PROCEEDINGS

AMERICAN ACADEMY

OK

ARTS AND SCIENCES.

NEAV SERIES.
Vol. III.

WHOLE SERIES.
Vol. XI.

FROM MAY, 1875, TO MAY, 1876.
SELECTED FROM THE RECORDS.

BOSTON:

PRESS OF JOHN WILSON AND SON.
1876.

\\

It- i'O

CONTENTS.

PAOB

I. Researches on the Hcxatomic Compounds of Cobalt. By

WOIXOTT GiBBS, M.D 1

II. On the Solar Motion in Space and the Stellar Distances.

By Tkuman Henry Safford 52

III. On the Veiled Solar Spots. By L. Trouvelot .... 62

IV. On Photographs of the Solar Spectrum. By Robert

Amory, M.D 70

V. Miscellaneous Botanical Contributions. By Asa Gray . 71
VI. Botanical Contributions. By Sereno Watson : —

1. On the Flora of Guadalupe Island 105

2. List of a Collection of Plants from Guadalupe

Island, made by Dr. Edivard Palmer, with his
Notes upon them 112

3. Descriptions of New Species of Plants, chiefly Cali-

fornian, with Revisions of certain Genera . . . 121

VII. Specimens of Milk from the Vicinity of Boston. By S. P.

Siiarples, S.B 119

Vm. On Portable Astronomical Instruments and their Use. By

Truman Henry Safford 157

IX. On some Physical Observations of the Planet Saturn By

L. Trouvelot 174

X. The Companions of Procyon.. By Rear-Admiral C. H.

Davis 185

XI. Notes on Magnetic Distribution. By Henry A. Rowland. 191

XII. On the Method of Least Squares. By Truman Henry

Safford 193

XIII. Brief Contributions from the Physical Laboratory of Har-

vard College. By John Trowbridge : —

4. On the Effect of Thin Plates of Iron used as Arma-

tures to Electro-Magnets 202

5. On the so-called Etheric Force 206

6. On a New Form of Mirror Galvanometer .... 208

XIV. On the Solar Motion and the Stellar Distances. By Tru-

man Henry Safford 210

IV • CONTENTS.

PAGE

XV. Contributions from the Physical Laboratory of Harvard
• College : —

8. On the Induction Spark produced in Breaking a

Galvanic Circuit betioeen the Poles of a Magnet.

By B. O. Peirce, Jr 218

XVI. Contributions from the Physical Laboratory of Harvard

College : —

9. Condensers and Geissler''s Tubes. By William P,

Wilson 228

XVII. On Viviparous Echini from the Kerguelen Islands. By

Alexander Agassiz 231

XVIII. On a Possible Explanation of the Method employed by
Nobert in Ruling his Test Plates. By William A.

Rogers 237

XIX. Mountain Surveying. By Prof. E. C. Pickering. . . 256

XX. Height and Velocity of Clouds. By Prof. E. C. Pick-
ering 263

XXI. Contributions from the Physical Laboratory of the Massa-
chusetts Institute of Technology : —

8. An ExperimeJital Proof of the Law of Inverse

Squares for Sound. By William W. Jacques 265

9. Diffraction of Sound. By William W. Jacques 269
10. ComparUton of Prismatic and Diffraction Spectra.

By Prof. E. C. Pickering 273

XXII. On Photographs of the Solar Spectrum. By Robert

Amory, M.D 279

XXIII. A New Form of Induction Apparatus. ■ By Henry P.

BOWDITCH 281

XXIV. Hydrographic Sketch of Lake Tilicaca. By Alexander

Agassiz 283

XXV. Contributions from the Physical Laboratory of Harvard
College : —

10. Distribution of Magnetism on Armatures. By Har-

old AViiiTiNG 293

XXVI. Contributions from the Physical Laboratory of Harvard
College : —
11. Change of Electrical Resistance in Wires by

Stretching. By George S. Pine 303

Proceedings 313

List of the Fellows and Foreign Honorary Members 375

Statutes and Standing Votes . . . . 383

Index 395

PROCEEDINGS

A M E 11 1 C A N ACADEMY

ARTS AND SCIENCES.

VOL. XI.
PAPERS READ BEFORE THE ACADEMY.

RESEARCHES ON THE HEXATOMIC COMPOUNDS OF

COBALT.

By Wolcott Gibbs, M.D.

Presented, June 8th, 1875.
{Continued from Vol. X. p. 38.)

Nitrates of Piirpureocohalt. — In our joint memoir, Genth and I
assigned the anhydrous nitrate, Co2(NH3)jQ(NO,)g, to the roseocobalt
series, upon the ground that with certain reagents it forms sahs iden-
tical with those which the hydrous nitrate, Co^(NH3)jy(N03)a-f--(^H^,
yields under the same circumstances. I am now satisfied that this
salt belongs in reality to the purpureocobalt series, partly because it
exhibits toward the hydrous nitrate relations precisely analogous to
those which exist between Co2(NH3)j„Clg and Co2(NH3)jQCIg-(-20Il2,
and partly because, while a few of its reactions correspond with
those of the hydrous salt, the greater number agree with those of the
jinhj'drous chloride. By dissolving the normal nitrate of purpureo-
cobalt in water containing amraonic nitrate in large quantity, with a
little free ammonia, Genth and I obtained a new salt in beautiful
violet-red talcose scales, readily decomposed by solution in water.
The formula of this salt is most probably

Co,(NH3),,.0.(N03),+60H„

as the following analyses appear to show : —

0-0675 gr. gave 0-0303 gr. SO^Co = 17-08% cobalt.
0-0729 gr. gave 0-0333 gr. SO.Co = 17-18% cobalt.
0-0769 gr. gave 0-0343 gr. SO,Co= 17-10% cobalt.

