments, and rolling along gravel, should form beds more
or less horizontal. But how can they form harrow ridges of sand and gravel,
VOL. XV. PART III. 6 P
486 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
from 40 to 50 feet high, and running for half a mile in nearly a straight line (as
is the case in Liddesdale), or for nearly two miles in a curved line, as in the case
of Dogden Moss in Berwickshire ? *
It is with the view of obviating these apparent objections, that glaciers have
been suggested ; as the agent which has produced the remarkable knolls and
ridges just referred to, — and which is said to be in Switzerland at this moment
giving rise to phenomena exactly similar.
But here, as it humbly appears to me, lies the fallacy of the explanation. I
do not believe that the accumulations of debris formed by glaciers, are exactly
similar to the knolls and ridges in this country above referred to. In outward
form they may be similar. Farther, they may often be in situations, precisely
analogous to those occupied by the moraines of Switzerland ; thotigh, assuredly,
they are also as often in situations, where no moraine, terminal, medial, or lateral,
is ever seen in Switzerland. But, in the internal structure of these gravel heaps,
and in the nature of the materials composing them, there appears to be a total
and entire dissimilarity.
All the knolls and gravelly ridges which I have seen in the border counties,
contain stratified beds of sand and fine gravel, which seem to me unequivocally to
demonstrate, that they were deposited by water ; and by water which, judging
from the form and nature of the pebbles, must have rolled them from a great dis-
tance. Now, it would appear, that moraines have a totally different structure.
There are in them no stratified beds of sand or gravel ; and the fragments are ge-
nerally angular. Thus, AGASSIZ states (I quote from a very good abstract of his
views lately published by Mr MACLAREN, a Fellow of this Society), that " The ma-
terials of moraines are not stratified, but huddled together in confusion. The frag-
ments are generally somewhat rounded by mutual attrition ; but some are angu-
lar. They may be distinguished from the banks of gravel formed at the margin
of lakes, by their internal structure."! To the same effect, Mr CHARPENTIER, in
an article published in the last number of Professor JAMESON'S Journal, says,
" The sedimentary deposits, whether stratified deposits of pebbles, sand, or day, are,
in my opinion, not the erratic formation (formed by glaciers), but diluvium, that
is to say, a sediment whose materials have been conveyed and deposited by mater"
On the same page, he adds, that " erratic deposits can always be distinguished
from the diluvium, by the frequency of well preserved angular debris."
If, then, according to the admission of the two greatest advocates of this
Theory, the accumulations of gravel formed by glaciers are characterized by
frequency of " angular debris ;" and if, as they also admit, stratified beds of
* For an account and surface-plan of Dogden Moss Kaims, see Paper by me, published in the
Transactions of the Highland Society for 1836.
t Glacial Theory, by Mr MACLAREN, p. 14.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 487
pebbles and sand could only have been deposited by water, then it cannot be
doubted by any one, who looks at the internal structure of the ridges of Liddes-
dale and of Kelso in Roxburghshire, or of Dogden Moss, and of Dunse, in Ber-
wickshire, that they must have been formed by aqueous and not glacial action.
These kaims, I may here observe, are not of rare occurrence, either in this
country or abroad, though, considering their very singular appearance, it is re-
markable how little the origin of them has, till lately, been speculated on. I
have mentioned two remarkable examples in Berwickshire, in addition to those
in Roxburgh ; and, probably, many persons here may have seen the one at Camp-
end,* about two miles north of Dalkeith. There is another to the south-west of
Arniston, near the Moorfoot Hills. In the State of Maine, in North America,
there is a ridge provincially termed Horseback, which Dr JACKSON, the State geo-
logist, says " consists of sand and gravel, built up exactly like the embankments
for railroads, the slope on either side being almost 30°, while it rises above the sur-
rounding lowlands to the height of 30 feet, its top being perfectly level, and wide
enough for two carriages to pass abreast." In the same district, there is another
horseback described as running for no less than six miles, and elevated about 15
feet above the swamps on each side. The horsebacks of New Limerick and
Houlton, in the United States, are much more elevated, some of them being (as is
said)f 90 feet above the adjoining places.
In Scania (a province of Sweden), a number of similar ridges prevail through
the country, a description of which is given in Mr LYELL'S Bakerian Lecture
on the rise of land in Sweden.^ He says that, near Stockholm, " remarkable
ridges of sand and gravel are seen, called in Sweden Sand-oasar. These oasars
are immense banks of sand, from fifty to several hundred yards broad, and from
fifty to more than one hundred feet in height, which may often be traced in un-
broken lines for a great many leagues through the country, but are breached
occasionally by narrow transverse valleys. They usually run in a direction from
north to south ; generally terminate on both sides in a steep slope, and are some-
times so narrow at the top, as to leave little more than room for a road. As they
afford excellent materials for road-making, a great many of the highways in Swe-
den are carried either along the summit or base of these ridges, so that the tra-
veller has many opportunities of observing their form and structure. In places
where they are composed of large rounded boulders, of about the size of a man's
head, no stratification is observable ; but where, as is more usual, they consist of
gravel and fine sand, they are invariably stratified, in the same manner as sand
and gravel in the beds of rivers. I shall offer, in another place, some speculations
* This word is probably a corruption for Kaim-end, — as Kaim is the term by which these elongated
ridges are universally designated in the south of Scotland. The ridge here referred to has been, in several
parts of Mr LAING'S farm, opened, both for gravel and for sand. Its length is about half a mile.
t HITCHCOCK, on Deluges, Part II., p. 103. \ London Philosophical Transactions for 1835.
488 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
on the probable origin of these ridges ; and I have merely alluded to them now, in
order to explain the position of some fossil shells which I am about to describe."
" They (the shells) occur at Solna, about a mile to the north-west of the city,
at the foot of one of the great ridges of sand and gravel before mentioned ; a
ridge which, passing southward, traverses the city of Stockholm, and is said to
have afforded fossil shells in the large pits at the Skantstull, in the southern
suburbs. These pits lie between the church of Solna and the public cemetery of
Stockholm. Both in the pits and in the adjoining ridge, the gravel and sand is
stratified, and in general no organic remains can be discovered in them ; but in
the pits, a little below the level of the road, there are some layers of loam mixed
with vegetable matter, where shells occur in abundance."
Since, then, sea-shells occur, if not in the heart of these ridges, at all events
at the base of them, and in gravel manifestly of contemporaneous origin, it is im-
possible to doubt that, at least in Sweden, these gravel and sand banks have been
formed at the bottom of the sea ; and, accordingly, Mr LYELL had, in the year
1834, no doubt that these oasars were of marine production.
Such being the character of these gravelly ridges, it seems not a little bold
and inconsistent in CHARPENTIER to lay down the proposition (I quote his words),
that " Oasars are Moraines, some having been formed by the oscillations to which
the great glacier was subjected during its retreat, others by the ice which remained
on elevated mountains and table-land, long after the low regions had been freed
from it."*
On the contrary, it humbly appears to me, that these oasars of Scania, like
the horsebacks of America, and the kaims of Scotland, composed as they all are
chiefly of rounded pebbles and beds of sand, must have been formed by water,
and cannot have been detritus, either transported on the surface of, or pushed for-
wards by, glaciers.
Mr POGGENDORFF, in an account of these oasars recently published in his
Annalen, mentions a circumstance which can leave no doubt as to their origin.
He says that they " always exhibit at their northern extremity, and only there, a
fixed standing rock ; a phenomenon which, on the assumption of a violent flood
from the north, has led to the conclusion, that it was these very rocks which, by
affording shelter from the flood, gave rise to the accumulation of the narrow and
far-extending alluvial hills."f
Perhaps I may be allowed to mention, that, when I examined several of the
kaims in Roxburghshire and Berwickshire, it was in company with a valued
friend of AGASSIZ, and an able supporter of his Glacial Theory. Whilst he pro-
nounced at least two of these gravel ridges, viz. that in Liddesdale, and the
* JAMESON'S Edinburgh Philosophical Journal for October 1843, p. 73.
t Ibid. vol. xxiii. p. 72.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 4gg
other at Dogden Moss, to be, the one a lateral and the other a terminal moraine,
he admitted the force of the objections to that theory, founded on the rounded form
of the pebbles, and the existence of sand in the heart of the ridges ; but he con-
tended, that, in these respects, the moraines in question had been altered by the ac-
tion of water, probably derived from the melting of the glaciers themselves ; and
he instanced the formation of small ponds in the glacial valleys of Switzerland,
along the sides of moraines, in which ponds, layers of sand, and even of small
pebbles, are frequently found. But admitting that there may be beds of sand
and fine gravel occasionally formed along the sides of moraines, would this ex-
plain the existence of such stratified beds in the moraines themselves ?
Another objection to this theory, and which seems to me equally decisive
with the existence of stratified beds in them, is suggested by the character of the
rock composing a large portion of the gravel, in these beds.
In the Liddesdale moraine, many of the pebbles (to the extent of fully 8 per
cent.) are granite. If, then, the pebbles have been brought by a glacier descending
the valley of the Liddell, — and this is the only valley by which a glacier could
have flowed past or reached the alleged moraine of Liddell bank, — there should be
granite rocks in the higher parts of that valley. But, as already mentioned, there
is not a trace of granite in those parts, — the nearest place where granite exists, be-
ing about 25 miles to the west, from which, on account of the levels and character
of the country otherwise, no glacier could have reached.
We must look, then, for some other cause or causes than glaciers, for the
transportation of these granite pebbles, and the formation of the knolls and
ridges containing them ; and I proceed now to offer the views which have occur-
red to me, as to these probable causes.
(1.) One caiise, by which I believe a very large class of diluvial phenomena
may be explained, is aqueous action on pre-existing beds of sand or gravel.
Assuming the country to have had spread over it, at least in many places, a
thick covering of sand and gravel, and which must, as already shewn, have been
deposited in a sea standing at a level 1100 or 1200 feet higher than at present,
what Avas the effect of the rising of this land to such a height, by which all these
sands and gravels became exposed to atmospheric influences ?
In the first place, the emergence of the land, unless it was gradual, must
itself have caused the beds of sand and gravel to be cut up by the force of the
retiring waters, in a very remarkable manner. Their action would vary in force
and direction according to the nature of the materials and the pre-existing
levels. Wherever there was a depression of surface, there the waters would act
most powerfully, and thus form deep cuts or gutters in some places, and high
ridges in others. Suppose what is now a valley (as that of the Liddell) to
have been, when under the sea, filled up with sand and gravel, — then, if the
VOL. XV. PART III. 6 Q
490 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
above views are correct, there would, on its emergence, be deep gutters nearly
parallel, cut through the whole of it. In the central, because the lower parts, the
largest portion would be scooped away, and along a line corresponding with the
general slope. At the sides, — gutters and ridges would be formed nearly parallel to
these sides, if the range of hills composing them did not rise high ; but, if other-
wise, the ridges and banks between the hollowed channels, would be slightly in-
clined away from the sides, and converge towards the lower part of the valley.
On the complete emergence of the land, the central parts of the valley would, of
course, be occupied by a river, which would gradually undermine and carry off
what gravel and sand had been left there. The lateral ridges and mounds at a
distance from the river, would continue undisturbed except by the minor influence
of rain and rivulets.
Suppose now the case of two valleys with a ridge between them, both nearly
filled up as before with sand and gravel. On the waters rushing off by a rapid
rising of the land, deep cuts, and high banks between the cuts, would be formed,
as above explained, — the middle of the valleys being the places where the least
quantity of gravel would be left, and the sides being the places where the gravel
banks would be most undisturbed. Then at the end of the ridge dividing the
two valleys, the sand and gravel would be little affected on the lee-side of the hill,
so that, in such a situation, it is easy to conceive how a ridge or bank should be
left, having a direction corresponding with the average direction of the two val-
leys which had guided the rush of water on each side of it.
It appears to me perfectly possible to explain in the way now suggested, many
of the banks and ridges of gravel which exist in Roxburghshire, and, in particu-
lar, those at Liddell Bank, and near the Elland or Allan Water, described in the
first part of this Memoir. The one at the place last mentioned, though now in
some places broken down into a series of knolls, has originally been parallel, or
nearly so, to the general axis of the Gala valley, and had extended for about three
quarters of a mile in length. It is evident that if, when the land emerged from
the sea, its surface had anything like the form which it now has, the great rush
of waters must have been on the north and south sides of this bank, so that in
their progress eastward, the waters must have had comparatively little effect on
the gravel accumulated there. Then as to the Liddell Bank ridge of gravel, if
the waters rushed off by a sudden rise of the land, which is the case supposed,
that ridge being situated at the west end of the hill or range of hills which divides
the Merse and Liddell valleys, the detritus there must have been protected by the
hill, and thus would form an elongated bank, its upper end inosculating with the
east side of the hill.
These effects, however, would follow only on the assumption, that the land rose
with sufficient rapidity to produce a rush of waters,
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 49]
(2.) If, however, this was not the case, then it remains to be seen what would
be the influences to which the beds and banks of sand and gravel, forming till
now the bottom of the sea, would be exposed.
Here, however, there is a preliminary inquiry necessary. In estimating the
eifects of the atmosphere and meteoric agents just adverted to, some considera-
tion must first be had of the form and shape of the beds and banks on which they
were to operate. Now it may be admitted, that the sand and gravel would in
general be spread pretty uniformly over the bottom, though, of course, where sub-
marine hollows or valleys existed, the greatest quantity would be deposited there.
But whilst this would in general be the case, it is well known that the bottom of
the sea, especially where currents prevail, presents in many places narrow banks
'with steep sides, and which, according to the course of the currents, are either
in straight or in curved lines.
It is very well known, that all around Great Britain, and particularly along
its southern and eastern shores, banks of sand and of gravel (or shingle, as it
is sometimes called) are formed by submarine currents. Sir HENRY DE LA
BECHE, in his Manual, describes two of these off the coast of Devonshire ; — and
any one who reads his description of them, cannot fail to be struck with the
strong resemblance which they bear, in form, size, and materials, to many of the
banks of sand and gravel now existing on the surface of the land. " The sea," to
use this author's words, " separates the Chesil Bank from the land for about half
its length, so that, for about eight miles, it forms a shingle ridge in the sea. The
effects of the waves, however, on either side, are very unequal : on the western
side, the propelling and piling influence is very considerable ; while on the east-
ern, or that part between the banks and the mainland, it is of trifling import-
ance." Unfortunately, neither the height of this ridge or bank above the bottom
of the sea, nor the slope of its sides, is given. But if the woodcut in illustration
of the description be correct, the sectional dimensions and shape accord com-
pletely with those of the Roxburghshire and Berwickshire kaims.
The other case described by the same author, is known as the Slapton Sands.
Sir HENRY describes these as composing, " at the bottom of Start Bay, and for
the distance of about five or six miles, a considerable bank, principally composed of
small quartz pebbles." " This bank," the author adds, " protects and blocks up
the mouths of five valleys ;" so that we have here what AGASSIZ would describe
as a terminal moraine, extending across the vomitaries of five glacial valleys. Sir
HENRY mentions, that, in November 1824, a breach was made by the sea, through
this protective barrier, and that it " continued open for nearly a year, becoming
gradually smaller. The complete restoration of the sands," he adds, " was has-
tened by throwing a few bags filled with shingles into the gap, upon which two
or three gales soon piled up a heavy beach." The upper portion of this bank
is described as being in some places above the level of the sea ; for Sir HENRY
observes, that " the old bank (that is, I suppose, before the breach was made in
492 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
it,) must have remained undisturbed for a long period ; for vegetation had become
active on it, as we see by those portions which remain uninjured, where turf and
even furze bushes have established themselves upon the shingles." The descrip-
tion of this bank, as in the former case, omits the height and slope of its sides ;
but a woodcut is given, which shews these to have been considerable.
On the east coast of England, and particularly off Essex, there are great num-
bers of naiTow banks, composed chiefly of sand, both straight and curved. The
most remarkable of them are laid down on the ordinary sailing charts.
There is the Gunfleet, about three miles from land, about fifteen miles long,
a quarter of a mile wide, and dry at low water. Its sides are steep, and close to
them, the depth of water at low tide varies from four to seven fathoms. This
bank is situated between the estuaries of the rivers Crouch and Black Water.
A still more remarkable sand-bank for length and narrow width, lies farther
to the seaward than the Gunfleet. It is situated between the estuaries of the
Thames and the Medway. Its upper part is called, on the charts, " Oaze Edge ;"
its middle part " Knock John ;" and its lower part " The Sunk." It is altogether
about thirty miles long. The greater part is dry at low tide, whilst on each side
there is from four to eight fathoms, and which rapidly deepens to ten and twelve
fathoms.
Parallel with this long sandy ridge, there are twenty or thirty smaller ones,
all laid down on the charts.
These are examples of straight ridges of sand. The following is an instance
of one which is curved. It is situated off Reculver, in the Isle of Thanet, and is
known by the name of the Horse. It would form a complete ellipse, but for a
break in one small portion of it. The longer diameter of the enclosed basin is
about a mile and a quarter in length, and its shorter diameter half a mile. At
low tide the bank is dry, and is less than fifty yards in width, and there is from ten
to eighteen feet of water close on each side of it. There is also round a great por-
tion of this bank, an outer rampart, of similar shape, at a distance of 200 yards.
These various cases compel every one to assent to the truth of the follow-
ing general proposition of Sir HENRY DE LA BECHE (with which he concludes
his account of shingle-beaches), " That if the present continents or islands were
elevated above the present ocean level, shingle-beaches would be found to fringe
the land, but not to extend far seaward."
As it thus appears that ridges are formed by submarine currents, com-
posed partly of pebbles and partly of sand, having a considerable height and
steepness of sides, and extending for several miles, sometimes in straight and
sometimes in curved lines, may not the kaims of Berwickshire and Roxburghshire
have been formed in the same manner ? That they have been formed by water, in
some way or other, is unquestionable. That the waters in which they were depo-
sited, were in the ordinary state of the ocean, and not in a state of debacle, seems
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 493
to be probable, from the structure of the shingle ridges described by DE LA
BECIIE, and from the impossibility that sand should be deposited in waters that
are very tumultuous.
Perhaps I may here be permitted to refer, in support of the above views, to
the case of a gravel bank or ridge, never hitherto described, which is situated
on the coast of Northumberland, about four or five miles south-east of Belford. It
is about three miles from the shore, and it runs nearly parallel with the shore
for about four miles. It is composed chiefly of large rounded pebbles, of all de-
scriptions of rocks, derived chiefly from the neighbourhood, — though there are
some, the origin of which I have not yet traced. Sand in stratified beds also
abounds, and in such quantities as to be worked. Its sides are steep, sometimes
exceeding 50° ; and in several places its top is from 40 to 50 feet above the ad-
joining grounds. This remarkable ridge is, at its base, about 120 feet above the
level of the sea, and affords, in my opinion, one out of many proofs, that this part
of our island has, at a very recent geological period, risen out of the sea. It ap-
pears to me, in short, to be one of those shingle banks, described by DE LA BECHK
as having been formed by submarine currents, and with which he says this island
would be found to be fringed, were it elevated above the ocean level. In con-
firmation of this opinion, I may add, that, at the north end of this ridge, viz. at
Waren Mill, there is a hill of greenstone, from which have apparently been de-
rived many of the rounded blocks and pebbles occurring in the ridge, and which
are most numerous towards the north end of it. It seems probable, that the
greenstone hill in question has been the means of forming an eddy on the south
side of it, in consequence of which a tail of gravel and sand was there deposited.
Accordingly, there is no appearance of either sand or gravel, in any form, on the
north side of Waren Hill.
I may only farther observe, in regard to this Belford gravel ridge, that it is
utterly impossible to account for its formation by glaciers, as there is no great
valley, not even a mountain, or any considerable hill, within 20 miles of it ; and,
moreover, it is situated at a level far below that to which any glaciers are pre-
tended ever to have reached, in this country.
I am not aware that the above view of the matter which I have ventured to
suggest, is backed by the opinion now entertained by any of our great geological
authorities, and therefore I offer it with distrust. I am glad, however, to find,
that this view was at one time, though it may not be now, entertained by Mr LYELL,
at least in regard to the production of the Swedish oosars, which I have shewn to be
identical in form and structure with the kaims of Scotland. Mr LYELL, since he
became a convert to the Glacial Theory, has most probably adopted M. CHARPEN-
TIER'S explanation of the formation of these oasars ; and, accordingly, he has re-
cently attempted to show, that the mounds and banks of gravel, clay, and sand in
Forfarshire, have been produced by glacial action. I may not therefore be able to
VOL. XV. PART III. 6 R
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
found upon Mr L YELL'S authority, in support of the opinion which I have just ex-
pressed, though advocated by himself at a former period. But it is a circumstance
in favour of that opinion, that it was the conclusion to which he came, after ex-
amining the kaims of Sweden. The following passage occurs in his Paper before
referred to : — " The occurrence of layers of marl containing littoral shells, as above
described, in the midst of a stratified ridge of sand and gravel, is opposed to the
theory of those geologists, who refer the formation of such ridges to a violent flood
or debacle rushing from the north. The perfect preservation of the shells at Up-
sala, and the repeated succession of thin alternating layers of gravel, sand, and
loam, which are seen almost everywhere, imply a gradual, and at times a very
tranquil, deposition of transported matter. If I am asked for a more probable
hypothesis in the room of that to which I.object, I may state that these ridges ap-
pear to me to be ancient banks of sand and shingle, which have been thrown down
at the bottom of the Gulf of Bothnia, in lines parallel to the ancient coast during
the successive rise of the laud ; or in other words, during the gradual conversion
of part of the gulf into land. I conceive that they may have been formed in those
tracts, where a marine current, flowing as now, during the spring when the ice
and snow melt, from north to south, came in contact with flooded rivers rushing
from the continent, or from the west, charged with gravel, sand, and mud. Ac-
cording to this view, these large Swedish ridges may be compared to smaller
banks known to have been formed within the last five or six centuries on the
eastern coast of England, at points where a prevailing marine current from the
north meets rivers descending from the interior, or from the east."
But whilst I adduce, in support of my view, the opinion of Mr LYELL, at least
as entertained in 1834, I know that its soundness must be tried, not by authori-
ties of that kind, but by an accurate survey of facts. I merely found on his opi-
nion, in order to bespeak, on behalf of the foregoing views, an attentive considera-
tion.
(3.) But farther, and independently of the operation of submarine currents
in forming elongated banks of sand and gravel, it remains to be considered what
effects would be produced on the bottom of the ocean, on becoming exposed to
atmospheric and other natural influences.
That the rain itself must act powerfully in washing away and carrying off
sand and small gravel, cannot be doubted ; and this agent, trifling as it is, appears
to me quite sufficient to have produced the almost innumerable mounds and knolls
which, as already remarked, are to be seen near Palinsburn, Gala House, and
Lamberton. It is impossible, indeed, to doubt that a thick and extensive bed of
sand and shingle would, by this cause, after the lapse of time, be cut up into sec-
tions of various dimensions ; and when the channels or gutters thus formed reach-
ed any considerable depth, the loose materials would begin to be undermined, and
separate mounds and banks would be speedily formed.
It is evident that no limit can be prescribed to the variety of forms which the
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 495
banks thus engendered may assume. They may be round, or oval, or elongated,
according to circumstances.
But to the influence of rain, must be added that of rivers and rivulets, as
capable of producing similar effects and in a more striking degree. And it is a
circumstance strongly favouring the supposition of their being capable of produc-
ing the effects in question, that rivulets are found flowing along or near the base
of many of the elongated gravel ridges, which have been compared to moraines, —
as, for instance, at Gala House and Dogden Moss.
On the whole, therefore, it appears to me that it is not necessary to resort to
glaciers, in order to account for the transportation of the boulders and gravel
which have been strewed over the south of Scotland, or to explain the formation
of knolls and elongated banks. It is, according to my humble opinion, quite pos-
sible to account for all the phenomena, by assuming that these boulders and
gravel were transported by submarine action, and subjected to processes of re-
arrangement, by subsequent aqueous action in the way just explained. Water,
as the true cause, is suggested by the arrangement and nature of the materials,
and is found capable of producing the required effects. Ice, as a cause, is nega-
tived by the arrangement and nature of the materials, and is, moreover, in many
situations, utterly inadequate to have produced any effects.
6. I have still to make some reference to the formation of the fairy stones
found in Allan or Elland Water near Melrose, and other places.
One of the theories on the subject, and supported by, if not originating with,
a Principal of one of our Scotch colleges, distinguished for his philosophical disco-
veries, is, that these stones are formed by the dropping of water, holding in solu-
tion earthy particles which cohere on its evaporation. But (1.) how does this
account for the general sphericity of these stones ? The^process just described
would form a columnar stalactite, — it never would form a spheroid. (2.), I have
in my possession several specimens of greywacke pebbles studded all round with
these stones. By the process above mentioned, one can understand how the drop-
ping of water should produce a deposit on one side, but it leaves unexplained the
formation of similar deposits on other sides of the same pebble.
Another theory, advocated by a writer in the Transactions of the Berwick-
shire Naturalists' Club, is, that these stones are formed into their spheroidal shape
by the attrition of the current, and rolling on the rocky channel of the river. But
there are many facts which shew the unsoundness of this theory. (1.) When these
stones are most perfect, they are not in the stream of the river, but on the side
of it, at the foot of the clay bank ; and when picked up in the channel, at some
distance from the clay bed, their characteristic shape is much obliterated. (2.) If
the theory suggested be sound, similar stones should be found, not only in higher
parts of the river, but in every other river whatever. Moreover, their like sphe-
roidal form should be acquired, not by one kind of stone only, but various other
496 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
kinds. All these conclusions, to which the theory necessarily leads, is utterly
inconsistent with observation.
A third theory has been lately propounded by Mons. PAEEOT, in describing
" les pierres d'Imatra," which, judging from his elaborate account, and still more
from the beautiful lithographic figures he has given of them, I think are identical
with the stones of both kinds mentioned in the first part of this Memoir, as found
in Elland and Kale Waters. This author maintains that " les pierres d'Imatra
sont des moUusques petrifie'es, sans coquellis." He modestly declines, however,
" to classify this new family of molluscs," leaving that labour to other zoologists ;
but he does not hesitate to name it, as one the existence of which can no longer
be doubted, and the name he gives to it is Imatra, in honour of the place where
it was first discovered.
This extraordinary theory is very zealously supported in a Memoir which
extends to 130 quarto pages, and is illustrated by no less than sixteen plates,
occupied partly with views of the locality, but chiefly with figures of the stones,
of which there are nearly 100.* The stones so figured are identical in size,
shape, and appearance, with those described in the present Memoir; and the
chemical analysis given by Mons. PARBOT, appears to be in entire accordance with
the composition of the Roxburghshire stones. I have read with attention the
arguments which he advances in support of his theory, that they are molluscoxis
animals in a fossil state ; but I confess that they have neither convinced nor in-
fluenced me. They have left only a feeling of surprise, that so extraordinary an
inference should have been adopted on such slender evidence.
In the first part of this Memoir I expressed an opionion, that these fairy
stones are concretions of clay produced by the homogeneous attraction of its par-
ticles. Though Mons. PARROT notices this hypothesis, and endeavours to combat
it, I think his arguments altogether futile, and several of his facts not a little
confirmatory of it. From the analysis which he gives of these stones of Imatra,
the following are the proportions of the substances composing them : —
Carbonate of lime, ....... .49
Silica 19
Alumina, ........ .12
Oxide of iron, ....... .13
Sulphur, 04
Water ... .01
.98
Mons. PARROT gives also an analysis of the clay which contains these nodules,
and which consists of sand .32, silica .37, alumina .13, and oxide of iron .15, =.97.
* This Memoir was published at St Petersbourg in 1840 by the Imperial Academy of Sciences.
6
ME MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 497
He remarks on the total absence of lime and sulphur from the clay, as proving
that the nodules which contain these two substances, could not have been formed
in the clay itself; and this is his chief argument for the organic origin of the
stones.
But this very diversity of chemical character, appears to me to explain the
formation of the concretions. If carbonate of lime and sulphur are capable of
exciting chemical attraction or repulsion, it is plain that these substances, origi-
nally existing in the clay, might easily produce concretions. Innumerable ex-
amples occur of the formation in this way, of nodules composed of iron pyrites,
carbonate of lime, and many other substances, the particles of which must have
separated from the general mass of matter through which they had been inter-
spersed, and formed bodies variously shaped.*
Whilst in this way it would not be difficult, on ordinary and well-known
principles, to account for the formations of these fairy stones in the interior of
the clay bed, certain it is that they are also formed when exposed to atmospheric
influence. Both at the Fairy Dean, and on the banks of the Tweed near Berwick,
I have picked up small portions of the clay about the size and shape of a walnut,
hard on the surface, but perfectly soft and plastic in the interior. They were
evidently in an incipient state of consolidation and chemical arrangement, pro-
bably induced by evaporation and the action of the external air. One of these
half-consolidated nodules I took home, and in a couple of days it became as com-
pact, and nearly as well shaped, as any of the rest.
I have stated that these stones, besides being of a spherical form, more or
less flattened, generally consist of laminae, which are the same in character with
the laminae of stratification in the bed of clay. This circumstance affords addi-
tional proof that these stones are concretions formed by chemical action in the
clay. In this respect they bear a very close resemblance to the calcareous nodules
described by DE LA BECHE as existing in the marl beds of Lyme Regis, f
I here conclude my Memoir on the Geology of Roxburghshire. Whatever
may be thought of the description which I have given of its different formations,
or of the views which I have offered in explanation of them, this much will be
conceded, that it is a district containing many phenomena of novelty and interest,
and the study of which is calculated to throw some additional light both upon the
structure of the earth and on revolutions which have taken place on its surface.
* See Lyell's Elements, p. 76, 77, for examples, and an explanation of this concretionary structure,
•f Geological Researches, p. 95.
VOL. XV. PABT III. 6 S
4,98 MB MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
Lists of Specimens illustrative of the foregoing Memoir on the Geology of Roxburgh-
shire, and lodged in the Royal Society's Museum.
1. Greywacke, fine-grained and blue, from vertical strata running east and west by compass. Edger-
stone Burn foot.
2. Greywacke, coarse and gritty, from a stratum about two feet thick, nearly vertical, running about east
and west. From a quarry on turnpike road, two miles north-west of Galashiels.
3. Greywacke, fine-grained and blue, from Do. Below Edgerstone North Lodge, in channel of Jed.
4. Greywacke, coarse and brown. Edgerstone North Lodge, in channel of Jed.
5. Greywacke, coarse and brown. From channel of Jed, where crossed by Hawick trap dyke, near Rink.
6. Greywacke, curiously veined with iron, from channel of Jed, near Peel, in Southdean parish.
7. Another specimen.
8. Do.
8 A. Greywacke, with organic forms, produced by structure.
8 B. Pebble of old porphyry, from conglomerate of old red sandstone at Byreslees on the Ale Water.
9. Old red sandstone with white spots, from right bank of Tweed opposite Dryburgh.
10. Five specimens of red and white varieties of old red sandstone, from Denholm Hill, on the north
side of Ruberslaw, where it is extensively quarried. The strata dip north at an angle of 8°.
11. Yellow sandstone, slaty, from Ancrum Park, overlaid by red sandstone strata. This yellow sand-
stone is composed either of disintegrated yellow porphyry, or it is one of the red sandstone rocks
from which the colour has been discharged by heat. (See p. 473.)
12. Old red sandstone, distant about 50 yards from porphyry rock, and apparently unaffected by it.
13. Old red sandstone, with a stripe of greenish white. This white stripe is at the side of a crack or
fissure in the rock. On the opposite side of the fissure, the red rock has a similar white stripe
of the same width. From Jed river, opposite to Fairneyhirst.
13. Another specimen containing two stripes, the specimen having been between two fissures. One end
was lately exposed to the heat of my kitchen fire, in order to ascertain the effect in changing the
colour.
13 A. Specimens from the same locality, with the red colour nearly all discharged, from some change
apparently in the chemical state of the iron.
14. Old red sandstone, with spherical white spots, from south bank of Tweed between Maxton Manse
and school-house.
15. Old red sandstone, lying nearly horizontal over vertical strata of greywacke. From river Jed, a
little below the north Lodge of Edgerstone. The junction of the two formations is shewn by
the woodcut on page 437 of the foregoing paper.
16. Calcareous sandstone, from right bank of Tweed opposite to Dryburgh.
17. Yellow sandstone interstratified with red beds of Do., from right bank of Tweed below Holm House.
18. White sandstone, from Doveston Hill, about a mile north-east of Edgerstone north lodge. A similar
stone got and quarried at Kilburn.
18 A. Conglomerate containing fragments of Cheviot porphyry, overlaid by the coal-measures at Mil-
lenden Burn. See page 449.
r o
18 B. Pebble of Cheviot porphyry, found in the conglomerate marked 18 A.
18C. Calcareous sandstone, lying above 18 A. at Mellenden Burn, and alternating with marly shales.
18 D. Conglomerate, from Sunlaws Quarry on Teviot, where the change apparently takes place from
the old red sandstone formation to the coal-measures, p. 449.
18 E. Stratum of hardened clay, very common in lower parts of coal-measures, near the junction with
old red formation. This specimen from Tweed above Floors Castle.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 499
18 F. Specimens of red and white gypsum, from strata of marl and clay on left bank of Tweed, half
way between Floors and Mackerston.
19. Limestone from Limekiln Edge, near Windburgh ; extensively quarried. Apparently altered by
heat from adjoining trap.
20. Do. from Do.
21. Do. from Carter Fell, on Cheviots ; extensively quarried. No shells have been found in it.
22. Do. from Do.
22 A. Coal sandstone, Eccop Hill (Cheviots).
23. Coal sandstone I brown and gritty, from a glen between Minto village and Minto Manse.
23 A. Marl, from Pinnacle Hill, opposite Kelso.
24. Coal sandstone ? from foot of greenstone hill, opposite to Ancrum Church.
25. Do. ? very gritty, from west side of Minto Greenhills, composed of tufa.
26. Another specimen.
27. Scales of Holoptichius, from old red sandstone, head of Wauchope Burn, east side of Windburgh.
28. Do. of Do., from old red sandstone at Plewlands Quarry, near Maxton school-house.
29. Do. of Do., of a smaller size, and probably belonging to a different species. From same locality.
30. Mould of a palate or other part of Holoptichius, from Jed river, near Peel, in Southdean parish.
Specimens of Sedimentary Rocks altered by heat.
31. Yellow sandstone, very near Craigoer rock of basalt, opposite to Merton. The same stratum at a
greater distance possesses the usual red colour of the formation.
32. Coal sandstone slightly altered by felspar porphyry, from Teviot, below Heaton.
33. Marly sandstone of coal formation, altered by overflowing mass of porphyry. Robert's Linn.
34. Do. Do. Do.
35. Do. Do. Do.
36. Do. Do., from Bedrule Hill.
37. Do. Do. Do.
38. Do. Do. Do.
39. Old red sandstone, or some lower member of the coal formation, altered by felspar porphyry. From
Liddesdale, four miles west of note of the gate.
42. Pitchstone porphyry, veined with iron, from near Hownam.
44. Jasper, from Jed, opposite Shaws, in the Cheviot porphyry.
45. Cheviot porphyry, from Tofts.
46. Do., from Letham.
47. Pitnhstone porphyry. Hownam.
48. Amygdaloidal porphyry. Chatto.
49. Porphyry. Above Morebattle, on Kale Water.
50. Felspar, from quarry west of Maison-dieu, near Kelso.
51. Felspar porphyry, from between Kerseknow and Frogdean.
52. Basalt \ Easter Softlaw.
53. Clinkstone. On Tweed, below Maxton Manse.
54. Felspar porphyry. Plewlands Burn.
55. Felspar porphyry. Plewlands Burn.
56. Amygdaloid, from opposite Mackerston.
57. Felspar, from right bank of Tweed, above Mackerston.
58. Felspar porphyry, from left bank of Tweed, below Mackerston.
500 MB MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
59. Felspar porphyry. Opposite Merton, and above Craigoer rock, on Tweed.
60. Basalt, from Craigoer rock, on Tweed.
61. Felspar, with brown mica. Sucklawrig, north of Mackerston.
62. Clinkstone. Woodenburn, near Kelso.
63. Red felspar porphyry, containing greywacke. Easter Eildon Hill.
64. Do. Bowsden Muir.
65. Clinkstone. Muirhouselaw clump.
66. Amygdaloid. Muirhouselaw onstead.
67. Trap tufa, from north-west part of Eildon Hills.
68. Yellow felspar, from the Holm opposite to Dryburgh.
69. Do.
70. Amygdaloid and tufa, from Do.
71. Tufa, from Bedrule Hill.
72. Felspar porphyry, from an extensive coulee on Do.
73. Felspar porphyry, from Do. Do.
74. Claystone porphyry. Ancrum Park.
75. Do., overlaying slaty and yellow strata. (See No. 11.) Do.
76. Greenstone porphyry, from Kirklands. Probably part of same mass or eruption as at Castlehill.
There are brown coal ? strata close to each horizontal.
77- Felspar or claystone porphyry, from Heaton onstead, at side of turnpike road.
78. Clinkstone from Windburgh.
79. Trap tufa, Ancrum Craigs.
80. Felspar from quarry south of Heaton.
81. Vein of compact red felspar from do. Vein runs north-west, and is about 4 inches thick. Of same
quality as vein at back of Springwood Park garden, in channel of Teviot, which runs through
felspar similar to No. 80 in a north and south direction. (See No. 91.)
82. Vein of copper from No. 80, united with No. 81.
83. Basalt from Hawick dyke, as seen at Halrule Mill, on Rule Water.
84. Basalt from Limekiln edge, which has flowed over limestone there, and is about 40 fathoms above it.
85. Greenstone from Cow rock, south-west of and near Heaton.
86. Do.
87- Felspar or claystone porphyry from Heaton Mill. (See Nos. 77 and 80.)
88. Clinkstone from Woodhead, on Ale Water, about a mile above Ancrum.
89. Greenstone from the Carter.
90. Do. Southdean Hill.
91. Felspar porphyry from Teviot, back of Springwood Park Garden. (See No. 81.)
92. Basalt from Smailholm Craigs, with opal.
93. Sulphuret of lead from Abbotrule.
94. Fairy stones from Allan or Elland Water, near Melrose.
95. Stones supposed to be formed from similar causes, found in the Kale Water, near Morebattle.
MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 5Q1
Fragments from Liddesdale boulders, collected and labelled by the Rev. Mr. BARTON of Can tie ton.
1 . In the bed of the river at the village in great abundance.
x 2. Castleton, about a mile south-east of the Manse, so numerous that they resemble a quarry, and
some of them so decomposed, that the earth surrounding them, upon being dug up with a spade,
presents nothing but their elements.
x 3. Tweedenhead, a little farther to the south-east of the former.
4. Powisholm, a very large block, blasted last year, on the west side of the Liddell, about 500 yards
to the north of the Manse.
x 5. Picked up in the bed of the river at the Manse.
x 6. Between Belshiels and the Manse, in a dyke about 300 yards south-east of the latter.
x 7. Near Newhouse, on which Mr Milne broke his hammer, about 150 yards from No. 6.
x 8. Thorlieshope, about seven miles north-east of the Manse, very abundant for many miles, especially
in the direction of the Carter.
9. Liddellbank, about seven miles to the south-west of the Manse; the most southern hill in the
parish.
10. Greena, about half a mile to the north of the former.
11. South Burnmouth, on rising ground about a mile to the north of No. 10, in a piece of good land,
very numerous, — ugly customers for the farmers.
12, 13, 14. At Ettleton ? and Burying-ground, very numerous.
x 1 5. Kershope. The boundary between England and Scotland, to the south-east of the Manse.
16. Blackburn, about a mile to the north-west of the village.
17- Berrycleuch, to the south-west of Blackburn, in great abundance.
18. Tinnisburn, about two miles to the south of Berrycleuch, in superfluity.
19. The upper millstone of an old querne, dug out lately from the foundation of a house to the north
of the Manse, on the other side of the river, about 100 yards.
Numbers 2, 3, 5, 6, 7, 8, ]5, marked with a x, are all on the east side of the Liddell. No. 5 is doubt-
ful, being found in the bed of the river.
Numbers 1, 4, 9, 10, 11, 12, 13, 14, 16, 17, 18, are all on the west side of the Liddell, and, as it
turns out, by far too numerous for the farmer.
Mr BARTON, alongst with the foregoing specimens, sent to Mr MILNE a letter, from which the fol-
lowing extracts are made : —
" You will observe that all the specimens from the east of the river, are to be found every where
from Kershope, on that side of the river, to the northern extremity of the parish, and are traceable,
as I am informed by shepherds, to the Carter, without any difficulty. At No. 8, and for several
miles in circumference from it, they abound to nearly the summit of the hills. On the west side
of the river, however, I have not yet discovered that they are so abundant, although you will perceive
that they are very numerous, especially at Nos. 1, 9, 10, 11, 12, 13, 14, 16, 17, 18, nor that they
are to be found so near the summit of the mountains as on the north side. At the same time, I may
observe, that the soil to the south of the Manse, and at No. 2, consists solely of the debris of the grey
and red granite, as was satisfactorily proved to me, who am no geologist, by a mason, who has some
VOL. XV. PART III. 6 T
502 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE.
knowledge of the subject, digging up several spadefuls and pointing out the component parts of the gra-
nite, and by convincing me that the hill in front of the Manse, from which the materials for making the
road, along which you and Dr B. went on the morning you left, was almost entirely constructed of the
same substances. To-day, for he is making some repairs on the Manse, he drew my attention to the
decomposition of rocks, by crushing with his foot several blocks of weathered granite, and then comparing
them with the adjoining soil, and fully demonstrated, to my satisfaction at least, that the two substances
were precisely the same. You will also notice that red granite is found, and that the soil is composed,
of a greater proportion of that than of the grey. You mention that Criffell is distant 20 miles from this,
but if you say 40, from where I write, you will come nearer to the truth, and find that the valleys of
Nith, Annan, Esk, Tarras, and Liddell intervene, and present many barrier acts, to the establishment
of Dr B.'s theory.
'' THOMSON has been very active in collecting specimens- If you want more, he or I will furnish
them with great pleasure. I hope those sent will arrive in safety."
K, -I
PLATE X1H l!,iy,il • '•:•
Fifi .'i
x Kin,
' ' I
/w /
( 503 )
XXXIII. — Description of a New Self-Registering Barometer.
By ROBERT BRYSON, F.R.S.E.
(Read 2d January 1844.)
ALTHOUGH many proposals have been made to obtain a series of hourly
meteorological observations by mechanical means, this desideratum has not, from
various causes, been completely attained. The chief obstacle to be overcome, in
such self-registering instruments, is the great amount of friction, which neces-
sarily vitiates all the results, more especially in delicate instruments, such as the
barometer and thermometer.
Dr ROBERT HOOKE was the first to propose a self-registered series of meteor-
ological observations, by an instrument, which he quaintly called a Weather-wiser ;
but no further notice is taken of this contrivance than a short description in one
of his tracts, bearing the date 5th December 1678, which would lead us to believe
that the instrument was never used. The late ALEXANDER KEITH, Esq. of Ravel-
ston also proposed a similar contrivance, a description of which is contained in this
Society's Transactions, Vol. 4th. This contrivance, from the constant friction ex-
cited by the marker on the revolving paper, seems likewise to have been abandoned.
The barometer now to be described does not seem liable to the objection of
the others. Fig. 1. exhibits a side-view of the barometer, with the clock-work
which moves the cylinder on which the observations are registered. A is the
fussee of a spring time-piece, placed between two brass frames, driving a pinion
B, which passes through the frame, and is pivoted into a small cock on the back-
plate, for the purpose of allowing the large horizontal bevel wheel C to pitch easily
into it. This wheel is, by the pinion B, made to revolve once during twenty-four
hours ; it carries twenty-four pins, placed at equal distances round its circum-
ference, and is fixed to the spindle L, which works in two puppets F and 0, the
upper extremity being shewn at R, after passing through the cylinder D. PP are
two milled nuts, which are used in adjusting the pitch of the wheel C into the
pinion B.
D is a tin cylinder about 3 inches in diameter, having the hours marked
from 1 to 12 A. M. red, and from 1 to 12 p. M. black. This cylinder has a brass
tube soldered through its axis, which fits easily upon the upper part of the spindle
L. To enable us to put this cylinder always on at the proper point, a small pin
is fixed into the wheel, and may be seen in the figure near C. This pin fits
into a small aperture in the bottom of the cylinder, and prevents any lateral mo-
tion which would change the marking of the hours ; this steady pin prevents
VOL. XV. PAET IV. 6 U
504 MR BRYSON'S DESCRIPTION OF A
entirely any chance of error when shifting the cylinder, as it will not reach the
wheel unless the aperture at the bottom be coincident. I is a small puppet car-
rying a lever, which is raised every hour by the transit of each pin of the wheel C ;
the axis of this lever is marked H, and the end where the pins act G. The action
of this lever will be better understood by reference to Figs. 2 and 3, where KK re-
presents a bent tube filled with mercury, forming the common syphon barometer.
Upon the surface of the mercury floats a spherical ball of ivory I/ attached to a flat
steel rod, which passes easily through a nozzle on the open end of the barometer,
marked P ; it is also passed through a slit in the end of the lever, which is better
shewn at P, fig. 3, which represents a section of the instrument. Here the float-
rod M is bent at right angles, and in form of a knife-edge, so as to mark the cylin-
der D ; K and K' are the sectional parts of the barometer tube ; H is the axis or
pivot of the lever ; N is the embracing arm which clasps the float-rod ; G is the
other arm of the lever, which is acted on by the transit of the pins. From this
short description, it will easily be perceived that when the wheel D revolves in
the direction of the arrows, each pin, as it passes the bent point of the lever at G,
will cause the float-rod M to be pressed against the cylinder, which removes a
small line of the white pigment covering the cylinder, and thus indicates the
height at which the float stands in the open end of the barometer. When the pin
has passed the arm of the lever G, it is forced into its former position by a spring
which gives a jerk to the float, and removes for the next observation any adhe-
sion of the mercury to the tube which may have been caused by moisture or
otherwise. The operation of marking occupies about eight minutes, during which
any change in the height of the mercurial column does not affect the float until it
is released from the embrace of the lever by the passing of the pin, when the float
is again free to rise or fall with every change of the atmospheric pressure, without
any restraint or friction, until the coming pin again brings it in contact with the
cylinder.
It is convenient to have seven cylinders, each marked with a day of the week ;
they are quite detached, may be removed, covered, and replaced, by any person
totally unacquainted with the management of instruments. After the cylinders
are read, they require merely to be streaked with chalk and water well levigated
and applied by a camel's hair brush ; and as the cylinders are japanned black,
the slight mark made by the point of the float is very easily perceived, as it is a
faint black mark on a white ground.
Fig. 4. is a representation of the reader for ascertaining the value of each
hour's mark on the cylinder; D is the cylinder, with the various registered
observations marked upon it ; a moveable pivot a presses the cylinder against
an opposite pivot ft, which is mounted with two milled nuts, binding it fast to
the upright through which it passes ; these pivots allow the cylinder to revolve
without any end-shake, which would vitiate the readings ; d is the scale where
NEW SELF-REGISTERING BAROMETER. 505
the values of the markings are indicated by the vernier fixed at c; e is the milled
nut attached to the screw which guides the pointer /to the various lines on the
cylinder.
When the barometer is first put in action, the scale is adjusted to its proper
height by observations made at the same hours of a standard barometer. Should
the register be found too high, the fixed pivot b is loosened and screwed out until
the vernier and scale correspond to the height observed at that hour on the stand-
ard barometer, after which it is fixed, and the other observations will be found
to correspond within the usual limits of discrepancies in barometric observations.
The following are the observations registered since the barometer was first
completed, June 22. 1843. They were made in Princes Street, Edinburgh, at the
height of 211 feet above the mean level of the sea.
All the observations are comparable with those at Greenwich and the Royal
Society of London, as the clock is kept at Greenwich Mean Time.
HOURLY REGISTER.
( 506 )
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{OT.,.2/fci OT>- A. • 2 kr 1^1 • A. • J • 1 ^^ • t •
— 2 L sm (p smt -75- + 2 K sin q> suv -TJ- -\ — -j- sm (b sm « i — - ^— sm (b sin kr
2 2 e dx e dx
R/-t — m x * ^ \ W Xvj! 1 — nt $ tx)
»l-e cosfdy)+--e sm
• - ?> I
m/Syj,
AN INTERRUPTED MEDIUM. 513
2 ILL 8 x 8 .?/ 8 /3 = 2 ^ (-t*+p2) sintf>cos20 | -2 I sin2 **
r
9Ar 1 «?I 1 e?R 1
+ 2 R sm2 -TT + - -T— sin * i -- -7— an « f >
2 e ax e ax )
the sum of which is
( k i
I -2 Isin2y + 2Rsin2-+ - — sin
c* . M . , /rfl rfR\
= TJ- sin d) (— I + R) + — sm rf> I - -- -j— )
2 e r \dx dx )
where M = 2 f 0r + ^5«> + ^ S*Sy
r — r ' sin
= 2 (0r + — 5 a:2) sin e8x cosf8y+ C.° ^ 2 — «y cos
/ Sill *JJ r
for both the incident and the reflected wave.
D = 2 r+ *2 l-<
Again, 2(^)r'+ 5a^2) 5ay=2 (^)/ + f2 cos2 $"+^2 sin2"$)
{/fee yfc o
- 2 T sin <£, cos ^ sin2 y + 2 T sin 0' sin & sin2 -g-
1 *-/ T1 1 ^V TH'
- -j — sin (£7 cos 6 sin k, e — ~j~j~ sul 0' sin 6' sin
2
where £ stands for either e or o, as the case may be ; and , cos 0
,
e' dx f dy f dy
+ Q-, («,-«)•
By a precisely similar process we find
<**& °2 A /T ox M /rfl
7F= ~2 cos * P + R) + T fc+
-^Tcos0/Cosa + |2 T' cos 0' sin 6' + — ' — cos , cos 0
W dT ,, . A, F dE, Ft dT, n „
-- r -— cos 0' sm 0' -f - -r-' + -~ -~- D Ry - D( Ty
e' dx f dy f dy
M/rfl' «?R'\ M, <^T . . M' dT f,
-( -j -- -3- ) +— ' — — sm0+— -- cos6'-
e\aa: dx ] e, dx e dx
AN INTERRUPTED MEDIUM. 51 5
d*a. d2 (3 d2y d2 a d* 8 d2 y , . -.