VOL. XI. (N. S. II.) 1

2 PROCEEDINGS OF THE AMERICAN ACADEMY

0-5480 gr. gave 161-75 c.c. nitrogen (moist) at IC^-S C and 755-4"""

(Ii = 118-8"^) = 29-82%.
0-5171 gr. gave 0-2955 gr. waters 6-36% hydrogen.
0-4590 gr. gave 0-2G99 gr. water = C-54f;^ hydrogen.

Calculated. Found.

Cobalt, 2 17-87 17-08 17-18 17-16

Nitrogen, 14 29-69 29-82

Hydrogen, 42 636 6-36 6-54

Oxygen, 19 46-06 — —

The analyses are those made with tlie salt originally prepared by
Genth and myself, as I have not succeeded in obtaining it a second
time. Tlie deficiency in the cobalt is pei'haps to be attributed to the
small quantity of salt at my disposal for analysis. Admitting the cor-
rectness of the formula, the scaly nitrate belongs to the basic series of
purpureo-salts, of which the chruraate already described, Coo(NH3),q.O.
(CrO^).,, furnishes an example. Its structural formula will then be, as
compared with that of the normal nitrate : —

Co,

f NH,— NO,
NRJ— NH,— NO
NH„— NIL
NH.;— Nil'

Nil,— NO.
NH.,— NH,— NO,

^ P, n NH.,— NH,— NO,

>o c«2 ^ nh;-nh!-no3

NH,— Nil,— NO3 NH,— NH.,— NO3

N H,— NO,, [ N H,— NO3

The formation of the basic nitra'e may be expressed by the equation : —

Co,(NH3),„(N03)„+2NH,+OH, = Co,(NH3),„.0.(N03),+
2NH,.N03.

The readiness with which it is decomposed by water renders it impossi-
ble to determine the reactions of the salt ; but, as I find that chloi'ide of
purpureocobalt is formed with evolution of chlorine when it is boiled with
clilorhydric acid, we have at least some positive evidence in favor of
tlie view which I have taken. The marked effervescence which oc-
curs on boiling the nitrate with clilorhydric acid is precisely similar in
chanicter to tliat which takes ])lace when ainmonic nitrate is heated
with the same acid. Tlie normal nitrate of iuir|)urc()coI)alt i'uriiishes
by far the most convenient method of passing from the pur|)ureo-serie3
to the ro-eo-series. It is only necessary to dissolve the salt in a solu-
tion of ammonia, and then to allow this solution to flow slowl}' into
moderately strong nitric acid, surrounded with ice or snow so as to
prt-vent any sensible rise of temperature. The nitrate of roseocobalt
separates iininrdiately as a red crystalline precipitate, nearly insoluble

OF ARTS AND SCIENCES. 3

in tlic excess of nitric acid. From tliis salt many otliei: salts of tiie
roseo-series may be prepared with facility.

Chloro-mtrate of Purpnreocobalt. — Acid sulphate of roseocobalt
not free from chloride of jiurpureocobalt was treated in the cold with
a solution of potassic nitrite and nitrate. After standing some days a
red mother licpior was formed, together with a mixture of a red crystal-
line salt, and a bright yellow powder. On filtering and washing with
hot water, a fine violet liquid was obtained, which, on standing, gav«
very well-defined large* octahedral crystals of a deep cherry-red color.
The crystals were easily soluble in hot water, and contained only a
trace of sulfihuric acid. Qualitative analysis showed the presence of
chlorine, nitric teroxide, cobalt, and ammonia. The salt gave the
reactions of nitrate or chloride of purpureocobalt with more or less
distinctness. Of this salt,

0*4olo gr. gave 0-1516 gr. silver = 8-30 (y^ chlorine.
0-4000 gr. gave 0-1332 gr. silver = 8-23% chlorine.
0-4809 gr. gave 0-2397 gr. SO,Co= 18-98% cobalt.
0-4448 gr. gave 0-2228 gr. SO.Co — 19-07% cobalt.
1-0770 gr. gave 0-4GoO gr. water = 4-79% hydrogen.

The formula Co,(NIL),oCl3(N03)3+Co2(NH3)ij,(N03)« requires

Cobalt, 4

Chlorine, 3
Hydrogen, GO

I can assign no plausible explanation of the formation of the chloro-
nitrate under the circumstances, and did not succeed in obtaining the
salt by mixing the chloride and nitrate of purpureocobalt in the proper
proportions, and allowing the mixed solutions to stand. The crystals
formed always consisted principally of the chloride, I was not more
successful in the attempt to form a chloro-nitrate with the formula,
Co2(NH3)j(,(N03)3Cl3, by mixing solutions of the chloi'ide and nitrate,
the chloride crystallizing from the mixtui'e unchanged. I remark,
however, that as the acid sulphate employed contained chlorine, prob-
ably as undecomposed chloride of purpureocobalt, and as the potassic
nitrite contained also nitrate, the reaction must have been between the
chloride and nitrate. Two chloro-nitrates of roseocobalt have been
observed by Krok, in combinatioD with mercuric and platinic chlorides,
the salts having respectively the formulas Co2(NIIg)jy(N03)3Cl3-|-
3IIgCl, and Co,(Nll3),,(N03),Cl,+2PtCl,.

Calculated.

Found.

19-28

18-98 19-07

8-55

8-30 8-23

4-80

4-79

4 PROCEEDINGS OF THE AMERICAN ACADEMY

Timgstate.. — When chloride of purpureocobalt is boiled with sodic
tunc^tate, WO^Na.,, it is quickly converted into a violet granular
crystalline mass, which, after washing with cold water, is perfectly free
from chlorine. When dried in vacuo over sulphuric acid, the crystals
have a fine deep violet color. The salt is but slightly soluble in either
cold or boiling water, even in presence of free nitric acid. It dissolves
readily in a solution of sodic or ammonic carbonate; the solutions have
a iine violet color. Of this salt,

1-0294 gr. gave 0-o418 gr. WO3 (by mercurous nitrate) = 5G'26%

WO,.
2-3912 gr. gave 1-71G3 gr. WO.Co (by careful ignition) = 75-9G%.

The formula Co,(NIl3)i„.0.(WOJ2 requires 55-ll%^VO, and 7G-7o%
WO.Co.

The salt cannot be recrystallized, and was therefore probably not
absolutely pure.

Oxalo-chloride. — W^hen a solution of ammonic oxalate is added to
one of chloride of purpureocobalt, violet needles are soon deposited,
which Genth and I considered as the normal oxalate of this series, and
to which we gave the formula, as we should now write it : —

Co,(NH3),o.O.(CA).2+30II,.

Two determinations of cobalt and one of oxalic acid agreed very
closely with this formula. Krok * subsequently discovered that this salt
contains chlorine, and he assigns to it the formula : —

Co,(NiL),,a(CA)..

On carefully re-examining this salt, I find that the percentage of
chlorine varies considerably in different preparations. Thus : —

J 0-7108 gr. gave 0-2512 gr. silver = 11-G1% chlorine.
(0-3G27 gr. gave 0-218G gr. SO, Co = 22-95% cobalt.
( 0-5093 gr. gave 0-2930 gr. SO, Co = 21-9(1% cobalt.
I 0-57G8 gr. gave 0-22-41 gr. silver == 12-78% chlorine.

It is therefore probable that the chloro-oxalate contains as an admix-
ture a greater or less percentage of another oxalate, possibly COjj(NII.j)jp.
0.(C^,0,)2. I did nut succeed in obtaining this salt from nitrate of
purpureocobalt and ammonic oxalate, the reaction residting only in

* Acta Univ. Lund. 1840. I believe that this is the only error which has
boon detected in the first part of this paper.

OF AUTS; AND SCIENCES. 5

the formation of oxalate of roseocobalt, — a result possibly <lue to the
preseuce of a little free ammonia. The cliloro-oxalate does not appear
to unite with metallic chlorides. Jt reduces i^old from ain'o-chloride
of sodium, AuC'l^Na, while with i)latinic chloride it forms only the
ordinary chlorplatiuate, Co2(NI-Ij)i(,Cly-[-21't^'4» J"-'"! with mercuric
, chloride the anhydrous 0-atom salt, Co.,(NIl3),„Clg-|-GIIgC'l^,. In this
respect it ditlers remarkal)ly from the oxalate of roseocobalt, which, as
I shall show, forms a well-detined salt with platinic chloride. The
chloro-oxalate dissolves readily in a hot solution of oxalic acid, and
crystallizes in violet needles which contain chlorine, and which appear
to be an acid chloro-oxalate.

Neutral Sulphate. — Schiff has described a violet-colored very
slightly soluble sulphate which he obtained, together with sulphate
of luteooobalt, by the action-of an alcoholic solution of ammonia upon
Fremy's sulphate of fusco-cobalt. To this salt SchilF gives a formula
corresponding with

Co,(NH3),„.0.(SO,),+30H,.

This would be the basic sulphate corresponding to the chromate which
I have described, and which has the formula Co2(NH.j),|,.0.(CrO^)2.
By the action of baric chloride upon this sulphate, Schiff" obtained, as
he asserts, a new chloriile with the formula : —

Co,(NH3),o.O.Cl,+30H„

which he regards as the true chloride of the purpureocobalt series.
From what I have already said, the existence of such a basic sulphate
and chloride may be regarded as not merely possible but probable.
On the other hand, Braun, on repeating SchifF's experiments, obtained
wholly different results. The action of ammonia upon salts of fusco-
cobalt yielded him only the ordinary salts of purpureocobalt, together
with salts of luteocobalt. Further researches are therefore needed to
establish the existence of Schitf's salts. lu a single experiment I
obtained a small quantity of a salt which appears to be the neutral
sulphate of purpureocobalt. A mixture of cobaltic sulphate with
excess of ammonia water was allowed to stand some weeks with fre-
quent agitation. The deep-red solution was filtered and precipitated
by alcohol. The heavy red liquid thrown down became solid after a
time. Cold water dissolved the larger portion of this mass, but left a
beautiful violet crystalline powder, which was washed on a filter till
the washings had a fine clear violet tint, and dried in vacuo over
SO^IIg for some days. Of this salt,

b PROCEEDINGS OF THE AMERICAN ACADEMY

0-4302 gr. gave 0-2332 gr. SO,Co = 20-21% cobalt.
0-7!)o2 gr. gave 0.9208 gr. SO,Ba= 47-71% SO,.