Moreover, ^y, ^', -jf respectively differ from -^, -jf, -^ only in hav-
ing Q,x (a - a,) in place of Q*, (a, - a), Qy (8 - /3,) in place of Qy, (/?,- 8), and
Q* (7-7/) n
But -2 = — c2 a, &c. = &c.
a i*
Hence the following equations result :
c2 • ^f-t -o\ M • ^/rfl ^R\ c2r • ^
— — -sm w (1 — K)+ — smffl I - --- — I — — 1 sin (b cos
2 e Vdz dx ) 2
c2rrv />, M, rfT . a M' .
-- 1 sin q) sin an -- : - sin (p. cos a -- - sin a> sin f
2 e, dx e' dx
, . . . . (1.)
'sine'-c2Ta. +<&,,+ Q^ («,-«) (2.)
By subtracting these equations, we get
or (c2 -Q,, - Q,) (a, - a) = 0
wherefore a, - a = 0 ......... (1.)
Similarly (3, - p = 0 ......... (2.)
7,-7 = 0 ......... (3.)
And by adding the above equations, and striking out the parts which are com-
mon to both sides, we obtain
M/rfl dR\ . , M, dT . a M' rfT .
— ( - --- — -IsinrfM -- '- smro. cose — — — sin (b sin u
e \dx dx I e, dx e' dx
= 0. . . . (4.)
dy f dy
M/dl dE\ , M, dT , fi M' dT ' ,, . &
— [ -- 1 -- I COS04 -- - COS0.COSC7 -- - — — COS 0) Sin U
e \dx dx) e, dx e' dx
FrfR, F, rfT, /c2 \ /c2 \
+7 77 + 7 ^7 U~ DJRy+ U"D')Ty-
M/dP rfR'\ M, rfT . ,3 M' dT' .,,
- ( _ -_— ) + — ' — sm 6 +— -—- cos 6'
e \d x dx) e, dx e dx
These equations differ from those which I gave in my Memoir on light reflected
at the surface of a crystal, in having the terms Ry, R-, Ty, T* additional. Thus it
VOL. xv. PART iv. 6 Z
516 PROFESSOR KELLAND ON THE VIBRATIONS OF
appears that the equations do not depend on the lave of force, but are equally
true in all cases.
Before I proceed with any further discussion of these equations, I desire to
prove some important theorems relative to the values of the constants in symme-
trical media.
THEOREM 1. — Relation between the sums of powers of one co-ordinate, and pro-
ducts of powers of different ones.
Let/ g, h be the co-ordinates of a particle; x-f, y-g,z—h those of another
measured from it. Then
Suppose the particle whose co-ordinates are/, g, h, to be moved to a point
f+a, ff+/3, A + 7, then 2 »?<£/, becomes 2w0^(#-/— a)2 + (#— .?— /3)2 + (z-A— 7)2.
Also (a._/_a)»+(y-£-j8)s-(*-A-7)s=rs
Let $ be the distance through which the particle is moved, and let
-g)P+(z-}i)y be denoted by e; then
2 m $ r,=2 m Vr2 -2e+82
/2e-S2\ 2«
= 2m0r + . . . +2mfrl — -5— \ + . . .
Now this must be a function of $ : consequently
2»&/,»-e2B must equal P 82n
or 2WZ//r{a(^-/)
P being some function of r.
By expanding each side we get
Hence we obtain
1.2
AN INTERRUPTED MEDIUM. 517
.j
n (»-])... (»-r+l) r(r-l) .. . (r-j + 1)
,,\2' 1-2 ____ / '1.2 ____ 8
-A) = 2tl(2l,_lM2<|_2r + 1) 2r<2r-l).(2r-2«
1 . 2 ....... 2 r 1.2...2«
fv.
THEOREM 2. — To find the relation between imf,r.(x—f'fn and Sm/r/-2"
This amounts to the determination of the* value of P in the above expression.
Let 6 be the angle between r and 8
then 6 = r 8 cos 6
j 2n 2» oS» 2» n
and e = r 0 cos 0
2n 2n a
P = 2mr COS C7/.*1
Now, the area of a spherical surface in the mass is //r2 sin 6 dd d
Hence for such a surface
P = /7V2 "+2 cos2 *0 sin 6d6 dtj>f,r
= -/-
= /'
2n+l
or 2w«-'-
This proposition might have been proved with little difficulty without having re-
course to integrals, but the result is so obvious, that I do not think it necessary
to add such a proof.
THEOREM 3. — A system of particles act on one another by forces which vary
inversely as the square of the distance between them. One of the particles
is removed from its position of equilibrium, to find the force put in play
on it.
Let the co-ordinates of this particle be measured in such directions that the
axis of x may be the line of motion.
518 PROFESSOR KELLAND ON THE VIBRATIONS OF
Now, it is evident that, since the medium is one of symmetry, the force put
in play is in the direction of the motion ; and is represented by
x—f—a.
2 m
x—f—a
{r2_2 (*-/)
The co-efficient of a2" in this expression is as follows :
(« + l)w(»— 1)
3.5. . .(2« + l) n 3 . 5 . . . (2 » + 3) 1.2.3
2 — - -
r 3.5. . .(« +
~2 m [2.4.... 2n
&c.
every term of which involves (x—f] as a factor. Hence this quantity is zero.
Again, the co-efficient of a2n+1 is
f 3.5... (2n + l) 1 3.6...(2n + 8) (n + 1) « 2« (»+/)»
12.4 ____ "
2» r2"+3 2.4...(2» + 2) 1.2
3.5... (2^ + 5) (» + 2) (»+l)n(n-l) 2* (»-/)*
2 .4 . . . (2w + 4) 1.2.3.4 r2»+7
3.5.. . (2n + 3) f .. 2 (a;-/)2 8 . 5 . . . (2«'+5)_ (n + 2) (« + 1) » 2»(g-/)4
2.4. . .(2w + 2)^ r2K+5 2.5 ... (2n + 4) 1.2.3 r2^7
3.5... (2^ + 7) (» + 3) (» + 2) (» + l) M (n-1) 25 (a;-/)«
" 1.2.3.4.5 r2l>+9
It remains that we find the sum of this series. To effect this, we remark that
the co-efficients can all be reduced by the result of Theorem 2. Applying this
theorem, the co-efficient is reduced to
m ( 3. 5. . . (2w+l) _ 3. 5 ... (2rc + 3) (n+l)n 2*
ir2»+3l2.4 ..... 2n 2 . 4 . . . (2n + 2) 1.2 3~
3.5 .. . (2» + 6) (n + 2) (» + !)» (n-1) 2*
f 2.4.. . (2» + 4) 1.2.3.4 5
3.5. ..(2» + 3) , 2 3 .5. . . (2» + 6) (n + 2) (n-^1) « 23
' 2.4...(2n + 2) ( ^ 3 + 2 . 4 . . . (2n + 4) ' 1.2.3 " T &C'
Now, we observe that the co-efficient of a2n+1 in
p-a . [8.5...(2n + l) 3 . 5 . . . (2it + 3) (n + l)«
(l-2j»a + aa)i J -12.4 ..... 2n 2 . 4 . . . (2«-t-2) 1.2
AN INTERRUPTED MEDIUM. 519
&c .... , .. 0 .... 23
2.4...(2» + 2) ( 2.4...(2» + 4) " 1.2.3
- &c.j
Hence the part of the required co-efficient which lies within brackets is evi-
2n + l f m _ a.
dently the same as that of a in J0 n_2 «a + a2)5 rf/>-
, - 2 t l-a2
* p 2 a* ~2a*
.-. The above co-efficient is the same thing as the co-efficient of a2" hi the
expansion of
m fl-a l-a2 VT+a? l-a2
-
r-2n+3 2a* - 2a2(l-a) " 2a2 2 a2
„ , ,,»»
S
But this co-efficient is evidently zero. Hence, every term in the expression of
' "- --« is
We have consequently proved, that a particle of a system exerting forces
which vary inversely as the square of the distance, will not tend to move at all
by the action of the other particles of the system on it when out of its position of
equilibrium.
Let us next proceed to find the values of c2, M, &c. For the first of them, we
will take the sum throughout an unform medium, whereby its value will become
c* = lm((pr + ^ d y2) 2 sm2 k S2X (1)
where 5 #, 8 y, d z are the co-ordinates of any particle m, measured from that
under consideration, r the distance between the two, and r 0 r the law of force.
Now, 2 sin2^ = 1 -cos k 8 x = 1 - (1 - (-^|^+ &c.)
.-. c* = ?m(4>r+ ^dy^-Zmtyr+^di,2) (1 - ^^ + &c.)
This expression can be reduced by means of the Theorems just obtained.
Equation A (1) gives im 8z* V"-2 — = \ - r 2 ™Sx-n ^
T ~ H — JL T
which, by applying equation (B), is reduced to
- m - > - ,
r (2n — i) (2B + i) r
VOL XV. PART IV. 7 A
520 PROFESSOR KELLAND ON THE VIBRATIONS OF
The same equations give likewise,
&c. &c.
By substituting these results in the value of c3 it becomes
d)'r fr2
~ "
3.51.2 5.71.2.3.4
~ &c'
Of this expression the first line is not dependent on expansion, the second and
third are. It is desirable to keep them distinct.
(pr T
To sum the series which multiply r and ~ respectively under the symbol 2 m.
sin kr
~kr~
which is the multiplier of 0 r.
r*_ k*r* k*r*
Let 3 " 3.5.1.2 +5.71.2.3.4
f u r2 k2r* *4r«
then Jo~ dr-.-. 0-3-T-3 + T— T-
3r* tfr5
'" ' :C
— sn
r d sin k "r
k3 dr r
1 /sin kr \
= 73- { - — — A cos k r I
** V r )
which is the co-efficient of ~-
By substituting these values in the expression for c2 it is reduced to
sin k r cb' r /sin k r cos kr
— - -- 2 m J- — — - -
kr r
/sin k r cos kr\ . .
( — - --- — - I (a\
\ k3r k2 J *> '
This is a remarkably simple expression for c2.
AN INTERRUPTED MEDIUM. 521
By combining the two portions, it may be written thus :
f „ r sin k r\ /r3 sin k r r cos k r
r2
sin k r r cos
If we write/1 (r) for r (r), the force at distance r, we get
r2 sin kr ,
(ft),
which is identical with M. Cauchy's equation (15), Nouveaux Exercises (Prague),
p. 187, and leads immediately to his equation (28), Exercises d" Analyse, &.C.,
p. 299. The facility with which I have deduced this equation, is a proof of the
utility of the method of proceeding which I adopted in the Memoirs from which
the original value of c2 is extracted.
It is worthy of remark, that, by converting sums into integrals at once, we
obtain the same result as by the process we have followed. We shall prove this
as follows :
Let r be the distance of a particle from the origin, Q the angle between r and
the axis of x, <$> the angle between the planes of x and r and x and z :
then the mass of an element is p r2 sin 6 d 6 d (j> d r
.•. 2m (j) r cos k d x = g I I I dr dQ d$> r2 (fir sin 6 cos k 8x
d x—r cos 6, 8y = r sin 6 sin
r cos kx=
) / / d r d Q r2 $ r sin Q cos (k r cos 6)
/, , sin kr cos 6
*rr0r(-- -j + C)
/, sin A r
i*rr$r — ^~
<£',. r/"' A23" '»•
and 2m— Oy2 = 1 1 I drdQdd)^- — r4 sin3 5 sin2 d)
y »A/o i/o r
=-7T p ff dr d Q <$>' r . r3 sin3 0
= <7T p / rf r (.— cos Q H 5 — + C) 0' r r3
4T? /»
O *^
2 w ^ — §y* cos (&5a;) = 7rp// dr dd (f)' r r3 sin3 0 cos (A r cos 0)
dr dv
522 PROFESSOR KELLAND ON THE VIBRATIONS OF
Now / »2 cos v dv=v2 sin v + 2 v cos r— 2 sin »
r dr f cosAr
_ --
Substituting all these results in equation (1), it gives
/>-oc Co, (b'rr8 , sin A r , . cos X; r sin kr\
-^irg I drlr2(t>r + i~ -- rtyr— — +r $'r — -^ -- =r2. In this case it is
evident that the above expression does not vanish when r=cc. The reason why
this is so, is that r 2fr is a finite quantity. Now, if we return to the original
expression for 'r * 9N / * , S \
e* = 2 m (9 r + L- - ojr) (cos a o x— cos k o x)
which, when the law of force is that of the inverse square of the distance becomes,
a_ym J" sin ar 3 sin a r 3 cos a r
r3 \ a r a3 r3 a2 r2
/sin kr 3 sin kr 3 cos k r'
v fc y tc "i K> f
If we now substitute integrals in place of sums, we obtain
fs\n ar 3 sin ar 3 cos a r
/<*> /<*
dr(
sin k r 3 sin A r 3 cos k r\
AN INTERRUPTED MEDIUM. 523
. cosar sin a r coskr sm
(cos a r sin a r cos k r sin k r\ a — ° •>
/ r=o J
= 0
Thus, that portion of the value of c3, which we obtain by substituting integrals
in place of sums, is zero. This conclusion I arrived at previously, and it appears
to be, in every way, conformable with the nature of the function.
Let us now recur to equation (d), and endeavour to obtain the approximate
form of c2 by summation. We will suppose (as an approximation merely) that the
particles may be regarded as aggregated in spherical surfaces about the molecule
under consideration. Let e be the distance between two consecutive particles,
r=n e, where n is a number ; then 4 T n2 is the number of particles in a spherical
surface, of which the radius is r. Putting, therefore, instead of 2 m, S 4 TT m n8,
where S refers to the number n : we get
1 f sin ane 3 sin an € 3 cos an €
c2=4:'!rmS ;-]- ,8,+ « a y •
we3 ane a* n6 e3 or tir €*
-(
sin knc 3 sin Awe 3 cos k n
~kn~e "•--*-*
• 4 TT m f 1 {sin (3 n 3 sin 0 n 3 cos /3 n
~~ ** 3
1 /sin an 3 sin an 3 cos a :
' a /»a«4 +'
a\n2 tfn* an
where /3 is written for a e, and a for k e.
_ 4'7r»M_f/Q6? ^sin /3 w cos /3 w1^ n d {sin a n cos a M
~ e3
4I7T>» y ( a d 1. _^_ —sin /3n _d 1 ^ —sin a w "1
~" Pd0pd~fi fin* aTa ddt an* J
rf /I rf /I sinaMxX . «? /I
-p-+— 23—+— 33- + &c. = -g toga— j- ^- + C-2- + D-2gg + &c
r>. „ sin a sin 2 a sin 3 a a3 , as
Finally, _14 - + — ^_ + ___ + &c. = _log« + Aa3 + Da- —^ + &c.
where A is a constant.
1 „ sin a n a2 , a4
d /I „ sin a n\ a a , a
J5 (a^-^-)-6+3loga + 2A-
l a
d a \a da^a »*
By substitution, we obtain,
2_47Tm fl a2 /I jS^ „ \ i
np"if~w" V3~i8o • ) }
,, . 4 7T OT A2
Hence in value, c2= — - —
and
180
4 7TWZ
180 e 45 e
This is precisely of the/o?-m which experiment requires. We learn from the
result, too, that m is negative, that is, that the force is repulsive.
It will be remarked that whilst approximation, on the hypothesis that the
principal effect is due to the particles in the immediate vicinity of that under
consideration, gives the same order to the first term in c2 as the process of summa-
tion does, it gives it a different sign.
This wiE appear by expanding either equation (1) or equation (a) in terms
of A.
From the former r + ^—dx2} sine 3 xcosfd y + —. — -r 2 m — — $3" 8 y cos e d x sin f8 v
r sin dr, 8 x=r cos 6, 8y=r sin 6 sin cf>.
Instead of cosfdy write 1, and instead of cos e 8 x write 1, for the other
parts of these expressions respectively are very small compared with these, as we
have just proved.
Now 2 m r - -^T- drd(t>
n Co j. 1 — cos er ,
= 27TO I r2 m r - d r
*J er
= IT p / e r3 (p r dr
2 m $-L dx2 sin e d x= fff§ ^ £-^-r2 cos2 d sin 6 sin (e r cos 6) dr d$ d 6
= 2 TT p r3 $' r -3 sin p dpdr
from j»=0 to p — er
//^ (f)' T d T C ~\
— *-s — I — 2 + 2coser + 2ersin er—e* rs cos er i
e3^ (. j
•TTpe /*
= — ^— / r1 § r dr
2 OT _L — 5 a; 5y sin/5y=£> III— — ^4 sin2 Q cos 0 sin ^> sin (Jr sin6 sin (f>) dr d6
526 PROFESSOU KELLAND ON THE VIBRATIONS OF
= ? I IH^- y4 sin ft - , f . . ,- dpdrdcf) sinp
JJJ r /8r3sm3<£
fromp = 0 to p=fr sin 0
= p if ' \ r2 f -2 + 2 cos (/r sin (p) + 2fr sin 0 sin (/r sin ft)
*J \J J T Sin Q) i.
—f2 r2 sin2 0 cos (Jr sin 0) \ dr d(f>
This cannot be integrated with respect to ft by any known process ; but the
form of the result (supposed to vanish at the upper limit) is
Hence M
e,
the integrals for x, being all negative
SimUarly 7+7=°
M F
Another equation — + -r = 0 must be employed in reducing the equations in
a symmetrical medium. But, although I am satisfied of the truth of the equa-
tion, I am not prepared to establish it by direct reasoning.
The application which I propose to make of the equations now established,
is, to determine the phase and intensity of the reflected vibration in the case
where there is no proper transmitted one.
-2 -2
— — D --D F
For the sake of brevity let us write a for 2 , and b for 2 __ ', s for — ^ ;
M ~~M~
the medium not being necessarily symmetrical.
Our equations of motion thus become (#=0).
(I-R)sin^ + Ra = Ta ................ . . (1)
(I + R)costf> + Ry = T,, .................. (2)
I'-R' + R, = T* ............. ....... (3)
,_ / dl dR\s'm(f) dEy I d^y 1
a Ra + b Ta + I -j -- -j — I -- r -- -j-2 - + a — ^ - = 0 .... (4)
\dx ax ) e dy e dy e \ '
R AT fdl • dR \<>os(t> dR* 1 flrfT,l
a Ky + o Ly + ( — -- f- -j — • I - '- -- —j— — + a — — — = 0 . . . . (5)
\dx dx ) e dy e dye
i'-4^V = 0 ........ ..... .. (6)
x dx e
AN INTERRUPTED MEDIUM. 527
Denote fy + ct by 6, and when x=Q
l=i cos 6, K=r cos (6 + a), ~RX = p cos (0 + /3)
Ta, = * cos (0 + /3'), Ry = a cos (6 + 7), T,, = r cos
The equations (1), (2), (4) and (5) become
(i cos 6— r cos 0 + a) sin 0 = * cos (0 + /3')— £> cos (0 + /3) ....... (1)
(i cos 6 + r cos 0 + a) cos (j)—r cos 8 + 7'—
— stsin (0 + /3') tan 0 = 0 . (4)
Now 0 is indeterminate ; hence, equating to zero the co-efficients respectively of
cos 0 and of sin 0 we obtain :
(i— r cos a) sin (p = t cos /3'— p cos /3 ...... , ..... . . (1)
r sin a sin 0 = — / sin /3' + £> sin /3 .............. (2)
(» + r cos a) cos (f) = v cos 7'— cos /3+6 t cos /3'— r sin a sin 0+trsin 7 tan 0 — * r sin y tan (p = 0 . . (5)
— a p sin /3— 6 ^ sin /3'— (z' + r cos a) sin 0 + = (a p + 1> t) cos {3 + (s—st) tan (p sin 7
(»' + /• cos a) sin <£=—(« g + bf) sin /?+(*—* r) tan (£ cos 7
r sin a cos 0 = — (a «• + 6 r) cos 7 — (p — * 0 tan <£ sin /3
(i — r cos a) cos 0= —(a ff+6 r) sin 7+ (p — * f) tan <£ cos /3
By substituting in the last four equations the values of cos /3, cos 7, &c, from
the first four, we obtain
ap + b t ,. «—s r
r sin a = • - (t — r cos a) + - - r sin a
t—§ r—e
, a p + b t . e—sr ,.
ft + r cos a) = — •* - r sin a + - (i + r cos a)
£— g r—e ^
a e+b r,. . p — « / ,
r sin a = -- — u + r cos a) + -S— - tan2 9 r sin a
r— • sin a
i2-*-2 cos2 a=r2 sin2 a
or »'=»•
Moreover, by means of the first four equations we get
(i2— r2) sin 0 cos (£> = ((— p) (r— «•) cos (fl — 1
— 7= 4j
a. If ^?,a=0
6. If «•=«•, a=?r
7T
c. If p — 7= -y sin p=cos 7, cos /3= — sin7
and
sina
= — tan /3 = cot 7 = — ;
1 — cos a
••• 7 = | and /3 = ^ + ~
sin a
AN INTERRUPTED MEDIUM. 529
For (a.) we get r=i, a=0, /?= ^-, 7=0
4 » 2 6 »
For (b.) we get *•=*, a=7r, (3=0, 7 = -
2z 2 ft*
cos /3'— £> h . . by (1)
r,, (i— r cos a) sin d) o h
and eos/3'=L _jL £ + £_
Similarly sin/3'=- "^"* + £L ..... by (2)
0 (i— r cos a) sin (i) th
cos/3= -7^- - + t=j-
0 r sin a sin d> te
530 PROFESSOR KELLAND ON THE VIBRATIONS OF
. . (i+r cos a) cos 0 e k
Also cos y = v ; — '- z + - by (3
r — o
r sin a cos (b e I
sm y = -£- 4 by (4)
T—e 7—6 J V J
(i + r cos a) cos p rk
cos 7 = > — *- + -
sin (hi—r cos a-er sin a) = 0 . . . (!')
l(r+ir) (/2 + A2) + 2cos 0 (Af+r cos a + ^r sin a) = 0 . . . (2')
By substituting the values of cos /3, cos p, &c. given above, in the remaining
four equations, they become
. N (i— r cos a) sin (b . . e—sr
(a p + b () * — r- — r.sm a sin ,. , . (a— sr) sin d) (i+r cos a)
(a p + b f) - — *- — (i + r cos a) sm d> + 5 - '- —
t— p 5 — «•
apte + bg(e , erk — srek -
____Ji + tan
— v
•r— «•
(A r sin a + e i— r cos a)
r-p
, (1 — *)ffr ,. . , .
+ tan
_
-±^ (i3-r2) sin 0 + '^J^-«-* (At + r cos a +
• •>
er sin a)
-f tan - (1— «) (*»'+»• cos a— k r sin a) = 0 . . . . . (II)
r— g
By treating (7) and (8) in a similar manner, we obtain
^— p cos2 d) + * /— p sin2 d)} (a + b}er,,
3 • a * / _t _i / f If jt SlTl ft /
(t— p) COS (/> r— ff
+ tan (1 — «) -5- — (e r sin a + /* i+r cos a) = 0 (Ill)
--- (z2 — r2) cos rf) + - "y " ' (ki—r cos a — lr sin a
— v — - v
r — tf
+ tan(/> (1 — ») -*— (ei— r cos a + hr sin a) = 0 ........ (IV)
TA.,, r. T /•?> ON • j. (1+*) r— 2 f . (a + fr) p t (hr sin a + e i—r cos a)
rrom 1. u2 — r2) sm ffl ^ - - -- h » - ^- — - - - = 0
r—e t—Q
II. (a p + b t~) (i2 — r2) sin
sin /3 + r sin a sin <£ cos (3
VOL. XV. PART IV. 7 D
PROFESSOR KELLAND ON THE VIBRATIONS OF
('i — r cos a) cos 6 — r sm a sin 0 .
t = > -H — 73 r^ — — sin 0
sin (0 — 4-)
i cos 6 — r cos (a — 6) .
_ i ^ Cl
sin(0 —
sin )
p ^ 2 sin 0 (i— y)g + (e— r) r . a2 — a
'' ' "
to no dimensions,
r = COS 0
I. hr$ina + e(t— rcosa)=— (Q — $) r a ~- (i—r)
Hence the equation to two dimensions is
i-r s— p- (i-rf-r (i-r} (a?-a~6~+^>)
- B + V
Dividing, we get
n /• \ /i Nz'7— r(a— 7)
z -l-.v --- -
i — r + r a (a — 0 + 4) + -
L ^^_- = 0
or
-n 4* . , 4; «'— r
But t= -- -sm0 .-. — -, — --n — 7 approx.
a + b a + b 6 — -4* rl
2 at 2 a 2-a
ami r = — , cos
a+b a+b 7— y
26 * 26 2y-a
cos) cos2 0-f (*J— p) sin2 —
COS(f>
=0
AN INTERRUPTED MEDIUM. 535
or
__ __. - -
cos 9 ' cos 9 [ a i (0— -40
, z2f27-a)('2y-a) ... .sin2® i2-/
- (a + 6) cos (b — ' — s - -^—r - '-+CL—»\ -- f — rra
— ' cu — -
J
-—r
7 — Y
- a 04) - '-')* = 0
or
or
_ -- 9
cos 9 y cos 9 a » (5 — 4) L 2
cos 9 ' cos
IV. To two dimensions :
, »,,
— r(a— 2-4/) ---- rcos9 (7—
9 a + 6 v y a + 6
a (2 y — r a — Y) + 6 (« 7 — r a — 7) . 2 ...
-i — '- - -. - * ' .. ..^ ' . - ^ cos a> fz2 — r- )
(7 - Y) (» + r)
a }=0
If a = 6; a = 7 + Y, a = ^ + ^ (by II.)
TTr . z2— r2 ., , sin2 d) 4*2 a.. . 4 06
III. glVeS —r — (I — *) - -r H^Cz-r) Z COSd) (7-7') fa= 0
cos 9 y cos 9 a — b 2i- « + 6
or H— (1— «)sin2 9 4-) (» — »•) = a cos2<|) (7— Y)
(i - r}
or 7 — Y = 5* -r-r nearly ;
i a cos * 9
7 + Y = «
:> - o
• — (1— *) sin2 (z— r) — =0
2 z
or a3 i(i— r)cos*(f) . a + t (z— r) a — (1— s) — («'—?•) sin2 0 = 0
2(1-*) .
— ^ - 1 2
d>
.. _ _
a 2 cos 4(f> + 1
Finally, I. gives to two dimensions
o/-2 ^!\ /i ^/•2 2%
2(z2-r2)-(l-*)(z2-/2)
-r) f i—
.
ff
_
2 a « cos *
i r
or .
,
_2 (<_r) - (1-,) < = (1-.) «
2
tan
r =
But if a be not equal to b, we have the following equations :
-~
27-0 _ 2a
7— Y
• • -'. CD
AN INTERRUPTED MEDIUM. 537
2Y-a_ 2b „.
7-Y : ~ST6
2 (Mr) - (l-*)''7"7^ t-r + ra(a-tfT*))=0 (4.)
(5.)
>s»0<»(7-y)=0 . (6.)
and IV. . .......... (7.)
From (1.) and (5.),
/i « 6 ,.
= -Z
a a ,. .
*-!> «('-*•>
From (2.) and (3.), * 7 + « Y = o
=
From (6-), 7-Y = -
*
a j .a
COSJ w I*
a + b i*-r>
— -A — £ ^2 - r^: nearly
4 a o i cos
_ a 6 . , a i—r
~ 2 2 a b i cos2 d> 2 2 « z cos2 ^>
^-s— a (f + r) — (o + 6) r O
IV. gives
2ab i cos2
(o + b) cos -. — a — ~ra — - — j- • ., j
r z+r abt* cos * 0 , , N sin- O) 4 z .
-J- 7 -TTJ-. r T — (1 — *V - —I y = 0
(a + o) (z — r) cos { '-e-'JEr
1(1- .
'
2 a b i c
_ a abi cos2 (f> a
(a + b) (i+r) a + b
»' Y~ >*(« — Y) _ fl <* 6* cos2 \
• f -i IN « f.'-r>2 , 2
r = z{ 1 — (s— 1) -- , + - — tan2
\ J a + l a(a + b)
{»?« »w2 , , 1
1 -- 5- + — 7 - pr tan * m >
a + b a (a + b) )
If a— b be not supposed small, there is another term, which is introduced thus :
2 .•'-,*+ &c. +
4 sin2 (p .- v (t — r)2 (a 5 cos4
(1"
8(1-*) sin2
2 sin2 d) ma? (ab cos4 0 + 1)
— ^ —
-- r
Thus the reflection increases with the angle of incidence, so far as this approxi-
mation proceeds.
It is not difficult to work out the solution for the vibrations parallel to the
surface.
Should the conclusions to be derived from the comparison of the two results
appear to give the law of elliptic polarization, I shall recur to the subject at some
future time.
VOL. XV. PART IV. 7 F
( 541 )
XXXV. — Chemical Examination of the Tagua Nut or Vegetable Ivory. By
ARTHUR CONNELL, Esq., Professor of Chemistry in the University of St Andrews.
(Read 15th January 1844.)
THIS remarkable seed or nut is now well known in London, as a substance
extensively carved into a variety of ornaments, and capable of receiving as high a
polish as the finest ivory ; which it also greatly resembles in colour. I lately
obtained various specimens both of the nut in its natural state and of the fine
turnings produced in the process of working it, being desirous of submitting them
to a chemical examination.
The nuts in my possession vary in size from a pigeon's to a hen's egg, and
have a somewhat angular shape. They are covered with a brown epidermis, and
have an outer shell & of an inch thick, and consisting of an outer white and an
inner brown layer. The inner mass of the nut is remarkably close grained and
homogeneous to the naked eye ; and when cut and polished exactly resembles
animal ivory. The hardness is considerable ; the white mass yielding with some
difficulty to a knife. Thin portions are translucent. The density of the white
mass is 1.376, at 53° F.
Dr BALFOUR, Professor of Botany in the University of Glasgow, has been so
kind as to inform me, that this vegetable ivory " is the albumen (botanically
speaking), of a palm called Phytelephas macrocarpa, which is found on the banks
of the river Magdalena in the Republic of Columbia. The natives call it Tagua
or Cabeza de Negre (Negro's head)."
Mr COOPER has described, in the Microscopic Journal,* the structure exhibit-
ed by a thin slice of this substance under the microscope. He found it to consist
of a homogeneous substance, without any appearance of cellular or other elemen-
tary structure, but traversed in one direction by parallel canals or tubes, some-
what irregular in their shape, and evidently filled with an oily fluid ; and he at-
tributes to the presence of these reservoirs of oil, joined to the compact texture of
the substance, the pure and lasting polish of which it is susceptible.
I had made considerable progress in my chemical examination of this curious
substance, before I was aware that it had been submitted to analysis by my friend
•Vol. ii.P. 97.
VOL. XV. PART IV. 7 G
542 PROFESSOR CONNELL'S ANALYSIS
Dr DOUGLAS MACLAGAN. I was then directed by Dr BALFOUR to Cormack's
Journal of Medical Science,* for the results of Dr MACLAGAN'S analysis. It ap-
pears that his specimen contained some soft matter as well as hard, and the por-
tion examined by him consisted partly of both these kinds. The constituents he
found were —
Hard woody fibre, 76.5
Vegetable albumen, . . . . . .1.5
Bitter matter, soluble in water and alcohol, . . 2.5
Gum, with phosphate of lime, .... 5.5
Ashes, 0.5
Moisture, ... . . 13.5
100.
The bitter matter, he states, evolved a urinous odour by heat ; and the ashes
were phosphates and a little silica. A portion of the harder part he found to
contain only 9 per cent, of moisture, and 2 per cent, of ashes, consisting of earthy
phosphates, silica, and various alcaline salts.
An allusion is made by Dr MACLAGAN to an examination of this substance
by Dr PERCY of Birmingham, but I have never seen his results.
My own results do not differ very materially from those of Dr MACLAGAN ;
and those differences which do occur, arise, I believe, chiefly from the circum-
stance that the azotised principles of vegetables have been much studied by
chemists, in the short interval which has elapsed since his analysis was made.
The leading difference is, that I have found the vegetable ivory to contain from
3 to 4 per cent, of an azotised substance, which appears to be either identical with
or closely allied to legumin or vegetable casein. T have also found nearly 1 per
cent, of fixed oil.
The matter examined by me, was, as already stated, the fine turnings obtained
in the process of working and carving the nut into ornaments. I got them from
one of the London workmen ; and, of course, they must be viewed as the hardest
portion of the nut. They constituted a white powdery substance, mixed with
some larger shavings, and were capable of being reduced to still finer particles by
rubbing in a mortar. When moistened with water, the transparency of the thin
shavings was increased.
When the turnings were heated they took fire and burned with flame, the
combustion sustaining itself like that of wood. A white ash was left, dissolved
by water acidulated with an acid. When pressed in blotting paper between
heated metallic plates, no oily stain was noticed, but it will afterwards be seen'
• 1841, p. 614.
OF THE TAGUA NUT 543
that a little fixed oil was obtained by the agency of solvents. Distilled with
water, no trace of any volatile oil was noticed. Heated with hot water, or allowed
to stand some time in contact with cold water, some soluble matter was taken up
which was obtained again by evaporation. Rubbed in a mortar with water, a
milky liquid was obtained, which gave only slight traces of coagulable matter by
boiling ; and yielded a soluble precipitate when heated with acetic acid. Both
alcohol and ether, when boiled on the powder, took up a very little matter.
Caustic potash ley, when boiled on it, became yellowish in colour, and when
supersaturated with muriatic acid, precipitation ensued. Muriatic acid, boiled on
the powder, also acquired a yellow tint.
Having, in preliminary trials, satisfied myself as to the general nature of the
constituents, the following method of analysis was adopted : —
A portion of the powder was rubbed dry in a mortar to reduce it to a finer
state of comminution. It was then rubbed for several minutes at a time, with
successive portions of cold distilled water. The milky liquids, after settling for
a few minutes, were poured out of the mortar and allowed to subside farther for
a night, and what subsided was added to the mass of solid matter. Another por-
tion of water was also left a night on the powder, and well rubbed on it next day,
and then strained through two plies of thick muslin, and allowed to subside for
half an hour. The whole of the milky liquids were then boiled for a few minutes.
A very slight appearance of coagulation ensued, and a very little matter speedily
subsided, which, from the manner in which it was obtained, was evidently a trace
of vegetable albumen.
The residual solid matter was now triturated with boiling water, and left all
night with the liquid : and this process was repeated several times with new por-
tions of boiling water. A milky liquid was again obtained, which remained so,
even after every thing mechanically suspended had been deposited by rest.
To the emulsion which had been boiled and separated from the albumen,
as well as to that prepared with boiling water, acetic acid was added as long as
a precipitate was formed. Next day the precipitate had subsided, and the liquid
was clear, or very nearly so. In a day or two it was collected on a weighed
filter, and dried by the heat of a salt bath and weighed. Treated with ether,
nothing was taken up.
This substance, from the manner in which it was procured, as well from its
leading characters with reagents, appeared to be either identical with, or nearly
allied to, legumin, or what has lately been called vegetable casein. Its solution
as has been seen, is not coagulated by heat, and in this respect it differs essentially
from albumen. On the other hand, it is precipitated by acetic acid, precisely as
an infusion of peas, which has deposited its starch, is precipitated by that acid.
Farther, it is more or less soluble in caustic potash ley, and it is an azotised sub-
544 PROFESSOR CONNELL'S ANALYSIS
stance. All these characters are sufficient . to shew its identity or close analogy
with legumin or vegetable casein : but in the present state of great doubt whether
LIEBIG is correct in holding legumin to be identical with animal casein ;* and
whether there is only one kind of legumin — Messrs DUMAS and CAHOURS asserting
that there are two — it would evidently be premature to attempt to determine,
with certainty, whether we are here dealing with a substance identical with, or
only closely allied to, the azotised principle of the leguminosse. Meanwhile,
however, as it differs essentially from vegetable albumen, and is procured by the
same means as the legumin of peas, and is an azotised body, I shall consider it
as legumin or vegetable casein.
The liquid which had yielded the casein was evaporated to dryness, when a
brownish- white matter was obtained, which was not soluble in alcohol, nor had
any sweet taste, and when slightly moist had a clammy consistence. It contained
no nitrogen, and seemed, in short, to have the ordinary properties of gum.
The whole of the original mass of the powder which had been rubbed with
cold and hot water, was now boiled with a quantity of water, and the whole
allowed to subside for a night. Next day the whole matter had subsided, leaving
the liquid nearly quite clear, and acetic acid no longer produced any effect on it.
Evaporated to dryness, a mere trace of gum was obtained.
The subsided powder was dried, and then treated with hot alcohol. This
alcohol, by evaporation, yielded a small but decided quantity of a yellow fixed
oil.
%
The residual powder was now treated with dilute caustic potash ley, aided
by gentle heat, and also by diluted muriatic acid. The former of these liquids
took up nothing ; the latter, a mere trace of a mixture of two or three different
matters, which were too small in amount to have their precise nature determined.
The residual white matter which had thus been successively treated with so
many solvents, was free from nitrogen, and was coasidered as woody matter or
lignin.
The powder was examined in many stages of its analysis for starch, but no
traces of that substance were found.
To determine the precise quantity of water contained in this substance, the
difference of loss of moisture in a dry air at 75° F., and on the sand bath at 240°,
was ascertained; the loss at the former temperature being reckoned merely
accidental hygrometric moisture, and that at the latter, constituent water.
The amount of ashes was ascertained by incinerating a portion of the powder;
and this amount, as well as that of all the solid constituents, was computed for
the powder as dried at 75°.
* See Berzelius Jahresbericht, 1842, p. 2?0, &c.
OF THE TAGUA NUT. 545
The result of the analysis was as follows : —
Gum, ... .... . . .,. . . 6.73
Legumin or vegetable casein, 3.8
Vegetable albumen, 0.42
Fixed oil, "*!'.''. . . . . 0.73
Ashes 0.61
Water, 9.37
Lignin or other woody matter, .... 81.34
100.00
In the ashes were found phosphate of lime, sulphate of potash, chloride of
potassium, carbonate of lime, and a little matter insoluble in acids, and apparently
siliceous. There was also a little iron ; but this might have proceeded from the
tools employed in working the ivory.
It thus appears, that this seed contains between 4 and 5 per cent, of azotised
matters, besides a much larger proportion of non-azotised substances ; all of which
are available for the nourishment of the future plant during germination, as
well as for the food of any animals which may partake of it. It is said, that
in the young and soft state of the nut, certain wild animals are fond of it. My
analysis does not present any substance which we can positively say would prove
deleterious to the animal economy ; although, of course, it is possible that some of
them, such as the oil, might be so. But I made no experiments in this point of
view, which, of course, it would be essential should be done, before it could be
suggested that the powdered nut might, from its azotised and other constituents,
be made available, in some shape or other, and to a certain limited extent, as an
article of food. It is said that large cargoes of these nuts are now occasionally
imported.
The chemical constitution of this substance appears to throw no farther light
on its remarkable state of cohesion, than to suggest the idea, that the gum and
other soluble constituents may have the effect of agglutinating the ligneous par-
ticles to such an extent as to cause its great density and tenacity.
Since this paper was read, it has been stated to me by Professor JOHNSTONE,
that Dr BAUMHAUER of Utrecht had lately found, by digesting the residual matter,
which I have considered lignin, in strong caustic potash for many days at the
ordinary temperature, the potash took up a matter, precipitated again by acids,
which he thought to be a new sort of starch, differing both from common starch
and from inulin. In ultimate constitution, it differed little from woody tissue or
from starch. This may be all very correct ; but I doubt much whether we can
VOL. XV. PART IV. 7 H
546 PROFESSOR CONNELL'S ANALYSIS OF THE TAGUA NUT.
with justice assume the previous existence of matters, obtained from organic sub-
stances by the agency of strong alkalies or strong acids. In considering the
residue as ligneous matter, I followed the directions of BEEZELIUS for obtaining
that substance from vegetable matters, and employed no re-agents which could
change the nature of the substances acted on. My object did not go farther.
( 547 )
XXXVI. — Account of a Repetition of several of Dr Samuel Brown's Processes for
the Conversion of Carbon into Silicon. By GEORGE WILSON, M.D., and JOHN
CROMBIE BROWN, Esq. Communicated by the Secretary.
(Read April 1. 1844.)
THE object of the following paper is to lay before the Royal Society the re-
sults of a repetition of several of Dr SAMUEL BROWN'S processes for the conversion
of carbon into silicon. The greater number of these processes were published in the
Society's Transactions for 1840-41 ; and certain additional ones have since appeared
in a separate form. The latter were much simpler, and more readily performed,
than those made public at an earlier period ; and to one of these we first directed
our attention.
Before stating, however, the results of any of our trials, we think it right to
mention, that most of the experiments which we now place on record, were regarded
at the time of their performance as only tentative and preliminary, and were not
registered with the minuteness of detail they would have been, had we expected
ultimately to publish them.
We tried the greater number of Dr BROWN'S processes, and rejected them
one after another, without pursuing their investigation farther, on finding they
would not yield quantitative proofs of the conversion of carbon into silicon. The
limited time which, from various circumstances, we could devote to the subject,
obliged us to follow this course ; and the confident expectation we entertained, till
a recent period, that each new process would supply what the rejected ones had
failed to afford, led us to neglect noting many particulars of our early trials, which
otherwise we should have recorded.
For the sake of brevity we leave unnoticed many subsidiary points connected
with our experiments, and restrict ourselves solely to those which bear upon the
question of an anomalous production of silicon, and the source whence it was de-
rived.
We commence with the account of our repetition of the process for the pro-
duction of silicon from the cyanide of lead. This had the great advantage over
most of the others, that it yielded the silicon uncombined, and not, as they did, in
combination with oxygen as silica. It consisted in enclosing the cyanide in a
glass tube shut at one end, and drawn out at the other into a capillary. Heat
was then to be cautiously applied, and ultimately raised as high as was compatible
with the glass remaining unfused. Treated in this manner with the precautions
VOL. XV. PART IV. 7 I
548 ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
described in his " Two Processes,"* cyanide of lead was found by Dr BROWN to
resolve itself entirely into nitrogen, which escaped in the gaseous form, and a
bluish-grey powder, which, when digested in dilute nitric acid, yielded its lead to
that solvent, and left silicon as an insoluble brown powder. The general precau-
tions indicated as essential to the success of the transmutation were easily attended
to, and the only point which was much insisted on, was the necessity for the cyanide
of lead being absolutely pure.
The realization of this desideratum proved much more difficult than we had
at all expected ; so difficult, indeed, that, after six weeks spent in unsuccessful at-
tempts to prepare a pure cyanide of the metal in question, we abandoned, for the
time, the process in despair.
The method given by Dr BROWN in his Two Processes, was to precipitate the
cyanide of potassium by the neutral acetate of lead. By this process, however,
and by another similar in principle, and likewise employed by that gentleman, in
which ammonia, supersaturated with hydrocyanic acid, was substituted for cyanide
of potassium, we did not succeed in preparing a pure cyanide of lead. The white
precipitate which fell when these reagents were made use of, was found on analysis
to give a proportion both of lead and of cyanogen, quite at variance with the pos-
sibility of its being the pure protocyanide ; the average proportion of cyanide of
lead present being, as nearly as possible, only a third of its whole weight. When
distilled with oil of vitriol in a water bath, it gave off acetic as well as hydrocyanic
acid ; and when heated alone in a tube, cyanide of ammonium was evolved in
large quantity.
We did not determine the exact composition of this compound, as it was suffi-
cient for our purpose to know that it was not the salt we were in search of. But
it appeared to consist of cyanide of lead mixed with a large proportion of a hy-
drated basic acetate of the same metal.
Besides the neutral acetate of lead, we employed that salt acidulated with
acetic acid, the tribasic acetate, the nitrate, the basic nitrate, and the nitrite, as
precipitants of the alkaline cyanide ; and we varied the proportions of hydrocyanic
acid and ammonia, and all the minor details of the several processes, without at-
taining the end we had in view. In every case the tendency of lead to form basic
salts, gave rise to the mixture of the cyanide produced, with subacetate and subni-
trate of the oxide of the metal.
We also digested cyanide of potassium in solution on ferrocyanide of lead, in
the expectation of removing ferrocyanogen, and leaving cyanide of lead, but the
process did not succeed. Nor were we more successful with another, where we
digested hydrated oxide of lead in dilute hydrocyanic acid.
Finally, we had recourse to the iodide and chloride of lead, which we dissolved
* Two Processes for Silicon, by Dr SAMUEL BBOWN. Edinburgh : Adam and Charles Black. 1843.
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON. 549
in water, and added in atomic proportions to solutions of cyanide of potassium.
Where the iodide was used, the yellow colour of the precipitate shewed that it was
a compound of the iodide and cyanide of lead. The precipitate varied in appear-
ance and properties, where the chloride was employed, according as it or the cya-
nide of potassium was made the precipitant ; but in every case it seemed to be a
mixture of cyanide and chloride of lead. It retained moisture with great obsti-
nacy, and could scarcely be deprived of it by heat without decomposition. It was
accordingly placed when moist in vacuo over sulphuric acid, and afterwards dried
completely in a current of heated air passed through chloride of calcium. But this
tedious desiccation introduced a new element of impurity ; for although the cyanide
of potassium employed was originally quite free from carbonate of potass, the pre-
cipitate, when dry, gave off carbonic acid when treated with dilute acids. The
proportion of chloride present in the precipitates varied much, and the physical
characters of the body along with it. Where the cyanide of lead preponderated, it
was, when dry, of a primrose yellow colour, and was changed by heat into a bluish
crumbling powder. When the chloride of lead was in excess it was cream-coloured ;
and when heat was applied, fused and adhered to the glass.
At this stage of the inquiry, we abandoned the cyanide of lead as a raw ma-
terial for transmutation, having exhausted for the time all our resources for its pre-
paration.
We subjected, however, most of the lead precipitates to the treatment pre-
scribed by Dr BROWN for the conversion of the carbon of the cyanide into silicon,
in the expectation of procuring sufficient quantities of the latter substance to esta-
blish its nature unequivocally.
When the precipitate prepared by his own methods was heated with the pre-
cautions indicated in his " Two Processes," we obtained a powder of a bluish-grey
colour, closely corresponding in physical characters to the " leaden " product he
describes. When this was treated with dilute nitric acid, all the lead of the com-
pound dissolved, and an insoluble brown powder remained, which we trusted was
silicon. It was quite soluble in oil of vitriol, and was only partially destroyed by
fusion with chlorate of potass. When it was fused with carbonate of potass, and
the product of fusion treated with muriatic acid, evaporated to dryness, and redis-
solved in water, according to the ordinary method for the separation of silica from
silicate of potass, an insoluble yellowish-white residue remained, amounting in
weight to a fraction of that of the original brown powder. Had the latter been
silicon, it should have yielded by this treatment twice its weight of silica.* In
one recorded experiment, we find that 4'5 grs. of the brown powder gave, after the
treatment described, 0-4 grs. of insoluble residue; in another, 2-1 grs. gave 0-3
grs ; and the proportion generally obtained was, as nearly as possible, a tenth of
the original powder.
* The atomic weight of silicon, according to Berzelius, is 22-22 ; that of silica 46'22.
550 ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
In our earlier experiments, we supposed we had erred in not heating the cya-
nide sufficiently. But we were not able, by any alteration in the mode of heating,
to procure a substance more resembling silicon than the one we have described.
"We have now cause to regret that we did not analyse the insoluble residue of
these processes more carefully. It was only cursorily examined at the time of
our meeting with it, as we were led to suppose it not silica, from its softness and
want of grittiness. But we have since had frequent occasion to notice that silica,
obtained from its native compounds, may be quite destitute of this property. The
body in question was not any compound of lead, for hydrosulphuret of ammonia
did not blacken it : it was quite insoluble in aqua regia : bore the full blast of
the blowpipe without diminution in bulk ; and fused with carbonate of soda into
a globule of a greyish colour. On the whole, it seems to us in the highest degree
probable that it was silica, but we cannot confidently affirm that it was.
The compound, or mixture of cyanide and chloride of lead, already referred
to, which did not fuse, yielded on heating, a bluish-grey powder, which dissolved
entirely in very dilute nitric acid, without the separation of any brown powder.
When the lead was precipitated by muriatic acid, the chloride removed by filtra-
tion, the liquid evaporated to dryness, and the residue plentifully washed with
boiling water, a trace of silica remained. The fusible precipitate was not subjected
to a particular examination.
Disappointed in the cyanide of lead, we turned our attention to the similar
salts of other metals ; for it is within the scope of Dr BBOWN'S hypothesis, that
every cyanide which can be converted into a paracyanide, may have its carbon
transmuted into silicon.
We rejected, after several trials, the cyanides of zinc and copper, and turned
our attention to one of the best known of all the compounds of this class, the cya-
nide of silver. This salt has the great advantage of being quite stable, and easily
prepared pure in any quantity. But, on the other hand, it gives off cyanogen at
so low a temperature, that it cannot be entirely converted into paracyanide by
heat in open tubes ; and the variable proportion of metallic silver which is thus
mingled with the product, entirely unfits it for yielding quantitative results. By
adopting a suggestion of Dr BROWN'S, however, and heating the cyanide in glass
tubes sealed at both ends, or in brass tubes closed by screw stoppers, we prevented
the evolution of cyanogen, which otherwise would have occurred.
Pure dry cyanide of silver heated under pressure in this way over a gas
flame, slowly changed into a brown powder, which, if the heat were not raised too
high, did not fuse or adhere to the glass. This powder, according to Dr BEOWN'S
views, is either a combination of two atoms of silver, and one of paracyanogen, a
sub or diparacyanide of silver, or a mixture of silver and paracyanogen, in these
proportions.
Where glass was used, when the tube was filed across, a slight explosion and
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON. 551
rush of air took place, shewing that some cyanogen, or nitrogen, or other gas, had
been evolved in spite of the pressure. But the loss in this way was so slight, that
quantities, such as 40 grs., did not lose more than O'l gr. by the heating.
The brown powder (diparacyanide of silver ?) obtained in this way, was fused
with pure carbonate of potass in a platina crucible ;* and the product of fusion dis-
solved in water, filtered, supersaturated with muriatic acid, evaporated to dryness,
and redissolved in water. A white, gritty, insoluble powder remained, having all
the properties of silica. But we shall return, after recounting the different pro-
cesses we tried, to the consideration of the proofs by which we satisfied ourselves
that what we term silica was really so. The quantity of silica was in every case
much less than it should have been, had the whole carbon of the cyanide of silver
been transmuted into silicon ;f and hydrocyanic acid was evolved abundantly on
the addition of the muriatic acid, shewing that much of the paracyanogen had
escaped the transformation of which, ex hypothesi, it is susceptible, and had decom-
posed the carbonate of potass, forming cyanide of potassium.
The liability of the sealed glass tubes to explode, which two-thirds of them did,
and the difficulty of regulating the temperature where metallic ones were em-
ployed, were serious objections to this process. Care and attention, however, might
have enabled us to overcome these, but the formation of cyanide of potassium,
in variable quantity, destroyed the possibility of obtaining proofs that the silicon
had been yielded by the carbon. On this account, accordingly, we relinquished the
cyanide of silver.
From the cyanides we passed to the ferrocyanides, in the expectation that, in
imitation of Dr BKOWN, we should be able to obtain silica in such abundance as to
disprove, by its very quantity, the objections that have been made to his conclu-
sions, on the ground that the silica was derived from the vessels or reagents made
use of.
No process for this purpose could be simpler than that given by Dr BKOWN
for producing silica from the ferrocyanide of potassium. That salt, thoroughly
dried, was to be reduced to powder, and mixed with three or four times its weight
of pure carbonate of potass. The mixture was then to be " ignited in a shut cru-
cible, made of hammered iron, during the space of four hours, and at a full white
heat."} The saline mass obtained at the end of the heating, when treated with
muriatic acid, &c., as if it were soluble silicate of potass, was found by Dr BROWN
to yield silica so abundantly, that in one experiment 5 grs. were procured from
* A platina crucible was used at the risk of destroying it by the fusion of the silver ; porcelain being
objectionable as containing silica.
| In the only experiment of which the exact quantities are recorded, 17'9 grs. of the brown powder
(diparacyanide of silver V) gave of silica 0'5 gr.
I Transactions of the Royal Society of Edinburgh, vol. xv. p. 244.
VOL. XV. PART IV. 7 K
552 ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
30 grs. of the ferrocyanide ; and the collected product of several others gave
1240 grs. of silica from 9334 grs. of the prussiate.*
We repeated this experiment many times, both in platina and iron crucibles,
but never could obtain more than traces of silica, although we employed large
quantities of material. The proportion of silica procured in our early trials was so
insignificant, that we did not attempt to ascertain its quantity. But in a recent
experiment, where 480 grs. of ferrocyanide of potassium were fused with 3 ounces
of bicarbonate of soda (which in this case was substituted for potass on account of
its purity), the quantity of silica obtained was only 0*3 gr., or less than a tenth of
a grain for each ounce of material, soda included.
We tried a single experiment with the variety of Prussian blue, formed by
exposing to the air and washing the salt left in the retorts, when ferrocyanide of
potassium is decomposed by sulphuric acid in the process for the preparation of
prussic acid. 619 grs. of this body were fused with three times their weight of
carbonate of soda, and treated otherwise like the ferrocyanide of potassium. At
the stage of the process where silica should have appeared, we obtained 12 grs. of
a soft yellowish-white insoluble powder, which, in the belief that it would prove to
be silica, we ignited for two hours in a platina crucible. It was not silica, how-
ever, but probably some organic compound ; for the crucible, on being opened, was
found quite empty.
From the ferrocyanide of lead, on which we made several experiments, we ob-
tained traces of silica.
From the ferrocyanide of copper fused with alkaline carbonates, and treated
otherwise like the similar salt of potassium, we obtained a larger amount of silica
than from any other salt of the same class. From 266 grains of a parcel of this
salt, prepared by one of us with great care, and fused with three times its weight
of white flux, we obtained 4'2 grs. of silica ; and other portions of the same spe-
cimen yielded us considerable, though variable, quantities.
These experiments were made early in the winter, at a time when we were
only anxious to ascertain if silica could be procured from such materials. In many
of them, accordingly, unweighed quantities of the ferrocyanide and the alkaline
carbonate were employed. As, however, we preserved nearly all the silica we
procured in this way, and are able to form an estimate of the quantity of the ferro-
cyanide made use of, from the space it occupied in a bottle of known capacity, we
can make a tolerably near approximation to the weight we must have employed.
On the whole, we are within the truth when we say, that from about three ounces
of ferrocyanide of copper, fused with twelve of alkaline carbonate, we obtained
ten grains of silica. The carbonate was ascertained by very careful analyses to be
quite free from silica, except in one case, where, owing to an accidental oversight,
* Transactions of the Royal Society of Edinburgh, vol. xv. p. 245.
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON. 553
a parcel of carbonate of potass was employed which had not been tested. This
remark applies to a single experiment, all the others having been made with car-
bonate of certified purity.
Encouraged by our success, comparative as it was, with the ferrocyanide of
copper, and anxious to procure quantitative results as to the amount of silica
yielded, we recently prepared several ounces of this salt, and washed and dried it,
with great care. On fusing it with carbonate of soda, however, we obtained only
traces of silica. Four specimens of the ferrocyanide were employed, two prepared
from ferrocyanide of potassium and sulphate of copper, and two from the former
salt and the nitrate of copper. All were washed and dried, and otherwise pre-
pared in the same way, and with the same care.
The following are the quantitative results we obtained : —
Ferrocyanide of Copper (from Nitrate), grs. 318-7, fused with Bicarbonate of Soda, grs. 1200; gave of Silica, gr. 0-3.
Do. do. 325-5 do. 1200 do. 1-3.
Do. (from Sulphate), 303.5 do. 1200 do. 1-0.
Do. do. 280-6 do. 1000 do. 1-3.
Do. do. 100- do. 200 do. 0-7.
From 1328-3 grains of ferrocyanide of copper, we thus obtained only 4-6 grains
of silica.
The last experiments we have to record, are those performed with paracyano-
gen. The paracyanogen employed was prepared by heating the cyanide of mer-
cury in iron tubes closed by screw stoppers, according to the process described by
Dr BROWN in his paper in the Society's Transactions for 1840.*
Paracyanogen prepared in this way, when freed from the cyanogen which,
according to his view, was mechanically condensed in it, was found by him to be
entirely converted into silicon and nitrogen by different modes of treatment. The
simplest of all these was to heat the paracyanogen alone out of contact with air,
when its nitrogen passed away in the gaseous form, and its carbon became sili-
con. In two remarkable experiments recorded by Dr BROWN,| paracyanogen was
found to give off a weight of nitrogen less by 8 per cent, than it should have given ;
and the weight of silicon left behind was " conformable to the combining propor-
tions of paracyanogen and carbon."
Satisfied that, could we shew a weight of silicon equivalent to that of the car-
bon, and one of nitrogen only 8 per cent, less than it should by calculation have
been, we should convince every chemist of the exceeding probability, if not the ab-
solute truth of the proposition, that carbon is transmutable into silicon, we carefully
repeated this experiment some ten or twelve times.
We were foiled, however, on the very threshold, by finding that paracyanogen
when heated alone, instead of yielding only cyanogen and nitrogen, as it had done
to Dr BROWN, gave off also carbonic acid and carbonic oxide.
f Transactions of the Royal Society of Edinburgh, vol. xv. p. 174. t Ibid. pp. 238, 239.
554 ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
We heated the paracyanogen in tubes of glass, of brass, and of iron, alone and
mixed with spongy platina, and at various temperatures from 600° up to a white
heat. The tubes were of small bore, and the included air was expelled as much
as possible by a gentle heat, before they were raised to the temperature at which
the paracyanogen decomposed. In spite, however, of every precaution calculated
to prevent the paracyanogen coming in contact with any source of oxygen, we
invariably procured carbonic oxide and carbonic acid.
The black matter left after the gases had been evolved, which should have
been silicon or a siliciuret, in all the cases where it was examined, except in one
very remarkable one which will be mentioned hereafter, was found to diminish
rapidly in bulk and weight before the blowpipe, and to consist chiefly of carbon.
Later researches have shewn us, that it was useless to look for quantitative
results from so impure and variable a body as crude paracyanogen. As it comes
from the iron tubes, it contains, according to Dr BROWN, absorbed cyanogen, and
frequently also silicon. We have always found metallic mercury present in a state
of very fine division, a soluble salt of mercury (which is not the cyanide, but, per-
haps, as Professor JOHNSTON has suggested, the cyanate), and often also carbon.
We have lately attempted to purify the paracyanogen so procured, by boiling
it with water for several hours to aggregate the mercury ; washing it on a filter to re-
move the soluble salt of that metal; and, according to the process given by Dr BROWN,
for depriving paracyanogen of its absorbed cyanogen,* afterwards boiling it with
carbonate of potass and water. From paracyanogen purified in this way, and heated
in brass and iron tubes, we procured nitrogen, carbonic acid, and carbonic oxide; and
the residue (carbon) was almost entirely dissipated before the blowpipe. In one ex-
periment, 3-3 grains of crude paracyanogen heated in an iron tube, gave off 5*75 cubic
inches of gases, of which 66 per cent, was absorbed by potass ; the remainder
burned with the blue flame of carbonic oxide, and was not farther examined as to
the presence of nitrogen. The potass, when examined by SCHEELE'S test, gave much
Prussian blue, shewing that the absorbed gas was chiefly cyanogen. In another
experiment 3 grs. of purified paracyanogen gave 6 cubic inches of gas, whereof
potassa absorbed 20 per cent., which, on examination, proved to be carbonic acid
with a trace of cyanogen. The residual gas, which burned with the characteristic
flame of carbonic oxide, was mingled with an equal volume of oxygen, and ex-
ploded by the electric spark. After the carbonic acid had been withdrawn, and
phosphorus had ceased to cause contraction, there remained 65 per cent, of nitro-
gen, shewing, of course, 15 per cent, of carbonic oxide.
Unable to confirm Dr BROWN'S results with paracyanogen heated alone, we
turned to his experiments on the fusion of that body with carbonate of potass.
Crude paracyanogen, when fused with that substance in a closed platina crucible
* Trans, of Royal Soc., vol. xv. p. 168.
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON.
555
for two hours, at a full white heat, was found by him to yield silica, when treated
with muriatic acid in the manner already referred to. " The weight of silicon was
never less than an llth, and never more than a 12th, under the calculable weight
of the constituent carbon."*
We have repeated this experiment many times, both with crude and purified
paracyanogen, and in the greater number of cases have obtained silica. In several
trials, however, and even with paracyanogen prepared by that gentleman himself,
we obtained no silica ; in others, the quantity from paracyanogen of our own pre-
paring was very small ; and, in all, it was much more than an llth under the weight
of the constituent carbon. The exact quantities of silicon we procured are given
in the subjoined table, from which it will be seen that, whereas the proportion of
silicon obtained by Dr BROWN was between 91 and 92 per cent, of the weight of
the carbon, the proportion we obtained, even from purified paracyanogen, was
never more than 15, and sometimes less than 1 per cent.
Paracyanogen.
Gave of Silica.
Containing Silicon equiva-
lent to
Should have given
of Silicon.
4-8 grs. crude,
0-3 grain,
Do.
o-i ...
3 purified,
A trace,
less than one per cent.
2-9
2-5 Do.
Do.
Do.
2-4
3 Do.
0-3 grain,
10 per cent.
2-9
3 Do.
0-45 ...
15 ...
2-9
We endeavoured to make this a quantitative process, by collecting and exa-
mining the gases evolved during fusion. According to Dr BROWN'S views, para-
cyanogen, when fused with carbonate of potash, should give off all its nitrogen in
the gaseous form, and have all its carbon transmuted into silicon. The latter
should then become silica at the expense of the carbonic acid, reduced thereby to
carbonic oxide; while the silica and caustic potash contemporaneously evolved
should unite to form silicate of potash. There should thus be calculable volumes
of carbonic oxide and nitrogen, as well as a calculable weight of silica produced.
And all three should agree (within the limits of error in experiment) with the anti-
cipated numbers, if a perfect transformation of paracyanogen into silicon and nitro-
gen occurred.
We made this experiment several times, but always found carbonic oxide and
* Transactions of the Royal Society, vol. xv. p. 236.
accidentally inverted, an llth being more than a 12th.
VOL. XV. PART IV.
The numbers, we suppose, have here been
7L
556
ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
nitrogen ; and the quantity of the two last was quite at variance with the volumes
they should have given, as the succeeding table will shew :-—
Paracyanogen.
Gave of Carbonic Oxide
and Nitrogen.
Whereof Carbonic Oxide.
Nitrogen.
4'8 grs. crude.
5'5 cubic inches.
66 per cent.
33 percent.
3
3
71 -
29 ...
3 purified,
2-75 -
68 ...
32 ...
We have reserved to the last the account of one remarkable experiment with
paracyanogen heated alone in an iron crucible. Dr BKOWX, described in his second
communication to the Royal Society, an experiment, in which a quantity of para-
cyanogen closely shut up in a Berlin crucible, and kept twenty days in a sand
bath, at a temperature of about 800° or 900° F., became converted into silicon.*
In imitation of this experiment, we enclosed 10'5 grains of crude paracyano-
gen in a Berlin crucible, and kept it at the temperature prescribed for four days.
An accident led to the crucible being opened at the end of this time, when the
original quantity was found diminished to 1*8 gr. This residue was of a light
brown colour, much lighter than paracyanogen, and gritty. It was fused with
carbonate of soda, and treated as if for silica, but gave only a trace of insoluble
matter.
This experiment was repeated with a small crucible of malleable iron weigh-
ing about 200 grains, containing 18'5 grains of crude paracyanogen. The lid
being luted on, and the whole crucible coated with stucco, it was placed over an
argand gas flame, and heated continuously for three days. At the end of this
period it was opened, and found to contain 4'2 grains of a nut-brown soft powder.
3'9 grains of this powder were fused with carbonate of potass, and the product
treated with muriatic acid as if it were silicate of potass. 10'4 grains of a reddish-
brown powder were obtained, which, when boiled with muriatic acid, washed and
ignited, left 8'4 grains of pure white silica. Had the original brown powder been
silicon, and by fusion with the carbonate become silica, it should have given 8'11
instead of 8'4 grains of the latter. There is thus an excess of 0-29 grain, or 3'6
per cent, of silica. In spite of this considerable excess, we believe that few will
refuse to acknowledge that the original body was silicon.
Had we been aware at the time of making this experiment, that our subse-
quent trials in other directions would prove so unsatisfactory as they have done,
we should have repeated it many times. But, as the object of our inquiry was to
ascertain whether carbon was transmutable into silicon or not, we left unrepeated
* Transactions of Ruyal Society, vol. xv. p 233.
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON. 557
an experiment which, however often successful, could not have established the
truth of that proposition. We did, however, repeat it once with 10 grains of para-
cyanogen, which were heated for three days in a small iron crucible. But on
opening it at the end of that time it was found quite empty.*
Throughout our paper, we have taken for granted that what we have named
silica was really so. The body to which we give this name was a white powder,
which was occasionally soft when first produced, but invariably became gritty when
exposed for some time to a high temperature. In several cases it was as sharp
and gritty as builders' sand. It could be boiled for hours in aqua regia, or kept at
a white heat in a platina crucible for a similar period, without a perceptible loss in
weight. It bore the full blast of the blowpipe without change j and when fused
before it with carbonate of soda, formed a transparent bead. It dissolved in alka-
line carbonates with effervescence, and could be recovered from them by muriatic
acid unchanged in all its properties. Several of our specimens were fused in this
way again and again, without varying in their deportment from true silica. These
characters would suffice to prove the body possessing them silica, and completely
distinguish it from hydromellonic acid, or any other organic compound, which
might be supposed to be formed by the reaction of compounds of cyanogen on
alkaline carbonates.
We were unwilling, however, to omit testing our supposed silica by its power
of forming fluosilicic acid when distilled with oil of vitriol and fluor spar. With
no little trouble we succeeded in providing ourselves with pure fluor, which was
ascertained, by repeated careful analyses, to be quite free from silica. The body
we were testing we distilled with the spar in a small leaden alembic, with its beak
dipping into water. The characteristic membranous tubes of silica formed rapidly,
and sank in gelatinous flakes to the bottom. After so decisive tests, we are quite
certain we were not mistaken in believing we had obtained silica.
We may farther mention, that potassium heated with what we may now term
silica, liberated a black powder quite undistinguishable from the body it separates
from common silica. We may also add, that we ascertained the specific gravity of
the silica we obtained in our earliest experiments with ferrocyanide of copper. It
was 2'25 — that given in the text books is 2'69. The difference is probably not
greater than that between different specimens of ordinary silica.
In conclusion, we need scarcely say, that we have been unable to supply any
proof of the transmutability of carbon into silicon. The utmost we may have done,
* When our paper was read, another repetition of this experiment was in progress, which has since
been completed. Twenty grains of purified paracyanogen were heated in an iron crucible for three days.
On examination, the powder was found so little changed in bulk and colour, that the lid of the crucible
was replaced, and the heating continued for three days more. A very pale brown powder was left,
amounting to 0'5 gr., which, when fused with carbonate of potass, left a trace of what appeared to be
silica.
558 ACCOUNT OF A REPETITION OF SEVERAL OF DR SAMUEL BROWN'S
is to have proved an unequivocal anomalous appearance or production of the latter
body. Our experiments, moreover, throw no light on the source of that silicon.
Taking the experiment with the iron crucible as the simplest in its conditions of
all those we have made, and not multiplying hypotheses unnecessarily, we shall,
nevertheless, be obliged to admit as equally tenable three views of the origin of
the silicon.
Paracyanogen, a compound of carbon and nitrogen, disappeared, and was re-
placed by' silicon.
We may say with Dr BROWN, that the latter came from the carbon ; or with
Mr KNOX,* that it came from the nitrogen ; or, for anything the experiment be-
trays to the contrary, that it came partly from both. Great difficulties lie in the
way of all of these hypotheses, which we feel it quite unnecessary to discuss, un-
less so far as to acknowledge that Mr KNOX'S theory stands on a broader basis of
alleged fact than either of the others, as he professes to have established his view of
the relation of silicon to nitrogen both by analytic and synthetic proofs. No one,
however, has repeated or confirmed his experiments.
We have, in the meanwhile, relinquished the farther trial of Dr BROWN'S pro-
cesses, because the experience of four months' failure has satisfied us that his ex-
periments cannot be repeated at will j that the conditions essential to their success
have not been satisfactorily ascertained ; and that none of his processes are suffi-
ciently wrought out in detail, to afford the means of establishing the transmuta-
bility of carbon into silicon on quantitative grounds, the only grounds on which such
a proposition can be based.
In particular, we have been deterred from farther trial, by finding that para-
cyanogen which, according to Dr BROWN, is a " true cyanide of cyanogen, decom-
posed neither by heat, because its constituents are equally volatile, nor by elec-
trolysis and reagents,"f is in reality susceptible of such a decomposition.
This is not the place or time for entering on this matter. But we may men-
tion, that paracyanogen, purified from adhering or absorbed cyanogen with the
utmost care, has been found by us to pass back or revert into cyanogen.J Fused
with carbonate of potass, or heated with potassium, it has given cyanide of potas-
sium abundantly. In one case where two grains of paracyanogen were heated with
potassium, and precipitated by nitrate of silver, acidulated with nitric acid, they
gave 4'4 grs. of cyanide of silver, containing of cyanogen 0'86 gr., and there re-
* An abstract of Mr Knox's paper, which has not, so far as we know, yet been published, will be
found in the London and Edinburgh Philosophical Magazine for 1843.
•f Trans, of Royal Soc., vol. xv. p. 175.
J We offer no opinion as to the constitution of paracyanogen. By the substance which we so de-
signate, we mean the black powder obtained by heating cyanide of mercury ; and in speaking of its re-
version into cyanogen, we purposely use the language of Dr BROWN, who supposes it to be a combina-
tion of two atoms of cyanogen.
PROCESSES FOR THE CONVERSION OF CARBON INTO SILICON. 559
mained of insoluble matter, which was found to be carbon, 0*4 = 0'88 gr. cya-
nogen, making together 1'74 gr. of the original weight of paracyanogen.*
This possibility of paracyanogen passing back into cyanogen, strikes at the
root of all the processes with paracyanogen, cyanides, ferrocyanides, &c., where
fusion with an alkali is prescribed ; and explains the uniform appearance of hydro-
cyanic acid, when acids were added to the products of fusion. So long as much of
the carbon and nitrogen of the paracyanogen is spent in forming cyanide of potas-
sium, quantitative proofs of the conversion of carbon into silicon, even should it
occur, cannot be secured by any fusion process.
Whether or not this remark applies also to paracyanogen heated alone we
cannot decide. By simply heating it, we have never been able to resolve it en-
tirely into cyanogen, nor, so far as we know, has any chemist. But it may resolve
itself into nitrogen and carbon, which would as effectually interfere with the end
in view.
* This fact has been already noticed by Professor JOHNSTON, Transactions of the Royal Soc. of
Edinburgh, vol. xiv. p. 37 ; and by Messrs SMITH and BRETT, London and Edinburgh Philosophical
Magazine, vol. xx. p. 29 ; but we have mentioned our experiment particularly, because it was made
with paracyanogen purified in the way already mentioned, and the quantity of cyanide of silver produced
was ascertained.
VOL. XV. PART IV. 7 M
PLATE I.
PLATE XIV. Royal Soc. Tram. Edin., Vol. XV. p. 561.
D c BDC
EA E
A,
/-.-.» * »
.
?
j
F F B EAB D C
XB S. Gontsir del!
PLATE II.
PLATE XV. Soyal Sue. Tram. Edin., Vol. XV. p. 561.
U. II. .< li
PLATE III
PLATE XVI. Royal Soe. Trans. Eclin., Vol. XV. p. 561.
-m.
f
561 )
XXXVII. — On the Development, Structure, and Economy of the Acephalocysts of
Authors ; with an Account of the Natural Analogies of the Entozoa in General.
By HAKRY D. S. GOODSIR, Conservator of the Museum of the Royal College
of Surgeons in Edinburgh.
(R*ad 1st April 1844.)
THE Acephalocyst, or simple Hydatid, is composed of a vesicle, containing a
watery fluid, which, in the normal state of the creature, is quite transparent
and colourless (PI. XIV., fig. 1.) The internal surface of the vesicle is generally
studded with numerous cells of various sizes, many of which are found de-
tached and floating loose in the fluid contained in the vesicle. These are the
young Hydatids.* Their development will be described when we come to that
portion of the present paper, which has been set apart for that purpose.
Hydatids, like the other entozoa, are incapable of sustaining an independent
existence, although, as independent creatures, they are similar to the other species
of entozoa. They infest all parts of the body, and are commonly lodged in cavities
containing fluid in Avhich the hydatids float.
From two circumstances, the true nature of hydatids has been very much
misunderstood. The first, depending on imperfect observation, has arisen from
specific characters being unattended to, and consequently, from external resem-
blance alone, these animals have been erroneously classed with other and very-
different pathological appearances, such as serous cysts.f The second cause of
misunderstanding has arisen from the limited number of known species prevent-
ing naturalists from arriving at any general views with regard to their proper
relations. Both of these circumstances have doubtless retarded our progress
towards proper conclusions relative to their true nature, and, at the same time,
afforded reasons in support of the views advocated by those who denied the ani-
mality of the Acephalocyst.
I am indebted to the kind attention of Dr GAIRDNER, for an opportunity of
examining a species of hydatid, which appears to have been hitherto undescribed,
the study of which has enabled me to detect several important circumstances re-
lative to the economy of the Acephalocysts, and also to trace out generally the
* Vide MONRO'S Morbid Anatomy of the Gullet, Stomach, and Intestines, p. 198 ; also Dr JOHN
HUNTER'S paper, in the 1st vol. of the Transactions of a Society in London for the Advancement of Medical
and Chirurgical Knowledge.
f HODGKIN. Transactions Medico-Chirurgical Soc. London, vol. xv. p. 266. HODGKIN. Lectures
on Morbid Anatomy, vol. i. p. 180, Lecture VII.
VOL. XV. PART IV. 7 N
562 MR H. D. S. GOODSIR ON THE DEVELOPMENT, STRUCTURE, AND"
analogies of the Entozoa. The patient from which this particular form of hydatid
was obtained, had been labouring for some time under great distension of the
abdomen. After death the cavity was found to be full of them, containing from
three to four gallons. On a superficial examination, they appeared to float free in
the fluid of the peritoneum ; but, on further dissection, they were found to be at-
tached to the lining membrane of the cavity, by narrow pedicles or more extended
bases. They were globular, of various sizes, from that of a pin-head up to a small
apple, and of a bright-straw colour, resembling in appearance the yolks of eggs.*
Their external surfaces were rough, as if covered by a false membrane. The mem-
brane, however, was ultimately discovered to have been produced, not by any in-
flammatory action, originating in the presence of the hydatids, (as was supposed),
but by the animal itself. When observed attentively with the naked eye, its surface
was found to be roughened in consequence of a great number of striae, disposed in
a regular manner, so as to form small irregular interspaces of an angular shape.
It covered closely all the hydatids up to the roots of the pedicles in those which
were insulated, and dipped deeply between those which were pressed together.
It also spread over the peritoneal surface to a short distance from the general
mass. Under this latter part, all the hydatids were generally small but became
enlarged as they approached the parent group.-j- (Plate XV., fig. 2.)
On two portions of peritoneum, to which neither the membrane nor hydatids
had yet extended, it was observed that the membrane became thinner and thin-
ner as it receded from the original stock. (PI. XIV., fig. 2 B.)
When observed under a high power, the membrane was found to be covered
at short intervals by numerous disks of various sizes. Larger disks, however,
were occasionally seen with smaller ones on their surfaces, and numerous tubuli
which arose by open mouths from the edges of each of them were ramified freely
over and throughout the membrane (PI. XIV., fig. 5.) Several of these stomata
seemed to open into one tube, and to be arranged round the aperture of the tube-t
(PI. XIV., fig. 5 C.) This occurred most frequently in the larger disks, and always
upon the edges of the same ; but in those of a smaller size, three or four small
tubes proceeded from the disk, all of which apparently opened by one mouth only,
the mouths being situated round its edge. (PI. XIV., fig. 7, B.) A large disk, there-
fore, might be said to represent a congeries of smaller ones, arranged together in
a particular form. The tube at the part near to its diskoid origin, was always of
* A cluster of these Hydatids, where there were largo and small ones grouped together, resembled.
very much the oyaria of the common fowl when in a state of activaty.
t The diseaso had proceeded to such an extent, and the abdomen was so distended, that this fact
could only be observed in two places.
I In cases like that mentioned in the text, what, on a superficial examination, appeared to be one:
tube only, was afterwards found to be a fascicle of smaller tubes..
ECONOMY OF THE ACEPHALOCYSTS OF AUTHORS. 5(53
a considerable size, but decreased very much as it gave off smaller branches in
its outward course. Sometimes a tube of considerable magnitude, or rather a
fasciculus of tubes, was seen connecting two neighbouring disks.
Immediately underneath that already described, was another membrane of
a much more delicate texture. (PL XV., fig. 5, G.) It was connected with the
former by means of condensed cellular texture, and sent off numerous very fine
septa, which traversed and intersected the body of the Hydatid, for the purpose,
apparently, of rendering it support. The body of the animal itself was composed
of a homogeneous gelatinous mass, of the colour and consistence of calf s-foot jelly.
The open stomata and tubes, which were seen in the external membrane, appeared
to be the organs of nutrition. They could not, however, be traced into the gela-
tinous mass, so that, probably, they only existed in that one membrane.
The mode of generation and of development in these animals is very simple.
When the internal surface of the vesicle of the common Hydatid is examined, it
will be found studded all over with numerous smaller vesicles of different sizes.
(Plates XIV. and XV., figs. 6 and 4.) These, as already stated, are young Hydatids.
A simple cell makes its appearance under the internal lining membrane of the
parent vesicle, which gradually increases in size, without any cellular develop-
ment whatever, but by dilatation alone from the increase of the quantity of
matter within it. (PI. XV., fig. 6.) In this way it increases to such a size as to
burst through the internal membrane, escape into the cavity of the parent vesicle,
and thus become an independent creature. This is the reason why we find the
internal surface of the vesicle so frequently broken up. The finest example of the
kind which I have seen, is one in the possession of Dr MONRO, and which he has
been so kind as allow me to examine. A very fine drawing of this may be seen
in his work already referred to, on the Morbid Anatomy of the Gullet, Stomach,
and Intestines, at PL IV., and fig. 18.
When a small portion of the external or tubular membrane of the new form
of Hydatid was placed under a powerful glass, its internal surface was found to
be studded with a number of small shining bodies or vesicles. In general, these
vesicles were compound, containing from one to four young cells in their interior
(PI. XIV., fig. 7, FFF) ; which cells, however, were occasionally seen free and
detached from the parent one. (PL XV., fig. 3, C.) I considered them to be the
gemmules of this Hydatid, which, like the other Acephalocystic Entozoa, is gem-
miparous.
The tubular membrane, as it spreads over the healthy peritoneum, and ap-
parently after it has reached a certain stage of growth, developes the cells, just
described, from its attached surface, and invariably from spots in the neighbour-
hood of the large tubes. (PL XIV., fig. 9, AA.) These gemmules enlarge without
any apparent cellular development ; but, like the simple Acephalocyst, by dilata-
tion from the addition of new matter within the cell. It varies, however, from.
564 MR H- D- s- GOODSIR ON THE DEVELOPMENT, STRUCTURE, AND
the former, inasmuch as the simple Hydatid was from its first appearance com-
posed of one cell only ; whereas, in this species, and particularly in this mode of
its growth, the cells, when first observed, contain a number of younger ones within
them, all of which afterwards become the separate and individual vesicle. (PL XV.
fig. 2, D G.) During this process, the tubular membrane increases in density
around and in the neighbourhood of the gemmules, owing to the increased number
of tubes necessary for their nourishment. It will be observed, that the young
original gemmule of this species resembles in its structure and functions, the adult
simple Acephalocyst.
This species of Entozoon has two modes of propagation, viz., the one whicli
we have just described, for the purpose of increasing the size and extent of its
own individual group ; and another, for the purpose of extending the species to
uninfested portions of the infested animal. In the last, the mode of propagation
would appear to proceed in the following manner : — The cells which have been
already described, in the preceding page, as occasionally seen detached from the
parent cell, and floating free in the gelatinous mass of the body of the parent
Hydatid, reach the healthy tissues which lie at some distance from the general
parasitic mass, (PL XV., fig. 2, C, D, and fig. 3, C), by some means which I have
been hitherto unable to detect. In general, they are no deeper than the subserous
tissue ; but when this has been already occupied, they are found much deeper,
where, as they increase in size, they tend always towards the surface of the in-
fested cavity, and at length burst from their confinement, adhering, at the same
time, to the bottom of their former, containing cellules by pedicles. (PL XV., fig. 2,
F.) In this manner a peculiar honey-comb appearance was produced, (PL XV.,
fig. 5, C and D), by the breaking up of the tissues, which became much more appa-
rent when the Hydatids were removed from the affected surface.
For the purpose of illustrating the series as completely as possible, I will
now describe the characters and mode of development of another form of Cys-
tic Entozoon. The Csenurus cerebralis is generally met with in the brain of
the sheep, and occasionally in the other ruminants. It consists of a vesicle
full of a transparent watery fluid. The cyst is double, the internal layer is
very delicate, Avhile the external is much stronger, acquiring additional strength
and thickness, in consequence of a great number of striae, which run through it
in all directions, and presenting, when seen under the microscope, all the charac-
ters, with the exception of the disks, of the tubular membrane of the new Ace-
pbalocyst, although not so strongly marked. Unlike the simple Hydatid, and
the parasite already described, the Csenurus possesses numerous heads (PL XVI.,
fig. 13), arising at right angles from its external surface in groups, but apparently
without any regularity. Each head consists of a pedicle (PL XVI., fig. 13, C, H),
and head proper (PL XVI. fig. 3, A), and is covered by a thin layer of the external
membrane of the vesicle. (PL XVI. fig. 13, E.) The head proper, and the pedicle,
ECONOMY OF THE ACEPHALOCYSTS OF AUTHORS. 5(55
are separated by a constriction, across which a diaphragm stretches (PI. XVI., fig.
13, C), formed of two layers, of very fine cellular substance, derived from, or con-
tinuous with, the cellular substance, and forming the walls of the head and pedicle.
This cellular substance is confined between two layers of membrane, namely,
that already described as derived from the external membrane of the vesicle, and
another which forms the internal cavitary surface of the pedicle. (PL XVI., fig. 13,
F-)
The head is armed superiorly with a double circle of long bent teeth (PL XVI.,
fig. 12, A), which are barbed on one edge, and arise from one common disk.
Around this dotible coronet of teeth, and on the sides of the head, are four trans-
versely oval suckers, which are surrounded by two concentric bands. (PL XVI.,
fig. 12, B.)
The pedicle to which this head is attached contains layers of gemmules, by
which this animal propagates. (PL XVI., fig. 13, G H.) I have been unable to de-
tect any organ by which these gemmules pass off from the pedicle to the place
where they are developed, i. 3 r* cos 2 co.
Let n=3 : then
(r2— 2 r rl cos co + rl2')3=r6 + 9 r* rf + 9 r2 / + r^
-2 r ^ cos CO {3 r* + 9 r2 rf + Srf}
— 2r* r^ cos 3 CO.
LEMMA II.
To expand (p — rcosco)" in multiple cosines, n being a positive integer.
By the binomial theorem we have
For the powers of cos co put their values in multiple cosines : then the expan-
sion becomes,
P" + '^2i r +~~L~23 — + ~ ^J5 +
L-^ + — ^ + ^ + — ^ h .... 1 cos co
~\
I
cos2w
f^3/?"-3r3 5^X'~5^ 21 17p"-7ri 1
L^- + "Jij|i -- + ~ ^jfr^-* • • .......... jcosSco
&c. &c. &c.
The law of the numerical co-efficients of the several powers of p and r are
580 MR THOMAS STEPHENS DAVIES ON
already known : but as (except those of the first line, which is clear of the cosines)
we shall not require them in these inquiries, it will be unnecessary to discuss
them, beyond the extent which our present purpose demands.
It will be observed, that all the terms, after the first, of the first line, arise
from the expansion of the even powers of cos w, and are, in fact, the absolute
terms of those expanded even powers. Let these powers be denoted generally by
2 fji : then the general form of these terms is
2^ ' 1.2.3 p.
This will take, very readily and obviously, the following forms in succession :
1 1.3.5.7. . ..(2/*-l)x2.4.6 2/z
22^ (1.2.3 /u)2
1 .3.5.7 (2jn-l)x2*.1.2.3..../A
V* (1.2.3 fjif
I 1,3.5.7
1.2.3 fji
1.3.5.7 .
2.4.6.8 2/j.
Giving to p- the successive values which are applicable to the successive cases
viz. 1, 2, .... w, we haye the form of the first line changed to
For examples of the general expansion, let n=2: then
fp—rcos w)2 = G»2 + « r3)— 2j9 r cos w + o r2cos2 &J,
2 2
Let n=3 : then
(p — rcos w)3= j03 + _ij- 3 (p2r + - r*) cos w + - pr2 cos 2 w — - rz cos 3 w.
— 9k m 4
Let w=4: then
(p — r cos w)4=jo4 + 3 p2 r2 + r4 — (4 p3 r + 3 p r3) cos w
+ (3 p2 r2 + - r*} cos 2 a) — p r3 cos 3 01 + 5 r4 cos 4 w.
li o
LEMMA III.
To expand (1 — cos w)" i« multiple cosines ofu, n being an integer.
This is, in fact, but a particular case of each of the preceding lemmas, and
its expansion might be deduced from either of them by making the requisite mo-
difications in the formulae.
DR MATTHEW STEWART'S GENERAL THEOREMS. 581
In the first lemma, by making rv=r, we should get
(r2 - 2 r /j cos w + rf)n = (2 r2)* (1 - cos «)" ;
and in the second, by making p=r, we should get
(p— r cos w)" =r"(l — cos w)".
We should thus obtain two different forms: but the expansion will be better
adapted to our present object when obtained as follows :—
Since(l— cosw)"=2"sin2n- w ; the ordinary formula, making the requisite
change in the form of the last term, gives
siu3" - w = (-_1-)n22K-1 ' { cos 2 n - w - -f cos (2 n-2) ^ w + ----
' 2' 1.2.3
In
, .„
{ > ' '
2 ' 1.2.3 ..... n
(for 2 n is always even, when n is an integer.)
If 2« 1
= (-l)"2a"-1t COSMW~ -j- cos («-!)&)+ ---- j
J_ 2»(2n-l) ----
22n ' 1.2.3
2w
If
= (-l)»22"-1\ COSM
l^ 1.3.5 ____ (2»-l)
2 '1.2.3 ..... n
LEMMA IV.
If ^i» ^2> ^3, .... 5«, be n angles in arithmetical progression, whose common dif-
2/Tj-
ference is — (or, which is the same thing, if they be the angles formed by lines
from the summits of a regular polygon with any arbitrary line, the centre of the
polygon being the origin of co-ordinates), we shall have simultaneously,
COS <9j + COS $2 + COS 03 +.... + COS 6n =0
cos 2 0X + cos 2 02 + cos 2 63 + ---- + cos 2 6n =0
cos 3 6l + cos 3 62 + cos 3 03 + . . . . + cos 3 &„ =0
cos (»-l) 61 + cos (»-l) 02 + ---- + cos (w-1) &„ = 0
VOL XV. PART IV. 7 s
582 MR THOMAS STEPHENS DAVIES ON
and
sin 6l + sin 02 + sin B3 +.... + sin 6n = 0
sin 2 0j + sin 2 62 + sin 2 03 +.... + sin 2 0B =0
sin 3 0j + sin 3 02 + sin 3 03 + .... + sin 3 0B =0
• • • • •* • •
sin («-l) Q! + sin («— 1) 02 +....+ sin (w — 1) 0n = 0.
These properties are already known, and hence only require to be put down,
without investigation.
SECTION II. THE PORISMATIC PROPOSITIONS.
PROPOSITIONS IX., X. PORISMS.
Let there be given in a plane the m points At, A2, . . . . Am, and as many magni-
tudes «p a2, . . . . am : then a point X may le found, such, that if we draw
AI X, A2 X, . . . . Am X, and likewise to any point Z in the same plane we draw
At Z, A2 Z, . . . . A« Z, and join X Z, we shall always have
at . A,Z2 + a2 . A2Z2 + ---- =0l . AX2 + a2 . A2X2 + ... -^(a^a^ + . ..)XZ2:
that is,
S(am.AmZ°-) = S(am.AmX?) + Sam . XZ2.
For, let the given points be denoted by i\ 0n r2 62 . . . rm Qm ; the porismatic
one by r0 6W and the arbitrary one by r &. Then the general type of the compo-
nent parts of the equation of the porism are
am . Am Z3 = am {r* -2 / rm cos (5 - 0ffi) + rm*},
an . AmX2 = am {r02-2r0»-m cos(00 - 6^ + r^},
Sam. XZ2 = Sam{r* ~2rr0 cos (6 -00) + r02}.
Inserting these in the general equation, cancelling common terms from the
equation, and equating to zero, the co-efficients of r cos 6, and r sin 6 (the only
forms in which the arbitraries appear in the expression), we shall have the follow-
ing conditional equations : —
S am . r0 cos 60 = S (am rm cos 6m) ........ (1)
S am . rc sin 00 = S (am rm$m.Qm} ........ (2)
S am . ra2 = r<, cos 6a . S (am rm cos 6m~)
+ r0 sin #0 . S (am rm cos 6m~)
The first and second are the equations of the centroid, and the third is in-
volved in the other two, as is obvious. Wherefore the porismatic point is the
centroid of the system.
[See, also, the note on these propositions.]
}
{
J
DR MATTHEW STEWART'S GENERAL THEOREMS. 583
PEOPOSITIONS XI., XII. POEISMS.
Let there be given m points and m magnitudes, as in the preceding : then there may
be found a circle, and likewise a point, such, that drawing any line through the
point found to cut the circle in X and Y, and that Z be any point whatever in
the same plane, we shall always have
S(kmZ*)=±Sam . (XZ' + YZ2)
For, let the given points, referred to the centro'id as origin, and any axis
whatever be rt 6lt r2 02, . . . , rm Qm ; and denote the points X, Y by Ui ult u2 w2, and
the radius of the circle by p ; and let Z be r 6.
Then, expressing the lines concerned in terms of these quantities, cancelling
San . r* from both sides, and equating to zero the co-efficients of r,
S()=±Sam(u* + ufi . . >. . . . (1)
Mj COS (5 — &J1) + M2COS(0 — W2) = 0 ..... (2)
But since also 0 is arbitrary, (2) becomes
Mt COS Wj + U-j, COS W2 = 0 ......... (3)
MJ sin Wj + W2 sin W2 = 0 ......... (4)
These two equations are satisfied by any two points in a line passing through
the origin, and equidistant from it, on opposite sides; or M1=w2> and «1='jr4-ws.
The point required to be found is hence the centro'id, and the circle has that
point for its centre.
It also follows, that «t = % = g the radius of the circle; and hence from (1)
we have
Whence the circle is entirely determined.
Dr STEWART porismatises, not a circle, but two points, X and Y, to be found.
The equations to which in such form the proposition gives rise, are precisely the
same as those above : wherefore there would be given only the three equations
(1, 2, 3) for the determination of four quantities uv «2, wlf w2, which obviously
leaves one of the quantities indeterminate. Dr SMALL notices, in another form,
this indetenninateness.
[See also note on these.]
PEOPOSITIONS XIII., XVIII. POEISMS.
Let there be given m parallel lines and m magnitudes av as, . . . , am : then there
. can be found another line parallel to these, and likewise a space /, such, that
584 MR THOMAS STEPHENS DA VIES ON
if from, any point whatever Z lines Z P1? Z P2, . . . . Z Pm 6e drawn perpendicu-
lar to the m, given lines, and ZP to the line found, we shall always have
Let the given lines be referred to any line perpendicular to them, as polar
axis ; and let the origin be the controi'd of the points in which the axis cuts the
given lines. Denote the distances of these respective points from the centroid by
pv p2, . . . . pm\ and "hyp, the distance of the porismatic line from the centroid.
Also, let r 6 denote the arbitrary point Z.
Then the equations of the given lines will be
p1 = r cos 0, p2 = r cos 6, . . . . pm = r cos 6.
And (see BUTTON'S Course, ii. p. 268, 12th ed.) the perpendiculars will be ex-
pressed by
Z Px = db (Pl - r cos 0), Z P2 = ± (p2 - r cos 0) ; etc.
Wherefore the equation of the porism becomes
ai (PI ~ r cos ^)2 + ^2 (PI ~ r cos ^)2 + • • • — Sa™ i(P ~ r cos ^)2 + *2} ;
or expanding, cancelling, and equating the co-efficients of cos 6 to 0, we have simply
p. Sam = S(ampm) ......... (1)
S(amPm) = Sam. (/ + *«) ....... (2)
Now, since the origin is the centroid, we have from (1)
S (ampm) = 0 ; and hence p = 0, . . . . (3)
or the line sought passes through the centroid.
Again, from (2) and (3) we get the porismatic space
Sa
PROPOSITIONS XV., XIX. PORISMS.
Let there be given m lines all meeting in one point, and m magnitudes
«j, «2, . . . , am: then there can be found tno other lines, also passing through
the same point, such, that if from any point Z there be drawn perpendicu-
lars Z Pp Z P2. . . . , Z Pm, to the given lines, and likewise Z Q15 Z Qa, to those
found, tee shall always have
2S(amZ PJ) = Sam.{ZQ1* + Z Q/}.
Let the points in which all the lines meet be taken as polar origin, the
axis being any whatever. Let the angles made by the perpendiculars to the
given lines with the axis be 6lt &, . . . , &m, and those made by the perpendiculars
to the porismatic lines be w^ w2 : then if r 6 be the arbitrary point Z, we shall have
Z Px = =fc r cos (0 - 6J, Z P2 = ± r cos (6 - 02), etc.
Z Qj = ± r cos (6 - wj, Z Q2 = ± r cos (Q - «,).
DR MATTHEW STEWART'S GENERAL THEOREMS. 535
Insert these in the equation of the porism (putting the expansion in multiple
cosines), cancel, and equate to zero the co-efficients of cos 2 0 and sin 2 0. Then
there results,
2 S (a., cos 2 0_)
cos 2 w, + cos 2w2 = - — ,
•s am
2 S (am sin 2 0m)
sin 2 co, + sin 2 Wo = - — .
tiam
The solution of these equations gives
Cos2w = £(«mcos20m)±R . S(amsin28m)
S (a, cos 2 0m) =F R . S (gm sin 2 0m)
COS .J Wo = F; ;
A am
g_ (S «,)* - {-S1 («, cos 2 gm)}2 - {g («M sin 2 0m)}'
{S (am cos 2 em)}a + {S (a, sin 2 0ro)}3
Since the angles are symmetrically involved in the general expression, we
see that the double sign does not imply different possible solutions, but merely
that the sign of cos 2 w3 depends upon that which we select as belonging to
cos 2 eor
That it is always real, is at once obvious : for the denominator of the ra-
dical is essentially positive ; and the numerator is convertible into
2fl1a2{l-cos2(<91 -
3 {l-cos2(02 - 03)}+2a2a4 {l-cos2(02 -04)}+ ____
+ 2am_1. am{l-cos2(0m_1-0m)}
which is, also, obviously positive.
Again, the expressions for the single angles wt, w2 are found from the pre-
ceding (3, 4), by means of the familiar relation,
COS W, =:
+ cos2w. j /I -t- cos 2 Wo
Iandcosw=±/ - —-
But it is easy to see that these double signs, in each case, only refer to the
two opposite branches of the same line in respect of the origin : so that, on the
whole, the solutions are found to be single, and that there is one, and only one,
pah* of lines which fulfils the conditions of the porism.
VOL. XV. PART IV. 7 X
586 MR THOMAS STEPHENS DAVIES ON
PROPOSITIONS XVI., XX. PORISMS.
Let there be given m lines, which are neither all parallel nor all meet in one point,
and m magnitudes, alt a? . . . . , am : then there can be found two other straight
lines and a space s\ such, that if perpendiculars Z P19 Z P2, . . . . Z Pm be
drawn to all the given lines, and others Z Qt, Z Q to those found, we shall
always have
2S(am Z Pm*) = S«m
For, let the several given lines be
Pi = r cos (0-0J, />, = ;• cos(0-02), ---- ,pm=rcos (0-0ra);
and let the porismatic lines be denoted by
qL = r cos (6 — Wj), and y2 = r cos (6 — «2).
Then the perpendiculars upon these from the arbitrary point Z, or r 6, will
be (HuTTON, ii. p. 268),
±(pl~rcos(6~ei)}, ±{j»2-r cos (0-02)}, etc.; and
±{0! — rcos(0 — Wj)}, and ±{?2 — »• cos(0-w2)}.
Insert these values in the equation of the porism, and arrange the results in
terms r cos 0, r cos 2 0, r sin 0, and r sin 20; then, as r2 cancels, we have
2S(amPm2) = Sam. {tf + gf + s2} .......... (1)
2 S(ampm cos 0m) = Sam . [ql cos o^+y., cos w2} ....... (2)
2 S(ampm sin 0m) = »S am . {^ sin «! + ?2 sin W3} ....... (3)
2 5 (am cos 2 0m) = 51 am . {cos 2 Wj + cos 2 W2} ....... (4)
2 S (am sin 2 0m) = S am . {sin 2 Wj+sin 2 W2} ........ (5)
From (4, 5) will be found, as in the preceding porism, the values of Wj wa";
from these results, combined with (2, 3), we shall obtain, by a simple equation,
the values of q^qi\ and from these values inserted in (1) we finally obtain the
value of the space s2.
PROPOSITIONS XVII., XXI. PORISMS.
Let there be given m lines, which are neither all parallel nor all meet in one point,
and m magnitudes, al5 a*, . . . . , am : then there can be found three lines, such,
drawing from any point, Z, the perpendiculars Z Pl? Z P2, . . . . , Z Pm to the
given lines, and Z Qi, Z Q2, Z Q} to those found, we shall always have
. (Z Q2).
DR MATTHEW STEWART'S GENERAL THEOREMS. 587
Such is Dr STEWART'S statement ; but forming the equations of condition,
as in the preceding Propositions, we have
3 ^ (am Pm COS 0«) = Sam • fa COS Wl + - • • +?3 COSW2} ..... (2)
3 S (am Pm Sln eJ = fifo» • fol Sln W! + - ' - + ?3 Sln W3} ..... (3)
3 S(am cos20J = Sam . {cos 2 WL + . . . + cos2wj ..... (4)
3 S (a sin 2 6 ) = S a . {sin 2 w, + . . . -t- sin 2 w,} . (5)
V TO TO' TO L OJ V /
Now, in the present case we have only five equations for the determination of six
quantities, w1, w2, w3, y^ q^ and y3. The condition of the porism cannot, therefore,
be fulfilled without another condition.