These analyses lead to the formula : —

Co,(NH3),,(SOj,+OR,.

Calculated.

Found.

Cobalt,

2

20-27

20-21

SO.,

3

47-42

47-71

The results of the analyses agree well with the formula given ; but it
is possible that the salt, which was not recrystallized, contained some
small impurity, and that it is really anhydrous, like the normal chloride
and sulphate. The sulphate is but slightly soluble in cold water, but
di>solves rather easily in hot water, forming a beautiful violet solution.
Auro-chloride of sodium gives a beautiful crystalline orange-red pre-
cipitate with a solution of the sulphate, differing apparently from the
corresponding salt of roseocobalt. In this salt,

0-2698 gr. gave 0-0924 gr. gold = 34-24%.

This percentage of gold corresponds very closely to that required by
the formula, Co,(NH3),o(SO,),Cl.,+2AuCl,, which is 34-02. The
sulphato-chloro-aurate of roseocobalt has, as I shall show, the formula
Co,(NH3),o(SO,)2Cl,+2AuCl34-40R„ the purpureo-salt showing, as
usual, a less disposition to unite with water of crystallization. The
above results were obtained with only three grammes of material ; but
they are sufficient, I think, to make it at least probable that the violet
salt in question is the true sulphate of purpureocobalt.

Pyrophosphate. — Sodic pyrophosphate gives a lilac or rose colored
precipitate with a solution of chloride or nitrate of purpureocobalt,
readily soluble in an excess of the precipitant, and crystallizing froni
the solution in beautiful rose-red efflorescent crysfcdline scales. The
salt is readily soluble in ammonia, and the solution yields beautifid
garnet-red measurable crystals, which are free from sodium. The jiyro-
phosphate was first carefully stuvlied and analyzed by C. D. Braun,
whose analyses agree closely with a formula which he writes,

5NIl3.Co,03-2PO,+21 HO

(old style). This formula must now be written

Co,(NIl3).„(PA3)4-2lOII,

in the inw notation, P^O^g, being hexatomic. In' the t^alt crystallized
from aiimionia : —

OF ARTS AND SCIENCES. 7

1-2456 gr. gave 0-5387 gr. Coj',0|^, by ignition = IS^l^ and

5G'7G(fo water, ammonia, and oxygen.
1 4484 gr. gave 0-9415 gr. water (burnt with CuO) = 7.2-2% liy'gen.
1'09G4 gr. gave 0-3'.)ll gr. water = 35-67% water of crystallization.

The formuhi Co,(NII,),oP,0,,+-2lOII, reiiuires 43-48 %Co,P,0,2,
and 56-529^ water, ammonia, and oxygen ; also 7*21% hydrogen, and
37'87<^ water of crystallization. These analyses fully confirm
Braun's results. The formation of the salt from sodic pyrophosphate
and chloride of purpureocobalt may be represented by the equation: —

Co,(NII,),,Cl,+2PA-Na,+0ir, = Co,(NIl3),„PA3+6NaCl+

20NaII.

The mother liquor from which the pyrophosphate has crystallized has
a strong alkaline reaction. The decomposition of the salt by heat
may be expressed by the equation : —

Co,(NIl3),„.P,0,3 = Co,P,O,,+O-[-10NH3,

though it is of course most probable that a part of the ammonia is
oxidized to water and nitrogen.

The pyi'ophosphate of purpureocobalt furnishes, if the formula given
be adopted, an instance of a true di-pyrophosphate bearing the same
relation to the ordinary salts of the acid which the disulphates, dichro-
mates, &c., bear to the normal sulphates and chromates. In other
words, two molecules of PgO-H^, or P20g.(01I)4 are fused together, so
as to form a single molecule of P^Oj.^H^, or P^O.(OH)g, an atom of
water being given off. Thus'we have in symbols : —

2.PA.(0H), = PA-(OH),+OH,.

The structure of dipyrophosphoric acid m-ay be briefly represented by
the expression : —

3(0H) ~ (PA)_0-(P,0,) Z (Oil),.

The corresponding salt of luteocobalt presents a similar instance.
According to Braun, the whole of the water of cryst;dlization is given
off at 100°C. ; but I found that one atom was retained at that tempera-
ture, the loss in my analysis being 35.67°, while the formula for 20
atoms requires 36.07%.

Ammonia-cobalt-nitrite. — A solution of the potassium salt of Erd-
mann's series, Co2(NH3)^(NO^,)gK^, gives with nitrate of purpureo-
cobalt a beautiful very dark orange-red precipitate in crystals, which
are sometimes acicular, and sometimes granular. The crystals are not

8 PROCEEDINGS OF THE AMERICAN ACADEMY

very soluble in cold, but dissolve quite easily in hot water. The solu-
tion gives the characteristic reaction with argentic nitrate. Of this
salt : —

0-4583 gr. gave 0-2466 gr. SO^Co = 24-11 <;^ cobalt.

The formula ^Co2(XH8),„^ |Co2(NH3),(N02)8}3 requires 24-20%.

The solution of this salt does not give the reactions of xanthocobalt at
first, but after some days ammonic oxalate throws down the character-
istic wine-yellow oxalate. The solution is decomposed by long
standing, large crystals of cobaltic nitrate, Co(NO.,)o, being formed
together with crystalline scales of the corresponding salt of xantho-
cobalt already described.