This indeterminateness, in respect of this proposition, has been noticed by
Dr SMALL, Ed. Trans., ii. p. 46. In the discussion of Props. 46-53 of this Series,
will be noticed again.
PROPOSITIONS XXIV., XXV. PORISMS.
Let there be given m lines and m magnitudes as before : then p straight lines can
be found, such, that if we draw the perpendiculars from any point Z to all the
lines given, and to all the lines found, we shall have
frMi.,fi^^.p[8(a«'zp~*')}=Sa»'S(>zW- bu ........ ,H«.,vr
The general form of the component terms of this equation is, Lemma ii.,
Whence, forming the equations of condition, we have the following series,
PS(amcos3ej = Sam .S(cos3&J4)
p S (am sin 3 6j =Sam.S(sm3u^)
P S K» Pm cos 2 0 J = S am . S (fft cos 2 w4)
P S (amPm sin 2 6J = S am • S (9t c°s 2 W4)
P s (am cos OJ = Sam- S (cos W4)
P S (am Sin 6J = S(lm- S (Sin W4>
P S (am Pm" COS 6J = Sa-S (i ^S W4)
588 MR THOMAS STEPHENS DAVIES ON
Now, as there are ten equations, all independent of each other, it follows
that jp=5 ; for there will be five gs and five ws to be determined from this sys-
tem, and these are the requisite conditions for finding five lines. Whence the
number of lines is incorrectly given by Dr STEWART who porismatises only four
lines ; but the Porism is evidently possible with the condition altered as here pro-
posed.
PROPOSITIONS XXX., XXXI. PORISMS.
Let there be given m points Aj, A2, . . . . Am, and m magnitudes, alt «2, • . • • am:
then there can be found tno lines OX, 0 Y, and a point P, together tcith
two magnitudes a. b ; such, that if from any point whaterer, Z, there be drawn
lines to all the given points, and to the point found, together with perpendicu-
lars Z X, Z Y to the lines found, me shall always haw
S (am . Am Z*) = S am . {P Z< + o»(Z X2 + Z Y2 + 6') }.
Let, as before, the given points be referred to the centroi'd as origin of polar
co-ordinates, and denoted by rl 6^ rz 02, • • • rm, 6m ; also denote P by r0 #0> Z by r 6,
and the lines O X, 0 Y by
/>1 = r cos (6— wj
pz—r co§ (6 — W2)
Then the perpendiculars on these from r B will be expresed as before by
Z X^rit^-r cos (0-wJ}
Z Y=db{j02-r cos (0- Wo)}
Also, the lines from Z to the several points will be expressed in power by
AM Z< = r< + 4 r»rw» + rw«-4r rm (rm* + r>) cos (6-6^ + 2 rm* r* cos 2 (fl-fl.)
P Z4 = r1 + 4 r2 r02 + r* - 4 r r0 (r02 + r2) cos (6- 00) + 2 ra2 r2 cos 2 (0- 00)
ZY2= (/;2 + r2)
—
With these values form the equation of the porism, cancel common terms,
and equate to zero the co- efficients of the arbitrary quantities which remain;
then we get the following system of conditional equations :
DR MATTHEW STEWART'S GENERAL THEOREMS. 577
= Sam.{r* + *-«*} ............ (1)
(2)
S(amrm cos 6m) = S am . r0 cos 60 ............. (3)
S (am rm sin 6m) = S am . r0 sin 00 ............. (4)
S (am rm3 cos 0,») = S am . {r3 cos 60 + -a? Qoj cos o^ +p2 cos w2)} . . (5)
4
' 5 (am rm3 sin 0TO = S am . [ra3 sin 60 + - a2 (^ sin Wj +_p2 sin W2)} . . (6)
S («« '•m2 cos 2 0m) = S am . {/-02 cos 2 00 + 1 a2 (cos 2 Wj + cos 2 W2)} . . (7)
5 («» rw» sin 2 0m) = 51 am . [r02 sin 2 ^0 + i a2 (sin 2 Wj + sin 2 w2)} . . (8)
Now, since the left sides of (3, 4) are zero, we find that r0=0, and that 00 is
indeterminate. The point P is, therefore, the origin of co-ordinates, or the cen-
troid of the given system itself.
Insert this value of r0 in (1) : then we get
Insert it in (7, 8) : then these become
4 S (am . rm2 cos 2 $,„)
v
^ '
(10)
4: S (am rm2 sin 2 6m)
=- C^|— - ........ (11)
from which wx and w3 may be found as in (xv. xix) ; and which, as in that place,
are real.
Put the value 0 of r0 and the values of Wj, w2 in (5, 6) : then we get the values
of PV pt.
Finally, from the insertion of the values ofpv p2 and ra in (2), we obtain the
value of b2.
PROPOSITIONS XXXII., XXXIII. POIUSM.
Let there be given m points Ax, A2, . . . ., Am, and m magnitudes a^ av . . . ., am:
then there mny be found four points B15 B», Bs, B4, swcA, #A«# if from any point,
Z, we cos 0J = Sam.S(VcosO (5)
4 5 (am rm3 sin 0m) = S aM . S («4» sin «,) (6)
4SK.O =Saw.S(V) . (7)
4#KO =Sam.S(V) (8)
in which, as eight conditional equations inevitably result from the porism, there
must be four points porismatised to be determined from them.
Since the origin is the centro'id, ±he left sides of (1, 2) become 0, and we see
that the porismatic points have the same centro'id as the given system.
PROPOSITIONS XXXV TO XXXVIII. POEISMS.
Let there be given m lines and m magnitudes, «15 02, . , . ., am : then there can be
foundp other right lines, such, that if from any point, Z, there be drawn perpen-
diculars Z Pls Z P2, . . . ., Z Pra, to the given lines, and Z Qt, Z Q,,, • . . ., Z Q,,,
to those found, we shall always have
p S (amZ Pm")= S am.S(Z Qp4)
Forming the conditional equations, as in the former cases, we have
p.S(ampm*) =Sam.S(qp*) (1)
p.S(ampm2) = S am . S (qp2) (2)
p. S(ampm3cos 6m) = Sam. S (gp3 cos up) (3)
p . S (am pm3 sin 0m) = S am . £ (qp 3 sin up ) (4)
• p . S (am pm cos 0m) = S am . S (qp cos up~) (5)
p . S (am pm sin 0OT) = S am . S (qp sin up ) : . (6)
p . S (am pm2 cos 2 6m) = S am . S (gps cos 2 up) (7)
p.S(ampn?sw26m') = Sam .S(gP2sin2uP) (8)
p. S(am cos 2 6m) = S am . S (cos 2 wp) (9)
p . S (OB, sin 2 6m) = Sam. S(sm2 wp) (10)
DR MATTHEW STEWART'S GENERAL THEOREMS. 591
p . S (am pm cos 3 6m ) = S am . £ (qp cos 3 up ) ........ (11)
p . S (am pm sin 3 0OT) = S am . S (qp sin 3 WP) ........ (12)
p . S (amcos 4:6m) = S am . S (cos 4: up) ......... (13)
p . S (am sin 4 0m) = S am . S (sin 4 «,) ......... (14)
which giving fourteen independent equations furnishes data for finding seven lines,
instead of Jive, as stated by Dr STEWART : that isp=7, instead ofp—5.
The preceding statement is that of Prop. 38, of which the others are parti-
cular cases. It becomes, Prop. 37, when al—a^= .... = am. When all the lines
are parallel it becomes the first case of Prop. 36. In this instance we have
61 = 62 = ....== Qm = — TT.
•
Substituting these values in the preceding equations, we have, by transposi-
tion,
) ......... (15)
*) .......... (16)
Sam. Sfap3 cos wp) =0 .............. (17)
S am . S (gp3 sin wp} =p . S (am pmz} ......... (18)
Sam . S(yp cos wp) =0 .............. (19)
S am . S (yp sin wp ) —p.S(ampm} .......... (20)
Sam .S(qp*cos2 Wp) = -j». S(ampm*} ......... (21)
Sam . S(yP2sm2 Up)=Q .............. (22)
S am . S (cos 2 up ) =—p.Sam ........... (23)
£aOT ./S(sin2 Wp) =0 .............. (24)
Sam .S(yp cos 3 wp) =0 .............. (25)
•Scm . £(?P sin 3 w^) =-p.S(ampm') . • ....... (26)
Sam . S(cos4 wp) =p . S am ............ (27)
S am . . S (am pm*~) ........ (32)
In this case we have j?=4, instead of p=2, as stated by Dr STEWAHT.
[See also, NOTE E.]
592 MR THOMAS STEPHENS DAVIES ON
Again, for the second case of Prop. 36, all the lines meet in one point ; and
this being the origin of co-ordinates, we shall have pl =p2 = • • • • =pm = 0 ; and hence
from (1,2) we have 5t1=9r2= • • • • =qp =0, and all the porismatic lines pass through
the origin.
For this reason, also, only those of the subsequent equations which do not
involve qr g2, • • • • qp have an existence in this case. These are (9, 10, 13, 14) ;
and under these circumstances they become
S am . S(cos2 up)=p . S(am cos 2 0OT) (33)
Sam . S(sm 2 «P)=/> . S (am sin 2 6m) (34)
Sam . S(cos4 wp)=p. S (am cos 4 0m) (35)
Sam . S(sin4 up)=p . S (am sin 4 0m) (36)
These, again, givep=4 instead of jp=3, as the proposition is stated by Dr
STEWART.
PROPOSITIONS XLIII,, XLIV. PORISMS.
Lei there be given m points A15 A2, . . . ., Am, and as many magnitudes^
015 (7 2, . . , am ; and let n be any number (subject to conditions to be hereafter
determined} : then there can be found p points Bl5 B2, . . . ., Bp, such, that if
from any point, Z, lines be drawn to all the given points, and likewise to the
points found, ice shall always have
p.S(am.Am 7?n) = Sam . S (B, Z2n ).
Let »*i 6V r3 6,,, . . . ., rm 6m be the given points ;
MjWpMjWj, . . . ., Up ttip the porismatic ones ; and
r &, the arbitrary point Z. Then,
Am Z2=r2-2r rm cos (6-6m) + rm2;
Bp Z2 =r*-2r up cos (6-top) + uP2 ;
which are the general types of the squares of the lines to be raised to the nih
power.
Let them be so raised by Lemma i. : then the terms in r- " cancel from the
equation being respectively
p (air'-n+a2 r*n+ ---- +am r2n), and
the latter being carried to p terms.
In the next place, equate the co-efficients of the several terms in r^ rf cos v 6,
and j * sin v 6, for all values of /j, and v within the degrees expressed by the
DR MATTHEW STEWART'S GENERAL THEOREMS. 593
expansion, to zero ; and we shall thus obtain the conditional equations of the
porism, viz. :
First, from terms clear of 6.
... .PS(am r-«<"-i>) = ,sr«w .£
••• -Sa r^~ = Sa . S
Secondly, from terms in cos Q and sin 6.
r....pS(am rm*n~i cos 0J = Sam . 5 (V "~ X cos wp
r3 •••pS(am rm2"-3 cos 6J = S am . S («ps- » cos W|>
^ •••pS(am rm2"-5 cos 6j = S am . S («/-« cos Wp
r2"-' -P8(am rm cos 6j =S am . S(upCOSUp}
and
pS(am rm sin dm) =Sam . S(upSin^
Thirdly, from terms in cos 2 6 and sin 2 6.
.PS(am rjn~2 cos 2 Om) = Sam . S (V»-2cos 2
~* cos 2
rs«~2 . JB S («m rm^ cos 2 6m] =Sam.S (up* cos 2 UP )
and
r* v.. . p S(am rm2"-2 sin 2 6j = Sam . S (up*»-* Sin2up
r* . . . . p S (am rm*»-* sin 2 6>J = S «m . >S («;>»-* sin 2 Wp
r2"-2 . p S (a. rm2 sin 2 0J =^am . >S (V sin 2cop )
Proceeding in this way, we arrive at,
Lastly, from terms in cos n 6 and sin n 6.
r"....pS(am rmn cos n 0m) =Sam . S (upn cos » wp )
r" . . . . p S (am rmn sin n 0m) =S «m . -S (««pn sin n 0), )
VOL. XV. PART IV. 7 X
594 MR THOMAS STEPHENS DA VIES ON
Now, to consider these in relation to the porism, we must find the number
of equations which are produced in this series. The forms of them are given
above ; but it will be more convenient to recur to the original development in
Lemma i., in order to discover this object of our inquiry.
1. From the terms clear of the 6, we have the alternate terms of a binomial
(disregarding the special co-efficients in all cases, which do not affect the actual
number of terms) of the 2nih degree : that is, exclusive of the term r2" which can-
cels in the porism, we have n terms.
2. In that which involves cos 6, we have the terms which were omitted in
the first line, viz. n terms : and a similar number in that which involves sin 6.
3. In each of those involving cos 2 Q and sin 2 6 we have all those of the
first line except the first and last ; or n— 1 in each case.
4. In each of those involving cos 3 Q and sin 3 & we have all those of the
second line except the first and last; or n -2 in each case.
Proceeding thus, we find at each successive step a diminution of one in the
number of terms belonging respectively to the cosines and the sines of the
multiple arcs : till in the last line we get one term involving cos n 6 and another
involving sin n 6.
Again, the number of lines which involve cosines and sines is the same as
the number of multiples of 0 which are involved : that is, there are n lines which
give the double of the number of powers of r in the co-efficients. Whence, in-
cluding the first line, there will be 2(1+2 + 3+ . .. +ri)+n=n(n + l) + n=n(n + 2)
equations of condition involved in the statement of the porism.
Now, the determination of a point involves two conditions : viz. such as
will enable us to find up and wp. Whence these n (n + 2) equations will require
that \ n (n + 2) points should be porismatised, instead of n + 1 as stated by Dr
STEWAHT.
Again, except n be even, the number of conditional equations will be odd; and
hence there will not be the requisite conditions for the determination of any
number of points — either giving one condition too few, which would render the
first point indeterminate, or one too many, which may be (and, generally, would
be) contradictory amongst themselves.
We thus see that except n be even, the porism cannot be true, which is a
limitation not laid down in the ' General Theorems' : and we see that when n
is even, the number of lines to be porismatised is ^ n (n + l)=p, and not n+ 1 as
there stated. The relation to be observed between m and n, will be discussed
hereafter, when we come to consider the structure and solution of the equations
of conditions themselves. It will hence be unnecessary to discuss this question
further in this place ; though we may remark, that this result, when applied to
a former case (Props. 34, 35), is in keeping with the conclusions there obtained.
For, in that case n+1 instead of \n (n + 2), n being equal to 2, or 3 instead of 4
points, are stated to be determinable.
DR MATTHEW STEWART'S GENERAL THEOREMS. 595
The next eight porismatic propositions (4t> to 53 inclusive) which close the
series of porisms respecting points and lines, are, in fact, but varieties of the same
general proposition, according to the positions of the given lines, the form of the
number n, and the relative values of the magnitudes av a2, . . . , am.
PROPOSITIONS XLVI. TO LIII. PORISMS.
Let there be given m lines, and as many magnitudes a^ a^ . . . am: then there
can be found p other lines, such, that if from any point whatever Z, there be
drawn perpendiculars Z Ax, Z A3, . . . . Z Am to the given lines, and ZBj,
Z B2 ..... Z Bj, to those found, ive shall have, for values of n, subject to con-
ditions which may be determined
PS(am .ZAmn) = Sam. S (Z B/)
The perpendiculars being respectively,
Z Am= + {pm— r cos (6—6m) }
ZBp = +{gp— r cos (0-Up~)}
we shall form the expression by means of Lemma ii. Also, as the process is
general, we may, in conformity with previous practice, omit the double sign of
these perpendiculars.
Taking, then, the conditional equations furnished by the developments of
Lemma ii., we shall have in succession : —
First, from terms clear of 6.
r" ____ p.S(ampmn} =Sam.S (?/)
r2 ____ p.S (amfmn-2) = Sam.S (q^}
r* ____ p.S(am pm"-*) =Sam. S 0/~4)
Second, from terms in cos Q and sin 6.
r . .. .p . S (am pmn~l cos 6m] = S am . S (ft)""1 cos Up)
r3 ____ p.S (amp^~* cos Qm} = Sam . S (qpn~* cos wp)
and
r ____ p.S (ampm"~l sin Qm} = Sam . S (g^1 sin
r» ____ p . S (am pmn~* sin Q^Sam.S (ft,""8 sin
596 MR THOMAS STEPHENS DAVIES ON
Proceeding thus through 2 6, 3 d, .... n 6 we get at last to
r""1 . . S (ampm cos (« — 1) 6,n) = Sam . S (qp cos (» — 1) wp)
rn~l . . S (am pm sin (n — 1) 0TO) = 5 «m . S (qp sin (w — 1) wp)
and, lastly;
r" . . . . S («m cos n Bm~) = S am . S (cos n Wp)
rn . . . . S (am cos n 6m~) =Sam . S (sin n wp)
Our business is, in the first place, to find the value of p corresponding to the
different forms of n. Now, it is familiarly known that for all the discussions re-
garding multiple arcs, all integer values of n may be considered under the forms
of 4ju, 4:/j. + l, 4/x + 2, and 4/z+3: but our purpose in the present instance will
be effected with equal completeness by considering n to exist under the forms
2 v and 2v + l whilst the length of the discussion will be diminished about one-
half.
1.
The first line has all the even powers of r (r° included) : the second has all
the odd powers : the third has all the even powers but the lowest, r° : the fourth
all the odd powers but the lowest, r1 : the fifth has all the even powers but the
two lowest, r° and r2 : the sixth has all the odd powers but the two lowest, r1 and
r3 : and so on.
Now, in the case supposed (n=2v) the first line will have j/ + l terms, r° be-
ing even. But by the general structure of these theorems, the last term is can-
celled from both sides of the equation of the porism : whence the number of
terms in the first line is v.
Pursuing the enumeration in the same manner as was done in the preceding
proposition, we shall find that :
the second line has v terms
... third ...... v
... fourth ...... v — 1
... fifth ...... v-l ...
... sixth ...... v—2 ...
... seventh ...... v-2 ...
and so on.
Again, there will be 2 j/+l lines; for all the multiple cosines are found in
them from 0 to 2 " inclusive. Leaving out of view, for the moment, the first line,
we shall have 2 v lines, which, in pairs, contain the same number of terms. The
last two of these will be
Lr2"-1^ cos (2 v-l) (0-0™),
DR MATTHEW STEWART'S GENERAL THEOREMS. 597
and each of these several equations will be doubled by the expansion of the
2v
cosines. Whence, for all the lines except the first we have 2 (1 + 2+ ..... v) —
= 2 (v + 1 ) v : or for the whole number of conditional equations 2v(v + l) + v=v(2v + 3).
We are, therefore, in this case, led to the conclusion, that except v be even,
there will be either an indeterminateness or contradiction in the results of the
hypotheses of the porism : that is, n if even must be of the form 4 fj. ; and when
this is fulfilled, p = /JL (4 p + 3), instead of 4 /JL + 1 as stated in the ' General
Theorems.''
When fjL =1 or v=2, we have 1 {4 + 3} =7, as before determined in reference
to Props. 35-38.
2.
The first line will have v + 1 terms
... second ...... v + 1 ...
... third ...... v
... fourth ...... v
... fifth ...... v-\ ...
... sixth ...... v— 1 ...
and so on.
Whence, as there are 2 v + 2 lines, having all the multiple cosines from 0 to
2 v + 1, we shall have in all (v + 1) (v + 2) terms. Also, with the exception of the
first, they are doubled by the expansions of the cosines, and the entire number of
equations of condition will be
2 (v + 1) (v + 2)-(j> + l) = 0 + l) (2v + 3)
When v is even, this condition cannot hold in reference to Dr STEWART'S
theorem ; for it will give either an indeterminate or an impossible condition, as
before. That is, the form «=4 /*+ 1 is precluded from the enunciation.
When v is odd, the condition is capable of fulfilment : that is, when n =4 /j. + 3.
In this case, if we denote v by 2 x + 1, we shall have^=(* + 1) (4 * + 5).
When v =1, the determination agrees with what was found in Props. 24-25 ;
for then 1(1 + 1) (2. 1 + 1) =5.
We have thus obtained the number of equations to be fulfilled for the general
forms of n, as well as the general forms of those equations themselves : and have
shewn that the number of lines porismatised is erroneously in all the cases, and
impossibly in some of them, laid down by Dr STEWART. For the case of n odd,
we see that there can be no number of lines porismatised, except «= 4/*+3, in
Propositions 50-53 : and in 46-49, except n=4 p.
Particular conditions will lessen this number. In 46-47 this takes place in
the two cases in each proposition.
VOL. XV. PART IV. 7 Y
598 MR THOMAS STEPHENS DAVIES ON
First, let the given lines be all parallel.
The equations in this case reduce to
p . S (ampm*n~l) = Sam . S (
p • S (am Pn? n-2) = Sam.S (?/ n~2)
p . S am pm) = S am . S (j-p)
which are 2 n in number, determining p=2 n, and all the lines found, parallel to
the given ones.
Second, let the given lines meet in a point.
In this case />1=j»2= . . . . p«,= 0, and we have only those terms left which
involve the absolute terms of the co-efficients of the multiple cosines. Whence
the equations become
p . S (am cos 2 n 6m) =S am . S (cos 2ntop)
p . S (am cos 2 (n-1) 6m) = S am . S (cos 2 (»-l) wp)
p.S(am cos 2 (n-2) 6m} = S am . S (cos 2 (n-2)
p . S (dm COS 2 0m) = S dm . S (COS 2 Up )
and
p . S (am sin 2n6m~) = S am . S (sin 2 n wp )
p . S (aro sin 2 (w-1) 0ro) =S «m . -S1 (sin 2 (n-1)
jt? . S (am sin 2 (n-2) 6m)=Sam.S (sin 2 (w-2)
• •*•..*••••
p . S (am sin 2 0m) =S am . S (sin 2 Wp)
Thus again, we have in this case p=2 n, all the porismatic lines passing
through the same point as the given ones.
The two conclusions in the latter particular cases agree with those which
were found in the still more special case of Props. 15 and 19. For then n=l ;
and either Dr STEWART'S general form, or the one here deduced, as applied to
that case, is precisely the same. In his view, 1 + 1=2: in what is here found,
2*1=2.
DR MATTHEW STEWART'S GENERAL THEOREMS. 599
SECTION III. INDETERMINATE THEOREMS.
These are divisible, with a few miscellaneous exceptions already proved by
Dr STEWART in the work, into three Classes ; and which we shall take in order.
1. Perpendiculars on the sides of a regular circumscribed polygon.
2. Lines drawn to the angular points of a regular inscribed polygon.
3. Perpendiculars upon lines which pass through a point and make equal
angles with each other.
CLASS I. — Regular Circumscribed Polygons.
PROPOSITIONS V., XXIX., XL.
Let there be a regular polygon circumscribed about a circle whose radius is p, and
let n be any number less than m ; also, from any point Z, whose distance from
the centre of the circle is r, let perpendiculars Z A1? Z A2, . . . . Z Am be
drawn to the sides of the polygon: then, if t0, tlt t?, . . . tn denote the co-effi-
cients of a binomial of the nth degree, we shall have
Without sacrificing generality, we may somewhat simplify our expressions
by taking the line from Z to the centre of the circle as angular origin, and the
centre itself as polar origin. Then, for the formation of the equations of the
sides we shall obviously have,
2V fi n 4T A ,, 2(m—
-- U, , 03 = — -- t>, , . . . . Om = — »
mm m
or the angles 0t . 02 ..... 6m in arithmetical progression whose common differ-
2TT
ence is —
m
Whence, since the general form of Z A*2" is
ZA, = p-rcos(± -<
lr \ m
we shall find upon forming the sum of them by the expansion in Lemma ii., that
all the terms involving the cosines disappear by virtue of Lemma iv. This sum
is, therefore, reduced to the first line of the expansion for each of the perpen-
diculars ; and these are all equal, and as many in number as there are perpen-
diculars ; that is, the sum is m times the first line of the development, as stated
in the proposition.
600 MR THOMAS STEPHENS DAVIES ON
The conclusion just obtained is Dr STEWART'S 40th proposition. If we put
«=2 it becomes the 29th; and if also in this case r=(>, we obtain the 26th.
Also, finally, if n=\, we obtain the 5th proposition.
[See also note F.]
PROPOSITIONS XXII., XXVIII., XXXIX.
Let there be a regular polygon of m sides circumscribed about a circle, whose
radius is (>, and let n be any number less than m : then, if from any point in
the circumference of the circle perpendiculars Z At, /A ....... X Am be drawn
to the sides ofthejigure, we shall have
S (Z Am ) =»* . -= — . O ,
1 . J . o . . . . n
For, in this case, we have the general form of the «th power of the perpen-
dicular
r,.n n f , /2kTT
ZA* = p
Expand each term, for all values of k from 1 to m, by Lemma iii., and we
find from Lemma iv. that all the terms involving the cosines vanish of them-
selves, and the expansion is reduced for each perpendicular to its absolute term.
As these are all equal, and m in number, we get at once the general form given
by Dr STEWART.
The proposition just proved is Dr STEWART'S 39th. When n=4, it becomes
the 28th; and when w=3, the 22d.
PROPOSITION III.
Let perpendiculars ZAJ5 Z A2 .... Z Am be drawn from any point Z to the
sides of a regular polygon ofm sides described about a circle whose radium is g :
then 'if the distance of Z from the centre of the circle be r, we shall have
For the general form of Z A* is Q—r cos -y ~^i '•> and we shall have, as
in former cases, all the cosines mutually cancelling, giving the proposition stated.
PROPOSITIONS XXII., XXIII.
From any point Z, (rO), draw perpendiculars Z A1? Z A2, . . . . Z A,,, to a re-
gular polygon of m sides circumscribed about a circle whose radius is (> .• then
we shall have
DR MATTHEW STEWART'S GENERAL THEOREMS. 601
For as before, expanding, and recollecting that 6V 02 , • • • • &m are in arith-
2 7T
metical progression, having the common difference — , the angular functions
will vanish of themselves from the expression of the sum of the cubes : hence
3 o r-
we have simply p3 + — v— for each perpendicular ; and hence again
-
which is equivalent to STEWART'S form.
This is Prop. 23 ; but putting r=^ we have another proof of Prop. 22, viz. :
2S (Z Am3~)=5mg3.
CLASS II. — Regular Inscribed Polygons.
PROPOSITIONS IV., XXVII., XLIV.
Let there be drawn from any point Z (7- 0) lines to all the angular points of a
polygon of m sides inscribed in a circle whose radius is p, namely, Z A15 Z A2,
. . . Z Am .• then we shall have (n being any integer less than m, and t0, t , . . . tn,
as before)
The general form of these values is
Z A*2" ={ ?2- 2? r cos (d-e^ + r'T .
Expand and add ; then, since ^, 02 , . . . . 6m are in arithmetical progression,
C\ —.
having the common difference — , all the angular functions will vanish from the
sum. Wherefore only the first line of the expansion in Lemma i. will remain,
and that one for each Z A. Wherefore the sum of them is m times that line ;
and the Proposition 42 follows at once.
• When n=2 it becomes Proposition 27 : and when also, n=§ it becomes Pro-
position 4.
Dr STEWART remarks, p. 38, that Prop. 2 is a particular case of the po-
rismatic Prop. 9. This will be apparent if we consider that the origin is, in this
case, the centroid of the angular points ; and hence that all the cosines involved
in the mutual expressions cancel among themselves. We shall, however, return
to this subject hereafter.
VOL. xv. PART rv. 7 z
602 ME THOMAS STEPHENS DAVIES ON
PROPOSITIONS XXVI., XLI.
Let there be a regular polygon of m sides inscribed in a circle whose radius is p,
and let n be any number less than m ; and from any point Z in the circum-
ference of the circle, let lines be drawn to all the angular points of the polygon •
then we shall have
For in this case r=§ ; and the expression for Z A*2" takes the form
= {2p2-2£2 cos (6-6k)}*
Expanding the binomial factor by Lemma iii., and keeping in view that
Qv 6-t , . . . . Bm are in arithmetical progression, having the common difference
2-7T
— , we see that all the angular functions vanish, by Lemma iv. Whence the sum
is reduced as before to m times the term clear of the angles, and we thus have
. 1 1.3.5 ---- (2«-l) 2»«0»*
) - 2^ ' 1.2.3.... - ^T -2 ?
1.3.5 ____ (2)1-1} „« s»
1.2.3.... ;r~ • 2 ? •
This is Proposition 41, as proposed by Dr STEWART. When n=2 it becomes
Prop. 26.
CLASS III. — Lines making equal A.ngles.
PROPOSITIONS XIV., XXXIV., XLV.
Let there be m lines meeting in a point, and making all the angles round the point
equal, and let n be any number less than m : then if from any point Z, whose
distance from the common point of section 'is r, perpendiculars be drawn to all
the lines, Z Alf Z A2, . . . Z Am, we shall have
!». m 1.3.5 ---- (2«-l) j»
2^ '1.2.3.... ^~
For simplification, take the line from Z to the given intersection as angular
origin, that intersection being the polar origin. Then Olt 62 } . , . . Qm of the
general equation are the angles made with this line by the perpendiculars to the
given lines. Also, in the equations of the given lines pl = p2 = . . . = pm — 0 ; and
0t, 02 , . . . . 6m are in arithmetical progression, having the common difference
- . Wherefore, the general form of the expression for Z Am2" is
„. 2n In 2» 2 klT
Z Am = r cos — • — .
DR MATTHEW STEWART'S GENERAL THEOREMS. 603
Expand, therefore, in the ordinary form, and bearing in mind that 2 n is
even, and the angular functions vanish, we have for each value of k from 1 to m
inclusive, the expression
1.3.5.... (2«-l) s»
1.2.3 w
and as these are m lines, we have at once the expression in question.
This is Prop. 45: also, when rc=2, it becomes Prop. 34; and when n=l it
becomes Prop. 14.
NOTES UPON THE PRECEDING DISCUSSION.
NOTE A, page 574.
The first case of the solution of any one of Dr STEWART'S General Theorems being pub-
lished, that I remember to have met with, is that of the 41st Proposition, by Professor
PLAYFAIR, in his paper on the Arithmetic of Imaginary Quantities, Phil. Trans. 1777 ; and
I am not aware, impressed as he was with the great beauty of these propositions, that he
published anything more on the subject, and even this one is taken up incidentally.
Dr SMALL, in the Edinb. Trans., vol. ii., gave solutions of Propositions 9, 10, 11, 12, 13,
14, 15, 16, 17, 19, 30, 31.
Professor Lo WRY gave solutions of 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
in vols. i. ii., O.S., of Leybourn's Repository ; and annexed to them several interesting, but
tolerably obvious deductions.
Mr SWALE of Liverpool also gave, in the same work, solutions of 15, 16, 17, 18, 19,
20, 21.
The three last-mentioned authors treat the subject by methods purely geometrical ; but
Dr SMALL has been inconsiderately censured for a " lack of geometrical purity," merely
because he mentions the " centre of gravity," notwithstanding he builds nothing upon it
deduced from its physical character. (Repos. i. p. 131.) Geometrical purity, however, is
not vitiated by the use of an injudicious term, but by the employment of methods which are
unrecognised by geometry, or inconsistent with those which are recognised. The standard
itself was originally arbitrary ; but being once recognised and generally admitted, it is the
proper criterion by which to judge of the purity of geometrical processes. Taking, however,
the strictest view of the subject, I confess I know of no flaw in Dr SMALL'S argument ; and
there is no doubt that to Dr SMALL'S paper we are in reality indebted for all that has been
effected concerning the porismatic part of Dr STEWART'S Theorems. It may be further
remarked, too, that the ordinary sense of the word geometrical is altogether inapplicable to
the greater part of theorems themselves, since they relate to magnitudes which the ancient
geometry does not recognise (viz., to fourth and higher powers of lines) ; and hence, as far
as purity is concerned, it seems to savour of the " gnat and camel" character, to affect a
rigid adherence to even the forms of the ancient geometry in attempting their solution. Dr
(504 MR THOMAS STEPHENS DAVIES ON
STEWART did not set such an example by attempting to antiquate the forms of their enun-
ciation ; and he does not even call them geometrical theorems, though, as they relate to the
properties of geometrical figures, he might have done so without impropriety. Whether
he even obtained them by geometrical considerations, in the first place, is open to question,
when we turn to what Professor PLAYFAIR remarks (Ed. Trans., i. p. 60) concerning the
probable origin of his inquiries on this subject. In fact, his being in possession of SIMSON'S
definition of the porism (which may be inferred from his formally distinct enunciations of the
porismatic part of his propositions), I do not think there is a single step in the present paper,
which it would have been at all improbable that Dr STEWART could readily take. Any slight
mistake in estimating the number of final equations would create no surprise, when we
recollect how much he was in the habit of "thinking out" his conclusions without the aid
of writing. Possibly, therefore. Dr STEWART'S investigations were not much unlike those of
the present paper, in their essential character. But to return : —
Mr GLENIE, of the Royal Artillery, gave, in the Edinburgh Transactions (vol. vi.), demon-
strations of nearly all the indeterminate theorems, except those proved by Dr STEWART him-
self, and the 41st theorem. Of this last, he afterwards gave a proof in a small tract (1813.)
Mr GLENIE'S course of investigation is remarkably elegant, and it discloses many curious
and interesting properties of the circle, of which uses, generally unsuspected, may yet be made.
This able geometer has, however, fallen into the prevailing error on the subject of geome-
r"
trical purity : that -^ra expresses an idea recognised by the ancient geometry ; but it in no
degree vitiates his reasonings as demonstrations, though it throws them, as all demonstrations
of these theorems must be thrown, into the domain of algebra.
Mr BABBAGE, after paying a high and deserved tribute to the genius of Dr STEWART,
gave (Quarterly Journal of Science, vol. i.) investigations of nearly all the indeterminate theo-
rems, by means of trigonometry. They differ from the investigations given in this paper
mainly in the forms of expansion employed ; and I gladly avail myself of the opportunity
of acknowledging my obligations to that paper, for some useful modifications of my own
primary processes respecting this class of propositions.
The late Mr THOMPSON published (in the Newcastle Magazine, 1826-27-28) investiga-
tions of a considerable number of these theorems. He adopted the mixed method — that is,
the employment of the ancient geometry, algebra, and trigonometry, as best suited his imme-
diate purpose. These solutions bear ample testimony to the mathematical powers of their
author ; but they are, unfortunately, so disfigured by an awkward and irregular notation,
and bad style of printing, as to be not only generally unintelligible to the ordinary reader,
but, in many cases, to almost defy interpretation by those who look into the subject with the
greatest care. I was much struck, when I first met with this work (three or four months
ago), with the near approach made, in some of his demonstrations, to the xise of the principle
which forms one of the foundations of this paper — the formation of conditional equations.
He seems, however, to use it as a matter of convenience rather than as a principle — as some-
thing that may answer a special purpose, rather than as a general method founded in the
nature of the algebraic analysis, and applying to all possible cases.
Owing to the circumstances before mentioned, had my own investigations been in a less
complete state than they were at that time, Mr THOMPSON'S papers could have afforded me
no assistance ; but I gladly embrace this opportunity of publicly recording the high estimate
DR MATTHEW STEWART'S GENERAL THEOREMS. 005
I form of the abilities of the author, as evinced by his varied correspondence with the most
valuable English periodicals devoted to mathematical researches.
My old friend and former pupil, Mr LESLIE ELLIS (in the Cambridge Mathematical Jour-
nal, May 1841), has proved a considerable number of the indeterminate theorems which
relate to inscribed and circumscribed polygons, by means of a very remarkable theorem
(which he has there investigated), which reduces the sums of the specified powers of the lines,
or perpendiculars, to a definite integral. The following is his theorem ; but, for the manner
of employing it, reference must be made to the paper itself.
In a letter to me, Mr ELLIS also suggests the application of the same process to sphe-
rical polygons. It may also, evidently, with slight modifications, be applied to regular poly-
hedrons, inscribed and circumscribed to a sphere.
Should any other English authors have discussed these theorems, their works are unknown
to me, and that, after taking much trouble to discover all that had been attempted relative to
them. I am not aware of any writer on the continent who has distinctly dwelt upon them,
except M. CHASLES, in his Aperfu Historique des Methodes en Geometric, though LHUILLIEE,
CARNOT, and many other distinguished continental geometers have made occasional reference
to SIMSON'S Porisms and STEWART'S Theorems. Both works are, however, by them con-
sidered merely as relating to indeterminate theorems. CHASLES forms the highest estimate of
STEWART'S researches ; but as his view of the ancient porism is so opposed to Dr SIMSON'S,
he was not likely to be led to any method of investigation adapted to the discussion of these
propositions : — in fact, he does not offer any. He, however, enunciates the " extension " of
two of the general theorems (pages 353-54), namely, the 44th and 53d. These extensions
will be true only when the original theorems respecting the numbers of porismatic points
and lines, as given by Dr STEWART, are corrected. In this case, all the equations of condi-
tion for different values of 8 are contained amongst those for 8 — 0 ; and hence the porismatic
lines, which fulfil the conditions for the value £ = 0, fulfil those, also, for all higher values
within the prescribed limits ; although the conditions of the porisms might be fulfilled with
a smaller number of porismatic points and lines for those cases.
CHASLES'S extensions are, in our notation,
the former being that of Prop. 44, and the latter that of Props. 49 and 53, as n is odd or even ;
and d being taken from 0, 1, 2, .... — jj— in the former case, and from 0, 1, 2, — ^— in
the latter.
Finally, it may be remarked that nearly all the general theorems have analogous ones in
respect to points, lines, or planes situated arbitrarily in space, the numbers of porismatic ones
being properly chosen. Several of them, too, have corresponding properties (with a different
porismatic number, of course), with respect to the hyperbolo'id of one sheet ; but this is not
the proper time for details on any collateral subject.
VOL. XV. PAKT. IV. 8 A
606 MR THOMAS STEPHENS DAVIES ON
NOTE B.
ON LEMMAS I, II, III, pp. 578-81.
I am not aware that the general forms of the co-efficients of the multiple cosines have
been given by any author ; and, indeed, since they are not required in any class of inquiries
which fall under the general objects of science, it is scarcely likely that they should have been
an object of research. Cases, however, having much analogy to them, are sufficiently well
known ; and the method by which they are treated, naturally pointed in the direction by
which these could be obtained when occasion called for them.
By taking r^=r in Lemma i., and p = r in ii., and comparing the terms in the two cases
clear of the cosines, with the corresponding ones in iii., we obtain two elegant formula, first
given by EULER in the Acta Acad. Petropolitance, 1781, viz. : —
2»(2n-l)(2n-2) ____ (n + 1)
tf + *? + tf + ..-. + f „_!* + *.' = - i . 2 . 3 .....»'
11.3 1.3.5 2M(2tt
0 2 2 274 4+2.4.6 6+'"= 1.2.3
NOTE C.
ON PROPS. IX, X, p. 582.
This theorem is well known, and has been demonstrated in a great variety of ways, as a
property of the centrdid ; though, probably, it has not been before considered in the light of
a porism, nor, consequently, investigated as such. It was suggested by CARNOT (Geom. de
Pos. p. 326), that it would offer some advantage to take this point as the origin of co-ordinates ;
and as it will illustrate the manner in which, under particular circumstances, the porismatic
proposition may become an ordinary indeterminate, the same property is here investigated,
with the centroid taken as origin of polar co-ordinates.
j Z2=aj r2 — 2^ rrl cos (6 —
cos
am.AmZ2 = amr*-2amrrmcos(d-dm) + amrJ!
Now, since the origin is the centroid, the middle vertical column on the right side is
zero ; and hence
S (a. . Am Z2) = S am . r* + S (a. O
NOTE D.
ON PROPS. XI, XII, p. 583.
These may be proved, as, indeed, most of the earlier propositions can be, very neatly,
but at greater length, by means of rectangular co-ordinates.
Let a, /3j, 02 &, . . . . am /3m denote the given points, xy the arbitrary point Z, a /3 the
DR MATTHEW STEWART'S GENERAL THEOREMS.
centre of the porismatic circle, p its radius, and K the inclination of the arbitrary diameter
to the axis of a:. Then we shall have
A'} (1)
Again, the equations of the porismatic circle and its arbitrary diameter will respectively be
y— fi=(x— a)tanK (3)
Denote, for the moment, the points X, Y by tfy' and x"y" : then from (2, 3) we get their
values
z1=« + ^)cosK a^'=a— p cos K
Whence
And therefore
XZ» + YZ> = 2{*s+y-2a*-2/8y + a» + |SI + p»} .... (4)
which, as in the former solution, is independent of the value of K.
With the elements (1) and (4) form the equation of the porism ; arrange the terms in
reference to the arbitrary quantities x and y ; cancel S am. (x2 + y2) and equate to zero the
remaining co-efficients in respect of x and y ; then there are given the three following condi-
tional equations for a, /3, and p.
o2 + . . . . + amam=Sam.a ......... (5)
(Si! + ---- + am/3m=Sam.(3 ........ (6)
....am(am*=pm*)=8am.(a'+p + f) .'. . (7)
From (5), (6), we have
Sfr.aJ ^BSg&J
Sam Sam
which are the co-ordinates of the centro'id ; and which point is, therefore, the centre of the
porismatic circle. Also, from (7) we have
That this value is always real, may be readily shewn by actual substitution of the values
of a, /B ; but it readily follows from transforming the origin to the centro'id, whose co-ordi-
nates are a /3. For since
«om.{(a-a)2 + (^-/3)2}=0,
the value of p2 becomes
So.
and every term of this being positive, their sum must be so, and the value of (> real.
608 MR THOMAS STEPHENS DAVIES ON &c.
NOTE E.
ON PROPS. XXXV, XXXVIII, p. 590.
To remove any latent suspicions that may be entertained of the correctness of the deter-
mination of the value of p, in consequence of any one of the former equations (29 — 32) being
virtually contained in the other three, it will be desirable to examine the consequences of such
an hypothesis in detail.
On the hypothesis of j» = 3, and the fourth equation being contained in the three others,
we can find the value q^ + q2* + y34 by means of the other three equations ; and if that hypo-
thesis be correct, we ought to obtain the same value of this function as is given in (32).
Put Sv Sa, S3, £4, for the sums of the first, second, third, and fourth powers of the roots
of the equation which results from the elimination of y2 and g3 from (29, 30, 31). Then it is
sufficiently well known that
6 St = 3 Sl S3 + 3 S, (S2- 2 S*) + Sf
Moreover, as the origin of co-ordinates is altogether arbitrary in the investigation by
which those equations are obtained, we are at liberty to take it so as to fulfil the condition
This will convert the equation above into
6St=3Sa2, or2S4=S22.
Substituting in this the values of S2 and 54 from (30, 32), we have
2Sam.S(amPmt}={S(ampm2)}*
an equation which is manifestly incorrect.
The same general result might have been obtained without any hypothesis regarding the
origin of co-ordinates ; but the expressions would have been more complex, and the examina-
tion of the results more troublesome.
We are hence (even without an actual solution of the several equations) entitled to infer,
that the case of three lines only (or p — S), as propounded by Dr STEWART, fulfilling the condi-
tions of the porism, is inaccurate. Moreover, as a general theorem ought to be true in all its
particular cases, it follows that the general statement given amongst the " Theorems " is also
inaccurate.
NOTE F.
ON PROPS. XL. AND XLII, p. 594.
The connection between the porismatic and indeterminate proposition is capable of a
striking exemplification, by a comparison of these propositions with the equations of the cor-
responding porisms. Owing, however, to the already extended space required for printing
the present part of the discussion, that exemplification must be deferred, as well as some other
necessary remarks on the porismatic proposition. See, however, Note C., which is a case in
point.
( 609 )
XXXIX — On a Remarkable Oscillation of the Sea, observed at various places on
the Coasts of Great Britain, in the first week of July 1843. By DAVID
MILNE, Esquire.
(Read 19th February 1844.)
THIS phenomenon presented a remarkable interference with those laws which
govern the ordinary movements of the ocean. It occurred at one place whilst
the tide was flowing, at another whilst it was ebbing ; in some cases, producing
a sudden retrocession of the waters, — and in others, as sudden an impulse of them
on the shore.
The period during which the sea thus continued to retreat and rise respec-
tively, was generally from ten to fifteen minutes. It then made a momentary
halt — after which, it began to flow in the opposite direction, and which it continued
to do, for about the same period which characterised its previous movement.
In this state of alternate flux and reflux, the sea was at most places observed
to continue, for three or four hours together.
The first day on which the phenomenon was observed, was Wednesday the
5th July 1843. During the three following days, the oscillation was at different
places perceptible ; but in no case so distinctly, as on the 5th July.
The same phenomenon appears to have frequently occurred before, and to
have occasionally given rise to discussions as to the cause of it. There will be
found a good many instances recorded in the earlier volumes of the Royal Society
of London, as well as in the Annual Register, and other such periodicals. In
several cases, the oscillation has been distinctly traced to submarine earthquakes.
The Lisbon earthquakes of 1755 and 1761 undoubtedly produced on the coasts of
Great Britain a flux and reflux of the sea, in many respects similar to that which
forms the subject of the present notice ; and as, on other occasions, no other ap-
parent cause suggested itself for these oceanic disturbances, there seems to have
been a general acquiescence in the opinion that they were produced by the same
cause. In a short notice given in the Edinburgh Philosophical Journal, of the
oscillations which occurred last July, I observe that earthquakes are suggested as
the cause.1
Deeming this explanation unsatisfactory, and thinking it of use to preserve
some record of a phenomenon, remarkable in itself, and not hitherto satisfactorily
explained, I have drawn up an account of the principal facts, and will venture to
suggest some views as to the probable cause of them.
' Edinburgh New Philosophical Journal for January 1844, p. 188.
VOL. XV. PART TV. 8 15
610 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
FACTS OBSERVED. I. The following are the places, where I have ascertained that the phenomenon
was observed on the 5th July ; and in mentioning each place, I shall notice the
most material circumstances attending it which occurred there : —
At Newlyn, in Mountsbay, Cornwall, at noon, about an hour and a half after high
water, the sea suddenly retired to the depth of 3 or 4 feet, rushing out
to the distance of at least half a mile. It then returned, in the same state
of agitation, to its former level. The time occupied in each of these move-
ments, was ten or fifteen minutes.
This ebbing and flowing was observed four times ; the duration of each
movement being throughout nearly the same.
The current produced by the flux and reflux, was about three miles an
hour.
At Penzance, Cornwall, about llh 30' A.M., three currents were observed flow-
ing parallel to one another, in opposite directions, and running at the rate of
four or five knots an hour. The agitation increased from noon till half-past
12, and at 1 p. M. its violence was not diminished.
At Marazion, three miles east of Penzance, one of the influxes was observed
about one o'clock. The sea then rushed in from the south to the depth of
4 or 5 feet, and from the distance of about 50 yards, and almost immediately
after retired to its previous level, occupying about ten minutes in each move-
ment. Between 2 and 3 P.M., and after the tide had entirely left the
causeway at Marazion, the sea returned and covered the central parts of it.
At each of the piers of Mousehole, Nervtyn, the Mount, and Portleven, a most
violent eddying current was observed for two or three hours, so remarkable
as to arrest the attention of all, and such as had not occurred during the last
fifty years. The boats were whirled about by it, in all directions. The ver-
tical height to which the sea rose and fell at those piers, was from 2 to 4 feet,
and each retreat and advance respectively occupied about 10 or 15 minutes. '
At Plymouth, the oscillation was observed a little earlier in the day. Captain
WALKER, R.N., the intelligent harbour-master there, writes to me, " I happened
to be standing on the pier, at the entrance of Sutton Pool, I think about 11
o'clock, a little after high water. My people were in the boat at the entrance
of the Pool, which is about 90 feet wide. I noticed, that all at once, the water
ran out of the Pool, carrying my boat and others along with it, and in a
minute or two, it had again ceased to ebb. My coxwain, who was in my
boat, tells me, that the water first ran into the Pool, carrying a barge and
boats along with it, and again ran out faster than it ran in."
At Dunbar, at the mouth of the Firth of Forth, the phenomenon was observed
about 6 P.M., or rather later. The sea was observed to flow up in the first
1 The notices here given in regard to Mountsbay, are abbreviated from an account which appeared
in the Literary Gazette of 15th July 1843.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
instance, and about 18 inches above its former level. The oscillation was
observed for two or three hours.
At North Berwick, about 10 miles west of Dunbar, the flux and reflux was
observed between one and two o'clock P.M. ; and it was noticed twice after-
wards in the course of the day, at short intervals of about ten minutes.
At Arbroath, the flux and reflux were first observed about 5 P.M.
During the making of the tide (it being high water on the 5th July at
8h 4' P.M.), the attention of the harbour master and others was drawn to the
unusual motion of the sea, which made the vessels shift from their usual
berths, and suggested the propriety of fastening them by additional moorings.
This was found necessary, from the manner in which they were driven about
by the currents.
When the phenomenon was first observed, the sea flowed in and rose from
18 to 24 inches vertically, and poured a strong current into the harbour.
The water stood at the level thus attained, for more than five minutes, and
then ran violently out of the harbour during the succeeding ten minutes, till
it reached a level, nearly 2 feet lower than that previously reached. There
it remained for some time, and then began to rise again as before. Each rise
was nearly 1 foot higher, and each fall a foot lower, than the medium level of
the tide at the time.
This flux and reflux was at its greatest height about 8 P.M., the time of
high water. The sea was then calm, the wind being from the north or NW.
The height of the tide was a little greater than ordinary, but not exceeding
a foot above its usual level.
The oscillation continued the whole of that tide, and also during the next
day ; but the rise and fall of the water decreased, being only from 15 to 18
inches. It gradually decreased during that day, and on the 7th July. On
the 8th July it became imperceptible.