Cohalto-nitrite. — The sodium salt of Fischer's series,
Co,(X'0,),,Na„
is soluble at the instant of formation in an excess of sodic nitrite.
Alcohol precipitates, after a time, some of the yellow insoluble
sodic salt, and gives a very deep orange-red sokition, from which the
alcohol may be expelled by evaporation. Tliis solution gives with
one of nitrate of purpureocobalt, after a short time, fine deep orange-
red to ruby-red octahedral crystals, which are very slightly soluble
in water even on boiling. This salt gave by digestion with a solu-
tion of thallous nitrate the characteristic scarlet crystalline salt,
Co^(N02)i2Tly, which I shall describe further on. On analysis : —

0-5598 gr. gave 0-3290 gr. SO.Co = 22.38% cobalt.
0-7324 gr. gave 188.5 c.c. nitrogen (moist) at 6°C and 773-4'"'" =
31-87% nitrogen.

The ratio is here exactly that of one atom of cobalt to six atoms of
nitrogen ; and the analyses lead to the formula : —

|Co,(NH,),,(NO,),f3 \ CX(NO,),, l,+90H,,

which requires 22-33% cobalt, and 31-79% nitrogen. The constitu-
tion of the salt is fully established by these analyses, and by the reac-
tion with the thallium salt given above, since we have : —

lCo,(NH3),„(NO,),^ 3 |Co,(NO,)„j,+12TlN03 = 3.Co,(NH3),,
(NO,),(NO,),-i-2.Co,(NO,),2Tl,.

The compound therefore belongs in reality to the xanthocobalt series ;
it gives the reactions of the ordinary salts of that series distinctly.
The formation of this remarkable salt may very pVobably be expressed
by the equation : —

OF ARTS AND SCIENCES. 9

3.Co,(NH3),o(NO,)«+3Co,(NO,)„Na„=|Co,(NIl3)„.(NO,).j3
|Co,(NO,)i.J,+18NaN08+2Co(NO,)2+2NO,.

I .shall allude to its composition again, when speaking of the metameric
compoiiiuls of the cohaltaniines.

The salt described is not the only one which is formed by the action
of a solution of Co^(NO^),2Nag on nitrate of purpureocobalt. In sev-
eral experiments I obtained an orange-red gi'anular salt readily soluble
in cold water. The solution of this salt gave with nitrate of luteo-
cobalt a beautiful crystalline precipitate of

|Co,(NH3X,nCo,(NO,),J.

With thallous nitrate it gave the characteristic scarlet salt Co.,(NO^)|2
Tly. On the other hand, it gave all the reactions of the salts of
xanthocobalt with great distinctness, including the highly characteris-
tic crystalline ferrocyanide. This salt could in no way be distinguished
from one obtained by the action of Co2(NO^),2Nay upon sulphate of
roseocobalt which, as I shall show, has the formula • —

lCo2(NH3),„nC02(N02),J or Co,{^R,),,(^0,),-{-Co,(m,),.

In acting upon solutions of purpureocobalt with solutions of cobalto-
nitrite of sodium in excess of sodic nitrite, it often happens that
neither of the salts above described is obtained in appreciable quantity,
but only nitrate of xanthocobalt and cobaltic salts formed by a total
reduction of the cobaltamines. It is therefore important to avoid an
excess of sodic nitrite as much as possible.

Chloro-JlaosiUcate. — When a hot solution of chloride of purpureo-
cobalt containing a few drops of free chlorhydric acid is poured into a
hot solution of fluosilicate of zinc, no precipitate is produced at first,
but after a time a beautiful violet-red crystalline salt separates. This
salt is very slightly soluble in cold water, but dissolves with a violet
tint in a large quantity of boiling water ; it is readily soluble in a hot
solution of sodic carbonate. It is decomposed very quietly by heat,
giving off white condensible vapors, and leaving a dull violet residue.
Of this salt : —

0-6379 gr. gave 0-2861 gr. SO.Co = \l-\0% cobalt.
0-8221 gr. gave 0-2479 gr. silver =z 9-91% chlorine.

The formula Co2(NH3)io(SiF6),Cl,,4-30H2 requires 16-93% cobalt,
and 10-18% chlorine.

The determination of the chlorine was made by dissolving the salt in
sodic carbonate, adding an excess of argentic nitrate, and afterwaid a

10 PROCEEDINGS OF THE AMERICAN ACADEMY

small excess of nitric acid. The cbloro-fluosilicate appears to combine
with auric and platinic chlorides to form crystalline salts containing
silicic fluoride, titrate of purpureocobalt gives with a solution of
fluosilicic acid, SiF^Hj, a beautiful violet-red granular crystalline pre-
cipitate, but slightly soluble in cold w^ater. I have not examined this
salt; it is probably the normal fluosilicate Co2(NH3)j^,(SiP',;)..,.

It occurred to rae that the fluorine compounds of the cobaltamines
mi"ht offer means of separating certain metallic elements which have
hitherto proved intractable by ordinary methods. The numerous ex-
periments made with this end in view have not, however, led to really
valuable results. I shall therefore content myself by briefly describ-
ing in this place a few reactions which will serve as starting-points to
those who may be disposed to enter upon this field of investigation.

Nitrate of croceocobalt gives a fine granular crystalline f-alt with
fluosilicic acid, and a beautiful salt in large granular crystals with
potassic fluo-titanate, TiF,.K,. Both salts are soluble in much hot
water, the solutions yielding large and perhajis measurable crystals.

Nitrate of xanthocobalt gives very fine granular crystalline salts
with fluosilicic acid and potassic fluotitanate. Both salts may be
dissolved in a large quantity of hot water, and recrystallized without
deC'imposition.

Sulphate of roseocobalt gave no precipitate with fluosilicic acid or
potassic fluosilicate even after long standing ; but a solution of the
iodo-sulphate of roseocobalt, Co^(NH3)]„(SO^)^l2, gave with fluosilicic
acid a dull violet-red crystalline precipitate very slightly soluble in
water.

Nitrate of luteocobalt gives beautiful granular orange-yellow crys-
talline precipitates with fluosilicic acid and solution of potassic fluo-
titanate. The fluotitanate is somewhat lighter in coloi- than tiie
fluosilicate. Both salts are almost insoluble even in boiling water.
Krok * observed that iodo-sulphate of luteocobalt gives a very in-
soluble crystalline precipitate with fluosilicic acid. I Had tiiat this
salt contains iodine, and it will probably pi-ove to have the formula
Co2(NII,,),2(SiF^)2T2. Iodide of luteocobalt gives a beautiful orange
crystalline precipitate with potassic fluozirconate, which rt'ijuires a
large quantity of boiling water for solution, and may be reci-ystallized
without dcconqxisition. Iodide of luteocobalt gives also crystalbne
very slightly soluble precipitates with potassic fluotantalate, fluo-
niobate, and oxyfluoniobate, not differing from each other, so fiir as I

* Acta Universit. Lund. 1870.

OP ARTS AND SCIENCES.

U

have been able to detorniine, sufficiently to be made available in analy-
sis, and probably isoiubrplious. Nitrate of luteocobalt gives line orange
crystalline, sliglitly soluble precipitates with potassic oxyfluotungstate,
oxylluoniolybdate, and tluoborate.

For convenience of reference I give here a list of the salts which, iu
my judgment, belong to the purpureocobalt series, and which have
been more or less completely described.

ChloVide,

Bromide (Claudet),

Iodide (Claudet),

Sulphate,

Nitrate,

Chloro-nitrate,

Chloro-oxalate,
Pyrophosphate (Braun),
Chromate (Braun),
Dichromate,
Amraonia-cobalt-nitrite,
Cobalto-nitrite,

Chloro-fluosilicate,
Platino-chloride,
Auro-chloride,
Antimonio-chloride,
Hydrargo-chloride «,
Hydrargo-chloride p',

NORMAL SKRIES.

Co,(NIl3)„Cle
Co,(NII,),„Br„

c<>,(Nn3),or,;

Co,(XIl3)„(SO;;,+OII,
Co,(NII,),,(NO,)«
Co,(NII,)„Cl,(NO,),+Co,(NIT3)j„
(N03)«

Co.,(NI-I,),oPp,,+2lOH2

Co,(NH,),„(CrOj3
Co,(NH3),,(Cr,0,)3+OH,
lCo,(NH,),,nCo,(NH,).(NO,)j3
^Co,(NH3),„(NO,),UlCo,(NO,),J,

H-90H.,
Co,(NH3),„(8iF,),a
Co,(NH3),,Cl,+2PtCl,
Co,(NII,),,Cl,+2AuCl3
Co.,(NIl3)ioCl„+SbCl3
Co;(NH3),„Cl„4-4HgCl,
Co,(NH3),,Cl,+6HgCI,

BASIC SERIES.

Chromate, Co,(NH3),„.0.(CrO,),+60H2

Hyposulphate (Rammelsberg), Co,(NH3)j,j.O.(S,Oj2
Nitrate, Co2(NH,) ,,.0. ( Nb8)^+60 H^

Chloride? (Schiff), Co2(NH,)io-O.Cl,

Sulphate? (Schiff), Co,"(NH,)„.0.(SO,)2

Tungstate, Co,(NH3)i,.0.(WOJ2

12 PROCEEDINGS OF THE AMERICAN ACADEMY

ROSEOCOBALT.

Sulphates of Roseocohalt. — In our joint memoir Genth and I have
stated that when a mixture of cobaltic sulphate and ammonia is ex-
posed to the air for some time three different salts are sometimes
formed, one of which is readily soluble in water, giving characteristic
reactions different from those of the normal sul})hate, while a second
salt dissolves in warm water, and gives orange-red crystals. 1 propose
now to give the results of my further study of these salts.

Soluble Sulphate of Roseocohalt. — Since the jjublication of the
memoir above mentioned, this salt has been studied by Braun, who
appears not to have been aware of its previous discovery by Genth
and myself. Braun prepared it by adding sulphuric acid to an oxi-
dized solution of ammonia and cobaltic sulphate and precipitating the
solution with alcohol. In this manner he obtained a rose-red crystal-
line powder, which on analysis gave the formula of the ordinary sul-
phate, first correctly analyzed by Genth and myself, Co2(NH3),p
(S0J.j-}-<''0H2, but which was readily soluble in water, with a cherry-
red color. My more recent investigations fully confirm Braun's
results as regai-ds the solubilitj' of this salt, which I have, however,
obtained by simply washing the oxidized dry mass of sulphates with
cold water in repeated small quantities. To fully estiiblish the differ-
ence between this salt and the ordinary sulphate, I determined the
solubility of the last-named quantitatively. Of the ordinary sulphate,
11-6205 gr. of a neutral solution saturated at 27*^0 gave on evapora-
tion 0-1967 gr. of the crystalline sulphate = 1-699^.