Allowing 10 minutes for each rise and each fall, and 5 minutes succeeding
each rise and fall, it may be estimated, that the fluxes attained their greatest
height at intervals of 30 minutes.
These are the only accounts received by me, which can be depended on for
the occurrence of the phenomenon, and its attendant circumstances, on the 5th
July. It was noticed also at Eyemouth, but at what hour is uncertain.
On the 6th July, besides Arbroath, which has just been mentioned, the oscil-
lation was perceived at the following places :—
At St Andrews, in the east coast of Fife, the oscillation was perceived in the
morning. The water (according to the account given by a pilot there) rushed
into the harbour as if it had been poured out from a number of sluices, and
immediately retreated with the same violence — this continuing for a consi-
derable time before and after full tide, which took place at 9h 8' A.M. The
612 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
salmon fishers on the SE. side of the bay stated, that on the same day their
nets were driven in one direction, and instantly after in an opposite one,
owing to a sudden flowing and retiring of the sea.
At Baltasound (Shetland) Mr EDMONSTONE writes me, that he had been informed
of the oscillation having been seen in the harbour there on the 6th July, and
also on the day following, though in a less degree.
" On the 6th July it was noticed between 10 and 12 A.M. The tide was
ebbing. A boat had grounded, and the men were preparing to get out (of
the boat ?), when the tide ran rapidly in, floated the boat again, and carried
it onwards to land several yards farther."
" The horizontal distance that the water reached, was about 50 to 60 yards ;
the vertical about 3^ feet."
"The flood retired again speedily to its first limit ; and this alternation went
on five or six times, perhaps oftener, for the observers did not wait until
they ascertained that all irregularity bad ceased."
" The wind was NE. ; the weather dry and mild through that day and night.
The boats went off to the deep sea fishing, and experienced nothing unusual.
The sea was calm."
" The appearances I have stated were noticed in other harbours and inlets in
this island. My accounts from Lerwick are as follows : — ' The time the cir-
cumstance was first observed was noon, on 5th July, * low water or nearly so.
The first feature was a flowing or returning of the sea ; vertical depth about
3 feet ; ebbing and flowing repeated perhaps seven or eight times. Retiring
was the last feature. About ten or twelve minutes, might be the periods
between the different turns of the tide.' "
At the Start Lighthouse (in the Orkneys) the oscillation appears to have been
noticed first at 3 A.M. on the 6th July. Mr LYALL, the lighthouse-keeper
there, states that " the flowing and ebbing continued for two days, but that
after 3 P.M. on the 7th July it diminished. The interval between the ebbing
and flowing, was from five to ten minutes. On the 6th July the sea was calm,
but on the 7fch July it was much agitated. On the 7th July, during the fore-
noon, some people were going to the cod fishing, who relate that their boats
were floated and grounded several times, by the rising and falling of the sea,
before they could get out. The same phenomenon was observed in Otterswick.
There was a great deal of thunder and rain on the night of the 5th July," *
1 I think that there is a mistake here for the 6th July, for on the 5th July it was low water at
10h 36' A.M., and on the 6th July at llh 41' A.M.
2 For this report, and all the others from lighthouse-keepers, quoted in the subsequent parts of
this paper, I am indebted to Mr STEVENSON, the engineer of the Northern Light Commissioners. And
I take this opportunity of acknowledging the readiness and liberality with which these authorities under-
took to obtain for me returns from all the lighthouse-keepers under their superintendence.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. 613
On the 7th July, the flux and reflux were observed at the following places : —
At Dundee, about 10h 20' A.M., about 5' after high water, by which time the
tide had ebbed about 3 inches, the sea suddenly returned and flowed 5 inches.
It then returned to its former level.
At Leith, at 9h 6' A.M. (which was an hour and a quarter before high water),
the sea suddenly rushed into the harbour, and raised the general level of the
water, as shewn by the tide gauge, 4 inches, but as estimated by the spec-
tators at least a foot. The reaction was equally violent, the waters shortly
after rushing out with great velocity. At 5 P.M. a similar event took place.
At Carnoustie, a few miles south of Arbroath, where the shores are flat and
sandy, a gentleman was, about 8 A.M., in a machine bathing ; whilst putting
on his clothes, he observed the sea suddenly retire, though it was then flood
tide, so that the wheels which were previously in water about 2 feet deep,
were left almost dry. The sea retired at least 100 yards. In about three
minutes afterwards, the sea began to return with great violence, and entered
the machine, so as to oblige the occupant of it to leap on the seat, clothes in
hand. The machine now ran some risk of being floated ; but fortunately
the circumstance was perceived by the man in charge of the machine, who,
without waiting for the usual signal, rode in with a horse, and drew the
alarmed bather ashore. The sea again retired, and again flowed as before.
The distance to which it retired was at least 100 yards, and the depth to
which it fell, was about 3 feet. At this time the sea was perfectly smooth,
and there was little or no wind.
At Campbelton, near Fort George, some carters were, at low water (at 2h 24' P.M.),
loading a vessel lying dry on the beach with timber, when suddenly the tide
advanced 50 or 60 yards towards the shore, surrounding men and horses to
a depth of about 18 inches. After a short space it as suddenly retired, and
then flowed up again as before. This flux and reflux was repeated several
times.
At Lerwick, and other places along the east coast of Shetland, the phenomenon
was noticed. I extract the following accounts from a report made on the
subject to Mr STEVENSON of the Northern Lights, by DAVID LAUGHTON : —
" An extraordinary rising and falling of the sea was observed at the Docks
near Lerwick, on Friday 7th July, near low- water, betwixt 12 and 1 P.M.
The water fell rapidly to a very low ebb, and immediately thereafter it rose
2 feet perpendicular, when it again receded twice, and advanced twice, in the
space of half an hour." " A person at the Dock, observed it suddenly
emptied of water, but which in a few minutes again returned, filling the
basin completely. This was repeated several times in the course of an hour."
" At Riva-head (a small promontory two miles north of Lerwick), some boats,
which were loading with peats, were about the time above mentioned sud-
VOL. XV. PART IV. 8 C
614 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
denly left dry ; as suddenly, in a little afterwards, the sea returned, and it
was with difficulty that the boats were preserved."
" The same phenomenon appears to have occurred all along the east coast of
Shetland, from Unst to Dunrossness, and to have continued for several hours.
Its occurrence on the west coast on this day, I have not ascertained. The
day was remarkably fine ; there was scarcely any wind ; it was rather
cloudy."
" The fishing-boats, on the commencement of the oscillation, fled to land, with
all possible speed, fearing some unheard-of judgment to be at hand. Thomas
Stone, carpenter, Lerwick, was on board a vessel, a short distance from the
shore. He says that the appearance and action of the water he can scarcely
describe. The feelings produced on his mind, were such as might be on the
dissolution of nature."
" A similar phenomenon occurred on the west side of Shetland some years ago,
attended with loud thunder."
The report from Mr LAWRENCE at Boddam, Dunrossness (Shetland), is as fol-
lows : — " On the 7th July, between 2 and 3 P.M., I was standing at the sea-
side, observing a boat hauling out to sea. I was astonished to observe her
suddenly get aground, and then in a few minutes float again. This occurred
three times in the course of half an hour. I marked it particularly, being
surprised to see the pool in which the boat was, filled and emptied three
times successively, by the action and reaction of the tide."
On the 8th July, the oscillation was, so far as I know, observed only
At Cullercoats, near Tynemouth, on the coast of Northumberland. The sea, at
10 A.M., was in a state of perfect smoothness. There was not the slightest
wind which could ruffle the surface. The tide had then flowed about half
way, when suddenly the sea receded to a distance of about 12 yards. After
remaining in this state for about two minutes, the tide then as suddenly
flowed again to the distance of about 2 feet, beyond the previous and regular
water mark. The tide thereafter flowed on, in its natural course, without
farther interference. The whole disturbance occupied ten minutes.
Whilst the above are the only places where the sea was observed and watched
when in a state of oscillation, or alternate flux and reflux, there are some other
places where the tide registers indicate a disturbance in the ordinary flow of the
tides.
At Bristol, where there is a very complete and accurate self-registering tide-
gauge, the tidal curve, as traced by the instrument, of which Mr BUNT has
kindly sent me a copy, exhibits, about 2 P.M. on the 5th July, several devia-
tions, indicating, first a fall, then a rise, and next a fall, of the oceanic waters
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
continuously. Mr BUNT farther informs me, that the sea at high water, on
the night of the 5th July, or rather at 1 A.M. on the 6th July, was 6 inches
higher than it should have been.
The following occurrences, or some of them, are probably connected with the
same phenomenon ; though some uncertainty on this point prevails, as the precise
date could not be ascertained.
At the Scitty Isles (as Mr EDMONDS of Penzance writes) the sea rose to an
" unusual height" on the 5th July 1843 ; and a correspondent there informed
him, that " the sea was much agitated, as if some violent force from beneath
the surface was lifting the body of water above, while the surrounding water
was perfectly calm and smooth."
At Portlogan, in Galloway, the tide, in the early part of July 1843, rose 3 feet
higher than it was ever known to reach there, even at the springs. The
weather was then moderate ; but it was soon followed by heavy rain, and a
gale from the SW.
At Cockenzie (ten miles east of Leith), in the Firth of Forth, Mr CADELL writes
me, "I recollect perfectly of remarking, during a forenoon, between 10 and
11 o'clock, when on the pier, the singular rise and fall of the tide, about
the period you mention, but, from not having taken any note of the pheno-
menon, I cannot speak positively as to the date."
Mr RITSON, the keeper of the Little Ross Lighthouse, wrote as follows to Mr
STEVENSON : — " One day last summer, near this place, Mr Ross and his men
were washing their nets, in the afternoon, at high water, when the tide re-
ceded about 3 feet. It then began to flow again, and continued to do so for
about half an hour. During that time, the sea rose 1^ feet above its previous
mark. Then it began to ebb again as usual. At this time there was no
storm, and the sea was perfectly smooth."
Having mentioned all the places at which the phenomenon was ascertained
to have occurred, it is proper to add, that there are various places on the British
coasts, where it certainly did not occur.
Liverpool is one of these places ; and where, from the flatness of the shores,
the multitude of shipping, and the number of tide-gauges, any flux or reflux dif-
ferent from the ordinary tides, would certainly have attracted general attention.
Through the kindness of Dr TRAILL, I obtained reports from several intelligent
observers at Liverpool, which satisfactorily establish that there was no oscillation
in that quarter.
At Sheerness, where there is a most accurate self-registering tide-gauge, the
invention of Mr MITCHELL, and the indications of which I have seen for the 5th,
6th, and 7th July, no oscillation appears to have taken place.
616 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
The Firth of Clyde is another part of the coast where, most probably, the
phenomenon, if it had occurred, would have been noticed ; but no extraordinary
movement of the waters was perceived there.
Inquiries were also made by me at Carlisle, Whitehaven, Ayr, Inverary, and
Belfast, at none of which places was any oscillation perceived.
It would appear, therefore, that the only parts of England where the pheno-
menon occurred, was on the coasts of Cornwall and Devonshire ; and that, on the
opposite side of the island, it was seen only along the coast of Northumberland,
and the east coast of Scotland.
OF PHE- II, I proceed now to offer some remarks as to the probable cause of the phe-
OMBNON. nomenon.
That it was produced by submarine earthquakes, I hold to be most impro-
bable. For if such had occurred, we would have obtained from other sources
some direct evidence of their occurrence ; and, moreover, other effects would have
been produced, which certainly did not occur.
The oscillations into which the sea was thrown by the Lisbon earthquakes,
consisted of not more than two or three waves, corresponding probably with the
subterranean explosions or eruptions which took place ; and the flux and reflux
of tide thus occasioned, did not, at any of the coasts where it occurred, continue
longer than an hour.
Here, however, the oscillations lasted three or four days ; so that, on the sup-
position of their having been caused by submarine earthquakes, it would be neces-
sary to suppose that explosions or eruptions had been going on for several days.
But it is scarcely possible to conceive that such could have occurred, without
producing shocks felt on the adjoining continents, and other effects equally un-
equivocal. Besides, it is exceedingly improbable, that eruptions or explosions
would continue so long at any one time or place. Farther, it is worthy of remark,
that at the time of the Lisbon earthquakes, not only was there an oscillation of
the sea, but the water in ponds and lakes was affected, by the concussion trans-
mitted through the earth's solid framework ; and some such appearances would
undoubtedly have been observed in July last, had the more extensive and pro-
longed oscillation which then occurred been produced by a similar cause.
Before directly explaining my own views as to the true cause of the pheno-
menon, I shall refer to its occurrence on former occasions, as some of the accounts
appear to me to throw important light on this part of the subject.
CASES. (1.) On the 16th July 1749, the sea at Milford Haven flowed and retired
seven times in a quarter of an hour. *
1 Gentleman's Magazine.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. 617
(2.) On the 13th February 1756, at all the ports in the mouth of the Thames,
there were for two days, great irregularities in the tides. On the 13th, the tide
ebbed only 2^ feet for four hours after high water, when it flowed again for a few
minutes. It then ebbed, but so little, that at low water there was 7 feet of water
at Sheerness, which was 5 feet more than usual. In the morning, during the
flood, it had blown very hard from the south of west. In the afternoon, during
the ebb, the wind had abated, and veered to the NW. To the force and change
of wind, the phenomenon was generally attributed. *
(3.) On the 17th or 18th July 1761, at 6 P.M., the sea at Whitby, both in
the harbour and on the open sea, rose and fell four times in a quarter of an hour,
to the height of nearly 2 feet each time. The sea was then calm. 2
(4). On 28th July 1761, the sea was at various places in a state of oscillation,
continuing for several hours alternately flowing and ebbing. At Falmouth, Fawey,
Plymouth, and Penzance, this oscillation was observed about 10 A.M. ; there the
tide rose suddenly 6 feet. At Carrick, Dungarvon, and Waterford, in Ireland,
it was not observed till 4 P.M., and it continued there rising and falling till 9
P.M.3
It is related, that the day was calm and very hot ; but that, in the evening,
the horizon was cloudy, with thunder and lightning. In the account given in the
London Philosophical Transactions, it is stated, that near Penzance the storm of
thunder and lightning came on about 7h 30' P.M. ; that it came from the NW. ;
and that there Avas the fiercest flash of lightning, and loudest clap of thunder,
ever experienced. About 8 P.M. a church there was struck, and partly de-
molished.
On the following day, there was in Yorkshire, about 6 P.M., a terrible storm
of thunder and lightning.
(5.) On the 18th September 1763, the sea at Weymouth suddenly rose 10
feet, and as suddenly went back again. *
(6.) On the llth February 1764, the tide in the Severn suddenly ebbed and
flowed.5
(7.) On the 5th September 1767, between 7 and 8 P.M., soon after high
water, the water in the Liffey at Dublin suddenly sunk 2 feet, and in a moment
after, rose above 4 feet, and immediately thereafter rose to its proper level. Much
about the same hour, it being low water at Ostend, the tide suddenly rose and
1 London Philosophical Transactions, vol. xlix. p. 530.
2 DODDSLEY'S Annual Register, vol. iv. p. 137; Gentleman's Magazine.
3 DODDSLEY'S Annual Register, vol. vi. p. 99.
4 DODDSLEY'S Annual Register, vol. iv. p. 142 ; Gentleman's Magazine ; London Philosophical
Transactions, vol. lii. p. 508.
5 London Philosophical Transactions, vol. iv. p. 83 ; DODDSLEY'S Annual Register, vol. vii.
p. 50.
VOL. XV. PART IV. 8 D
618 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
stirred up the mud in an extraordinary way. This continued for a quarter of an
hour. The air was serene, and the wind moderate. l
In the Meteorological Register kept at Carlisle (the only one for that date to
which I have obtained access), there is the following entry : — " 6th September
1767. — Thunder, with showers."
(8.) On the 20th February 1766, an unusual tide ebbed and flowed in the
Thames ; and on the same day, a most violent storm occurred in Bedfordshire. 2
(9.) On the 9th August 1770, it is mentioned, that " during a violent thunder-
storm at Brighthelmstone, the sea flowed at one motion 50 feet. The oldest man
living (it is added) never remembered the like." 3
The following is an extract from the Meteorological Register kept by Dr
BORLASE near Penzance : — " On 8th August 1770, close and calm in the morning.
About 5 A.M., thunder, with much lightning; about 6 A.M., rained violently;
at 9 A.M., cleared off, and a fine day. On 9th August, at 2 A.M., thunder and
lightning, but not so violent as on preceding day ; wind easterly." *
(10.) On the 17th July 1793, between 7 and 8 A.M., the tide flowed and
ebbed in an extraordinary way at Plymouth. Three times, in less than an hour,
it rose and fell about 2 feet perpendicular.5
(11.) On the 10th August 1802, the sea at Teignmouth rose and fell nearly
2 feet several times in ten minutes."
(12.) On 31st May 1811, " an alarming and most uncommon flux and reflux of
the sea took place" at Plymouth, which is described by Mr LUKE HOWARD. 7 " It
commenced about 3 A.M., and did not terminate till 10. The sea fell instantane-
ously about 4 feet, and immediately rose about 8 feet. Universal consternation
pervaded the whole port. The vessels in Catwater were thrown about in the
greatest confusion ; many dragged their anchors, some drifted, and several lost
their bowsprits and yards. About 6h 45' the sea rose to the height of 11 feet, and
again receded. At 9h 30' the tide (half flood) suddenly stopped, and in a moment
ebbed 6^ inches; at 10 it ebbed again, in the same most extraordinary manner,
and then flowed as usual to high water."
" Two gales from SSW. and E. preceded this astonishing phenomenon ; but
at the time of its occurrence, the wind was light at SSW."
On consulting Mr HOWARD'S register of the weather for that day, at Plaistow,
near London, I observe it stated, that the wind was SE., and that the barometer
had sunk on that day nearly two-tenths, being 29.48, which was much lower
1 DODDSLEY'S Annual Kegister, vol. x. p. 126 ; Gentleman's Magazine ; London Philosophical
Transactions for 1768.
2 DODDSLEY'S Annual Register, vol. ix. p. 67. 3 Ibid, vol. xiii. p. 99.
4 London Philosophical Transactions for 1771.
5 DODDSLEY, vol. xxxv. p. 32, and Gentleman's Magazine. 6 Gentleman's Magazine.
7 Climate of London, vol. i. Table 57.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. 619
than usual. Farther, from the Royal Society's Meteorological Register, kept at
Somerset House, I extract the following : —
31st May 1811 at 8h 3(X A.M. Barom. 29.47 Wind NNE. Rain, thunder, and lightning.
SMO'p.M. ... 29.41 ... S. byE. Rain.
1st June — 8h3(yA.M. ... 29.69 ... S. Cloudy.
(13.) On the 8th June 1811, the following phenomenon is mentioned by Mr
LUKE HOWARD, as having occurred at Plymouth : — " About 4 o'clock the tide
again flowed and ebbed several feet in as many minutes, which continued at inter-
vals for the space of four or five hours, during which the immense swell, commonly
called the boar, drove into the harbours of Sutton Pool and Catwater, at the rate
of four knots an hour, subjecting the vessels at anchor there to great danger.
The wind was variable, but mostly SW. During the operation of the boar, it
thundered and lightened excessively."
In the Annual Register,1 I find the same or a similar phenomenon alluded
to, as having happened at Plymouth on the 4th June, with these additional par-
ticulars,— that the boar was accompanied by a violent gust of wind from the SW. ;
that the boar was from 9 to 1 1 feet high ; that it occurred at dead low water ;
and that the quicksilver in the barometer was observed to sink and rise with a
tremulous motion during the progress of the boar."
There is one circumstance mentioned in this last account, which makes it
doubtful whether the phenomenon recorded in it, and by Mr LUKE HOWARD, was
one and the same occurrence. According to Mr HOWARD, it continued from 4 till
8 or 9 o'clock ; according to the other account, the boar occurred at dead low
water. Now, by the Edinburgh Almanac, it appears that, on the 8th June, it
was low water at Plymouth about 12h 35' P.M., — not within the limits mentioned
by Mr HOWARD. On the 4th June, it was low water at 9h 35' A.M., and 9h 57'
P.M. ; so that, if the phenomenon mentioned in the two accounts was one and
the same, it is probable that it occurred on the 4th June.
From the Somerset House Meteorological Register, I extract the following : —
4th June 1811 at 9 A.M. Bar. 29.93 Wind SW. Cloudy.
4 P.M. ••• 29.88 •-• S. byW. Cloudy.
5th 8h 3(X A.M. ••• 29.63 ••• S. Rain. Blew hard all night.
3h P.M. ... 29.63 ..- W. by N. Rain.
8th 8h 30' A.M. ... 29.86 ••• E. Fair.
3h 15' P.M. •-. 29.75 -•• S. Rain. A thunder-storm at 6 P.M.
9th 8h 45' A.M. ... 29.11 ••• SW. Cloudy.
Mr LUKE HOWARD mentions, that on the 8th June, " a severe storm of rain,
hail, and lightning, took place in Birmingham and the neighbourhood. The hailv
or rather pieces of ice, which fell, are described of prodigious size. At Worcester,
the storm of thunder, lightning, and rain, took place about 11 A.M., and was
most tremendous."
1 DODDSLEY, vol. liii. p. 62.
620 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
(14.) On the 19th August 1812, at Folkestone, the sea rose and fell 3 feet per-
pendicular three times, in less than a quarter of an hour. l
(15.) At Portsmouth, on the 4th March 1818, in the evening, there were the
highest spring tides (at about 10" 40' P.M.) ever remembered. At Hull, the fol-
lowing phenomena were observed :— At high water, about 4h 30' P.M., the wind
then blowing from the SW., with moderate weather, the tide flowed at the dock-
gates 18 feet 6 inches. After the tide had fallen from 1 to 2 inches, it began
to flow again to the height of 4 or 5 inches. A tempestuous night ensued.
The wind blew a heavy gale from the SW., and at high water (5 A.M.) next
morning, the tide flowed only 14 feet 1 inch, although, the spring tides having
put in, the water ought to have flowed to a higher level than on the preceding
evening.
From the accounts given by Mr HOWARD of the weather on the day in ques-
tion, it appears that there was a very severe storm in every part of England. In
the Isle of Wight, it seems to have continued from 4h 30' P.M. to II11 30' P.M.
In London, it continued from 8 P.M. till past midnight. At Yarmouth, it com-
menced about 8 P.M.
Mr HOWARD observes, in explanation of the tidal phenomena at Portsmouth
and at Hull, that, " if we suppose this gale arriving suddenly from the southward
(which appears to be the fact), a swell produced by the compression of the water
in the Channel and Straits of Dover, may have been propagated on the surface of
the sea northward, with greater swiftness than the storm could make its way
across the land to Hull. The arrival of this swell at the critical time of the tide's
turning, accounts for the first fact. With regard to the second, it is matter of
historical record, that an off-shore wind (as this was at Hull), if it blow long
enough, and with sufficient force, may so remove the sea from the coast as to
suspend a whole tide. Portsmouth and Hull were therefore placed, on this occa-
sion, by the operation of the same cause, in opposite circumstances. The one had
the highest tide ever remembered, and the other, a tide later, nearly 5 feet less
water than was expected."
The only difficulty in the way of this explanation, arises from the fact, that
the effects produced by this supposed swell manifested themselves at Hull sooner
than at Portsmouth. If, however, the gale and the swell both came from the
southward, they should have been first felt at Portsmouth.
(16.) In July 1832, I understand from Mr EDMONDSTONE, the sea was at the
Shetland Islands in a state of oscillation similar to what occurred in July last. At
this time, it appears, there was a furious gale of wind, which continued for several
days, and was fatal to many fishing boats.
(17.) On the 12th September 1841, at Kilmore, on the south coast of Ireland,
the inhabitants, about noon, were attracted by a number of short, loud, but rather
smothered reports out at sea, which they supposed to be cannons fired by a ship
1 Gentleman's Magazine.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. (}21
bewildered in a thick fog then prevailing. The tide had flowed pretty well at the
time, and the fishing boats in the harbour were all afloat, when, in the space of
two or three minutes, the water receded from the pier, and some walked dry-shod,
where, that short space before, the boats had been floating in 5 or 6 feet of water.
In the course of a few minutes, the waters began to return, much in the same
way as they had receded, and the tide continued to rise for the usual time. After
repeated rolls of thunder, and some heavy showers, the sky cleared up. The
wind had in the forenoon been from the SSW. ; but immediately before the recess
of the tide, the wind lulled, and the low growl of distant thunder was heard.1
(18.) On the llth March 1842, it was observed by Mr CAMPBELL, the keeper of
the Island Glass Lighthouse (on the Isle of Lewis), that the tide did not rise or fall
more than 3 feet during the whole day ; whereas, according to the state of the
tides (then neap) it should have risen and fallen about 9 feet perpendicular.
He states that, on the same day, there was a very heavy gale, accompanied
by thunder and rain, of which accounts were received shortly after from various
parts of the neighbourhood. The thunder was not heard at the lighthouse, owing
to " the violence of the storm." The wind was, at 9 A.M., about SW., and by
6 P.M. it had veered to the WNW.
This gale, so severe in the West Hebrides, was probably the same referred
to in the following paragraph, extracted from the Annual Register : — " On 10th
March 1842, about 10 P.M., at Brighton, the wind began to blow with great
violence, accompanied by pelting showers of rain. In the course of a few hours,
it increased to a hurricane, which continued the whole of the night. The gusts
of wind shook the houses to their foundations."
Now, of these eighteen cases, in which the same or a very similar pheno-
menon occurred with that of last July, it will be observed, that fully one-half
of them were accompanied by remarkable atmospheric disturbance. Gales of
wind, or thunder and lightning, and a depressed barometer, in all these cases
characterised the weather when they occurred. Nor would it be fair to infer that
no such disturbance existed, in those cases where no proof of it is expressly given ;
indeed, it is probable that a person drawing up an account of any anomalous tidal
phenomenon would confine his remarks to it, and take little or no account of the
weather at the time. Farther, on examining the seven or eight cases of these
phenomena before noticed, which are not expressly stated to have been accom-
panied by atmospheric disturbances, five of them occurred in July and August, the
months in which, of all others, thunder-storms are the most abundant.
Looking, therefore, to the accounts given of the same or similar phenomena
at former periods, I think that a strong presumption arises, that they are pro-
duced by, or are at least in some way connected with, violent atmospheric dis-
turbances.
1 Extracted from a Wexford paper.
VOL. XV. PART IV. 8 E
622
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
STORM OF STH
JULY 1843.
SEVERITY OF
STORM.
This inference is greatly strengthened by the circumstance that, during the
first week of July 1843, a succession of thunder-storms passed over different parts
of the British Islands ; and that, on the 5th July, in particular, one occurred,
which, for severity and extent, has been rarely equalled.
Independently of the bearing which it has on the oscillation of the sea at
that period, it is interesting to trace the progress of this last mentioned storm,
and to shew the nature of it.
The severity of the storm may be judged of from the damage which it did
at various places.
Near Gloucester, the lightning killed a man, and struck two other persons to
the ground. The hailstones which fell, measured 3J inches in circumference.
At Huddersfield, a man was killed by the lightning.
At Milling, in Lancashire, a boy was killed by the lightning, and two others
were for several hours rendered insensible.
At Worcester, it killed two horses and six sheep. It also exploded in a
house, filling the room with heat and sulphureous vapour.
At Leicester, it set fire to a hay-rick, killed three cows, and knocked down
three men and a horse.
At Stafford, the lightning struck two houses.
At Coclcermouth, the lightning struck several persons, and set fire to the cur-
tains of a bed.
At Whitehaven, the electric fluid was seen to issue from the earth, and to
communicate with a nimbus above.
Near Longtown, upwards of 100 trees were torn up by the roots in less than
two minutes. A man-servant was lifted from his feet, by the force of the wind.
Near Peebles, the lightning killed thirty-four sheep, breaking and scattering
the stones of the fold in which they had taken shelter.
In Edinburgh, two curious circumstances were mentioned in the newspapers.
One was, that whilst a servant girl was polishing a steel fork in a house in the
Lothian Road, she received a severe shock of electricity, which caused her life to
be despaired of. Dr PEDDIE, of Rutland Street, was called in, and succeeded in
resuscitating the patient. At the same moment, the house immediately opposite,
next to LAING'S Bazaar, was damaged, the electric fluid having struck the
chimneys, and partly rent the gable.
The other circumstance was, that in Great Stuart Street, immediately before
the violent discharge, about 7h 20' P.M., a maid-servant was ironing some articles
of dress, when she perceived a circle of fire vibrating round the irons she held in
her hand. The phenomenon was repeated three times with extraordinary rapi-
dity, and shed such a glare of light on the article she was ironing, that she
thought it was on fire. The violent claps of thunder accompanying the light-
ning, together with the vividness of the fire-circle streaming from the irons,
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
623
threw the girl into a swoon, in which she lay for about two minutes. When she
opened her eyes, she could not see for some minutes.
At Blairgowrie, the lightning struck several people, some of whom had at the
time metal spoons in their hands, which were driven out of them. It also demo-
lished a byre.
At Aberdeen, the lightning killed a man, a girl, and a cow. Several houses
were struck and damaged.
The following data shew that the progress of the storm was in a direction TRACK OF
from S. or S. by W. to N. or N. by E. As, however, it moved northwards, it seems STORM-
to have enlarged or spread over a wider space than it occupied when it first reached
England.
Penzance.— During the occurrence of the oscillation of the sea (which, as
already mentioned, continued from noon till 3 P.M.), " the sky was overcast
with thunder-clouds towards the SE., and early in the morning of that day (the
5th July) a distant thunder-storm was heard in that direction. In the afternoon,
before the agitation had entirely subsided, a sudden storm of wind came on from
the south, and, almost simultaneously, a heavy sea, so that the large fishing boats
which were out at the time had a narrow escape ; and the sudden cessation of the
wind and sea was as remarkable as their sudden rise."
Plymouth. — I have been favoured by Mr SNOW HARRIS with the following
extract from his Meteorological Register. The force of the wind is indicated by
its pressure on a square foot expressed in Ibs. : —
Days
of Month.
Hours.
Direction and Force of Wind.
Temp.
Ext.
Pressure
of
Atmosphere.
E.
SE.
S.
sw.
w.
5th July
7 A.M.
.3
61
29.681
8 ...
.3
63.5
.660
9 ...
.4
...
65
.632
...
10 ...
...
.4
66
.624
...
11 ...
.3
66
.637
• *
12 ...
.5
...
...
66
.640
...
1 P.M.
...
.6
...
63
.652
...
2 ...
...
.7
• « •
...
64
.622
...
3 ...
...
.9
...
65
.645
4 ...
1.0
...
62
.645
5 ...
...
1.5
...
...
62
.654
• * •
6 ...
...
1.5
...
• • •
60
.653
• * •
7 .'..
...
2.0
...
...
59
.664
...
8 ...
2.0
...
58
.660
...
9 ...
1.6
57
.666
...
10 ...
1.5
57
.670
• • •
11 ...
1.0
...
56
.678
...
12 ...
.7
56
.682
6th July
1 A.M.
.4
55
.686
J
2 ...
.3
55
.686
3 ...
.3
54
.697
4 ...
.3
54
.714
...
5 ...
.3
54
.722
624
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
From this extract it appears that the storm was at Plymouth not very severe,
as it never exceeded a pressure of 2 Ibs. on the square foot. It will be remarked
that the gale commenced at 8 A.M., with the wind at E., and that it ended in
fifteen or sixteen hours, with the wind at W., having the same intensity at the
beginning as at the end. The barometer reached its lowest point about 10 A.M.
Bristol. — Mr BUNT had the goodness to send an extract from a Meteorological
Register kept there, and which contains the following information : —
Days
of Month.
BAROMETER.
Wind for
Day.
Weather.
9h30'A.M.
No .
6 P. M.
9h30'P.M.
4th July
29.970
29.942
29.842
29.850
WSW.
Cloudy.
5th ...
.644
.600
.630
.640
North.
( Stormy, with thunder
\ and lightning.
6th ...
.764
.798
.840
.864
WSW.
Fine.
From this Table it appears that, just as at Plymouth, there was, on the 5th
July, a fall and a rise of the barometer, corresponding with the approach and the
retirement of the storm ; and that the barometer reached its lowest point, proba-
bly about 2 P.M. It is important to observe, that the wind was here from the
north on the day in question.
Greenwich. — The very accurate register, kept at the Royal Observatory (from
which Mr AIREY has sent to me full extracts), supplies the following informa-
tion : —
Days
of Month.
Hours.
Barometer
corrected.
Therm,
dry.
Wind,
direction.
Wind,
force.
Amount
of clouds.
Remarks.
{A few cirri and small
5th July
8 A. M.
29.607
70.0
Calm.
...
1
cumuli are scattered over
the sky.
...
10 ."
.637
82.1
South.
i
1
A few light clouds.
...
12 P.M.
.592
84.8
SSE.
4
3
Do.
...
2 ...
.574
81.7
South.
i
8
f Fleecy clouds. The air is
\ extremely close.
...
4 -
.507
87.3
S. by E.
!
3
Cirri and clouds.
( Cirrostratus, scud, and
...
6 -
.475
81.7
S.
i
7
< cirri. Sky east of meri-
( dian clear.
...
8 -
.514
72.8
SSW.
*
8
f Undefined clouds cover
\ greater portion of sky.
...
10 -
.550
64.8
ssw.
4
9|
( Nearly overcast. Cirro-
\ stratus and scud.
...
12 ...
.584
61.1
sw.
*
9|
Do.
6th July
10 A.M.
.649
64.0
WSW.
i
6
f Clear in zenith. Rest of
\ sky nearly covered.
...
12 P.M.
.671
66.8
WSW.
i
10
f Cirrostratus and scud.
(_ Rain falling.
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. 625
From this register it appears that the storm was little felt at Greenwich, and
that the barometer reached its lowest point about 6 P.M., some hours later than
at Plymouth and Bristol. Farther, it is important to observe that the gale (if such
it can be called) began there with the wind at SSE., and ended in about twenty-
four hours after, with the wind at WSW.
Gloucester. — The storm is said to have been at its height here, between 3 and
5 P.M.
Doncaster. — Almost immediately after noon, the atmosphere exhibited signs
of great disturbance. At 3 P.M. dark clouds, mass rolling over mass, approached
from the SW., bringing with them comparative darkness. After a short pause, a
sudden rush of wind indicated, that a more violent storm was at hand. It speedily
approached with increasing gloom, and blew a complete hurricane, but it was of
short continuance.
Derby. — The storm of thunder and lightning commenced about 4 P.M. A
house was struck.
Brimington, Derbyshire (about ten or fifteen miles south of Sheffield). — The
storm is described as the most terrific remembered. At 5 P.M. it thundered inces-
santly, and continued till 6 P.M. without ceasing for an instant. At 6 P.M. the
storm came on in all its violence, accompanied by wind and hailstones.
Sheffield. — The following account is extracted, in a letter addressed to me by
Mr LUCAS of The Mills, near that town : — " The storm, as you will have learnt,
was most disastrous in its effects, considering that it only lasted in its utmost fury
for about five minutes, in which time something approaching to L.I 0,000 damage
was done, and the town afterwards presented the appearance of having sustained
a siege, or of having been in the hands of a mob for some hours ; for not only
were the windows broken, but in some instances even the frames were partially
destroyed.
" There had been evident indications of an approaching storm all the after-
noon ; and having occasion to pay a visit to a friend, resident across the Derbyshire
moors, about twelve miles in a direction about due west of the town, I observed
several heavy storms pass off on each side of me as I rode along, and fully
expected to have been caught in one myself, but I luckily escaped. I also observed
that there was an accumulation of nimbi in the zenith, that appeared perfectly
stationary, at the same time the atmosphere was densely close and oppressive ;
and although we had a heavy thunder-storm where I was, at about 7 P.M., there
was little or no hail, and no damage done. At the town of Sheffield, however, it
came on about the same hour very suddenly, with a fall of hailstones, some of
which were the size of marbles, or rather perhaps of large hazel nuts, as they
were of a very irregular shape, and somewhat oblong. As far as I could learn, the
storm approached from a point rather S. of W., and passed off in a direction some-
what N. of E. The fall of hailstones, however, appears to have been very capri-
cious, and to have been confined in some instances to a limited space ; for all that
VOL. xv. PART iv. 8 P
626 MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
portion of the town lying towards the W. suffered most severely, whilst that por-
tion lying towards the N. and NE. suffered in a much less proportion ; and at this
place only, about one and a quarter miles from the centre of the town, no damage
was sustained, but about one and a half miles farther N. some damage was done ;
and again, at seven or eight miles NE., or between Barnsley and Rotherham,
there was considerable damage done ; again, in a southerly direction from the
town, within a mile or two, no damage of any moment was sustained ; but at
the villages of Norton and Dronfield, about four and six miles distant, consider-
able damage was done.
" To shew you, however, the capricious nature and limits' of the storm, I
happened, about a week after, to be walking in the neighbourhood of our Botanical
Gardens with a friend, and I observed that a field of standing corn, that was
within 100 yards of the Gardens, did not appear to have sustained any damage,
whilst at the Gardens themselves, above 3000 squares of glass were broken ; and
I have heard of a similar instance of all the glass in one gentleman's vinery being
demolished, whilst his adjoining neighbour's, that was within a few hundred yards,
sustained no damage whatever.
" Perhaps it may not be amiss here to state, that for two evenings preceding
this storm, I had observed there was something peculiar in the atmosphere, as
the odour from the new made hay, as well as from many of the odoriferous plants,
was particularly strong and overpowering."
Mr JACKSON, surgeon in Sheffield, who read an account of the storm to the
Literary and Philosophical Society of that town, has also favoured me with some
information. He mentions, that " the temperature, for several days previous to
the 5th, had been high, ranging as high as 85° in the shade ; and about noon of
that day, the atmosphere was exceedingly sultry and oppressive." " The wind,
about noon, passed round from the W. by N., and at 2 P.M. stood to the E. From
4 to 5 P.M. it veered round to the S., and, as the storm approached, it moved a
little to the W. of S., from which quarter the hurricane came. Its continuance
was not more than half an hour, after which the wind settled in the W. The
temperature was extremely high during the whole of the 5th, till about 4 P.M.,
when it fell till the occurrence of the storm, the variation being in some places as
much as 30° ; in a contiguous town, it was mentioned by a gentleman, as much as
50°. The barometer was but little disturbed during the day ; one correspondent
observed the barometer to fall an inch, during the passage of the storm over his
house."
I wrote to Mr JACKSON in regard to this last observation, and, in reply, he
stated that " the individual, who furnished me with the information respecting
the barometer having varied so much as an inch, is a gentleman (W. BUTCHER,
Esq.), merchant, residing about a mile from the town. His residence is rather
high, and the storm raged there with great violence. Since you wrote last, I have
communicated with that gentleman, and he states that his observation of the
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
627
barometer was somewhat casual, but affirms, that there could be no doubt as to
the great variation."
Dr HARWOOD of Sheffield wrote to me that the extreme severity of the storm
lasted only four minutes, in which short interval a noble range of conservatories
was destroyed ; but a field of corn 25 or 30 yards from them was uninjured.
From the Sheffield newspapers I gleaned the following additional particulars.
The barometer was sinking during all the afternoon. During the day, the wind
had been generally from the NE. Immediately previous to the hurricane, there
was a dead and sultry calm. From 5h 30' P.M. to 6h 30' P.M. the thunder con-
£
tinued without intermission. About 6 P.M. the sky was overcast by clouds from
the SW., and the blackness continued to increase for a quarter of an hour. The
storm commenced with rain, which was quickly followed by a most impetuous
wind, driving before it volleys of bullets of hard clear ice — the size of small
marbles. In Botanic Garden 5700 panes of glass, and in another garden 10,000
panes, were broken by hailstones.
Wentworth, West Riding of Yorkshire (eight miles north of Sheffield). — During
the afternoon the day had been intensely hot, with a gentle southerly breeze.
There were a few fleecy clouds floating about, and occasionally some drops of rain
fell. About 4h 30' P.M. there was distant thunder. From this. time till 6h 30' P.M.
it continued to thunder, when the storm suddenly commenced, and lasted more
than half an hour. The lightning was one continued flame, accompanied with
gusts of wind. From 9 to 10 P.M., the lightning from N. to S., above a dense
cloud on the visible horizon, was seen darting to and fro with amazing rapidity,
and highly illuminating the atmosphere with every shade of orange colour.
Norton. — About 3 P.M. thunder was heard in the distance. It gradually
came nearer till about 6 P.M. Dark clouds approached from the SW. Shortly
after, rain and hail fell in torrents, and the wind blew violently for a few minutes.
The hailstones were as large as marbles.
Birmingham. — The height of the barometer and thermometer, the force and
direction of the wind, are shewn in the following Table, furnished to me by Mr
OSLER. The greatest force of the wind was at 5h 15' P.M.
Wind.
Days
of Month.
Hours.
Barometer.
Thermometer.
Force.
Direction.
5th July
9AM.
29.370
62°
...
E. by S.
..
12 ••
29.30
...
1 Ib
ESE.
..
2 -
...
78
2 ••
S.byE.
3, -
29.238
7.6
2 ••
South.
..
4 -
...
...
3 ••
S.byW.
..
5 -
•
....
4 •-
SSW.
7 ••
...
...
1 -
...
..
8 -
...
...
1 ..
...
12 ••
29.30
52
3 ••
West.
028
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
Liverpool. — The thunder-storm occurred about 5h 30' P.M. It passed off in
about half-an-hour, and went towards the N., which was remarked to be the ordi-
nary direction of severe thunder-storms. During the height of the storm, the
wind was very violent, stripping houses of their plaster. At Hilbre Island, hail-
stones fell, some of which were 4 inches in circumference.
Howden, in Yorkshire (about ten miles W. of Hull). — The storm began about
6 P.M.
York. — A gentleman travelling on the railway, writes that, " about 7 P.M.,
when ten miles south of York, a most unusually violent thunder-storm, with very
vivid lightning, came on from the south."
Scarborough. — The storm began at 7h 30' P.M. The thunder and lightning
continued till near midnight.
Newcastle. — The following extracts from a Meteorological Register, shew the
time at which the storm arrived there, and the manner in which the wind
veered : —
Days
of Month.
Hours.
Barometer.
Wind.
Weather.
5th July
9 A.M.
29.696
wsw.
Dull.
...
3 P.M.
.640
SE. by S.
( Fine. Thunder shower between
\ 4 and 5 p. M.
...
9 •••
.524
S. by W.
( Rain. Violent thunder-storm be-
\ tween 8 and 10 p. M.
fith
9 A.M.
.524
WSW.
Cloudy.
...
3 P.M.
.628
NW.
Cloudy.
...
9 ...
.760
NW by W.
Clear.
It is stated in the newspapers that at 8 P.M. the storm commenced, and at
this time, the lightning was very vivid. It was over in an hour.
Sunderland. — It is stated that the storm came on here about 5 P.M. ; but it
did not reach its greatest violence till about 8 P.M. The surrounding atmosphere
appeared then to be one mass of flame. At 9 P.M. it moderated, and soon after
became fair.
Carlisle. — The storm began shortly after 6 P.M., and continued till near 9 P.M.
Dumfries. — The storm occurred there between 6 and 7 P.M. It was the
most awful which had occurred, within the memory of the present generation.
There were from twenty to twenty-five flashes in a minute.
Glasgow. — Here the thunder-storm commenced a few minutes before 7 P.M.
But no thunder was heard twenty or thirty miles west of Glasgow ; — and it is
still more remarkable, that there was no gale of wind at Glasgow at all. The
Anemometer Register at the Observatory, of which an extract was sent to me by
Professor NICHOLL, shews not only that the wind during the course of the day
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
629
and night was moderate, but that it blew steadily from the east. Previously, the
atmosphere and ground had been much parched by cold NE. winds.
Mackerston. — The following extracts were furnished to me by our President,
Sir THOMAS BRISBANE, from the very accurate Meteorological Register, kept there
by Mr BROWN, his principal assistant.
Days
of Month.
Hours.
Barom.
Therm,
dry.
Fore
Max.
e of
Pres.
Direction
of Wind.
Remarks on Weather.
5th July
ih ior P.M.
29.587
66
.1
.1
NE.
f Scud from SSE. Thick cirrhous haze
\ above.
. . .
3hl(X ...
.548
62.7
.6
.5
NE.byE.
Do. Do.
...
&1V ...
.504
61.1
.9
.2
NE.byE.
f Scud from S. Thick mass of clouds
|_ above. Heavy thunder-showers.
/A good deal of thunder, with vivid
flashes of lightning, within the last
hour, from dark mass of scud to
SW. and W. The scud was from the
SSW. Cirrhous haze above, loose
smoky scud low from ENE. At
7" 10' ...
.416
58.5
.7
.4
...
7h 13' P.M. a vivid flash, with a
\ peal of thunder. At 7h 15' a gene-
ral Scotch mist with light rain ; 8h
20' frequent peals of thunder since
7h 10', with vivid flashes. It has
now passed off. There is now loose
scud, acted on by various currents,
moving principally from W.
9h 10' ...
.430
57.
.4
0
Here, it will be particularly observed, that the wind, previously prevailing,
was from the N.E. ; and, even during the passage of the storm, it appears to have
retained this direction on the earth's surface. The upper regions of the atmos-
phere indicated, however, a different set of currents, which commenced with
SSE., and ended with W.
It so happened, that on this day, Sir THOMAS was endeavouring to deduce the
height of his observatory, above the sea at Berwick pier, by barometrical admea-
surement. He had for that purpose a very correct barometer placed at Berwick
pier, the indications of which were frequently observed. Sir THOMAS has handed
to me a note of these, from which it appears that the greatest depression of the
mercury was reached about 7h 40' P.M., — in which respect it agrees with the baro-
meter at Mackerston Observatory. The following were the heights at Berwick
pier, and they shew the almost constant variation of pressure taking place in the
atmosphere.1
1 Sir THOMAS BRISBANE informs me that his attempts on the 5th July to deduce the height of
Mackerston above the sea, were completely frustrated, the three excellent barometers which he employed,
VOL. XV. PART IV. 8 G
630
MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA.
Hours.
Barometer.
Ext. Temp.
2h 5\
the external margin of the cups of each vertebra, the
articular surfaces, or rather the internal cavity, of the cup is nearly circular.
The same general structure was found present in the Spinax Acanthias, the
Picked Dog-fish, in the Scyttium Canicula, the Spotted Dog-fish, the Scyllium Ca-
tulus, the Common Dog-fish, and the Galeus vulgaris, the Common Tope. It is
reasonable, therefore, to infer, that the same structure will be found present in
all the allied species.
In the other genera of the great family of Squalidse or Sharks, the osseous
portion of the vertebral column presents various modifications of structure. In
the Selache maximus, or Basking Shark, the vertebrae are of much larger dimen-
sions, in proportion to the size of the animal, than in the genera above alluded
to. This is easily accounted for when the structure of these vertebrae is exa-
mined. The osseous matter is not, as in the dog-fish, deposited as a central
nucleus of stony hardness, but is deposited in concentric plates, each of which is
separated from the adjoining one by a layer of cartilage. From the centre to
the circumference of the vertebrae, therefore, there is presented alternate layers
IN THE VERTEBRAL COLUMN OF CARTILAGINOUS FISHES. (J51
of bone and cartilage. These osseous plates are all beautifully cribriform, and,
by their numerous apertures, allow a free communication between the adjoining
layers of cartilage. The plates of bone, however, do not appear to send proces-
ses from one osseous plate to the other: each forms an in- Kg 10
dependent plate or layer encircling the layers within it. The
adjoining figure represents a section of this vertebra, — A A re-
presenting the section of the two cup-shaped articular surfaces,
B B the concentric layers of osseous matter. The internal
layers are more condensed than the external ones. It ought
to be mentioned, that the osseous plates are partially interrupted on four sides.
With this structure no additional means are required for giving support to
the vertebrae in violent motions of the animal, and none else are found present.
In the Carcharias mdgaris, or White Shark, each vertebra is composed of two
very flat slightly hollowed discs, formed of concentric layers of osseous matter.
These discs are supported on four sides by very broad supports, which extend
from the outer margin to the centre of the discs. The lateral supports are by
much the broadest ; in fact, each supports about a third of the circumference of
the vertebral cups. These supporting columns are formed of plates of spongy
osseous matter, which extend from the circumference to the centre of the verte-
brae, and, in this respect, differ essentially from those of the Selache maximus,
which have a concentric arrangement. A central aperture perforating the body
of the vertebra is barely perceptible.
In a young specimen of the Pristis antiquorum, or Saw-fish, an animal be-
longing to the same family as the Sharks, I found the internal portion of each
vertebra composed of a solid osseous portion, which, however, differed in its
specific characters from that of the other cartilaginous fishes. Each vertebra
was composed of two flat, but strong, somewhat rounded, cup-shaped bodies, so
flat, however, as to resemble two discs united by a narrow neck. In fact, the
vertebral column almost exactly resembled a continued series of the joints of some
of the Crinoidese. I could not detect any aperture piercing the body of the ver-
tebra, so as to allow the flat cup-shaped articular surface of the one side to com-
municate with that of the other. As the specimen was a young one, and had
but few of the vertebrae remaining, the rest having been removed for the purpose
of stuffing it, I am unable to give further particulars regarding them, or of the
mode by which they are strengthened ; but, from then* form, great strength, and
solidity, I do not think it likely that they receive Pig. n.
any strengthening pillars. Figure 11 represents the
general form of the osseous portion of the vertebrae
of the Saw-fish — viz., two rings or discs separated by
a neck, and hollowed into shallow cups on each articular surface.
In the Chimcera, which belongs to a family closely allied to the Sharks, the
VOL. XV. PART IV. 8 N
652 DR JAMES STARK ON THE EXISTENCE OF AN OSSEOUS STRUCTURE
vertebrae are extremely solid, and bear a very close resemblance to those of the
saw-fish. Each vertebra is formed of two flat shallow saucer-shaped discs of
bone, united to each other by four very broad osseous pillars which extend from
the margins of the cups to the centre of the vertebra. The margins of the cups pro-
ject somewhat beyond those broad supports which form the body of the vertebra.