The soluble sulphate recpiires between one and two parts of cold
water for solution, as nearly as I could judge, my salt containing small
portions of animonic and cobaltic sulphates. The reactions of the solu-
ble sulphate differ so slightly from those of the ordinary sulphate, that
I do not regard the statement made by Genth and myself as fully
confirmed by further experience, and believe that the sail with whirh
our experiments were made contained small portions of the yellow
sulphate presently to be described. On the other hand, the derivatives
of the soluble sulphate appeared in many cases to be more soluble
than the corresponding salts prepared from the ordinary sulphate.

Want of material and of proper fiicilities for work have prevented
me from examining the subject with the requisite care and tliorough-
ness. In what follows, however, I have in each Case specified which
of the two red sulphates was employed.

OP ARTS AND SCIENCES. 13

Iodo-siilj>/i(ite of Baseocobalt. — Wlien a solution of pottissic iodide
is added to one of the soluble sulphate of roseocobalt a beautiful cin-
nabar-red crystalline salt is thrown down, which may be dissolved
without much ditliculty in hot water, and crystallizes from the solution
in granular crystals of an intense orange-red color. This salt has
essentially the formula Co.^(NH8)i„(SOJJ._,-|-20IL, which is that of
the iodo-suli)hate described by Krok, and obtained by the action of
iodine upon a boiling solution of ammonia and cobaltic sulphate.
Krok's analyses agree fairly well with the requirements of the formula.
I found, however, that the salt precipitated as above varied in different
preparations not inconsiderabl}'. I prepared the salt also from the
onliuary sulj)hate of roseocobalt for the sake of comparison, but could
detect no really essential difference between the two. The following
are the results of my analyses : —

Of the iodo-sulphate from the ordinary red sulphate of roseocobalt : — •

I. 0-6300 gr. gave 0-2073 gr. SO.Co = lG-15% cobalt.
0-4284 gr. gave 0-1170 gr. silver = 32-12% iodine.
0-5689 gr. gave 0-3516 gr. SO,Ba= 25-46% So,.

Of the iodo-sulphate from the soluble sulphate : —

JI. 0-4045 gr. gave 0-1776 gr. SO,Co = 16-72% cobalt.
0-4045 gr. gave 0-1763 gr. SO,Co = 16-60% cobalt.
0-4647 gr. gave 0-1096 gr. silver =: 27-76% iodine.
0-4935 gr. gave 0-3027 gr. SO,Ba:= 25-27% SO,.
III. 0-3579 gr. gave 0-1442 gr. SO, Co = 15-33% cobalt.
0-7586 gr. gave 0-3816 gr. silver = 27-18% iodine.
0-7099 gr. gave 0-4308 gr. So,Ba = 25-32% SO,.

The formula Co,(NH,),o(SO,),l,+20H, reqmres: —

Calculated. i. ii. ui.

Cobalt, 15-33 16-15 10-66 (mean) 15-33

Iodine, 32-99 32-12 27-76 27-18

SO,, 24-93 25-46 25-27 25-32

These analyses show at least that the reaction between potassic iodide
and the soluble sulphate is less definite than in the case of the iodide
and the ordinary sulphate. Krok states that he did not obtain sul-
phate of xautliocobalt by the action of argentic nitrite u])on iodo-
sulphate of roseocobalt, but only a rose-red solution, giving off nitrous
acid with the stronger acids. I found, however, that the iodo-sul|)hate
obtained from the soluble sulphate of roseocobalt, when digested with

1-4 PROCEEDINGS OF THE AMERICAN ACADEMY

argentic nitrite and a little free acetic acid, gave argentic iodide and
a clear sherry-wine-colored filtrate giving with amnionic oxalate a
salt which 1 cuuld not distinguish from the ordinary oxalate of xantho-
cobalt. Treated with nitric acid this oxalate gave an octahedral
nitrate showing all the reactions of nitrate of xanthocobalU The rose-
red solution which Krok obtained as above, may prove to contain a
red moditifation of xanthocobalt, and deserves further study.

Acid Sulphate. — The acid sulphate described by Genth and my-
self, and to which we gave the formula (old style) oNH3.C02O3.4SO3
-|-5H0, may be formulated in various ways. We may regard it as a
basic disulphate with the formula,

Co,(NtL),,.0.(S,0,),+50H2-
It is difficult to see how such a basic salt could be formed in a solution,
and in presence of an excess of free sulphuric acid. The fact that the
salt does not exhibit a strong acid taste and reaction does not in itself
furnish a very strong argument. Schultz-Sellack has shown that
disulphates of the type SgO-R, are formed by dissolving normal sul-
phates in warm fuming sulphuric acid; but it has not been sh^wn in
any case that a normal sulphate by digestion with sulphuric acid can
form a pyrosulphate, — an atom of water being given off. It seems,
therefore, more probable that the acid sulphate has the formula,

Co,(NH3),,(SO,)3+SO,H,+40H, ;

but it is worthy of notice that the salt is not formed when normal sul-
phate of roseocobalt is boiled with dilute sulphuric acid. In this case
the normal sulphate crystallizes without change. The type of the acid
sulphate of roseocobalt is the same as that of the acid carbonate of
luteocobalt described by Genth and myself: —

and with that of the acid oxalo-bisulphate, which in my view has the

formula,

Co,(NIl3),o(CA)(SO,),+C,HA+20H,.