These strengthened portions are on the abdominal and dorsal, and two lateral sur-
faces : the intermediate portions, however, are hollowed out, and form square
cavities filled with cartilaginous matter, which extend nearly to the centre of the
vertebra. (Fig. 12 represents one of the dorsal vertebrae. Kg. 12.
A the anterior or abdominal supporting plate ; B the lateral hol-
low ; C the flat articular surface.) The examination of the ar-
ticular surface shews that, in these vertebrae, the osseous mat-
ter of the cups is deposited in concentric layers, as in all the other cartilaginous
fishes ; but not having had an opportunity of making a section of the bone, I am
unable to speak of the peculiar disposition of the supporting plates which form
the body of the vertebra.
Two other orders of fishes are arranged under the chondropterygious sub-
class, viz., the Cydostomi and Sturiones. These two orders, however, differ in
many essential points from those cartilaginous fishes the structure of whose
vertebrae we have been considering : For, while the Plagiastomi, which include
all the Sharks and Rays, possess, generally speaking, an organization of a higher
order than that of the osseous fishes, the Sturiones, but especially the Cydostomi,
possess an organization of an inferior order, — an organization which renders them
in some measure the connecting link between the more highly organized Mol-
lusca and the Fishes.
This circumstance is accordingly not only seen in their digestive, generative,
and nervous development, but extends, in a remarkable degree, to what ought to
constitute their internal skeleton. In the Sturiones, or Sturgeons, the spinal
column is formed of a continuous purely cartilaginous tube, divided at intervals
into regular pieces, but with no osseous matter whatever in that part which
ought to constitute the bodies of the vertebrae. Mr JONES, therefore, must have
made some mistake in the passage above quoted, in instancing the spinal column
of the Sturgeon as one in which osseous matter is encroaching on the cartila-
ginous matter of the bodies of the vertebrae ; while Dr GRANT and CUVIER are
strictly correct in describing the vertebral column of the Sturgeon as consisting
of soft transparent cartilage, having earthy salts only deposited on the laminae.
It is to be recollected that the Sturgeon is one of those animals in which the
external skeleton is very strongly developed ; and the different rows of osseous
plates or shields are so placed as mutually to support one another, and thus keep
the body extended, even although no osseous structure is developed in the spinal
column.
IN THE VERTEBRAL COLUMN OF CARTILAGINOUS FISHES. ($53
I have not had an opportunity, as yet, of examining minutely the vertebral
column of the Lamprey, Pride, or Hake, the fishes which belong to the order
Cyclostomi ; but I have every reason to believe, that CUVIER and Dr GRANT are
correct in describing that column as consisting of a simple cartilaginous tube.
As doubts may arise in the minds of some as to whether the osseous struc-
ture, which is above described, be really bone, or is simply condensed cartilage,
impregnated with earthy matter, I submitted it to a chemical examination, and
found it to yield in every case the same amount of earthy and of animal matter
as the most solid bones of osseous fishes.
The osseous portion of the vertebrae of the Skate and Thornback Ray yielded
69.1 per cent, of earthy, and 30.9 of animal matters ; while the common cartila-
ginous skeleton of the same animals yielded only 35.0 per cent, of earthy, and
65.0 per cent, of animal matters. In the various species of Dog-fish or Sgualidce
examined, the proportions of earthy and of animal matters were found to be
within a fraction of those of the Rays, being, in the perfectly cleaned osseous
portion of the vertebrae, 68.9 per cent, of earthy, and 31.1 per cent, of animal
matters. In the osseous laminae of the vertebrae of the Squalls maximus or
Basking Shark, I found 71.5 per cent, of earthy matters, and 28.5 per cent, of
animal matters. These proportions are almost the very same as those which I
have found to be present in the perfectly cleaned bones of osseous fishes. The
earthy matters were chiefly composed of phosphate of lime ; carbonate of lime
was also present, but in very small quantity.
CHEVREUL and MULLER are the only writers known to me who have pub-
lished analyses of the hard parts of cartilaginous fishes. CHEVREUL appears to
have undertaken the analyses for Baron CUVIER, and in 100 parts of the vertebra
of the Basking Shark (Squalus maximus), he found of azotized matter and of oil
64.85, sulphate of soda 18.59, chloride of sodium 13.62, subcarbonate of soda
2.00, phosphate of lime, &c., only 0.94. M. CHEVREUL thought that all these
soluble salts did not exist in a solid state in the cartilage, but were held in solu-
tion by the large quantity of water which recent cartilage contains, — a quantity
amounting to no less than 90 per cent, of the weight of recent cartilage.
It is quite apparent from this analysis, that M. CHEVREUL had only analysed
a portion of the enveloping cartilage of the vertebrae, and none of the truly osseous
structure which constitutes the essential basis of these bodies. The circumstance
of meeting with no phosphates proves this point : — it does more ; it proves he had
not even included in his analysis any appreciable amount of the concentric osseous
plates of the vertebras.
MULLER, on the other hand, analysed each of the varieties of cartilage which
he found present in cartilaginous fishes. In what he calls tubercular cartilage,
he found a small proportion of earthy matter, which chiefly consisted of the
phosphate of lime. In what he terms the ossified cartilage, he found in one case
654 DR JAMES STARK ON THE EXISTENCE OF AN OSSEOUS STRUCTURE
41.55 per cent, of earthy matter, and in another 42.068 per cent, of earthy mat-
ter. These earthy matters consisted chiefly of phosphate of lime, with a small
proportion of carbonate of lime, sulphate of lime, muriate of soda, &c.
It is evident from this analysis, that MULLER had not discovered the exist-
ence of the osseous structure which I describe, but had analysed the whole ver-
tebrae, laminae and all, considering it all to be what he terms ossified cartilage.
He had, in fact, made no distinction between the osseous nucleus and its en-
veloping cartilage, with its covering of calcareous granules. When I analysed the
vertebra in the same way, that is to say, with its cartilaginous laminse and envelop-
ing cartilages, I got, in one instance, in the Skate 53.3 per cent, of earthy matter,
and 46.7 of animal matter, and in the Thornback Ray 54.2 of earthy, and 45.8
of animal matters. But this gives no information as to the real amount of earthy
or animal matters in any part of the structure, seeing that the osseous base of
the vertebra contains a very different amount from the enveloping cartilage ;
and seeing, also, that the proportions will vary according to the relatively greater
or lesser size of the cartilaginous laminae and enveloping cartilage.
The essential portion, then, of the vertebrae of cartilaginous fishes is true
bone, which has the same composition, and the same concentric laminar arrange-
ment, as the bones of osseous fishes. This fact appears to be of no small im-
portance in enabling us to arrive at more just conclusions regarding the position
which cartilaginous fishes ought to occupy in the scale of animated beings.
Possessing, as all the Plagiostomi do, in so far as their nervous, generative, and
digestive, systems are concerned, an organization superior to that of most fishes,
it always appeared an anomaly that they should, by their imperfect skeletons,
approach so much nearer the mollusca than other fishes. The discovery, how-
ever, of a perfect osseous structure in their vertebral column, — that column
Avhich is the distinguishing mark of their belonging to the higher classes of ani-
mated beings, — at once serves to explain the supposed anomaly, by shewing it
resulted from an imperfect knowledge of their true anatomical structure.
In fact, the Plagiostomi ought to constitute a separate sub-class of fishes ;
and, in a descending scale of organization, be placed at the head of the fishes, as
they manifestly form the connecting link between the Fishes and Reptiles.*
While the Sturiones and Cydostomi ought to constitute another and distinct sub-
class, to which the term Cartilaginous might still be retained, and be placed after
the Osseous fishes in the descending scale of natural classification, forming, as they
undoubtedly do, the connecting link between the higher organised mollusca, and
the lower organised fishes.
* Even the intervertebral ligamentary apparatus in the Plagiostomi makes a very close approach
to the same structure in the Amphibia. In many of the species, especially in those whose vertebral
cups are flat, it consists of concentric rings of fibro-cartilaginous matter, with softer albuminous or albu-
mino-cartilaginous matter between them.
IN THE VERTEBRAL COLUMN OF CARTILAGINOUS FISHES. (555
But, though these facts be interesting to the student of zoology, it is, per-
haps, to the geologist to whom they will prove of most value. It is a known
fact in geology, that though the dorsal spines, teeth, and palates, of Sharks and
other cartilaginous fishes, have been met with in great abundance in various
strata, few or no remains of their skeletons have been discovered ; and Dr
GRANT,* and other writers on comparative anatomy, state, that there is no likeli-
hood of such remains being ever found, on account of the destructible nature of
the cartilage, of which they suppose the skeleton is alone formed. It is true
that M. AGASSIZ, in his great work on Fossil Fishes, has given five figures of
three nearly complete impressions of cartilaginous fishes, — viz., of one allied to
the Dog-fish — one allied to the Saw-fish, — and one allied to the Skate. In these
impressions, the forms of the vertebral column, as well as of the fins and scales,
have been preserved ; but still, with these exceptions, it is from the scales, teeth,
palates, or dorsal spines alone, that all the species of cartilaginous fishes are
known. The vertebrae, in fact, have not been recognised when met with in a
separate state. It is interesting, however, to remark, that in those impressions
of entire fossil cartilaginous fishes, figured by M. AGASSIZ, the form of the osseous
vertebrae may at once be recognised, so as, from their character alone, to deter-
mine to what order the fish belonged. Thus, in the two plates representing the
Spinacorhynus polyspondylus (Plates 42 and 43 of Vol. III.), any one who pre-
viously examines the vertebrae of the Saw-fish, laid on the table, could at once
say that the animal figured by M. AGASSIZ must belong to that division of cartila-
ginous fishes. The same is true of the other impressions of cartilaginous fishes
figured in that work.
One circumstance may be noticed as shewing the probable importance of re-
cognising in the fossil state these osseous portions of the vertebral column.
When the teeth or dorsal spines of cartilaginous fishes are found imbedded in
the strata, the size of the animal to which they belonged can only be judged of
by comparing these remains with the analogous structures of recent species. In
this way, however, wrong inferences may occasionally be drawn. Thus, in con-
tact with one of the dorsal spines of a Shark figured by M. AGASSIZ, which, from
its size, he thinks had belonged to a very large species (the Spinax major), a few
vertebral remains occur. From their character, they evidently belong to the
same animal to which the dorsal spine belonged ; but they prove that, far from
the animal having been of gigantic dimensions, it could not have exceeded two
feet in length — so much have the weapons of defence of the antediluvian races
exceeded those of our day.
Not being sufficiently conversant with this branch of geology, I applied to
one or two known geologists, and through them to the great Oxford authority,
* GRANT, Lectures in Lancet, Jan. 1834, p. 576.
VOL. XV. PART IV. 8 O
656 DR JAMES STARK ON THE EXISTENCE OF AN OSSEOUS STRUCTURE, &c.
to ascertain whether the vertebrae of cartilaginous fishes were known to occur in
a fossil state, — whether they had themselves seen any,— or, if recognised, what
they were taken for. In answer, it was stated, that the vertebrae of cartilaginous
fishes were unknown in a fossil state, nor were they ever expected to be met
with on account of the destructible nature of the cartilaginous matter of which
they were supposed to be alone composed. Dr HIBBEBT WARE added, that M.
AGASSIZ had several times expressed to him the same sentiment. Both Dr
HIBBERT WARE and Mr TREVELYAN, however, think they have seen in the chalk,
and in the new tertiary strata, bodies like what I have shewn constitute the
essential portion of the spinal column of cartilaginous fishes. This, along with
the circumstance of the exact figures of the osseous portions of the vertebra
being preserved in the impressions of the cartilaginous fishes figured by M.
AGASSIZ, shews that, when the attention of geologists is drawn to the subject,
they will probably meet with them in the same strata as those in which the teeth
and spines occur.
Specimens of the structures above described were laid on the table.
21 HERIOT Row.
( 657 )
XLII. — On the Conversion of Relief by Inverted Vision. .ZtySir DAVID BREWSTER,
K.H., D.C.L., F.R.S., and V.P.R.S. Edin.
(Read 6th May 1844.)
UNDER the name Conversion of Relief , an expression first used by Mr WHEAT-
STONE, I include all those optical illusions which take place in the vision of cameos
and intaglios, of elevations and depressions, whether they are produced with
opaque or transparent bodies, — on surfaces with or without shadows, — in reflected
or transmitted light,— while using one or both eyes, — or by erect or inverted
vision. In these various forms of the phenomenon, the illusion is modified by
certain secondary causes, which were regarded both by Mr WHEATSTONE* and
myself f as primary causes ; so that we were led away, each in a different direc-
tion, from the right path of inquiry.
The phenomenon occurs in its most general and simple form, when it
is produced by viewing a shadowless depression, or elevation, made in an
extended surface, through an inverting microscope, or the inverting eye-piece
of a telescope, and at an angle intermediate between 0° and 90°. In so far as I
know, the phenomenon has never been thus limited, and, consequently, no ex-
planation of it has ever been given. That which I shall now submit to the So-
ciety is capable of the most rigorous demonstration ; and when it is once in our
possession, we can have no difficulty in recognising the secondary causes which
increase or diminish the influence of the primary one, and which, in its absence,
are sometimes the immediate cause of the illusion.
Let A, Fig. 1, be a deep spherical concavity, and A', Fig. 2, a high spherical
Fig. 1. Kig. 2.
convexity in an extended horizontal table MN, M'N', and let them be shadowless^
or illuminated by a quaquaversus light, like that of the sky. If the observer, placed
at a moderate distance, view these objects in the directions E A, E' A', either with
* Phil. Trans., 1838, pp. 383, 384.
t Edin. Trans., Vol. xv. p. 365 ; Edin. Journal of Science, Vol. iv. p. 97 ; and Lettert on
Natural Mayic, p. 98.
VOL. XV. PART IV. 8 P
658
SIR DAVID BREWSTER ON THE
one or with both eyes, his accurate appreciation of the distances E A, E'A', will
prove to him that A is a concavity, and A' a convexity ; but if E A, E' A' approach
to equality, either from the distance of the observer, or from the shallowness of
A, or the slight elevation of A', he will cease to recognise any difference in the
distances E A, E' A', and will be unable to tell which is the convexity, and which
the concavity. So great, indeed, is this uncertainty, that, from causes which he
cannot discover, they will sometimes appear convex and sometimes concave. In
this indetermination of the judgment, a touch of A, A' by the finger, or the intro-
duction of a shadow, will remove or confirm the illusion, whatever it may be.
The same result will be obtained, if we view A and A' vertically, with an erect
or inverting eye-piece. In all these cases, we suppose that the circular, or
rather the elliptical, base of the convexity or concavity is distinctly seen.
Let us now look at A, A', at obliquities varying from 0° to 90°. In Fig. 1 the
concavity A will have an elliptical section at all obliquities, till, at 90°, it appears
a straight line; but in the convexity the effect is very different. In passing
from 0° to the position E', Fig. 2, the circular section of A' will appear an ellipse ;
but in passing from E' to 90°, the appearance of A' will lose all resemblance to
A. When the eye is at e', for example, the summit A' of the convexity will cover
the point a of the table, and a m will be invisible ; and near 90°, the convexity A
will eclipse the whole surface of the table m M, however extended it may be, and
will rise above it.
Let us now suppose that the eye at E, Fig. 3, views the concavity A through
the inverting eye-piece E G H, the hori-
zontal table M N must obviously be in-
verted as well as the hollow A ; but the
apparent change, produced by inversion,
is very different from the real change.
The surface M N, out of which A is ex-
cavated, and upon Avhich the observer
leans, and rests the lower end H of his
inverting eye-piece, appears to remain where it was, and still to look upwards, in
place of appearing inverted, and looking downwards. AVhen he strikes the table
with the end H of the eye-piece through which he looks, he believes that it is the
lower end of the field of view that strikes the table, and rests upon it. With
these convictions, he sees what is re- rig. 4.
presented in Fig. 4. The concavity
mAn, Fig. 3, appears inverted ; and as
the visible part of the concavity A m,
Fig. 3, is nearest the eye in Fig. 4, and
the invisible part A n, Fig. 3, farthest
from the eye in Fig. 4, m A n must ap-
Fig. 3.
CONVERSION OF RELIEF BY INVERTED VISION. 659
pear a concavity in Fig. 4, solely because it seems to rise out of the surface
M N, which looks upward, as if it had not been inverted by the eye-piece.
Now, in this experiment, the conversion of the concavity into a convexity
depends on two separate illusions, one of which springs from the other. The
first illusion is the belief that the surface Fig. 5.
M N is looking upwards, whereas it is really
inverted, as shewn in Fig. 5 ; and the second
illusion, which arises from the first, is, that
the point n appears farthest from the eye,
whereas it is nearest to it, as shewn in Fig. 5.
All these observations are equally applicable
mutatis mutandis to the vision of convexities ; and hence it follows, that the
conversion of relief, occasioned by the use of an inverting eye-piece, is not pro-
duced directly by the inversion, but by an illusion, in virtue of which we conceive
the remotest side of the convexity or concavity to be nearest our eye when it is
not.
In order to demonstrate the correctness of this explanation, let the concavity
m A n be made in a narrow stripe of wood, as in Fig. 5, and let it be viewed, as
formerly, through the inverting eye-piece. It will now appear, as in Fig. 5, really
inverted, and free from both the illusions which formerly took place. The narrow
surface M N being now wholly included in the field of view, and the thickness
NO of the stripe of wood distinctly seen, the inversion of the surface MN, which
now looks downward, will be at once recognised. The edge n of the concavity
will appear nearest the eye,* as it really is, and the concavity, though inverted, will
still appear a concavity. The very same reasoning is applicable to a convexity on
a narrow stripe of wood.
When, as in Fig. 4, the concavity is seen as a convexity, let it be viewed
more and more obliquely. The elliptical margin of the convexity mill always
be visible, which is impossible in a real convexity ; and the elevated apex will
gradually sink till the elliptical margin becomes a straight line, and the imaginary
convexity completely levelled. The struggle between truth and error is here so sin-
gular, that while one part of the Figure m A n has become concave, the other part
retains its convexity !
In like manner, when a convexity is seen as a concavity, the concavity loses
its true shape, as it is viewed more and more obliquely, till its remote elliptical
margin is encroached upon by the apex of the convexity ; and, towards an incli-
nation of 90°, the concavity disappears altogether, under circumstances analogous
to those already described.
If, in place of using an inverting eye-piece, we invert the concavity m A n, by
* The inversion of an object never makes the nearer part of an object more remote, nor the re-
mote part nearer.
6(50 SIR DAVID BREWSTER ON THE
looking at its image in the focus of a convex lens, it will sometimes appear a con-
vexity, and sometimes not. In this form of the experiment the image of the con-
cavity, and consequently its apparent depth, is greatly diminished. Hence any
trivial cause, such as a preconception of the mind, or an approximation to a
shadow, or a touch of the hollow by the point of the finger, will either produce a
conversion, or prevent it.
In the preceding experiments we have supposed the convexity to be high and
the concavity deep and circular, and we have supposed them also to be shadow-
less, or illuminated by a quaquaversus light, such as that of the sky in the open
fields. This was done to get rid of all secondary causes, which interfere with and
modify the normal cause when the concavities and convexities are shallow, and
have distinct shadows, or when the concavity has the shape of an animal, or any
body which we are accustomed to see convex.
Let us now suppose that a strong shadow is thrown upon the concavity. In
this case the normal experiment, already explained and shewn in Fig. 5, is much
more perfect and satisfactory. The illusion is complete, and invariable when the
concavity is in an extended surface ; and it as invariably disappears when it is
in a narrow stripe.
In the secondary forms of the experiment, the inversion of the shadow
becomes the principal cause of the illusion ; but, in order that the result may be
invariable, or nearly so, the concavities must be shallow, and the convexities a
little raised. At great obliquities, however, this cause of the conversion of Form
ceases to produce the illusion, and in varying the inclination from 0° to 90°, the
cessation takes place sooner with deep than with shallow cavities. The reason of
this is, that the shadow of a concavity is very different at great obliquities from
the shadow of a similar convexity. The shadow never can emerge out of a cavity
so as to darken the surface in which the cavity is made ; whereas the shadow of
a convexity soon extends beyond the outline of its base, and, finally, throws a long
stripe of darkness over the surface on which it rests. Hence it is impossible
to mistake a convexity for a concavity, whenever its shadow extends beyond its
base.
When the concavity is a horse or a dog upon a seal, it will often rise into a
convexity when seen through a single lens which does not invert it ; but the illu-
sion disappears at great obliquities. In this case the illusion is favoured, or pro-
duced, by two causes : the first is, that the convex form of the horse or dog is
the one which the mind is most disposed to seize ; and the second is, that we use
only one eye, with which we cannot measure depths as well as with two. The
illusion, however, still takes place when we employ a lens three or more inches
wide, so as to admit the use of both eyes, but it is less certain, as the binocular
vision enables us to keep in check, to a certain degree, the other causes of illusion.
The influence of these secondary causes is strikingly displayed in the follow-
CONVERSION OF RELIEF BY INVERTED VISION. 601
ing experiment. In the armorial bearings upon a seal, the shield is often more
deeply cut than the surrounding parts. With hinocular vision the shallow parts
rise into a convexity sooner than the shield, or continue so while the shield
remains concave ; but if we shut one eye, the shield then becomes convex like the
rest. In these experiments with a single lens, a slight variation in the position of
the seal, or a slight change in the direction or intensity of the illumination, or par-
ticular reflections from the interior of the stone, will favour or oppose the illusion.
In viewing the shield, or the deepest portion, with a single lens, a slight rotation
of the seal round the wrist, backwards and forwards, will remove the illusion, in
consequence of the eye perceiving that the change in the perspective is different
from what it should be.
In a paper in the Edinburgh Journal of Science, already referred to, I have
described several other examples of the conversion of form, in which inverted
vision is not employed. As seen by the naked eye, hollows in mother of pearl,
and other semi-transparent bodies, rise into relief; and the same thing happens
on surfaces of agate and woods of various kinds, when transparent circular por-
tions are illuminated by refraction, at those parts of their circumference where
they would have been illuminated had they been convexities.* But the most
interesting cases of conversion of form are those in which the mind alone operates,
and receives no aid either from inversion, shadow, or monocular vision. " If we
take, as I have elsewhere remarked, one of the Intaglio moulds, used in making
the bas-reliefs of that able artist Mr HENNING, and direct the eyes to it steadily,
without noticing surrounding objects, we may coax ourselves into the belief that
the Intaglio is actually a bas-relief. It is difficult a,t first to produce the deception,
but a little practice never fails to accomplish it. We have succeeded in carrying
this deception so far as to be able, by the eye alone, to raise a complete hollow
mask of the human face into a projecting head. In order to do this we must
exclude the vision of other objects ; and also the margin or thickness of the cast.
This experiment cannot fail to produce a very great degree of surprise in those
who succeed in it ; and it will, no doubt, be regarded by the sculptor (who can
use it) as a great auxiliary in his art."f
From these observations it will be seen that the conversion of Form, except-
ing in the normal case, depends upon various causes which are effective only
under particular conditions ; such as the depth of the hollow or the elevation of
the relief— the distance of the object — the sharpness of vision— the use of one or
both eyes— the inversion of the shadow — the nature of the object— and the means
* In examining, under the microscope, the shallow fluid cavities within the substance of a film
of sulphate of lime, described in the Edinburgh Transactions, vol. x. p. 35, they frequently appeared
as elevations on the surface of the plate next the eye.
f Edinburgh Journal of Science, No. VIII. p. 109, Jan. 1826.
VOL. XV. PART IV. 8 Q
QQ2 CONVERSION OF RELIEF BY INVERTED VISION.
used by the mind itself to produce the illusion. In the normal case, however,
where the cavity or convexity is shadowless, and upon an extended surface, and
where inverted vision is used, the conversion of Form depends solely on the illu-
sion, which it is impossible to resist, that the side of the cavity or elevation next
the eye is actually farthest from it — an illusion not produced by inversion, but by
a false judgment respecting the position of the surface on which the form is
placed.
ST LEONARD'S COLLEGE, ST ANDREWS,
May 4. 1844.
PLATE 17 J?.W Sac, trans Lim :
Tig 5
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 II 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
iiiiiiiiiiiniii immiiimiiimii
fig 4
( 603 )
XLII1— On the Knowledge of Distance given by Binocular Vision. By Sir DAVID
BBEWSTER, K.H., D.C.L., F.R.S., and V.P.R.S. Edinburgh.
(Read 15th April 1844.)
IN analysing Mr WHEATSTONE'S beautiful discovery, that in binocular vision
we sefe all objects of three dimensions by means of two dissimilar pictures on the
retina, I trust I have satisfied the Society that the dissimilarity of these two
pictures is in no respect the cause of our vivid perception of such objects, but,
on the contrary, an unavoidable accompaniment of binocular vision, which
renders it less perfect than vision with one eye. On the other hand, it is quite
true that, in Mr WHEATSTONE'S experiment of producing the perception of objects
of three dimensions by the apparent coalescence of two dissimilar representations
of such objects in piano, the dissimilarity of the pictures is necessary in the exhi-
bition of that beautiful phenomenon.
In performing, with the eye alone, the various experiments detailed in a
former paper, I was very much struck with the fact, that the apparent solid figure,
produced by the union of its dissimilar pictures, never took its right position in
absolute space : that is, in place of appearing suspended between the eye and
the plane upon which the dissimilar figures were drawn, the base of the solid
seemed to rest on that plane, whether its apex was nearer the eye or more remote
than its component plane figures.
With the view of finding the cause of this, I placed the component figures on
a plate of glass suspended in the air, so as to have no vision of the surface on
which they rested, and after uniting these figures by binocular vision, and con-
cealing the two outstanding single figures, I obtained results which, though not
entirely satisfactory, proved that there existed some disturbing cause which pre-
vented the united image from placing itself in the binocular centre, or the inter-
section of the optical axes. This disturbing cause was simply the influence of
other objects in the same field of view, whose distance was known to the
observer.
In order to avoid all such influences, and to study the subject under a
more general aspect, it occurred to me that these objects would be gamed by
using a numerous series of plane figures, such as those of flowers or geome-
trical patterns upon carpets or paper-hangings. These figures being always
at equal distances from each other, and almost perfectly equal and similar, the
coalescence of any pair of them, by directing the optic axes to a point between
the paper-hangings and the eye, is accompanied with the coalescence of every
VOL. XV. PAET IV. 8 R
664 SIR DAVID BREWSTER ON THE KNOWLEDGE OF
other pair. When the observer, therefore, places himself in front of that side
of a papered room in which there are neither doors nor windows, and conceals
from his eye the floor, the roof, and the right and left hand sides of the room,
the whole of his retina will be covered with the images of the united plane
figures, and there will be no interposing objects to prevent him from judging of
the distance of the picture that may be presented to him.
Let the observer, therefore, now place himself three feet in front of the
papered wall, and unite two of the figures, suppose two flowers, at the distance
of twelve inches. The whole wall will now be presented to his view, consisting
of flowers as before, but each flower will be composed of two flowers super-
imposed at the binocular centre, or the point of convergence of the optical
axes. If we call D the distance of the eyes from the wall or three feet, C the
distance between the eyes or two-and-half inches, and d the distance between
the similar parts of the two flowers, we shall have x the distance of the bin-
ocular centre from the wall, x — = — - = 30 inches nearly, and D - x = 6 inches,
the distance of the binocular centre from the middle point between the two eyes.
Hence the whole papered wall, with all its flowers, in place of being seen,
as in ordinary vision, at the distance of three feet, is now suspended in the air, at
the distance of six inches from the observer. In maintaining this view of the wall,
the eye will, at first, experience a disagreeable sensation ; but after a few ex-
periments the sensation Avill disappear, and the observer will contemplate the
new picture with the same satisfaction and absence of all strain as if he were
looking directly at the wall itself: for there is a natural tendency in the eyes
to unite two similar pictures, and to keep them united, provided they are not
too distant.
When this picture is at first seized by the observer, he does not, for a
while, decide upon its distance from himself. It sometimes appears to advance
from the wall to its true position in the binocular centre, and, when it has
taken its place, it has a very extraordinary character : — the surface seems
slightly convex towards the eye ; it has a sort of silvery transparent aspect,
and looks more beautiful than the real paper; it moves, with the slightest
motion of the head, either laterally or to or from the wall. If the observer, who
is now three feet from the Avail, retires from it, the suspended wall of flowers
will follow him, moving farther and farther from the real wall, and also, but
very slightly, farther and farther from the observer : that is, the distance of the
observer from the real wall increases faster than the distance of the suspended
wall from it, according to the law expressed by the preceding formula. The bin-
ocular centre, therefore, recedes from the eye as the observer retires, and the strain
consequently diminishes.
in order to observe these phenomena in the most perfect manner, the paper
DISTANCE GIVEN BY BINOCULAR VISION.
should be pasted upon a large screen, previously unseen by the observer, uncon-
nected with the roof or the floor, and placed in a large apartment. The decep-
tion will then be complete ; and when the picture stands suspended before the
observer, and within a few inches of himself, he may stretch out his hand and
place it on the other side of the picture, and even hold a candle on the other
side of it, so as to satisfy himself that in both cases the picture is between his
hand and himself.
When we survey this picture with attention, several very curious phenomena
present themselves. Some of the flowers, when narrowly examined, appear
somewhat like real flowers. In some the stalk gradually retires from the general
plane of the picture ; in others, it rises above it : one leaf will come farther out
than another, or the flower will appear thicker and more solid, deviating con-
siderably from the plane representation of it seen by each eye separately. All this
arises from slight and accidental irregularities in the two figures which are united,
thus producing an approximation to three dimensions in the picture. If the dis-
tance, for example, of the ends of two stalks in two coalescing flowers is greater
than the distance of corresponding points in other parts of the stalk, the end
of the stalk will rise from the general surface of the figure, and vice versa. In
like manner, if the distance between two corresponding leaves is greater than the
distance between other two corresponding leaves, then the two first, when united,
will appear nearer the eye than the other two, and hence the appearance of a
solid flower is partially given to the combination. These effects are better seen
in old and imperfectly made paper-hangings than in those which are more care-
fully executed.
In continuing our survey of the suspended image, another curious phenomenon
presents itself : a part of one of the pieces of paper, and sometimes a whole stripe
from the roof to the floor, will retire behind the general plane of the image, or
rise above it ; thus displaying, on a large scale, an imperfection in the workmanship
which it would have required a very narrow inspection to discover. This defect
arises from the paper-hanger having cut off too much of the white margin of
one or more of the adjoining pieces, so that when the two halves of a flower
are united, part of the middle of the flower is left out ; and hence when this
defective flow*er is united with the one on the right hand of it, and the one
on the left hand united with the defective one, the united or corresponding
portion, being at a less distance, will appear farther from the eye than those
parts of the suspended image composed of complete flowers. In like manner,
if the two portions of the flowers are not brought together, but separated by
a small space, the opposite effect will be produced. This will be understood from
Fig. 1 (Plate 17), where M N, 0 P represent portions of two separate pieces of paper,
each twenty-one inches wide. In this specimen, there are only two flowers in
each piece, namely one white flower, A or B, and two halves. If the two halves
QQQ SIR DA\7ID BREWSTER ON THE KNOWLEDGE OF
C, D, are united as in the figure, it is obvious that the flower is incomplete, a
part of the central circle of the corolla having been cut off from each half.
If we now, by straining the eye, unite C D with B, and also with A, then, at the
same time, E will be united with the second or left hand image of A, and G
with the second or right hand image of B. But since a piece has been cut out
of C D, the half a a of A is nearer the half D D than the other half a a is to the
other half C C ; and, in like manner, the half b b of B is nearer the half C C than
the other half j3 /3 is to the other half D D. Hence, when the strained eyes unite
« a to D D, the binocular centre is more remote than when a a is united to C, and
the same is true of the other halves ; consequently, the halves D D and b b must
appear, as it were, sunk in the wall, or as farther removed from the observer ;
and if the defective cutting exists along the line RS from the floor to the
ceiling, the whole stripe of paper between R S and 0 P, from the floor to the
ceiling, will appear sunk in the papered wall. But if the defect is confined to a
portion only of the flowers, then a rectangular space of the breadth R 0, and of
a height equal to the defective portion, will appear sunk in the paper. If every
junction has the same defect as that at R S, then the whole will appear to
consist of equal stripes, every alternate one being raised and the other depressed.
In the preceding example, there are only two flowers in a breadth, and
their distance is 10^ inches, which is also the breadth of the sunk stripes. But
21 9l
if the flowers are three or four in number, and their distance -=-, - inches, the
o 4
sunk stripes will vary according as we unite two flowers whose distances are
in the one case 7 or 14 inches, and 5£ or 10^ or 16f or 21 in the other. Calling
B the breadth of the paper, n the number of flowers or figures in that breadth,
T> f) T> O T>
and W the width of the sunk stripe, then we have W= - or — or — according
n n n
as we unite the two nearest, or the first and second flower, the first and third,
or the first and fourth. When W=B, the sunk stripes will cover the whole
paper, and all the flowers will lie in the same plane.
These results afford an accurate method of examining and discovering de-
fects in the workmanship of paper-hangers, carpet-makers, painters, and other
artists whose profession it is to combine a series of similar patterns in order to
form an uniform and ornamental surface. The smallest defect in the similarity
and equality in the figures or lines which compose a pattern, and any difference
in the distance of the single figures, is instantly detected ; and, what is remark-
able, a small inequality of distance in a line perpendicular to the axis of vision,
or in one dimension of space, is exhibited in a magnified form as a distance co-
incident with the axis of vision, and in an opposite dimension of space !
At the commencement of this class of experiments, it is difficult to realize,
and very easy to dissolve, the singular binocular picture which we have been
DISTANCE GIVEN BY BINOCULAR VISION. 667
describing ; but after the eyes have been drilled for a while to this species of
exercise, the pictures become very persistent. Although the air-suspended image
might be expected to disappear after closing one eye. and still more after having
closed and re-opened both, yet I have found it in its original position in this
latter case, and even after rubbing my eyes and shaking my head ; and I have
sometimes experienced a difficulty in ascertaining, after these operations, whether
it was the real or the air-suspended wall that was before me. On some occasions
a singular effect was produced. When the flowers on the paper are distant six
inches, we may either unite two six inches distant, or two twelve inches distant.
In the latter case, when the eyes have been accustomed to survey the suspended
picture, I have found that, after shutting and opening them, I neither saw the
picture formed by the two flowers twelve inches distant, nor the papered wall
itself, but a picture formed by uniting the flowers six inches distant ! The bin-
ocular centre had shifted its place, and instead of advancing to the wall, as is
generally the case, and giving us ordinary vision of it, it advanced exactly as much
as to unite the nearest flowers, just as on a ratchet wheel the detent slips over
one tooth at a time ; or, to speak more correctly, the binocular centre advanced
in order to relieve the eyes from their strain, and when the eyes were opened,
it had just reached that point which corresponded with the union of the flowers
six inches distant.
In the construction of complex geometrical diagrams consisting only of fine
lines, and in which similar figures are repeated at equal distances, it is very
difficult to attain minute accuracy. The points of the compasses sink to different
depths in the paper, and the lines which join such points seldom pass through
their centres. Hence arises a general inaccuracy which the eye cannot detect ;
but if we examine such diagrams by strained binocular vision, their imperfections
will be instantly displayed. Some parts will rise higher than others above the
general level, and the whole will appear like several cobwebs placed at the
distance of a tenth or a twelfth of an inch behind each other.*
In all the experiments made by Mr WIIEATSTONE by the stereoscope, and in
those described in my former paper, the dissimilar figures are viewed in a direc-
tion perpendicular to the plane on which they are drawn. A series of very
interesting results, however, are obtained by uniting the images of lines meeting
at an angular point, when the eye is placed at different heights above the
plane of the paper, and at different distances from the angular point.
Let A C, B C be two lines meeting at C, the plane passing through them being
the plane of the paper, and let them be viewed by the eyes at E'", E", E', E at
different heights in a plane G M N perpendicular to the plane of the paper.
* This effect is finely seen in the diagram of the Homogeneous Curve, which forms Plate IX. of Mr
HAY'S work " On the Harmony of Form."
VOL. XV. PART IV. 8 S
668 SIR DAVID BREWSTER ON THE KNOWLEDGE OF
Let R be the right eye and L the left eye, and when at E"' let them be strained
so as to unite the points A, B. The united image of these points will be seen at
the binocular centre D'", and the united lines A C B C will have the position
D'" C. In like manner, when the eye descends to E'", E', E, the united image
D'" C will rise and diminish, taking the positions D" C, D' C, DC till it dis-
appears on the line C M, when the eyes reach M. If the eye deviates from
the vertical plane GMN the united image will also deviate from it, and is
always in a plane passing through the eye and the line G M.
If at any altitude E M the eye advances towards A C B in the line E G, the
binocular centre D will also advance towards A C B in the line E G, and the
image D C will rise and become shorter as its extremity D moves along D G,
and after passing the perpendicular to G E it will increase in length. If the
eye, on the other hand, recedes from A C B in the line G E, the binocular centre
D will also recede, and the image D C will descend to the plane C M and
increase in length.
The preceding diagram is, for the purpose of illustration, drawn in a sort of
perspective, and therefore does not give the true positions and lengths of the
united images. This defect, however, is remedied in Fig. 3, where E, E', E', E'"
is the middle point between the two eyes, the plane GMN being, as before,
perpendicular to the plane passing through A C B. Now, as the distance of
the eye from G is supposed to be the same, and as A B is invariable as well as
the distance between the eyes, the distance of the binocular centres O, D, D',
D", D'", P, from G will also be invariable, and lie in a circle 0 D P whose
centre is G, and whose radius is G 0, the point 0 being determined by the
formula G 0=G D = -r-^ — ^— r • Hence, in order to find the binocular centres D,
A ±> + iv JU
D', D", D'", &c., at any altitude E, E' &c., we have only to join E G, E'G, &c.,
and the points of intersection D, D', &c., will be the binocular centres, and the
lines D C, D' C, &c., drawn to C, will be the real lengths and inclinations of the
united images of the lines AC, B C.
When G 0 is greater than G C there is obviously some angle A, or E" G M
C* f1
at which D" C is perpendicular to G C. This takes place when cos. A = -, -=-,
When 0 coincides with C, the images C D, C D', &c., will have the same positions
and magnitudes as the chords of the altitudes A of the eyes above the plane
G C. In this case, the raised or united images will just reach the perpendicular
when the eye is in the plane G C M, for since G C=G 0, cos. A=l, and A=0°.
When the eye at any position, E" for example, sees the points A and B
united at D", it sees also the whole lines A C B C forming the image I)"C. The
binocular centre must, therefore, run rapidly along the line I)" C : that is, the
inclination of the optic axis must gradually diminish till the binocular centre
DISTANCE GIVEN BY BINOCULAR VISION.
reaches C, when all strain is removed. The vision of the image D" C, however,
is carried on so rapidly, that the binocular centre returns to D" without the eye
being sensible of the removal and resumption of the strain which is required in
maintaining a view of the united image D" C.
If we now suppose A B to diminish, the binocular centre will advance towards
G, and the length and inclination of the united images D C, D' C, &c., will diminish
also, and vice versa. If the distance R L (Fig. 2) between the eyes diminishes,
the binocular centre will retire towards E, and the length and inclination of the
images will increase. Hence persons with eyes more or less distant will see the
united images in different places and of different sizes, though the quantities A
and A B be invariable.
While the eyes at E' are running along the lines A C, B C, let us suppose
them to rest upon the points a, b equidistant from C. Join a b, and from the point
#, where a b intersects G C, draw the line g E", and find the point d" from the
formula q d"—9-^ *", . Hence the two points a, b will be united at d", and when
a b + K L
the angle E" G C is such that the line joining D and C is perpendicular to G C, the
line joining d" C will also be perpendicular to G C, the loci of the points D" d" d' d
will be in that perpendicular, and the image D C, seen by successive movements
of the binocular centre from D" to C, will be a straight line.
In the preceding observations we have supposed that the binocular centre
D", &c., is between the eye and the lines A C B C ; but the points A, C, and all
the .other points of these lines, may be united by fixing the binocular centre
beyond A B. Let the eyes, for example, be at E" ; then if we unite A B when
the eyes converge to a point, A" (not seen in the figure), beyond G, we shall have
G A" = T -pg-, and if we join the point A" thus found and C, the line A' C will
\\ JL — A 13
be the united image of A C and B C, the binocular centre ranging from A" to C, in
order to see it as one line. In like manner, we may find the position and length of
the image A"' C, A' C, and A C corresponding to the position of the eyes at E"' E
and E. Hence all the united images of A C, B C : viz. C A'", C A", &c., will lie be-
lo\v the plane of A B C, and extend beyond a vertical line N B continued ; and they
will grow larger and larger, and approximate in direction to C G as the eyes de-
scend from E'" to M. When the eyes are near to M, and a little above the plane
of A B C, the line, when not carefully observed, will have the appearance of coin-
ciding with C G, but stretching a great way beyond G. This extreme case repre-
sents the celebrated experiment with the compasses described by Dr SMITH, and
referred to by Professor WHEATSTONE. He took a pair of compasses, which may be
represented by A C B, A B being their points, A C B C their legs, and C their joint ;
and having placed his eyes about E above their plane, he made the following
experiment : — " Having opened the points of a pair of compasses somewhat wider
670 SIR DAVID BREWSTER ON THE KNOWLEDGE OF
than the interval of your eyes, with your arm extended, hold the head or joint
in the ball of your hand with the points outwards, and equidistant from your
eyes, and somewhat higher than the joint. Then, fixing your eyes upon any remote
object lying in the plane that hisects the interval of the points, you will first per-
ceive two pair of compasses (each by being doubled with their inner legs crossing
each other, not unlike the old shape of the letter W.) But by compressing the
legs with your hand, the two inner points will come nearer to each other ; and
when they unite (having stopt the compression), the two inner legs will also
entirely coincide and bisect the angle under the outward ones, and will appear
more vivid, thicker and larger, than they do, so as to reach from your hand to the
remotest object in view even in the horizon itself, if the points be exactly co-
incident."* Owing to his imperfect apprehension of the nature of this pheno-
menon, Dr SMITH has omitted to notice that the united legs of the compasses lie
below the plane of A B C, and that they never can extend farther than the bin-
ocular centre at which their points A and B are united.
There is another variation of these experiments which possesses some inte-
rest, in consequence of its extreme case having been made the basis of a new
theory of visible direction by the late Dr WELLS.| Let us suppose the eyes of the
observer to advance from E to N, and to descend along the opposite quadrant
on the left hand of N G, but not drawn in fig. 3 (plate 17), then the united image
of A C, B C, will gradually descend towards C G, and become larger and larger.
When the eyes are a very little above the plane of A B C, and so far to the
left hand of A B, that C A points nearly to the left eye, and C B to the right eye,
then we have the circumstances under which Dr WELLS made the following ex-
periment : — " If we hold two thin rules in such a manner that their sharp edges
(A C, B C in Fig. 3) shall be in the optic axes, one in each, or rather a little below
them, the two edges ivill be seen united in the common axis (G C in Fig. 3) ; and this
apparent edge will seem of the same length with that of either of the real edges,
when seen alone by the eye in the axis of which it is placed." This experiment,
it will be seen, is the same with that of Dr SMITH, with this difference only, that
the points of the compasses are directed towards the eyes. Like Dr SMITH, he
has omitted to notice that the united image rises above G H, and he commits the
opposite error of Dr SMITH, in making the length of the united image too short.
If in this form of the experiment we fix the binocular centre beyond C, then
the united images of A C, B C descend below G C, and vary in their length, and in
their inclination to G C, according to the height of the eye above the plane of
ABC, and its distance from A B.
It is a remarkable circumstance, that no examples have been recorded of
false estimates of the distance of near objects, in consequence of the accidental
* SMITH'S Optics, vol. ii. p. 388, § 977. t Essay on Single Vision, &c., p. 4i.
DISTANCE GIVEN BY BINOCULAR VISION. (J71
binocular union of similar images. This has, no doubt, arisen from the rare oc-
currence of these circumstances or conditions, under which alone such illusions
can be produced. In a room where the paper hangings have a small pattern, or
similar figures recurring at the distance of 1, 1^, or 2 inches, a short-sighted per-
son might very readily turn his eyes on the wall, when then* axes converged to
some point between him and the wall, which would unite one pair of the similar
images ; and, in this case, he would see the wall nearer him than the real wall,
and moving with the motion of his head like something aerial. In like manner,
a long-sighted person, with his optical axes converged to a point beyond the wall,
might see an image of the wall more distant, and of an aerial character ; — or a
person who has taken too much wine, which often fixes the optical axes in oppo-
sition to the will, might, according to the nature of his sight, witness either of the
illusions above mentioned.
In the preceding observations, we have confined ourselves to the binocular
union of figures upon an opaque ground. This limitation almost necessarily pre-
cluded us from observing the results when the binocular centre is beyond the
plane where these figures are situated, because it is not easy to adjust the eyes to
a distant object, unless we look through the surfaces containing the figures. Now,
this is by far the most interesting form of the experiment, and it has the advan-
tage of putting scarcely any strain upon the eyes, not only because the binocular
centre is more distant, but because we cannot, in this way, unite figures whose
distance exceeds 2^ inches, the interval between the eyes. Transparent patterns
for these experiments may be cut out of stiff card paper, or thin plates of metal,
or they may be made of paper pasted upon large panes of glass. Experiments
may be made with trellis work, or with windows composed of small squares or
lozenges ; but the readiest pattern is the cane bottom of a chair, and I have per-
formed my experiments by simply placing such a chair upon a high table, with
its cane bottom in a vertical position. The distance of the centres of the eight-
sided open figures in the direction of the width or depth of the chair, varies in
different patterns from 0.54 to 076 of an inch. In order to simplify the calcula-
tions, we shall take the distance at 0-5, or half an inch. Then let
D = 12 inches be the distance of the pattern from the eyes.
d = 0*5 the distance of the centres of the similar figures.
+ A = distance of suspended image from, and in front of, the pattern.
— A' = distance of suspended image from, and behind, the pattern.
C = 2'5 the distance between the eyes.
Then we shall have
Dd Dd
+ A =:~^ and ~ A == ' Hence
D — A = distance of suspended image from the eye, and in front of the pat-
tern, and
D + A' = its distance from the eye, and behind the pattern.
VOL. XV. PART IV. 8 T
QT2
SIR DAVID BREWSTER ON THE KNOWLEDGE OF
From these formulae we have computed the following table, adapted to simi-
lar figures, whose centres are distant ^ an inch, 1, 1^, 2, and 2^ inches; but in
reference to the positive values of A and D, we may consider them as feet, 0-5
being in that case = 6 inches.
D
Inches.
d = 0-5
d = 1-0
d = 1-5
d — 2-0
d = 2-4
d = 2-5
+ A
— A
+ A
— A
+ A
— A
+ A
— A
+ A
— A
+ A
— A
6
1
1-5
1-72
4
2-25
9
2-66
24
2-94
144
3
Infin.
12
2
3
3-43
4-50
18
5-33
48
5-88
288
6
Infin.
24
4
6
6-86
16
9
36
10-66
96
11-76
576
12
Infin.
48
8
12
13-7
32
18
72
21-33
192
23-52
1152
24
Infin.
Taking the case where D is 12 inches, and uniting the two nearest openings
where d is 0-5, let M N (Fig. 4, PL 17) be a section of the transparent pattern, L, R
the left and right eyes, L a d, L b c lines drawn through the centres of two of the
open figures a b, and R b d, Rce lines drawn through the centre of b and c, and
meeting Lad, Lie aid and e, d being the binocular centre when we look at it
through a and b, and e the binocular centre when we look at it through b and c.
Now, the right eye R sees the opening b at d, and the left eye L sees the opening
a at d, hence the image at d consists of the similar images of a and b united. In
like manner e consists of b and c united, and so on with all the rest, so that the ob-
server at L R no longer sees the real pattern M N, but a suspended image of it at
m n, three inches behind M N. If the observer now approaches M N, the image
m n will approach to him, and if he recedes, m n will recede, being 1-J inches dis-
tant from M N when the observer is G inches from M N, and 12 inches from M N
when he is 48 inches from M N, the image m n moving from M N with a velocity
of that with which the observer recedes. These two velocities are in the ratio
n T\ i
of D to
Resuming the position in the figure where the observer is 12 inches distant
from M N, let us consider the important results to which this experiment cannot
fail to lead us. If the observer, with his eyes at L R, grasp the cane bottom or
pattern at M N, as shewn in Fig. 4, pi. 17, his thumbs pressing upon M N, and his
fingers trying to grasp m n, he will then feel what he does not see, and see what he
does not feel ! The real pattern is absolutely invisible at M N, and stands fixed at
m n. The fingers may be passed through and through — now seen on this side of
it — now in the middle of it, and now on the other side of it. If we next place
the palms of each hand upon M N, feeling it all over, the result will be the same.
DISTANCE GIVEN BY BINOCULAR VISION.
No knowledge derived from touch — no measurement of real distances — no actual
demonstration from previous or subsequent vision, that there is a real solid body
at M N, and nothing at all at m n, will remove or shake the infallible conviction
of the sense of sight that the object is at m n, and that d L or d R is its real dis-
tance from the observer. If the binocular centre be now drawn back to M N, the
image seen will disappear, and the real object be seen at M N. If it be brought
still farther back to/, the object M N will again .disappear, and will be seen at
M », as described in a former part of this paper.
In making these experiments, the observer cannot fail to be struck with the
remarkable fact, that though the openings at M N, m n, and /* v, have all the same
angular magnitude, that is, subtend the same angle at the eye, viz., d L e, d R g,
yet those at m n appear larger than those at M N, and those at p v smaller. If
we cause the image m n to recede, and ^ > to approach, the figures in m n will
invariably increase as they recede, and those in P » will diminish as they approach
the eye, and their visual magnitudes, as we shall call them, will depend on the re-
spective distances at which the observer, whether right or wrong in his estimate,
conceives them to be placed.
Now, this is an universal fact, which the preceding experiments demonstrate ;
and though the estimate of magnitude thus formed is an erroneous one, yet it is
one which neither reason nor experience is able to correct.
When Ave look at two equal lines, whose difference of distance is distinctly
appreciable by the eye, either directly, or by inference, but whose difference of
angular magnitude is not appreciable, the most remote must necessarily appear
the smallest. For the same reason, if the remoter of two lines is really smaller
than the nearer, and, therefore, its angular magnitude also smaller from both
these causes, yet, even in this case, if the eye does not perceive distinctly the dif-
ference, the smaller and more remote line will appear the larger.*
The law of visual magnitude, which regulates this class of phenomena, may
be thus expressed.
If we call A the angular magnitude of the nearest of two lines or magnitudes
* MALEBRANCHE seems to have been the first who introduced the apparent distance of objects as
an element in our estimate of apparent magnitude. De la Recherche de la Verite, torn. i. liv. i. ; torn,
iii. p. 354. See also Bouguer, Mem. Acad. Par. 1755, p. 99. These views, however, have been
abandoned by several subsequent writers, and the real distance of objects has been substituted for their
apparent distance. VARIGNON, Mem. Acad. Par. 1717, p. 88. M. LEHOT, for example, says,
" L' expression de la grandeur visuelle d'un corps est egale a la grandeur reelle, multiplied par le lo-
garithme de la distance reelle divisee par cette distance." Nouvelle Theorie de la Vision, \" Mem.
Suppl. p. 7, 8. Paris, 1823. This estimate of distance is incompatible with experiment and observa-
tion.
074 SIR DAVID BREWSTER ON BINOCULAR VISION.
whose apparent distance is d, a the angular magnitude of the remoter line, whose
apparent distance is D, and V, v the visual magnitudes of the two lines, then
V:« = Ax«?:«xD.
Now, let the two lines MO, N P, be the two sides of a quadrilateral figure
seen obliquely by an eye at E, then, if the apparent distances of M O, N P, are
such, that
A x d -^- a x D, then V -^ v,
and the lines M N, 0 P, will converge to a vanishing point beyond N P. But if
A x d = a x D, then V = »,
and the line M N, OP, will appear to be parallel. And if
A x d ^L a x D, then V ^. v,
and the lines M N, OP, will converge to a vanishing point between M 0 and the
observer.
These results may be considered as laying the foundation of a new art, to
which we may give the name of VISUAL PERSPECTIVE, in contradistinction to
GEOMETRICAL PERSPECTIVE. This art furnishes us with an immediate explana-
tion of a great variety of optical illusions which have never yet been explained :
and there is reason to believe that some of its principles were known to ancient
architects, and even employed in modifying the nature and position of the lines
and forms which enter into the construction of their finest edifices.
ST LEONARD'S COLLEGE, ST ANDBEWS,
April 10. 1844.
APPENDIX.
SIR DAVID BKEWSTER ON BINOCULAR VISION. (575
APPENDIX.
When I wrote the paragraph in page 647, 1 had no expectation of learning that
any example of such an illusion had ever occurred. A friend, however, to whom
I had occasion to shew the experiments, and who is short-sighted, mentioned to
me that he had been on two occasions greatly perplexed by the vision of these
suspended images. Having taken too much wine, and being in a papered room,
he saw the wall suspended near him in the air ; and on another occasion, when
kneeling and resting his arms on a cane-bottomed chair, he had fixed his eyes on
the carpet, which accidentally united the two images of the open-work, and
threw the suspended image of the chair bottom to a distance, and beyond the
plane on which his arms rested.
The following case, communicated to me by Professor Christison, is still more
interesting. " Some years ago, when I resided in a house where several rooms
are papered with rather formally recurring patterns, and one, in particular, with
stars only, I used occasionally to be much plagued with the wall suddenly stand-
ing out upon me, and waving, as you describe, with the movements of the head.
I was sensible that the cause was an error as to the point of union of the visual
axes of the two eyes ; but I remember it sometimes cost me a considerable effort
to rectify the error ; and I found that the best way was to increase still more the
deviation in the first instance. As this accident occurred most frequently while
I was recovering from a severe attack of fever, I thought my near-sighted eyes
were threatened with some new mischief; and this opinion was justified in find-
ing that, after removal to my present house — where, however, the papers have
no very formal pattern — no such occurrence has ever taken place. The reason
is now easily understood from your researches."
VOL. XV. PART IV. 8 U
PROCEEDINGS
OF THE
EXTRAORDINARY GENERAL MEETINGS,
LIST OF MEMBERS ELECTED AT THE ORDINARY MEETINGS,
SINCE NOVEMBER 23. 1840.
PROCEEDINGS, fa.
Monday, November 23. 1840.
At a Statutory General Meeting, Sir T. M. BRISBANE in the Chair, the following Council
was elected : —
Sir THOMAS M. BRISBANE, Bart., K.C.B., President.
Sir WILLIAM MILLER, Bart.,
Dr HOPE,
Sir D. BREWSTEH, K.H.,
Vice-Presidents.
Rev. Dr CHALMERS,
Dr ABERCROMBIE,
Professor FORBES, General Secretary.
Dr CHRISTISON, i
„.-—•-» \ Secretaries to the Ordinary Meetings.
Mr DAVID MILNE, J
Mr RUSSELL, Treasurer.
Dr TRAILL, Curator of Library and Instruments.
Mr STARK, Curator of Museum.
COUNSELLORS.
Mr THOMAS THOMSON. Professor HENDERSON.
Mr J. T. GIBSON-CRAIG. Professor KELLAND.
Dr GRAHAM. Sir GEORGE WARRENDER, Bart.
Dr ALISON. Sir JOHN ROBISON, K.H.
Sir H. JARDINE. Sir JOHN M'^EILL, G.C.B.
JOHN SHANK MORE. Professor SYME.
The following Committee was named to audit the Treasurer's Accounts :—
Sir HENRY JARDINE. GILBERT FINLAY, Esq.
DAVID SMITH, Esq.
On the motion of Lord GREENOCK, seconded by Dr HOPE, the thanks of the Society were
conveyed by the Chair to Mr RUSSELL for his valuable services as Treasurer.
VOL. XV. PAET IV. 8 X
680 PROCEEDINGS OF GENERAL MEETINGS,
It was moved by the President, and carried by acclamation, That the Society view with
extreme regret the Resignation by Sir JOHN ROBISON of the office of General Secretary to
the Society, which he has now held for the period of thirteen years :
That they can never too highly appreciate the obligation under which they lie to him,
for the zeal with which he has constantly discharged its duties, and for the great share he has
had in promoting the prosperity of the Society during that long period ; and that the cordial
thanks and the regrets of the Society be communicated to him on this occasion.
The Treasurer then said, that, while he heartily concurred in this Resolution, he thought
that some more substantial expression of the Society's sentiments than a vote of thanks should
also be offered to Sir JOHN ROBISON, as a mark of the sense which the Society entertains of
his valuable services ; and he therefore moved, That the Council be requested to consider, and
report to a Special General Meeting, the nature of a proper Testimonial to be presented to
Sir JOHN, as a mark of their entire approbation of his conduct in the discharge of his duties
as Secretary. Which motion, being seconded by Mr NAIRNE, was carried unanimously.
Lord GREENOCK moved that an Address should be presented to Her Majesty on the oc-
casion of Her Majesty having recently given birth to a Princess. Which motion, being se-
conded by Mr JOHN SHANK MORE, was carried unanimously ; and the Council were directed to
prepare a suitable Address, and bring it before the next Ordinary Meeting of the Society, on
the first Monday of December.
(Signed) GREENOCK, V. P.
Memorandum. — December 7. 1840. — At the Ordinary Meeting of this date, it was agreed,
that the following Address to the QUEEN on the birth of the Princess Royal be transmitted
through the President to the DUKE of SUSSEX, for presentation to her Majesty : —
TO THE QUEEN.
WE, the President and Fellows of the Royal Society of Edinburgh, beg leave to offer to
your Majesty our unfeigned congratulations on an event which has filled the hearts of your
Majesty's faithful and loving subjects with universal joy, and with a deep-felt sense of that
gracious and overruling Providence under which your Majesty's safety, and the security and
happiness of your realms, have hitherto been so signally protected. Impressed as we are with
a conviction of the vast importance of whatever may tend to the stability of the hereditary
throne of these kingdoms, and with a lively interest in whatever may be calculated to promote
and secure your Majesty's happiness, and that of your Majesty's illustrious Consort, our earnest
desires are for the permanence of the blessings thus auspiciously conceded to the prayers and
hopes of a loyal and grateful people.
We are,
May it please your Majesty,
Your Majesty's most faithful and dutiful Subjects,
THE PRESIDENT AND FELLOWS OF THE ROYAL
SOCIETY OF EDINBURGH.
THOMAS MAKDOUGAL BRISBANE, P.
JAMES D. FORBES, Sec.
AND LIST OF MEMBERS ELECTED. 68]
December 7. 1840.
MEMBERS ELECTED.
ORDINARY.
JAMES ANSTRUTHER, Esq.
January 4. 1841.
JAMES HUNTER, M.D. Col. MORRISON, C.B., Madras Artillery.
J. P. MUIRHBAD, Esq.
January 18. 1841.
HONORARY. ORDINARY.
Professor ENCKE, Esq., Berlin. JOHN MILLER, Esq., Civil-Engineer.
February 1. 1841.
GEORGE SMYTTAN, M.D. JAMES HAMILTON, Esq.
February 18. 1841.
GRAHAM SPEIRS, Esq.
April 5. 1841.
EGBERT SPITTAL, M.D.
April 19. 1841.
JAMES DALMAHOY, Esq.
December 6. 1841.
JAMES KINNEAH, Esq., W.S.
Memorandum. — December 21. 1841. — On the motion of the Council, referring to the Remit
by the Society on the 23d November, it was resolved, " That the Society do vote the sum of
L.300 to Sir JOHN ROBISON, in acknowledgment of his long services as General Secretary, —
that being the form adopted in the case of each of his predecessors."
November 22. 1841.
At a Statutory General Meeting, Lord GEEENOCK in the Chair, the following Council was
elected : —
Sir T. M. BRISBANE, Bart., President.
Sir WILLIAM MILLER, Bart.,
Dr HOPE,
Sir D. BREWSTER, K.H.,
T . „ Vice-Presidents.
Lord GREENOCK,
Dr CHALMERS,
Dr ABERCROMBIE, /
682 PROCEEDINGS OF GENERAL MEETINGS,
Professor FORBES, General Secretary.
Dr CHKISTISOK, •»
D. MILNE, Esq., ) Secrctaries to Ordinary Meetings.
JOHN RUSSELL, Esq., Treasurer.
Dr TRAILL, Curator of Library.
Mr STARK, Curator of Museum.
COUNSELLORS.
Sir H. JARDINE. Professor SYME.
J. S. MORE, Esq. Mr A. BELL.
Professor HENDERSON. MR W. A. CADELL.
Professor KELLAND. Dr MACLAGAN.
Sir G. WAHRENDER, Bart. Mr JAMES WILSON.
Sir J. ROBISON, K.H. Bishop TERROT.
The Treasurer laid his Accounts on the Table. The following Committee was appointed
to audit them ; —
SIR H. JARDINE. W. PAUL, Esq. JAMES WALE.EB, Esq.
On the motion of Lord GREENOCK, the following Address to Her MAJESTY, prepared by
the COUNCIL, was unanimously adopted by the Meeting, and desired to be transmitted to the
Secretary of State through the President of the Society :—
TO THE QUEEN.
MAY IT PLEASE YOUR MAJESTY,
We, your Majesty's loyal and devoted subjects, the President and Fellows of the
Royal Society of Edinburgh, beg leave to approach your Majesty with our heartfelt congratu-
lations upon the auspicious event by which a merciful Providence has at once granted a happy
completion to the tenderest desire of our Sovereign's maternal heart, and to the wishes and
prayers of all her faithful and affectionate subjects, in the birth of an Heir- Apparent to the
Throne on which your Majesty and your Royal Ancestors have so long ruled this great Empire.
We acknowledge a happy omen for the perpetuity of that union of liberty and social order un-
der which the power and happiness of these realms have grown up and flourished ; and an
additional reason to hope that, under the parental rule of your Majesty and your Royal
Descendants, we and our children, and our children's children, shall continue to enjoy those
national blessings which we gratefully acknowledge that we have received under your Majesty's
mild and beneficent administration of the high powers committed to your hands.
That your Majesty may, through a long and prosperous reign, be supported by that
Divine aid which has hitherto been so conspicuous in the happy events both of your public and
private life ; that you may long enjoy all the domestic happiness which can crown the wishes
of a wife and a mother, together with the gratifying conviction of being the instrument of
happiness, and the object of grateful and respectful affection, to a great and united nation ;
7
AND LIST OF MEMBERS ELECTED. 683
that the Royal Infant, on whose birth we now congratulate your Majesty, may grow up to be
worthy of the race from which he is sprung, and the destiny to which he is called ; and that he
may gratify your Majesty's most sanguine hopes, whether springing from the feelings of the
parent or of the Queen, is the sincere prayer of
Your Majesty's faithful and devoted subjects,
THE PRESIDENT AND FELLOWS OF THE ROYAL
SOCIETY OF EDINBURGH.
Signed in the name, and by appointment, of the Society,
THOMAS M. BRISBANE, Pres.
JAMES D. FORBES, Secy.
Sir GEORGE MACKENZIE gave notice, that, at a future Meeting of the Society, he should
move that the office of Vice-President be no longer permanent, but that two Vice-Presi dents
shall retire annually.
MEMBER ELECTED.
ORDINARY.
January 3. 1842.
JAMES THOMSON, Esq., Civil Engineer.
Memorandum. — On the 7th February 1842, at an Extraordinary Meeting of the Society,
after special notice of more than four weeks' standing, Sir G. S. MACKENZIE moved the fol-
lowing Resolution : —
That the first part of Law XVI. shall remain under that number ; the remainder, together
with Law XVII., shall be altered, and stand thus, under Law XVII. : —
" The Council shall consist of a President, Six Vice-Presidents, Twelve Counsellors, a
General Secretary, Two Secretaries to the Ordinary Meetings, a Treasurer, a Curator or
Curators of the Museum and Library. The President shall be elected annually, and may be
re-elected. Of the Six Vice-Presidents, the three seniors may be re-elected annually, and their
number filled up on vacancies occurring, by the choice of Members who have distinguished
themselves for a lengthened period as eminent and active Fellows of the Society. One of the
remaining three who shall be resident in Edinburgh shall go out of office annually by rotation,
and not be eligible for one year. The other office-bearers to be elected annually. The Council
shall conduct the Publications, and regulate the Private Business of the Society."
Sir HENRY JAKDINE seconded the motion.
Dr TRAILL moved, as an amendment, That the office of Vice-President shall remain as at
present ; which was seconded by Mr W. A. CADELL.
The President having put the motion and amendment, the amendment was carried.
MEMBERS ELECTED.
ORDINARY.
February 22. 1842.
Dr JOHN DAVY, Insp. Gen. of Hospitals. ROBERT NASMYTH, Esq., F.R.C.S.E.
March 7. 1842.
Sir JAMES FORREST, Bart. JAMES STARK, MJ)., F.R.C.Ph.E.
JAMES MILLER, Esq., Prof, of Surgery. JOHN ADIE, Esq.
VOL. XV. PAKT IV. 8 Y
684 PROCEEDINGS OF GENERAL MEETINGS,
August 29. 1842.
At an Extraordinary General Meeting of the Society, called by advertisement in the
Newspapers and by Circulars, in consequence of orders from the Council, Lord GREENOCK, as
the Senior Vice-President present, took the Chair ; and stated that the object of the Meeting
was to consider the propriety of voting Addresses of Congratulation to Her MAJESTY and to
PRINCE ALBERT, on the occasion of their expected arrival in Scotland, and also of electing
PRINCE ALBERT an Honorary Fellow of the Society.
The Lord JUSTICE-GENERAL (BOYLE) then moved, and JOHN RUSSELL, Esq., seconded,
the following Address to Her Majesty : —
UNTO HER MOST EXCELLENT MAJESTY THE QUEEN.
MAY IT PLEASE YOUR MAJESTY,
The Royal Society of Edinburgh, instituted for the promotion of Letters and Science,
beg leave to join in the universal expression of joy, on your Majesty's happy arrival on the
scene of their humble exertions.
They are aware that when all their fellow-subjects are eager to be permitted to offer their
loyal congratulations, those of individual bodies should be briefly expressed. They now, there-
fore, beg leave to approach your Majesty, in order to offer this humble tribute of their devoted
loyalty ; and that it may please Almighty God to grant your Majesty many and happy years,
and to repay to your Majesty the happiness which your Majesty's arrival has so widely diffused
in Scotland, is the prayer of,
Your Majesty's faithful and devoted subjects,
THE PRESIDENT AND FELLOWS OF THE ROYAL
SOCIETY OF EDINBURGH.
Signed at Edinburgh, on the 29th August 1842, in the name, and by the appointment, of
the Society.
This Address was unanimously approved of by the Society, and the Vice-President in the
Chair was appointed to sign it.
Thereafter, Dr ABERCROMBIE moved, and Sir CHARLES MENTEITH of Closeburn seconded,
the following Address to PRINCE ALBERT : —
UNTO FIELD-MARSHAL HIS ROYAL HIGHNESS PRINCE ALBERT,
K. G., &c. &c.
MAY IT PLEASE YOUR ROYAL HIGHNESS,
The Royal Society of Edinburgh beg leave to offer their respectful congratulations to
your Royal Highness, on your arrival in this portion of the dominions of your Illustrious Con-
sort, our beloved Queen ; and to cherish a hope, that this visit, which has afforded so much
joy to Her Majesty's Loyal Scottish Subjects, may tend to interest your Royal Highness in a
country and people with whose welfare your Royal Highness is now connected by the most en-
dearing ties.
AND LIST OF MEMBERS ELECTED.
That Almighty God may long preserve to your Koyal Highness the enjoyment of your
present domestic felicity, with many other blessings, is our fervent and united prayer.
Signed at Edinburgh, on the 29th August 1842, in the name, and by appointment, of the
Society.
This Address was unanimously approved of, and the President in the Chair was appointed
to sign it.
Thereafter, Dr COOK of St Andrews moved, That a Deputation be appointed to present
the Addresses, and to take the proper steps for ascertaining at what time and in what manner
they should be presented ; — the Deputation to consist of such of the Office-bearers of the So-
ciety as may be selected by the President, after it has been ascertained whether there is any
rule as to the number of persons who will be allowed to compose a Deputation for the pre-
sentation of Addresses.
This Motion was seconded by Mr STARK, and unanimously agreed to.
Thereafter, Sir JOHN ROBISON stated, that it was the opinion of the Council, that PRINCE
ALBERT, who was already a Fellow of the Royal Society of London, and who was in all re-
spects worthy of being an Honorary Fellow of this Society, should have this honour now con-
ferred on him. The Resolution of the Council to propose his Royal Highness to be elected an
Honorary Fellow, had been notified to the Members.
This Motion, having been seconded by Dr MACLAGAN, was unanimously agreed to.
A Diploma in favour of PRINCE ALBERT was signed by the President in the Chair and by
the Secretary.
The Deputation above named for the Addresses, was appointed also to present the
Diploma to PRINCE ALBERT.
(Signed) JOHN ABERCROMBIE, V. P.
November 28. 1842.
At a Statutory General Meeting, Minutes of last Meeting read and approved ; after which
Mr MILNE read the following Report : —
REPORT by Mr MILNE, as to the Proceedings connected with the Presentation of the
Addresses to the QUEEN and to PRINCE ALBERT, and of the Diploma to PRINCE
ALBERT.
Mr MILNE, with the view of carrying into execution the Resolutions of the General Meet-
ing of the Society, held on the 29th August, addressed a Letter to Lord ABERDEEN, as one of
the Secretaries of State attending Her Majesty, and then staying at Dalkeith Palace, of which
Letter the following is a Copy : —
MY LORD, Edinburgh, 10 York Place, August 30. 1842.
As one of the Secretaries of the Royal Society of Edinburgh, I take the liberty of ac-
quainting your Lordship, that, at a General Meeting of that body, held yesterday, an Address
to the QUEEN was resolved on, and signed by the President in the Chair, congratulating Her
Majesty on her arrival in Scotland.
686 PROCEEDINGS OF GENERAL MEETINGS,
I have farther to mention, that a Deputation of the Office-Bearers of the Society was ap-
pointed to present this Address to Her Majesty ; and I will feel obliged by your Lordship in-
forming me, when and where this Address may be received by Her Majesty.
I may add, that I have been informed that when KING GEORGE IV, visited Scotland, a
similar Address from the Royal Society was received by His Majesty in the Royal Closet.
I have the honour to remain,
MY LORD,
The Right Honourable Your very obedient servant,
The EARL of ABERDEEN, &c. &c. (Signed) DAVID MILNE.
To the foregoing Letter the following answer was received by Mr MILNE.
SIR, Dalkeith, September 2. 1842.
Under the circumstances connected with the Queen's visit to Scotland, Her Majesty
will not be enabled to grant any audiences in the Royal Closet, on the present occasion.
With respect to the presentation of the Address of the Royal Society of Edinburgh, I beg
to acquaint you, that it may be presented at the General Reception ; or if you will transmit it
to me, I shall have much pleasure in laying it before Her MAJESTY.
I have the honour to be, Sir, your obedient servant,
(Signed) ABERDEEN.
DAVID MILNE, Esq.
Mr MILNE also addressed a Letter to the Hon. Colonel ANSON, Private Secretary to
His Royal Highness PRINCE ALBERT, then staying at Dalkeith Palace.
SIR, Edinburgh, 10 York Place, August SO. 1842.
As one of the Secretaries of the Royal Society of Edinburgh, I have to acquaint you,
that, at an Extraordinary General Meeting of that body, held in their hall yesterday, a loyal
and dutiful Address, congratulating his Royal Highness PRINCE ALBERT on his arrival in Scot-
land, was resolved on. I now beg to enclose a copy of this Address.
A Deputation was appointed, of some of the Office-Bearers of the Society, to present this
Address to His Royal Highness.
I have also to acquaint you, that the Royal Society, at the same Meeting, unanimously
resolved on electing His Royal Highness an Honorary Fellow of the Society ; and his Diploma
was thereupon signed by the President in the Chair.
May I be permitted to inquire, whether it will be agreeable to His Royal Highness to
receive the Deputation, for the purpose of presenting the Address, as well as the Diploma ?
It has been usual for all Fellows of the Royal Society of Edinburgh, as of the Royal Society
of London to enrol their names when any opportunity of doing so offers, in a book kept for that
purpose ; and, if agreeable to His Royal Highness, this book will be presented by the Deputation,
in order that the Society may have the honour of possessing His Royal Highness' signature,
in their book of Members. If His Royal Highness intends to visit the Institution in Princes
AND LIST OF MEMBERS ELECTED. 687
Street, where the Royal Society Apartments are, and where also various other Public Bodies,
instituted for the study of the Arts, Sciences, and Antiquities, hold their Meetings, it may be
more convenient for His Royal Highness to receive the deputation on that occasion. But
wherever, and at whatever time, it may be most agreeable to His Royal Highness, to have the
Address and the Diploma presented to him, the Deputation will attend, on your giving me a
few hours' previous notice.
I have honour to remain, Sir, your most obedient servant,
The Honourable GEORGE ANSON, (Signed) DAVID MILNE.
Sec?, to H. R. H. PRINCE ALBERT.
To this Letter, the following answer was received.
SIR, Dalkeith House, September 1. 1842.
I beg to acknowledge the receipt of your letter of the 30th ult., and, in reply, to
inform you, that H. R. H. Prince Albert will be happy to receive the address from the Royal
Society of Edinburgh, at Her Majesty's reception at Dalkeith House, on Monday next, at two
o'clock.
I have it farther in command, to request you will convey to the Members of the Royal
Society of Edinburgh, the assurance of H. R. Highness' gratification in finding that they have
elected him an Honorary Fellow of their Society. If the Book of the Royal Society were
transmitted to Mr ANSON, H. R. Highness would be happy to inscribe his name in the usual
manner.
I am, Sir, your most obedient Servant,
DAVID MILNE, Esq. (Signed) G. E. ANSON.
Mr MILNE immediately on receiving the Letters from the Earl of ABERDEEN and Colonel
ANSON just referred to, went to Lord GREENOCK, and having, on the 3d September, received from
his Lordship a list of the office-bearers proposed by him to form a Deputation to present the
Addresses and Diploma voted by the Society, notice was sent to Sir JOHN ROBISON, Dr
ABERCROMBIE, Sir DAVID BREWSTER, and Dr HOPE, to request them to accompany Lord
GREENOCK to the general reception at Dalkeith, to be held on the 5th September.
Mr MILNE, on the same occasion, delivered to Lord GREENOCK the Addresses and the
Diploma.
In consequence of the difficulties and delays which occurred to prevent the possibility of
any regularity being insured, with regard to arriving at Dalkeith Palace on the day of the
reception in time for the regular assembling of the Deputation, previously to the presentation
of the Address and Diploma, Lord GREENOCK, who was unable to reach the palace until near
the close of the Drawing-Room, was under the necessity of presenting the Addresses by himself
to Her MAJESTY and PRINCE ALBERT on his reaching the presence, which duty he duly per-
formed by delivering the Address to the QUEEN, to Her Majesty's Lord in Waiting, and that
with the Diploma for PRINCE ALBERT to Colonel ANSON, His Royal Highness' Secretary.
It had been intended, that the Society's Book of members should have been taken out to
VOL. XV. PART IV. 8 Z
PROCEEDINGS OF GENERAL MEETINGS,
the reception at Dalkeith, on the 5th September, in order that PRINCE ALBERT might there
inscribe his name in the Book ; but the Prince having, beetween 9 and 10 o'clock A.M. of that
day, rodo into Edinburgh, and visited the Society's Apartments, the Book was then presented
to His Royal Highness by Mr JOHN RUSSELL and Sir JOHN ROBISON, when he inscribed
his name in it.
As it may be desirable to preserve some account of the manner in which the Address of
of the Society to His Majesty GEORGE IV. was presented when he visited Scotland, reference
may here be made to a letter from Sir DAVID BREWSTER, then Secretary of the Society, to
Mr RUSSELL, Treasurer, dated 29th August 1842.
St Leonardos College, St Andrews,
DEAR SIR, August 29. 1842.
Sir WALTER SCOTT had arranged that the Address of the Royal Society should
be presented to GEORGE IV. in the Closet by a Deputation ; but it was found that this would
have been troublesome to the KING, as several other bodies had the same title to this mode
of presentation. The Address was therefore presented by the President ; but whether along
with any of the Vice-Presidents, I do not recollect. I remember, however, that I, as Secretary,
did not accompany the President. Sir WALTER SCOTT was much annoyed at the change, and
did what he could to prevent it.
I am, dear Sir, ever most truly yours,
JOHN RUSSELL, Esq. (Signed) D. BREWSTER.
Mr MILNE also received from Sir THOMAS D. LAUDER a Letter, dated 30th August,
regarding the access to the Society's Apartments during Her Majesty's Procession, which
he now produced.
He has only farther to report, that the Institution was, on the night of the 2d September,
illuminated by a device which covered the entire front of the Building, and that the share of
the expense which was paid by the Royal Society amounted to L.G, 3s.
The above Report having been heard, it was directed to be engrossed in the General
Minute-Book.
The Meeting then proceeded to ballot for Office-Bearers for the year 1842-3, the Ballot-
box having been examined by the President, the following gentlemen were found to be duly
elected : —
COUNCIL FOR 1842-3.
Sir T. MAK.DOUGALL BRISBANE, K.C.B., Bart., President.
Sir WILLIAM MILLER, Bart.,
Dr HOPE,
Sir DAVID BREWSTEK, K.IL,
, V ice Presidents.
Lord GREENOCK,
Dr ABERCUOMBIE,
Principal LEE,
AND LIST OF MEMBERS ELECTED. 689
Professor FORBES, General Secretary.
Dr CHRISTISON, and j gecretaries to Ordinary Meetings.
D. MILNE, Esq.,
JOHN RUSSELL, Esq., Treasurer.
Dr TRAILL, Curator of Library.
J. STARK, Esq., Curator of Museum.
COUNSELLORS.
Sir GEORGB WARRENDER, Bart. JAMES WILSON, Esq.
Sir JOHN ROBISON, K.H. Bishop TERROT.
Professor SYME. Dr DAVY.
ARCHIBALD BELL, Esq. Dr PARNELL.
W. A. CADELL, Esq. Dr CARSON.
Dr MACLAGAN. Sir JOHN MACNEILL, G.C.B.
The following gentlemen were named to audit the Treasurer's Accounts : —
Sir HENRY JARDINE. J. T. GIBSON-CRAIG, Esq.
WILLIAM PAUL, Esq.
MEMBERS ELECTED.
ORDINARY.
December 5. 1842.
JOHN GOODSIR, Esq., Edinburgh.
January 9. 1843.
A. D. MACLAGAN, M.D., F.R.C.S.E.
February 6. 1843.
JOHN ROSE CORMACK, M.D., F.R.C.Ph.E.
ALLEN THOMSON, M.D., Professor of the Institutes of Medicine.
February 21, 1843.
JOSEPH MITCHELL, Esq., Civil-Engineer, Inverness. DUNCAN DAVIDSON, Esq. of Tulloch.
March 6. 1843.
ANDREW COVENTRY, Esq., Advocate. D. BALFOUR, Esq., Younger of Trenaby.
JOHN HUGHES BENNETT, M.D., F.R.C.Ph.E., Edinburgh.
March 20. 1843.
HENRY STEPHENS, Esq., Edinburgh.
690 PROCEEDINGS OF GENERAL MEETINGS.
April 17. 1843.
W. H. NORIE, Esq.
November 27. 1843.
At a Statutory General Meeting, held for the purpose of appointing Office-Bearers for
the ensuing Session, —
Dr ABERCROMBIE, V. P., in the Chair. The Ballot was taken in the usual way, and the
Box having been examined, the following gentlemen were found to be duly elected : —
COUNCIL FOR 1843-4.
Sir T. MAKDOUGAL BRISBANE, Bart., President.
Sir WILLIAM MILLER, Bart..
Dr HOPE,
Sir DAVID BREWSTER, K.H.,
, Vice Presidents.
Bight Honourable EARL CATHCART, /
Dr ABERCROMBIE,
The Very Rev. Principal LEE, /
Professor FORBES, General Secretary.
DAVID MILNE, Esq., -^
Professor KELLAND, ) Secretaries to Ordinai7 Meetings.
JOHN RUSSELL, Esq., Treasurer.
Dr TRAILL, Curator of Library.
Mr STARK, Curator of Museum.
COUNSELLORS.
W. A. CADELL, Esq. Sir JOHN MACNEILL, G.C.B.
Dr MACLAGAN. Sir G. S. MACKENZIE, Bart.
JAMES WILSON, Esq. Sir THOMAS DICK LAUDER, Bart.
Bishop TERROT, ALAN STEVENSON, Esq.
Dr PARNELL. JAMES T. GIBSON-CRAIG, Esq.
Dr CARSON. Dr CKAIGIE.
MEMBERS ELECTED.
ORDINARY.
December 18. 1843.
ARTHUR FORBES, Esq. of Culloden. J. BURN MURDOCH, Esq.
January 2. 1844.
Honourable Lord MURRAY.
February 5. 1844.
Lieutenant-Colonel JOHN Low.
AND LIST OF MEMBERS ELECTED.
February 19. 1844.
ARCHIBALD SWINTON, Esq., Professor of Civil Law.
JAMES BEGBIE, M.D., F.R.C.S.E., Edinburgh.
March 18. 1844.
NICHOLAS GRUT, Esq., Edinburgh.
Rev. ARCHIBALD BJJNNIE, Edinburgh.
J. Y. SIMPSON, M.D., Professor of Midwifery.
DAVID STEVENSON, Esq., Civil-Engineer, Edinburgh.
April 15. 1844.
THOMAS R. COLLEDGE, M.D., F.R.C.Ph.E.
VOL. XV. PART TV. 9 A
( 692 )
LIST OF THE PRESENT ORDINARY MEMBERS, IN THE ORDER
OF THEIR ELECTION.
Major-Gen. Sir THOMAS M. BRISBANE, Bart., G.C.B., &c., F.R.S. Lond.,
PRESIDENT.
Date of
Election.
Sir William Miller, Bart., Lord Glenlee.
The above Gentleman is the only surviving member of the Edinburgh Philosophical Society.
THE FOLLOWING MEMBERS WERE REGULARLY ELECTED.
1787 James Home, M.D., Emeritus Professor of the Practice of Physic.
1788 Right Honourable Charles Hope.
1798 Alexander Monro, M.D., Professor of Anatomy, $c.
1799 Sir George Stuart Mackenzie, Baronet, F.R.S. Lond.
Robert Jameson, Esq., Professor of Natural History.
1802 Colonel D. Robertson Macdonald.
1805 Thomas Thomson, M.D., F.R.S. Lond., Professor of Chemistry, Glasgow.
George Dunbar, Esq., Professor of Greek.
1807 John Campbell, Esq. of Car brook.
Thomas Thomson, Esq., Advocate.
1808 James Wardrop, Esq.
Sir David Brewster, K.H., LL.D., F.R.S. Lond.
1811 Major-General Sir Thomas Makdougal Brisbane, B.T., G.C.B., G.C.H.,F.R.S. Lond
John Thomson, M.D., Emeritus Professor of General Pathology, Edinburgh.
James Jardine, Esq., Civil Engineer.
Captain Basil Hall, R.N., F.R.S. Lond.
J. G. Children, Esq., F.R.S. Lond.
Alexander Gillespie, Esq., Surgeon, Edinburgh.
W. A. Cadell, Esq., F.R.S. Lond.
Macvey Napier, Esq., F.R.S. Lond., Professor of Conveyancing.
James Pillans, Esq., Professor of Humanity.
1812 Sir George Clerk, Bart., F.R.S. Lond.
1813 William Somerville, M.D., F.R.S. Lond.
6
LIST OF ORDINARY MEMBERS.
693
Date of
Election.
J. Henry Davidson, M.D., Edinburgh.
1814 Sir Henry Jardine.
Patrick Neill, LL.D., Secretary to the Wernerian and Horticultural Societies.
Right Honourable Lord Viscount Arbuthnot.
John Fleming, D.D., Professor of Natural Philosophy, King's Coll., Aberdeen.
Alexander Brunton, D.D., Professor of Oriental Languages.
Professor George Glennie, Marischal College. Aberdeen.
1815 Robert Stevenson, Esq., Civil Engineer.
Sir Thomas Dick Lauder, Bart, of Fountainhall.
Henry Home Drummond, Esq. of Blair- Drummond.
Sir Charles Granville Stuart Menteath, Bart, of Closeburn.
William Thomas Brande, Esq., F.R.S. Lond., and Professor of Chemistry in
the Royal Institution.
1816 Colonel Thomas Colby, F.R.S. Lond., Eoyal Engineers.
Leonard Horner, Esq., F.R.S. Lond.
Henry Colebrooke, Esq., Director of the Asiatic Society of Great Britain.
George Cooke, D.D., Professor of Moral Philosophy, St Andrews.
Honourable Lord Fullerton.
Hugh Murray, Esq., Edinburgh.
1817 Right Honourable Earl of Wemyss and March.
John Wilson, Esq., Professor of Moral Philosophy.
Alexander Maconochie, Esq. of Meadowbank.
Sir David James Hamilton Dickson, M.D., Clifton.
William P. Alison, M.D., Professor of the Practice of Physic.
Robert Bald, Esq., Civil Engineer.
1818 Robert Richardson, M.D., Harrowgate.
Patrick Miller, M.D., Exeter.
John Watson, M.D.
Right Honourable John Hope, Lord Justice-Clerk.
Wiliam Ferguson, M.D., Windsor.
1819 His Grace the Duke of Argyll.
Patrick Murray, Esq. of Simprim.
James Muttlebury, M.D., Bath,
Thomas Stewart Traill, M.D., Professor of Medical Jurisprudence
Alexander Adie, Esq., Edinburgh.
William Couper, M.D., Glasgow.
Marshall Hall, M.D., London.
John Borthwick, Esq., Advocate.
Richard Phillips, Esq., F.R.S. Lond.
Reverend William Scoresby, Exeter.
George Forbes, Esq., Edinburgh.
1820 James Hunter, Esq. of Thurston.
Right Honourable David Boyle, Lord Justice-General.
James Keith, Esq., Surgeon, Edinburgh.
LIST OF ORDINARY MEMBERS.
Date of
Election.
1820 James Nairne, W.S., Edinburgh.,
Charles Babbage, Esq., F.R.S., Lond.
Thomas Guthrie Wright, Esq., Auditor of the Court of Session.
Sir John F. W. Herschel, Bart., F.R.S., Lond.
Adam Anderson, A.M., LL.D., Prof. Nat. Phil. St Andrews.
John Shank More, Esq., Professor of Scots Lam.
Samuel Hibbert Ware, M.D.
Robert Haldane, D.D., Principal of St Mary's College, St Andrews.
Sir John Mead, M.D., Weymouth.
Dr William Macdonald, Edinburgh.
Sir John Hall, Bart, of Dunglass.
Sir George Ballingall, M.D., Professor of Military Surgery.
1821 Robert Graham, M.D., Professor of Botany.
Sir James M. Riddell, Bart, of Ardnamurchan.
Archibald Bell, Esq., Advocate.
John Clerk Maxwell, Esq., Advocate.
John Lizars, Esq., Surgeon.
John Cay, Esq., Advocate.
Robert Kaye Greville, LL.D., Edinburgh.
Robert Hamilton, M.D., Edinburgh.
Sir Archibald Campbell, Bart, of Garscube.
Sir David Milne, K.C.B.
A. R. Carson, Esq., LL.D., Rector of the High School.
1822 James Smith, Esq. of Jordan/till, F.R.S. Lond.
William Bonar, Esq., Edinburgh.
Captain J. D. Boswall, R.N., of Wardie.
George A. Walker-Arnott, Esq., Advocate.
Very Reverend John Lee, D.D., Principal of the University.
Sir James South, F.R.S., Lond.
Lieutenant-General Martin White, Edinburgh.
Walter Frederick Campbell, Esq. of Shawfield, M.P.
W. C. Trevelyan, Esq., Wallington.
Sir Robert Abercromby, Bart, of Birkenbog.
Dr Wallich, Calcutta.
The Right Honourable Sir George Warrender, Bart, of Lochend.
John Russell, Esq., W.S., Edinburgh.
John Dewar, Esq., Advocate.
1823 Sir Edward Ffrench Bromhead, Bart., A.M., F.R.S., Lond. Thurlsby Hall.
Captain Thomas David Stuart, of the Hon. East India Company* 's Service.
Andrew Fyfe, M.D., Lecturer on Chemistry, Edinburgh.
Robert Bell, Esq., Advocate, Procurator for the Church of Scotland.
Captain Norwich Duff, R.N.
Warren Hastings Anderson, Esq.
Alexander Thomson, Esq. of Banchory, Advocate.
LIST OF ORDINARY MEMBERS. (J95
Date of
Election.
1823 Liscombe John Curtis, Esq., Ingsdon House, Devonshire.
Robert Knox, M.D., Lecturer on Anatomy, Edinburgh.
Robert Christison, M.D., Professor of Materia Medico.
John Gordon, Esq. of Cairnbulg.
1824 Dr Lawson Whalley, Lancaster.
William Bell, Esq., W.S., Edinburgh.
Alexander Wilson Philip, M.D., London.
Sir Charles Adam, R.N.
Robert E. Grant. M.D., Professor of Comparative Anatomy, Univ. Coll., London.
Claud Russell, Esq., Accountant, Edinburgh.
Rev. Dr William Muir, one of the Ministers of Edinburgh.
W. H. Playfair, Esq., Architect, Edinburgh.
John Argyle Robertson, Esq., Surgeon, Edinburgh.
James Pillans, Esq., Edinburgh.
James Walker, Esq., Civil-Engineer.
Sir William Newbigging, Surgeon, Edinburgh.
William Wood, Esq., Surgeon, Edinburgh.
1825 The Venerable Archdeacon John Williams, Rector of the Edinburgh Academy.
W. Preston Lauder, M.D., London.
Right Honourable Lord Ruthven.
Dr Reid Clanny, Sunderland.
Sir William Jardine, Bart, of Applegarth.
Hon. Lord Wood.
1826 Sir George Macpherson Grant, Bart, of Ballindalloch.
William Renny, Esq., W.S., Solicitor of Stamps.
Sir David Hunter Blair, Bart.
John Stark, Esq., Edinburgh.
Dr John Macwhirter, Edinburgh.
1827 John Gardiner Kinnear, Esq. Edinburgh.
William Burn, Esq., Edinburgh.
James Russell, M.D., Edinburgh.
Henry Thornton Maire Witham, Esq. of Lar ting ton.
Rev. Dr Robert Gordon, one of the Ministers of Edinburgh.
James Wilson, Esq., Edinburgh.
Very Rev. Edward Bannerman Ramsay, A.M. of St John's College* Cambridge.
George Swinton, Esq., Edinburgh.
1828 Erskine Douglas Sandford, Esq., Advocate.
David Maclagan, M.D., Edinburgh.
Sir William Maxwell, Bart.
John Forster, Esq., Architect, Liverpool.
Thomas Graham, A.M., Professor of Chemistry, London University.
David Milne, Esq., Advocate.
Dr Manson, Nottingham.
William Burn Callender, Esq.
VOL. XV. PAET IV. 9 B
690 LIST OF ORDINARY MEMBERS.
Date cf
Election.
1829 A. Colyar, Esq.
William Gibson-Craig, Esq., Advocate.
James Ewing, LL.D., Glasgow.
Sir Charles Ferguson, Bart., Advocate.
Right Hon. Duncan MacNeill, Lord- Advocate.
Rev. John Sinclair, A.M., Pembroke College, Oxford,
Arthur Connell, Esq., Professor of Chemistry, St Andrews.
Bindon Blood, Esq., M.R.I.A.
James Walker, Esq., W.S.
William Bald, Esq., M.R.I.A.
1830 J. T. Gibson-Craig, Esq., W.S.
Archibald Alison, Esq., Advocate, Sheriff-Depute of Lanarkshire.
Hon. Mountstuart Elphinstone.
James Syme, Esq., Professor of Clinical Surgery.
Thomas Brown, Esq., of Lannfine.
James L'Amy, Esq., Advocate, Sheriff-Depute of Forfarshire.
Thomas Barnes, M.D., Carlisle.
1831 James D. Forbes, Esq., F.R.S. Lond., Professor of Natural Philosophy.
Right Honourable Lord Dunfermline.
John Abercrombie, M.D., Edinburgh, First Physician to her Majesty in Scotland.
Donald Smith, Esq.
Captain Sir Samuel Brown, R.N.
O. Tyndal Bruce, Esq., of Falkland.
David Boswell Reid, M.D., London.
T. S. Davies, Esq., A.M., Woolwich.
1832 John Sligo, Esq. of Car my le.
James Dunlop, Esq. Astronomer, New South Wales.
James F. W. Johnston, A.M., Professor of Chemistry in the University of Durham.
William Gregory, M.D., Professor of Chemistry.
Robert Allan, Esq., Advocate.
Robert Morrieson, Esq., Hon. E.I.C. Civil Service.
Montgomery Robertson, M.D.
1833 Captain Milne, R.N.
Alexander Earle Monteith, Esq., Advocate.
His Grace the Duke of Buccleuch.
A. T. J. Gwynne, Esq.
David Craigie, M.D., Edinburgh.
George Buchanan, Esq., Civil-Engineer.
Sir John Stuart Forbes, Bart, of Pitsligo.
Alexander Hamilton, Esq., LL.B., W.S.
Right Honourable Earl Cathcart.
1834 Mungo Ponton, Esq., W.S.
Isaac Wilson, M.D., F.R.S. Lond.
David Low, Esq. Professor of Agriculture.
LIST OF ORDINARY MEMBERS. 597
Date of
Election.
1834 Thomas Henderson, Esq., Professor of Astronomy.
Rev. Dr Chalmers, Edinburgh.
Alexander Kinnear, Esq.
Patrick Boyle Mure Macredie, Esq., Advocate.
John Davie Morries Stirling, Esq.
Thomas Jameson Torrie, Esq., Edinburgh.
William Copland, Esq. of Collision.
John Steuart Newbigging, Esq., W.S.
Rev. Dr Welsh, Edinburgh.
John Haldane, Esq., Haddington.
1835 John Hutton Balfour, M.D., Professor of Botany, University of Glasgow.
William Sharpey, M.D., Professor of Anatomy, University College, London.
Right Honourable Lord John Campbell.
William Brown, Esq., F.R.C.S., Edinburgh.
Reverend Edward Craig.
R. Mayne, Esq.
1836 William Paul, Esq., Accountant.
Robert Paul, Esq., Secretary to Commercial Bank.
David Rhind, Esq., Architect.
James Anderson, Esq., Civil- Engineer.
Martin Barry, M.D., F.R.C.P.E.
Archibald Robertson, M.D., F.R.S. Lond.
J. Macpherson Grant, Esq., younger of Ballindalloch.
Alexander Gibson Carmichael, Esq.
1837 Archibald Campbell, Esq., W.S.
John Scott Russell, Esq., A.M.
Charles Maclaren, Esq., Edinburgh.
A. Smith, Esq., B.A., F.T.C., Camb.
Richard Parnell, M.D.
Peter D. Handyside, M.D., F.R.C.S., Edinburgh.
John Clark, M.D., K.H.
1838 William Nicol, Esq.
William Scot, Esq., H.E.I.C. Service.
Thomas Mansfield, Esq., Accountant.
Alan Stevenson, Esq., Civil- Engineer.
1839 James Auchinleck Cheyne, Esq. of KUmaron.
David Smith, Esq., W.S.
Adam Hunter, M.D., Edinburgh.
Rev. Philip Kelland, A.M., Professor of Mathematics.
Henry Marshall, Esq., Dep. Inspector Gen. of Army Hospitals.
William Ferguson, Esq., Professor of Surgery, King's College, London.
William Alexander, Esq., W.S.
F. Brown Douglas, Esq., Advocate.
Lieutenant-Colonel Swinburne.
698 LIST OF ORDINARY MEMBERS.
Date of
Election.
1840 Alan A. Maconochie, Esq., Professor of Civil Lam, Glasgow.
Martyn J. Roberts, Esq.
Robert Daun, M.D., Dep. Inspector-Gen, of Army Hospitals.
Robert Chambers, Esq., Edinburgh.
James Forsyth, Esq.
Sir John MacNeill, G.C.B.
John Cockburn, Esq., Edinburgh.
Sir William Scott, Bart.
Right Rev. Bishop Terrot, Edinburgh.
The Rev. R. Traill, D.D.
Robert Bryson, Esq., Edinburgh.
Edward J. Jackson, Esq.
John Shedden Patrick, Esq. of Hessilhead.
John Learmonth, Esq. of Dean.
Right Hon. T. B. Macaulay, M.P.
John Mackenzie, Esq., Edinburgh.
John Thomson, Esq.
James Anstruther, Esq., W.S., Edinburgh.
1841 J. P. Muirhead, Esq., Advocate.
Colonel Morison, C.B., Madras Artillery.
John Miller, Esq., Civil- Engineer.
George Smyttan, M.D., Edinburgh.
James Hamilton, Esq.
Robert Spittal, M.D., Edinburgh.
James Dalmahoy, Esq.
James Kinnear, Esq., W.S., Edinburgh.
1842 James Thomson, Esq., Civil- Engineer, Glasgow.
John Davy, M.D., Inspector Gen. of Hospitals.
Robert Nasmyth, Esq., F.R.C.S., Edinburgh.
Sir James Forrest, Bart., of Comiston.
James Miller, Esq., Professor of Surgery.
James Stark, M.D., F.R.C.P., Edinburgh.
John Adie, Esq., Optician, Edinburgh.
John Goodsir, Esq., Edinburgh.
1843 A. D. Maclagan, M.D., F.R.C.S., Edinburgh.
John Rose Cormack, M.D., F.R.C.P, Edinburgh.
Allen Thomson, M.D., Professor of the Institutes of Medicine, Edinbwxgh.
Joseph Mitchell, Esq., Civil- Engineer, Inverness.
Duncan Davidson, Esq. of Tulloch.
Andrew Coventry, Esq., Advocate.
John Hughes Bennett, M.D., F.R.C.P., Edinburgh.
D. Balfour, Esq., Younger of Trenaby.
Henry Stephens, Esq., Edinburgh.
W. H. Norie, Esq.
LIST OF ORDINARY MEMBERS. 699
Date of
Election.
1844 The Honourable Lord Murray.
Arthur Forbes, Esq. of Culloden.
J. Burn Murdoch, Esq., Advocate.
Lieut.-Colonel John Low.
Archibald Swinton, Esq., Professor of Civil Lam.
James Begbie, M.D., F.R.C.S., Edinburgh.
Nicholas Grut, Esq., Edinburgh.
Rev. Archibald Bennie, one of the Ministers of Edinburgh.
James Y. Simpson, M.D., Professor of Midwifery.
David Stevenson, Esq., Civil-Engineer, Edinburgh.
Thomas R. Colledge, M.D., F.R.C.P.E.
LIST OF NON-RESIDENT AND FOREIGN MEMBERS.
ELECTED UNDER THE OLD LAWS.
NON-RESIDENT.
Charles Hatchett, Esq., F.R.S., Lond.
Thomas Blizzard, Esq.
Sir James Macgrigor, Bart., M.D.
Richard Griffiths, Esq., Civil- Engineer.
FOREIGN.
Dr S. L. Mitchell, New York.
M. P. Prevost, Geneva.
VOL. XV. PAKT IV. 9 C
( 700 )
LIST OF HONORARY FELLOWS.
His Majesty the King of the Belgians.
His Imperial Highness the Archduke John of Austria.
His Royal Highness the Archduke Maximilian.
His Royal Highness Prince Albert.
BRITISH SUBJECTS (LIMITED TO TWENTY, BY LAW X.)
Robert Brown, Esq., F.R.S.
Sir John F. W. Herschel, Bart., F.R S.
Dr Faraday, F.R.S.
G. B. Airy, Esq., F.R.S., Astronomer-Royal.
Sir W. R. Hamilton, M.A., M.R.I.A., Astronomer-Royal, Ireland.
THE FOLLOWING EIGHT NAMES WERE INCLUDED WITH THE ABOVE PRIOR TO THE CHANGE IN
THE LAW, 18TH JANUARY 1836.
Baron Humboldt, Berlin.
M. Gay Lussac. Paris.
M. Biot, Do.
M. Arago, Do.
Chevalier Hammer.
M. Berzelius. Stockholm.
FOREIGNERS (LIMITED TO THIRTY-SIX.)
M. Brochant, Paris.
Le Baron Von Buch, Berlin.
M. Gauss, Gottingen.
Le Baron Degerando, Paris.
5 Le Baron Krusenstern, St Petersburgh.
M. Oersted, Copenhagen.
M. Schumacher, Altona.
Sir Henry Bernstein, Berlin.
LIST OF HONORARY FELLOWS.
701
Bishop Munter,
10 Baron Charles Dupin,
M. Brongniart,
Chevalier Biirg,
M. Bessel,
M. Thenard,
15 M. Haidinger,
M. Mitscherlich,
M. G. Rose,
M. Hausmann,
J. J. Audubon, Esq.,
20 Chevalier Bouvard,
M. L. A. Necker,
M. Agassiz,
Le Baron Cousin,
M. Plana,
25 M. Quetelet,
M. Struve,
Professor Tiedemann,
Professor Encke,
Zealand.
Paris.
Do.
Vienna.
Konigsberg.
Paris.
Vienna.
Berlin.
Berlin.
Gottingen.
United States.
Paris.
Geneva.
Neuchatel.
Paris.
Turin.
Brussels.
Dorpat.
Heidelberg.
Berlin.
( 702 )
LIST OF FELLOWS DECEASED, EESIGNED, AND CANCELLED.
FROM 1840 TO 1844.
HONORARY FELLOWS.
His Royal Highness the Duke of Sussex.
M. De Candolle, Geneva.
Right Honourable Lord Wallace.
DrDalton, F.R.S.
James Ivory, Esq., K.H., F.R.S.
M. Simond de Sismondi, Geneva.
Le Baron Larrey, Paris.
M. Dnlong, Paris.
ORDINARY FELLOWS DECEASED OR RESIGNED.
Thomas Charles Hope, M.D., F.R.S. Lond., Professor of Chemistry.
William Wallace, L.L.D., Emeritus Professor of Mathematics.
Robert Ferguson, Esq. of Baith, F.R.S. Lond.
Sir Charles Bell, K.H., F.R.S. Lond., Professor of Surgery.
David Ritchie, D.D., Emeritus Professor of Logic.
Daniel Ellis, Esq., Edinburgh.
Sir John Robison, K.H., Edinburgh.
George Augustus Borthwick, M.D., Edinburgh.
Sir Francis Chantrey, F.R.S. Lond.
Right Rev. Bishop James Walker, D.D., Edinburgh.
Sir Francis Walker Drummond, Bart, of Hawthornden.
Thomas Hamilton, Esq., Edinburgh.
James Hope Vere, Esq. of Craigiehall.
Thomas Edington, Esq., F.G.S.
G. A. Stuart, Esq.
James Hunter, M.D., Edinburgh.
RESIGNATIONS.
John Craig, Esq., Edinburgh.
Rev. Geo. Coventry, Edinburgh.
Gilbert Lawrie Finlay, Esq.
Graham Speirs, Esq.
ELECTIONS CANCELLED.
William Dyce, Esq., A.M.
Rev. J. P. Nichol, Professor of Practical Astronomy, Glasgow. ~.
( 703 )
LIST OF DONATIONS.
(Continued from Vol. XIV. p. 731.)
December 7- 1840.
DONATIONS.
The American Journal of Science and Arts. Conducted by Benjamin Silliman,
LL.D. For January, April, July, and October 1840.
Proceedings of the American Philosophical Society. January, February, May,
June, July.
On the Heat of Vapours and on Astronomical Refractions. By John William
Lubbock, Esq.
Researches in Embryology. (Second Series.) By Martin Barry, M.D., F.R.S.E.
Transactions of the 'Cambridge Philosophical Society. Vol. vii. Part 1.
Memoires de la Societe de Physique et d'Histoire Naturelle de Geneve. Tome
viii. Part 2.
Transactions of the Society instituted at London for the Encouragement of Arts,
Manufactures, and Commerce. Vol. Hi. Part 2.
The Quarterly Journal of Agriculture ; and the Prize Essays and Transactions
of the Highland and Agricultural Society of Scotland. For June, Sep-
tember, and December.
Journal of the Asiatic Society of Bengal. For June, July, August, September.
Asiatic Researches ; or Transactions of the Society instituted in Bengal for in-
quiring into the History, the Antiquities, the Arts and Sciences, and Li-
terature. Vol. xix. Part 2.
De Graphite Moravico et de phsenomenis quibusdam originem Graphitse illus-
trantibus Commentatio. E. F. De Glocker.
Proceedings of the Geological Society of London. Nos. 67 to 71.
Astronomische Nachrichten. Nos. 387 to 399.
Memoirs of the Wernerian Natural History Society for the Years 1837-38.
Vol. viii. Part 1.
Journal of the Royal Asiatic Society. May 1840.
Collec9ao de Noticias para a Historia e Geografia das Nafoes Ultramarinas que
vivom nos dominios Portuguezes ou Ihes sao visinhas ; publicada pela Aca-
demia Real das Sciencias. Tomo v. No. 2.
Astronomical Observations made at the Royal Observatory, Edinburgh. By
Thomas Henderson, F.R.S.E., Professor of Practical Astronomy. Vol. iii.
Report on Education in Europe, to the Trustees of the Girard College for Or-
phans. By Alexander Dallas Bache, LL.D., President of the College.
Tijdschrift voor Natuurlijke Geschiedenis en Physiologie. Uitgegeven door J.
Van Der Hoeven, M.D., Prof, te Leiden, en W. H. De Vriese, M.D.,
Prof, te Amsterdam. Deel vi. St. 4. Deel vii. Stks. 1. 2.
Bulletin de 1' Academic Royale des Sciences et des Belles Lettres de Bruxelles,
1840, Nos. 1 to 8.
VOL. XV. PAET IV. 9
DONORS.
The Editor.
The Society.
The Author.
The Author.
The Society.
Ditto.
Ditto.
Ditto.
Ditto.
Ditto.
The Author.
The Society.
Prof. Schumacher.
The Society.
Ditto.
The Royal Aca-
demy.
The Royal Society,
Lond.
The Author.
The Editors.
The Academy.
704
LIST OF DONATIONS.
DONATIONS.
Brevi Cenni di Alcuni Resti delle Class! Brachiopodi di G. Michelotti.
De Solariis in Supracretaceis Italiae Stratis repertis. Auctore Joanne Miche-
lotti.
Transactions of the Geological Society of London. (Second Series.) Vol. v.
Part 3.
The Rod and the Gun. Being Two Treatises on Angling and Shooting, by
James Wilson, Esq., F.R.S.E., and by the Author of the '' Oakleigh
Shooting Code."
Madras Journal of Literature and Science. 1839. July, September, and De-
cember.
Oryctographie du Gouvernement de Moscow. Publiee par Gotthelf Fischer De
Waldheim.
Einiges gegen den Vulkanismus. Von B. M. Keilhau.
Notice sur les Gallas de Limmon. Par M. Jomard.
Notation Hypsometrique ou Nouvelle Maniere de Noter les Altitudes. Par M.
Jomard.
Quelques Recherches sur la Chaleur Specifique. Par MM. les Professeurs De
la Rive et Marcet.
Deuxieme Memoire sur les Variations Annuelles de la Temperature de la Terra
£ differentes profondeurs. Par A. Quetelet.
Second Memoire sur le Magnetisme Terrestre en Italic. Par A. Quetelet.
Resume des Observations Meteorologiques faites en 1839, 3. 1'Observatoire
Royal de Bruxelles. Par A Quetelet.
Memoires Couronnes par I' Academic Royale des Sciences et Belles Lettres de
Bruxelles. Tome xiv. lere partie.
Fisica de Corpi Ponderabili ossia Trattato della Constituzione Generale de' Corpi
del Cavaliere Amedeo Avogadro. 2 vols. 8vo.
Memorie della Reale Accademia delle Scienze di Torino. (Serie Seconda.)
Tomo i.
Proceedings of the Linnean Society of London. Nov. 6. 1838 to March 17-
1840.
Transactions of the Linnean Society of London. Vol. xviii. Part 3.
Ancient Laws and Institutes of England ; comprising Laws enacted under the
Anglo-Saxon Kings from Athelbirht to Cnut, with an English Translation
of the Saxon ; the Laws called Edward the Confessor ; the Laws of Wil-
liam the Conqueror, and those ascribed to Henry the First ; also Monu-
menta Ecclesiastica Anglicana, from the seventh to the tenth century ; and
the ancient Latin Version of the Anglo-Saxon Laws.
Ordnance Survey of Ireland — County of Carlow in 28 sheets ; and King's
County in 49 sheets.
Disquisizione delle Dottrine sulla Struttura e sulle Funzioni del cuore e delle
Arterie. G. M. Zecchinelli.
Footsteps of the Cheirotherium as shewn on Slabs of New Red Sandstone from
Storeton Hill Quarry, Cheshire ; illustrated in 3 plates.
Elements of Chemistry. By the late Edward Turner, M.D. Enlarged and re-
vised by Justus Leibig, M.D., Wilton G. Turner, and W. Gregory, M.D.
Part 3. No. 2.
Transactions of the American Philosophical Society held at Philadelphia for
promoting Useful Knowledge. (New Series.) Vol. vii. Part 1.
Memoires de la Societe des Sciences Naturelles de Neuchatel. Tome ii.
Memoires de 1' Academie Imperiale des Sciences de Saint Petersbourg. (Sciences
Mathematiques, &c.) Tome ii. Livna 3, 4.
DONORS.
The Author.
Ditto.
The Society.
The Authors.
The Editors.
The Imperial So-
ciety of Natura-
lists of Moscow.
The Author.
Ditto.
Ditto.
Ditto.
Ditto.
Ditto.
Ditto.
The Royal Aca-
demy.
The Author.
The Academy.
The Society.
Ditto.
The Commissioners
on the Public
Records of the
Kingdom.
The Lord Lieute-
nant of Ireland.
The Author.
Dr Buckland.
The Editors.
The Society.
Ditto.
Ditto.
LIST OF DONATIONS.
705
DONATIONS.
M&noires de 1'Academie Imperiale des Sciences de Saint Petersbourg. (Sciences
Politiques, &c.) Tome iv. Livns 4, 5.
Do. Do. (Sciences Naturelles.) Tome iii. Liv"8 1, 2, 3, 4.
Recueil des Actes des Seances Publiques de 1' Academic Imperiale des Sciences
de Saint Petei-sbourgh, tenues le 29 Dec. 1838 et le 29 Dec. 1839.
Voyage dans la Kussie Meridionale et la Crimee. Par M. de Demidoff. Livns
2, 3, des planches.
Do. Do. (Partie Scientfique) LivM 6, 7, 8, 9, 10, en 8vo, et planches en folia.
Comptes Rendus Hebdomadaires des Seances de 1' Academic des Sciences de
Paris 1840. ler Semestre No. 13, 14, 15, 16, 17, 18, 19.
Memoire sur la Formation de 1' Indigo dans les Feuilles du Polygonum Tincto-
rium, ou Renouee Tinctoriale. Par Ch. Morren.
Recherches sur le Mouvement et 1' Anatomic du Style du Goldfussia Anisophylla.
Par M. Ch. Morven.
Twentieth Report of the Council of the Leeds Philosophical and Literary So-
ciety at the close of the Session 1839-40.
Essays and Heads of Lectures on Anatomy, Physiology, Pathology, and Sur-
gery. By the late Alexander Monro, Secundus, M.D., F.R.S.E., upwards
of fifty years Professor of Anatomy and Surgery in the University of
Edinburgh. With a Memoir of his Life by his Son and Successor.
Mr Greenough's Geological Map of England.
A Collection of Specimens of Fossil Organic Remains.
December 21.
Elements of Chemistry, including the actual State and prevalent Doctrines of
that Science. By the late Edward Turner, M.D., F.R.S.L. and E.
Edited by Justus Leibig, M.D., F.R.S.L. and E., and William Gregory,
M.D., F.R.S.E.
A Tabular View of the Yearly Quantity of Rain which falls in different parts
of Great Britain. By Joseph Atkinson, Harraby, near Carlisle.
Memoirs of the Royal Astronomical Society, Vol. xi.
Astronomische Nachrichten. Nos. 400 to 411.
A Collection of Fossil Fishes from Orkney.
January 4. 1841.
Bericht iiber die zur Bekanntmachung geeigneten Verhandlungen der Konigl.
Preuss. Akademie der Wissenschaften zu Berlin. Juli 1839 bis Juni
1840.
Abhandlungen der Kb'niglichen Akademie der Wissenschaften zu Berlin. 1832.
Thiels 3 and 4, and 1838.
Flora Batavia. No. 120.
Annuaire Magnetique et Meteorologique du Corps des Ingenieurs des Mines de
Russia. Annee 1838. Par A. F. Kupffer.
January 18.
Journal of the Asiatic Society of Bengal. No. 97. 1840.
Madras Journal of Literature and Science. January to March 1840.
Bulletin de la Societe d' Encouragement pour 1'Industrie Nationale pour les an-
nees 1838 et 1839.
Proceedings of the American Philosophical Society. No. 13.
DONORS.
The Imperial Aca-
demy.
The Author.
The Academy.
The Author.
Ditto.
The Society.
Dr Monro.
The Geological So
ciety.
Chevalier Miche-
lotti of Turin.
The Publishers.
The Author.
The Society.
Prof. Schumacher.
Dr Traill.
The Academy.
Ditto.
King of Holland.
The Author.
The Society.
Ditto.
Ditto.
Ditto.
roe
LIST OF DONATIONS.
DONATIONS.
Tijdsclirift \oor Natuurlijke Geschiedenis en Physiologic. TJitgegeven door J.
Van der Hoeven, M.D. en W. H. de Vriese, M.D. Deel 7. Stks. 3, 4.
Experimental Researches on the Strength of Pillars of Cast Iron, and other
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714
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Memoires de la Societe de Physique et d'Histoire Naturelle de Geneve. Tome
ix. ptie 2.
Journal of the Royal Asiatic Society of Great Britain and Ireland. No. 13.
Magnetische und Meteorologische Beobachtungen zu Prag, von Karl Kriel.
(Zwieter Jahrgang.)
1st ?nd 2d Bulletins of the Proceedings of the National Institution for the pro-
motion of Science at Washington.
Researches in Physical Geology. By W. Hopkins, Esq. Parts 1, 2, 3.
On the Errors of Chronometers, and Explanation of a New Construction of the
Compensation Balance. By E. J. Dent, Esq.
Twenty-second Report of the Council of the Leeds Philosophical and Literary
Society, 1841-42.
Transactions of the Royal Cornwall Polytechnic Society, 1842. No. 1.
System der Krystalle, ein Versuch von M. L. Frankenheim, Professor an der
Universitat von Breslau.
Abhandlungen der Kb'niglichen Akademie der Wissenschaften zu Berlin 1840.
Bericht liber die zur Bekanntmachung geeigneten Verhandlungen der Kongl.
Preuss. Akademie der Wissenschaften zu Berlin. Juli 1841 bis Juni 1842.
Liber Cartarum Prioratus Sancti Andree in Scotia e Registro ipso in Archivis
Baronum de Panmure hodie asservato. (Printed for the Bannatyne Club.)
The Grasses of Scotland. By Richard Parnell, M.D., F.R.S.E.
The Second Supplement, completing the Seventh Edition of Dr Turner's Che-
mistry. By Justus Liebig, M.D., and William Gregory, M.D.
Transactions of the Society instituted at London for the Encouragement of Arts,
Manufactures, and Commerce. Vol. Hi., Part 2.
Journal of the Royal Geographical Society of London. Vol. ix., Part 2.
Abhandlungen der Mathematisch-Physikalischen Classe der Koeniglich Bayeris-
chen Akademie der Wissenschaften. Band iii., Abth. ii.
Prodromus zu einer neuen verbesserten Darstellungsweise der Hohern Analy-
tischen Dynamik, vom Grafen Georg von Buquoy. 1 Lieferung.
Proceedings of the Zoological Society of London. Nos. 93 to 108.
Transactions of the Royal Institute of British Architects. Vol. i., Pt. 2.
Historical Transactions of the Royal Society of Copenhagen. 6 Vols.
Pilote Fran^ais comprenant les Cotes Septentrionales de France depuis Barfleur
jusqu'a Dunkerque. Public par ordre du Roi. Partie 5me.
Ueber das farbige Licht der Doppelsterne und eineger anderer Gestirne des
Himmels, von Christian Doppler.
Comptes Rendus Hebdomadaires des Seances de 1'Academie des Sciences.
Tome xiv., Nos. 13-26, et Tome xv., Nos. 1-8.
A number of Mineral and Fossil Organic Specimens, from various localities.
Specimens of Land and Fresh-water Shells, chiefly from the neighbourhood of
Edinburgh.
Specimens of Marine Shells, chiefly from the Firth of Forth.
Specimens of Zoophytes, chiefly from the Firth of Forth.
December 19.
Astronomical Observations made with Ramsden's Zenith Sector, together with
a Catalogue of the Stars which have been observed, and the amplitudes of
the Celestial Arcs, deduced from the observations at the different stations.
Published by order of the Board of Ordnance.
7
DOXOHS.
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Ditto.
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The Master-Gene-
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LIST OF DONATIONS.
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Proceedings of the London Electrical Society. Part 6. Session 1842-43.
Bulletin de 1' Academic Royale des Sciences et Belles Lettres de Bruxelles.
1842. Nos. 3-9.
Nouveaux Memoires de 1' Academic Royale des Sciences et Belles Lettres de
Bruxelles. Tome xv.
Annales do 1'Observatoire Royal de Bruxelles. Publiees par le Directeur, A.
Quetelet. Tome ii.
Annuaire Magnetique et Meteorologique du Corps des Ingenieurs des Mines de
Russie, ou Recueil d'Observations Magnetiques et Meteorologiques faites
dans 1'etendue de 1'Empire de Russie. Par A. T. Kupffer. Anneel840.
Astronomische Nachrichten. Nos. 447-461.
Transactions of the Philosophical Society of Cambridge. Vol. vii., Part 3.
Scheikundige Onderzoekingon, gedaan in het Laboratorium der Utretchtsche
Hoogeschool. Stuk 4.
Specimens illustrative of Mr Stark' s paper an the Food of the Herring and
Salmon.
Specimens of the Woods of Ceylon (fifty different kinds.)
Specimens of Minerals and Fossil Organic Remains from Malta, the Ionian
Islands, and Ceylon.
Geological Specimens from the Velay and Vivarais (Haute Loire and Ardeche.)
January 9. 1843.
Maps of the Ordnance Survey of England and Wales. Nos. 80, 81, and 90.
Maps of the Irish Ordnance Survey, containing the County of Clare. 77
sheets.
Report made at the Annual Visitation of the Armagh Observatory. By the
Rev. T. R. Robinson, D.D.
Proceedings of the American Philosophical Society. Vol. ii., No. 23.
Journal of the Asiatic Society of Bengal. Nos. 122 and 123.
Specimens of Fossil Organic Remains from East Kilbride and neighbourhood,
Lanarkshire. Collected by the late Rev. David Ure, A.M. ; and a num-
ber of them figured in his " History of Rutherglen and East Kilbride,"
Tail of a Wild Elephant from Ceylon.
Specimens of Fossil Fishes from Syria.
January 23.
Proceedings of the London Electrical Society. Part 7.
De Fide Uranometrise Bayeri Dissertatio Academica. Scripsit D. F. G. A.
Argelander.
Memoirs of the Royal Astronomical Society. Vol. xii.
Philosophical Transactions of the Royal Society of London, 1842. Part 2.
Arsberattelser om nyare Zoologiska Arbeten oeh Upptackter. Afgifne for
Aren 1837-40. At' C. J. Sundewall.
Kongl. Vetenskaps-Academiens Handlingar, for Aren 1839-40.
Arsberattelse om framstegen i Fysik och Kemi Afgiven den 31 Mars 1839
and 31 Mars 1840. Af Jac. Berzelius.
Arsberattelse om Technologiens Framsteg, Afgiven den 31 Mars 1839 and
31 Mars 1840. Af G. E. Pasch.
Three Specimens of Salmon, showing the rapid growth (on descending to the
sea) of the Smolt to the state of Grilse, and of the latter to the adult con-
dition.
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John Stark, Esq.
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Professor Forbes.
Master- General of
the Ordnance.
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Observatory.
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Rob. Bryson, Esq.
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VOL. XV. PART IV.
9
716
LIST OF DONATIONS.
DONATIONS.
February 6.
Elements of Chemistry, including the Applications of the Science to the Arts.
By Professor Graham, University College, London. Part 6.
Maps of the Irish Ordnance Survey, containing the County of Waterford, in
42 sheets.
Specimens of Volcanic Rocks from Vesuvius, and Minerals from Derbyshire.
Specimens of Fossil Shells from Grignon, collected by Dr Stark in Oct. 1833.
February 20.
Voyage dans la Russie Meridionale et la Crimee, par M. Anatole de Demi-
doff. Tome iv. aveo un Atlas des Planches.
Bulletin de la Societe Geologique de France, from 15th March to 9th Septem-
ber 1841.
Proceedings of the Glasgow Philosophical Society, 1841-42.
March 6.
Monthly Notices of the Astronomical Society of London, containing Abstracts
of Papers and Reports of the Proceedings of the Society. Vols. i. ii. iii.
iv. and Vol. v. Nos. 1-27.
Memoirs of the Royal Astronomical Society. Vol. xiv.
Examination Papers of the several Faculties in the University of London, for
1842.
Memoire sur la Chaleur des Gas Permanens, par Jean Plana, Astronome Royal,
et Directeur de FObservatoire de Turin.
Journal of the Asiatic Society of Bengal. Nos. 124 and 125, for 1842.
The Quarterly Journal of Agriculture, and the Prize Essays and Transactions
of the Highland and Agricultural Society of Scotland. No. 60, for
March 1843.
A Specimen of a Vegetable Impression from Burdie House.
March 20.
Archives du Museum d'Histoire Naturelle, publiees par les Professeurs-Admi-
nistrateurs de cet Etablissement. Tom ii. Liv. 3.
Comptes Rendus Hebdomadaires des Seances de 1' Academic des Sciences.
Tome xv. Nos 9-26, et Tome xvi. Nos. 1-7.
Monthly Notices of the Astronomical Society of London. Vol. v. No. 28.
Specimen de 1'Imprimerie de Bachelier, Rue de Jardinet.
March 27.
Bulletin des Seances de la Societe Vaudoise des Sciences Naturelles. Nos. 1
and 4.
Essai Historique sur les Phenomenes et les Doctrines de I'Electro-Chimie. Par
Elie Francois Wartmann.
Comptes Rendus Hebdomadaires des Seances de I'Academie des Sciences.
Tome xvi. Nos. 8 and 9.
On the Transparency of the Atmosphere and the Law of Extinction of the
Solar Rays in Passing through it. By James D. Forbes, F.R.S., &c.
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versity.
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Hoogeschool. St. 5.
Natuurkundige Verhandelingen van de Hollandsche Maatschappij der Wetten- The Society,
chappen te Haarlem. Deel 2.
Series of Specimens of the different Rock Formations. (150 specimens.) Lord Greenock.
Specimens connected with Mr Shaw's paper on the Development and Growth of Mr John Shaw.
the Sea-Trout of the Solway.
April 17.
The Quarterly Journal of Meteorology and Physical Science. Edited by J. W. The Editor.
G. Gutch, M.R.C.S. No. 6. for April 1843.
Proceedings of the London Electrical Society. Part 8. The Society.
Annual Report of the Council of the Yorkshire Philosophical Society, for 1842. The Society.
Elements of Agricultural Chemistry. By Sir Humphrey Davy, Bart. (Sixth Dr John Davy.
Edition.)
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Proceedings of the Royal Society. Nos. 55 and 56.
Revised Instructions for the use of the Magnetic and Meteorological Observa- Royal Society.
tories, and for the Magnetic Surveys. Prepared by the Committee of
Physics and Meteorology of the Royal Society.
May 1.
Transactions of the Geological Society. (Second Series.) Vol. vi. Part 2.
Archives du Museum d'Histoire Naturelle, publiees par les Professeurs-Admi-
nistrateurs de cet Etablissement. Tome iii. Livr"8 1, 2.
A Head of Boodhoo in Dolomite from Ceylon.
Specimens of Coal from Penteraclea, the Ancient Heraclea, on the Black Sea.
Specimen of " Burn Trout" or Salmo Fario, taken from the Compensation
Pond, weighing 6 Ib.
A Specimen of Chalcedony, from Iceland.
Six Specimens shewing the Actions of Glaciers on Rocks : —
1. Limestone taken from under the Ice of the Glacier of La Brenva, in
Piedmont, in July 1842.
2. 3. 4. Specimens of Granite from the Grimsel, supposed to shew Gla-
cier Polish.
5. 6. Specimens of Limestone from the Jura, shewing (supposed) Glacier
Polish.
Specimens of Fossil Fish, from the Old Red Sandstone of Morayshire, named
by M. Agassiz.
December 4.
Journal of the Asiatic Society of Bengal. Nos. 126, 127, 128, 129, 130,
and 131.
The American Journal of Science and Arts. Conducted by Professor Silliman.
Vol. xliv., No. 2 ; and vol. xlv., Nos. 1 and 2.
Proceedings of the Academy of Natural Sciences of Philadelphia. Vol. i.,
Nos. 20, 21, 24, 25.
Proceedings of the Royal Astronomical Society. Vol. v., Nos. 30, 31, and 32.
Het Instituut of Verslagun en Mededeelingen, uitgegeven door de vier classen
van het koninklijk Nederlandsche Instituut van Wetenschappen, Letter-
The Society.
The Editors.
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kenzie.
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kunde en Schoone Kunsten, over den .Tare 1841. Nos. 1, 2, 3, 4; and
1842, Nos. 1, 2, and 3.
Journal of the Royal Geographical Society of London. Vol. xii., Part 2.
Historia e Memorias da Academia Real das Sciencias de Lisboa. Tomo xii.,
Part 2.
Discurso lido em 22 de Janiero de 1843 na Sessao publica da Academia Real
das Sciencias de Lisboa per Joaquim Jose da Costa de Macedo.
Astronomische Nachrichten. Nos. 462-477.
Scheikundige Onderzoekingen gedaan in het Laboratorium der Utrechtsche
Hoogeschool. Deel 2. St. 1.
Tijdschrift voor Natuurlijke Geschiedenis en Physiologie. Uitgegeven door J.
Van Der Hoeven M.D., en W. H. De Vriese M.D. Deel x. St. 1.
Flora Batava. Nos. 127 and 128.
Proceedings of the American Philosophical Society. Vol. ii., Nos. 24 and 25.
Transactions of the American Philosophical Society, held at Philadelphia, for
promoting Useful Knowledge. Vol. viii., Parts 2 and 3.
Address to the Anniversary Meeting of the Royal Geographical Society, 22d
May 1843.
Reports on the Fishes, Reptiles, and Birds of Massachusetts.
Annales des Sciences Physiques et Naturelles, d' Agriculture et d' Industrie,
publiees par la Societe Royale d'Agriculture, &c. de Lyon. Tomes i. ii.
iii. et iv.
Applications of the Electric Fluid to the Useful Arts, by Mr Alexander Bain ;
with a Vindication of his claim to be the first Inventor of the Electro-
Magnetic Printing Telegraph. By John Finlaison, Esq.
The Journal of Agriculture, and the Transactions of the Highland and Agri-
cultural Society of Scotland. July and October 1843.
Proceedings of the Zoological Society of London. Nos. 108 to 119.
Magnetische und Meteorologische Beobachtungen zu Prag. Dritter Jahrgang.
Von Karl Kreil.
Journal of the Statistical Society of London. Vol. vi., Part 3.
The Transactions of the Microscopical Society of London. Vol. i., Part 1.
The Electrical Magazine, conducted by Mr Charles V. Walker. Vol. i., Nos.
1,2.
Proceedings of the Geological Society of London. Nos. 92-3.
Archives du Museum d'Histoire Naturelle publiees par les Professeurs-Admini-
strateurs de cet Etablissement. Tome ii. Livr. 3.
Astronomical Observations made at the Royal Observatory, Edinburgh. By
Thomas Henderson, F.R.SS.L. & E., Professor of Practical Astronomy
in the University of Edinburgh. For the year 1839.
Memoirs of the Chemical Society of London. Vol. i.
Annuare de 1'Observatoire Royal de Bruxelles pour 1843, par A. Quetelet,
Directeur de cet Etablissement.
Observations des Phenomenes Periodiques. Par Monsieur Quotelet.
Annuare de 1'Academie Royale des Sciences -et Belles Lettre de Bruxelles.
Pour 1843.
Noveaux Memoires de 1'Academie Royale des Sciences et Belles Lettres de
Bruxelle. Tome xvi.
Me'moires Couronne's et Memoires des Savants Etrangers, publiees par 1'Aca-
demie Royale des Sciences et Belles Lettres de Bruxelles. Tome xv.,
ptie 2.
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Bulletin des Seances de 1' Academic Royale de Bruxelles. Tome ix., Nos. 10,
11, 12 ; and Tome x., Nos. 1, 2, 3, 4, 5, 6, 7.
Journal of the Bombay Branch Royal Asiatic Society. Nos. 3, 4. January
and April 1842.
Notizie relative a tre specie d'Insetti Nocivi all' ulivo dall Dr Passerini.
Osservazioni sulle Larve, Ninfe, e Abitudini della Scolia flavifrons del Dr C.
Passerini.
Notizie sulla moltiplicazioni del' uccello Americano, Paroaria cucullata, dal Dr
Passerini.
Memoires de la Societe Geologique de France. Tome v. Ptle" 1, 2.
Carte Geologique du Department de 1'Aisne, executee et publiee sous les Aus-
pices de M. Legrand, Sous-Secretaire d'Etat des Travaux Publiques.
Editee par la Societe Geologique de France, 1842.
Niewe Verhandelingen der Eerste Klasse van het Koninklijk-Nederlandsche
Instituut van Wetenschappen, Letterkundo en Schoone Kunsten te Am-
sterdam. Deel viii., Sts. i. ii. ; Deel ix., Sts. i.
Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin 1841.
Thiels 1, 2, 3.
Bericht iiber die zur Bekanntmachung geeigneten Verhandlungen der Konigl.
Preuss. Akademie der Wissenschaften zu Berlin. Juli 1842, bis Mai 1843.
Memoirs of the Royal Astronomical Society. Vol. xii.
Astronomical Observations made at the Royal Observatory, Greenwich, in the
year 1841 ; under the direction of George Biddell Airy, Esq.
Tenth Annual Report of the Royal Cornwall Polytechnic Society, 1842
The Quarterly Journal of Meteorology and Physical Science. Edited by
J. W. G. Gutch, M.R.C.S. for April 1843. No. 6.
An Introductory Lecture on Botany, considered as a Science, and as a Branch
of Medical Education. By Edward Forbes, Professor of Botany in King's
College, London.
Memoires de P Academic Imperiale des Sciences de Saint Petersbourg.
(Sciences Politiques, &c.) Tome vi., Livrais 1-3.
Do. do. (Sciences Naturelles.) Tome v. Livrais 1, 2.
Do. do. (Sciences Mathematiques.) Tome iii. Livrais 1, 2, 3.
Do. do. Memoires presentes par divers Savans. Tome iv. Livrais 1.
Recueil des Actes des Seances Publiques de 1'Academie Imperiale des Sciences
de Saint Petersbourg, tenues le 31 Decembre 1841, et le 30 Decembre
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Comptes Rendus Hedbomadaires des Seances de l'Academie des Sciences.
Tome xvi., No. 9—25, et Tome xvii., Nos. 1-19.
Maps of the Irish Ordnance Survey, containing the county of Tipperary, in 93
sheets.
Transactions of the Royal Irish Academy. Vol. xix., Part 2.
December 18.
Journal of the Asiatic Society of Bengal. Nos. 132 and 133.
Proceedings of the American Philosophical Society. Nos. 26 and 27.
January 15, 1844.
14 Specimens of British Land and Fresh-water Shells.
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The Hon. Mrs
M. Cathcart.
Block of Sandstone, with organic remains imbedded in it, found in one of the
VOL. XV. PART IV. 9 H
720
LIST OF DONATIONS.
DONATIONS.
Dry Docks at Leith, when enlarging it ; originally from Rosyth Quarry,
Fifeshire.
Portrait of James Mitchell, at the age of 46 years, well known, and described
in the Transactions of this Society, by the late Professor Dugald Stewart
and others, as the blind, deaf, and dumb boy. This portrait was given by
his sister, Jane G. Mitchell, to, and presented by
Proceedings of the Geological Society of London. Nos. 94, 95, and 96.
Journal of the Statistical Society of London. Vol. vi., Part 4.
Journal of the Asiatic Society of Bengal. Nos. 50, 51, and 52.
Comptes Rendus Hebdomadaires des Seances de 1'Academie des Sciences de
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The Journal of Agriculture, and the Transactions of the Highland and Agricul-
tural Society of Scotland. Jan. 1844.
Elements of Agricultural Chemistry and Geology. By James F. W. Johnston,
M.A., F.R.SS.L. & E., &c.
Transactions of the Institution of Civil Engineers. Vol. iii., Parts 2, 3, 4, and 5.
Minutes of Proceedings of the Institution of Civil Engineers for Sessions 1840,
1841, 1842, 1843.
Flora Batava. Nos. 139, 140.
Descriptive Catalogue of the Anatomical and Pathological Museum of the
School of Medicine, Park Street, Dublin. By John Houston, M.D.
Transactions of the Society instituted at London for the encouragement of Arts,
Manufactures, and Commerce. Vol. liv.
The Journal of the Royal Asiatic Society of Great Britain and Ireland. No. 14.
Tijdschrift voor Natuurlijke Geschiedenis en Physiologie. Uitgegeven door J.
van der Hoeven, M.D., en W. H. De Vriese, M.D. Deel x., Stuk. 4.
Abhandlungen der Koniglichen Gesellschaft der Wissenschaften zu Gottingen.
Band 1.
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Vol. xviii., Suppl. ii., et Vol. xix., Pars. ii.
Almanach der Koniglichen bayerischen Akademie der Wissenschaften. 1843.
Twenty-third Report of the Council of the Leeds Philosophical and Literary
Society. 1842-43.
Bulletin de la Societe Imperiale des Naturalistes de Moscow. 1842, No. 4,
et 1843, Nos. 1, 2, 3.
February 19.
The London University Calendar for 1844.
The Examination Papers of the London University for the year 1844.
The Transactions of the Linnsean Society of London. Vol. xix., Part 2.
Proceedings of the Linnsean Society of London. Nos. 15, 16, 17, 18.
Astronomical Observations made at the RadclifFe Observatory, Oxford, in 1840
and 1841. 2 vols. By Manuel J. Johnson.
Maps of the Irish Ordnance Survey, containing the county of Dublin, in 30
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Nouveaux Memoires de la Societe Imperiale des Naturalistes de Moscow.
Tome vii.
March 4.
Annuaire Magnetique et Meteorologique du Corps des Ingenieurs des Mines de
Russie. Par A. T. Kupffner. Annee 1841.
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Journal of Agriculture, and Transactions of the Highland and Agricultural So-
ciety of Scotland, March 1844.
Observations on Days of unusual Magnetic Disturbance made at the British
Colonial Observatories, under the Departments of the Ordnance and Ad-
miralty. Printed by the British Government, under the superintendence
of Lieutenant-Colonel Sabine, of the Royal Artillery. Part 1. 1840-
1841.
March 18.
Journal of the Royal Geographical Society of London. Vol. xiii. Part 1.
The American Journal of Science and Arts, conducted by Professor Silliman
and Benjamin Silliman, Jun. January 1844.
Scheikundige Onderzoekingen, Gedaan in het Laboratorium der Utrechtsche
Hoogeschool. 2d Deel. 2d Stuk.
Flora Batava. No. 131.
Maps of the Ordnance Survey of England and Wales. Sheets Nos. 88 and 89.
Kongl. Vetenskaps — Academiens Handlingar for Ar. 1841.
Arsberattelse om Framstegen i Kemi och Mineralogi, af Jac. Berzelius, for
1841, 1842, och 1843.
Arsberattelse om Technologiens Framsteg Ar 1841, af G. E. Putsch.
Arsberattelse om Zoologiens Framsteg under Aren 1840, 1842, af C. H. Bo-
heman.
Berattelse om Astronomiens Framsteg for Aren 1837, 1841, af N. H. Se-
lander.
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Nos. 30, 31, 32, and 33.
Proceedings of the Royal Irish Academy for the years 1841—42, and 1842-43. The Academy.
Sketch of the Civil Engineering of North America. By David Stevenson, The Author.
Civil Engineer.
A Treatise on the Application of Marine Surveying and Hydrometry to the Ditto.
Practice of Civil Engineering. By David Stevenson, Civil Engineer.
April 15.
The Electrical Magazine. Conducted by Mr Charles V. Walker. Vol. i., No. 2. The Editor.
Literarische Sympathien oder industrielle Buchmacherei : Ein Beitrag zur The Author.
Geschichte der neueren Englischen Lexicographic, von Dr J. G. Flugel.
Fifty-Fifth Annual Report of the Regents of the University of the State of Dr Christison.
New York.
Journal of the Asiatic Society of Bengal. Nos. 136, 137, 138, and 139. The Society.
Travels through the Alps of Savoy, and the other parts of the Pennine Chain, The Author.
with observations on the phenomena of Glaciers. By James D. Forbes,
F.R.SS.L. & E., &c. &c.
May 6.
Memoires presented par divers Savants a I1 Academic Royale des Sciences de The Royal
1'Institut de France. Tome viii. demy.
Memoires de la Societe de Physique et d'Histoire Naturelle de Ge'ne've. The Society.
Tome x., Part 1. &
Aca-
722
LIST OF DONATIONS.
DONATIONS.
Annales des Sciences Physiques et Naturelles d' Agriculture et d' Industrie de
Lyon. Tome v.
Bulletin de la Societe Geologique de France. (Deuxieme Serie.) Tome i.
Feuilles 8-10.
Memoirs of the Literary and Philosophical Society of Manchester. Vol. vii.
Part 1.
Journal of the Statistical Society of London. Vol. vii., Part 1.
Scheikundige Onderzoekingen, gedaan in het Lahoratorium der Utrechtsche
Hoogeschool. Deel ii. Stuk. 4.
Comptes Rendus Hebdomadaires des Seances de 1'Acaderaie des Sciences.
Tome xvii., Nos. 25 et 26 ; Tome xviii., Nos. 1—14.
DONORS.
The Royal Society
of Agriculture
at Lyons.
The Society.
Ditto.
Ditto.
The Editors.
The Academy.
INDEX TO YOL. XY.
A
Acephalocysts of Authors, on the development, structure, and economy of the, 561.
Address to HER MAJESTY on the Birth of the PRINCESS ROYAL, 680.
Address to HER MAJESTY on the Birth of the PRINCE OF WALES, 682.
Addresses of Congratulation to HER MAJESTY and PRINCE ALBERT, on the occasion of their expected
arrival in Scotland ; and also of electing PRINCE ALBERT an Honorary Fellow of the Society, 684.
ALISON (W. P., M.D.). On certain physiological inferences which may be drawn from the study
of the nerves of the eyeball, 67.
Amphioxus Lanceolatus, on the anatomy of, 247.
ANDERSON (THOMAS, M.D.). Analysis of caporcianite and phakolite, two new minerals of the Zeolite
family, 331.
Aqueous and Alcoholic Solutions, farther researches on the voltaic decomposition of, 151.
B
Barometer, description of a new self-registering, 503.
Bebeeru Tree of British Guiana, on the, 423.
BELL (Sir CHARLES). Biographical notice of the late, 397.
BENNETT (JOHN HUGHES, M.D.). On the parasitic vegetable structures found growing in living
animals, 277-
Berg-Meal, or Mineral Flour, examination and analysis of the, found in the parish of Degersfors, in
the province of West Bothnia, on the confines of Swedish Lapland, 145.
BKEWSTER (Sir DAVID). On the law of visible position in single and binocular vision, and on the re-
presentations of solid figures by the union of dissimilar plane pictures on the retina, 349. On
the optical phenomena, nature, and locality of muscat volitantes : with observations on the struc-
ture of the vitreous humour, and on the vision of objects placed within the eye, 377- On the
conversion of relief by inverted vision, 657. On the knowledge of distance by binocular vision, 663.
BROWN (JOHN CROMBIE, Esq.). Account of a repetition of Dr Samuel Brown's processes for the con-
version of carbon into silicon, 547.
BROWN (SAMUEL M., M.D.). On the preparation of paracyanogen in large quantities ; and on the iso-
merism of cyanogen and paracyanogen, 165. Experimental researches on the production of sili-
con from paracyanogen, 229.
BRTSON (ROBERT, Esq.). Description of a new self-registering barometer, 503.
c
Caporcianite, a new mineral of the Zeolite family, analysis of, 331.
Charcoal and Plumbago, on the property belonging to, in fine plates and particles, of transmitting
light, 335.
CHRISTISON (ROBERT, M.D.). On the action of water upon lead, 265.
CONNELL (ARTHUR, Esq.). Further researches on the voltaic decomposition of aqueous and alcoholic
VOL. XV. PART IV. 9 1
724 INDEX.
solutions, 151. On the presence of organic matter in the purest waters from terrestrial sources,
417. Chemical examination of the tagua-nut, or vegetable ivory, 541.
Cyanogen and Paracyanogen, on the isomerism of, 173.
D
DA VIES (THOMAS STEPHENS, A.M.). An analytical discussion of Dr Matthew Stewart's general theo-
rems, 573.
DAVY (JOHN, M.D.). On the quarantine classification of substances, with a view to the prevention of
plague, 307. On the property belonging to charcoal and plumbago, in fine plates and particles,
of transmitting light, 335. On the specific gravity of certain substances commonly considered
lighter than water, 387.
E
Earthquake Shocks, on the theory and construction of an instrument for measuring, 219.
Elephant, on the mode in which musket bullets, and other foreign bodies, become inclosed in the ivory
of the tusks of the, 93.
Entozoa, account of the natural analogies of the, 561.
Eye, observations on the structure of the vitreous humour, and on the vision of objects placed within
the eye, 377.
Eyeball, on certain physiological inferences which may be drawn from the study of the nerves of
the, 67.
F
Fishes Cartilaginous, on the existence of an osseous structure in the vertebral column of, 643.
FORBES (JAMES D., Esq.). Researches on heat ; fourth series, 1. On the effect of the mechanical
texture of screens on the immediate transmission of radiant heat, ibid. Account of some additional
experiments on terrestrial magnetism, made in different parts of Europe, in 1837, 27- On the
theory and construction of a seismometer, or instrument for measuring earthquake shocks, and
other concussions, 219. On the determination of heights by the boiling point of water, 409.
Fossil Fishes, notice of the, found in the old red sandstone formation of Orkney, particularly of an
undescribed species, Diplopterus Agassiz, 89.
G
Geological Account of Roxburghshire, 433.
GOODSIR (HARRY D. S., Esq.). On the development, structure, and economy of the acephalocysts of
authors ; with an account of the natural analogies of the entozoa in general, 561.
GOODSIR (JOHN, Esq.). On the mode in which musket bullets, and other foreign bodies, become in-
closed in the ivory of the tusks of the elephant, 93. On the anatomy of amphioxus lanceolatus,
247. On the ultimate secreting structure, and on the laws of its function, 295.
Grilse and Salmon, on the growth of, 343.
H
Heat, researches on; fourth series. By James D. Forbes, Esq., 1. On the effect of the mechanical
texture of screens on the immediate transmission of radiant heat, ibid.
Heights, on the determination of, by the boiling point of water, 409.
Human Society, on the supposed progress of, from savage to civilized life, as connected with the do-
mestication of animals, and the cultivation of the cerealia, 177.
I
Indian Grass Oil, notice concerning the, 639.
Italy, De Salariis in supracretaceis Italias stratis repertis, 211.
INDEX. 725
K
KELLAND (Rev. P.). On the plane and angle of polarization of light, reflected at the surface of a
crystal, 37. On the theory of waves ; Part II., 101. On the theoretical investigation of the
absolute intensity of interfering light, 315. On the vibrations of an interrupted medium, 511.
Lead, on the action of water upon, 265.
Light, on the plane and angle of polarization of light reflected at the surface of a crystal, 37- On the
theoretical investigation of the absolute intensity of interfering, 315. On the property belonging
to charcoal and plumbago of transmitting, 335.
M
MACLAGAN (DOUGLAS, M.D.). On the Bebeeru Tree of British Guiana, 423.
M'NEiLL (Sir JOHN). Biographical notice of the late Sir Charles Bell, K.H., 397.
Magnetism, account of some additional experiments on terrestrial, 27.
Medium, on the vibrations of an interrupted, 511.
MICHELOTTI (JOANNES.). De solariis in supracretaceis Italiae stratis repertis, 211.
MILNE (DAVID, Esq.). Geological account of Roxburghshire, 433. On a remarkable oscillation of the
sea, observed at various places on the coasts of Great Britain, in the first week of July 1843, 609.
MUSCOB Volitantes, on the optical phenomena, nature, and locality of, 377-
0
Oil of Andropogon Calamus-aromaticus, notice concerning the, 639.
Paracyanogen, on the preparation of, in large quantities, 165. On the isomerism of cyanogen and
paracyanogen, 173. On the preparation of silica from, 229.
Parasitic Vegetable Structures, on the, found growing in living animals, 277-
Phakolite, a new mineral of the zeolite family, analysis of, 331.
Plague, on the quarantine classification of substances, with a view to the prevention of, 307.
Q
Quarantine Classification of Substances, on the, with a view to the prevention of the plague, 307.
E
Retina, on the representation of solid figures by the union of dissimilar plane pictures on the, 349.
ROBISON (Sir JOHN.). Testimonial and thanks of the Society accorded to him in acknowledgment of
his long services as General Secretary, 680 and 681.
Roxburghshire, geological account of, 433.
s
Salmon, on the growth of, 343.
Sea, on a remarkable oscillation of the, observed at various places on the coasts of Great Britain, 609.
Sea-Trout, on the growth and migrations of the, of the Sol way, 369.
726 INDEX.
Secreting Structure, on the ultimate, and on the laws of its function, 295.
Seismometer, or instrument for measuring earthquake shocks, and other concussions, on the theory
and construction of a, 219.
SHAW (Mr JOHN.). On the growth and migrations of the sea-trout of the Solway (Salmo Trutta), 369.
Silicon, account of a repetition of Dr Samuel Brown's processes for the conversion of carbon into, 547.
Experimental researches on the production of, from paracyanogen, 229.
Society, Royal of Edinburgh, Proceedings of the extraordinary general meetings, and list of members
elected at the ordinary meetings, since November 1840, 677.
List of the present ordinary members in the order of this election, 692.
List of non-resident and foreign members, 699.
List of honorary members, 700.
List of members deceased, resigned, and cancelled, from 1840 to 1844, 702.
List of donations, continued from Vol. XIV., 703.
Specific Gravity of certain substances commonly considered lighter than water, 387.
STARK (JAMES, M.D.). On the existence of an osseous structure in the vertebral column of cartila-
ginous fishes, 643.
STARK (JoHN, Esq.). On the supposed progress of human society from savage to civilized life, as con-
nected with the domestication of animals, and the cultivation of the cerealia, 177.
T
Tagua Nut, or vegetable ivory, chemical examination of the, 541.
Terrestrial Magnetism, account of some additional experiments on, made in different parts of Europe
in 1837,27.
Theorems General, analytical discussion of Dr Matthew Stewart's, 573.
TILLEY (THOMAS GEORGE, Phil. D.). Notice concerning the Indian grass-oil, or oil of andropogon
calamus-aromaticus, 639.
TRAILL (T. S.,M.D.). Notice of the fossil fishes found in the old red-sandstone formation of Orkney,
particularly of an undescribed species, Diplopterus Agassiz, 89. Examination and analysis of
the berg-meal, or mineral flour, found in the parish of Degersfors, in the province of West
Bothnia, on the confines of Swedish Lapland, 145.
Vibrations, on the, of an interrupted medium, 511.
Vision, on the knowledge of distance by binocular, 663. On the law of visible position in single and
binocular, 349. On the conversion of relief by inverted, 657.
Voltaic Decomposition of Aqueous and Alcoholic Solutions, further researches on the, 151.
w
Water, on the action of, upon lead, 265. On the presence of organic matter in the purest waters from
terrestrial sources, 417-
Waves, on the theory of, 101.
WILSON (GEORGE, M.D.). Account of a repetition ofDr Samuel Brown's processes for the conversion
of carbon into silicon, 547-
Y
YOUNG (Mr ANDREW.). On the growth of grilse and salmon, 343.