On the other hand, the acid oxalate of roseocobalt, which I shall de-
scribe, has the formula,

Co,(NH3).,(aO,)3+4CJi,0„

the type not being that of the ordinary double oxalates containing a
hexatomic metallic element.

Yellow Sulphate of Roseorohalt. — A small quantity of crude sul-
])hate of roseocol)alt, which had stood for some j'ears in my laboratory.

OF ARTS AND SCIENCES. lO

presented orange-red crusts of indistinct octuliedraJ crystals. These
were rubbed to powder, washed with a little cold water, and dissolved
in hot water with a little free sulphuric acid. Fine yellow crystals
separated, which could not be distinguished in appearance from sid-
phate of luteocobalt, but appeared to be less soluble in water. Of
these crystals, —

0-5018 gr. gave 0-2341 gr. SO.Co = 17-76^ cobalt.

0-7GU gr. gave 0-7992 gr. SO, Ba = 43-25% So,.

1-1G18 gr. gave 213 c.c. nitrogen at 13'^C and 7G()-47""" =21-G2%.

The formula Co,(NH.,),„(SO,),,4-50II,, which is also that of the
ordinary and of the soluble modification of sulphate of roseocobalt,
requires : —

Calculated.

Found.

Cobalt,

17-71

17-76

SO,,

43-24

43-25

Nitrogen,

21-02

21-G2

The formula Co,(NII,)„(S0,),-|-50IT, — sulphate of luteocobalt —
requires IG.85% cobalt, 41-14%SO,, and 24-00% nitrogen. The
analyses show clearly that the salt was not sulphate of luteoco-
balt. The solution of the new sulphate gave beautiful yellow or
orange-yellow crystalline precipitates with various I'eagents closely
resembling in color the corresponding salts of luteocobalt. Thus with
potassic bromide it gave a buff yellow, and with potassic iodide a fine
orange-yellow crystalline precipitate. With the platino-chloride and
auro-chloride of sodium it gave beautiful yellow salts, the analyses of
which will be given in connection with those of the ordinary salts
of roseocobalt. By double decomposition with baric nitrate the yellow
sulphate gave a fine yellow solution, which on standing yielded crystals
of the nitrate of this series readily soluble in hot water. In these
crystals, —

0 2517 gr. gave 0-1092 gr. SO,Co = 16-50% cobalt.

This percentage of cobalt would indicate the formula Co2(NH,),q
(NOg)j-|-30H2, which requires 16-52%. Nitrate of luteocobalt con-
tains 17-00% cobalt.

The sulphate gave also with baric chloride a fine yellow solution
and baric sulphate. The solution of the chloride gave beautiful yellow
salts, with the chlorides of gold and of platinum. Unlike the ordinary
and soluble modifications of chloride of roseocobalt, it did not give
chloride of purpureocobalt by boiling with chlorhydric acid. The yel-

16 PROCEEDINGS OF THE AMERICAN ACADEMY

low nitrate gave a beautiful orange-yellow crystalline precipitate with
excess of potassic iodide.
Of the yellow chloride, —

0-4187 gr. gave 0-2430 gr. 80^ Co = 22-09% cobalt.

The formula Co2(NH3)joCl6+20H2, which is that of the oudinary red
modification, requires 2\-^l ^fo cobalt.

The results above mentioned, together with the analyses of the gold
and platinum salts to be described, are confessedly incomplete, but are
all which I could obtain with the very small amount of material — less
than five grammes of the sulphate — at my disposal. I regard them
as rendering it extremely probable that there is an extensive series of
yellow salts isomeric with the ordinary salts of roseocobalt, but differ-
ing from them in color, solubility, and perhaps other particulars. It
seems not impossible that the so-called xanthocobalt salts belong to
this series, as I find that when the beautiful scarlet crystalline iodo-
sulphate of roseocobalt is treated with argentic nitrite, a cherry-red
solution is obtained, which must contain a salt having the formula,
Co.,(NHo)jq(N02)2(SO^)2, since we have the reaction expressed by the
equation
Co,(NH3),„(SOJ J,-h2AgN0, = Co,(NH3),„(NO,),(SO,),+2AgI,

and since the red solution on boiling with a few drops of acetic acid
readily passes into the ordinary sulphate of xanthocobalt.

The salts of the yellow modification of roseocobalt at present more
or less perfectly analyzed and described are as follows : —

Chloride, Co2(NH,),oCl,+20H2

Nitrate, Co,(NH,)„(NO,),+3bH2

Sulphate, Co2(NII,),„(!^0,),4-50H2'

Sulphato-chlorplatinate, Co.(NH3),„(SO^),Cl,-f-PtCl^

Suljihato-chloro-aurate, Co,^(NH„),„(SO,)XC-|-2AuCl3-|-40H,.

I may remark in this connection, that rhodium forms two series of
salts, one of which is red, and the other yellow, and that the chloride
of Claus's base, Rh.,(Nri„)„|Cl,;, which is yellow, unlike the well-de-
fined double chlorides containing Rh^Cl,;, may be the true analogue of
the yellow modification of Co,(NH3),oClg+20H,,.

CItlorphitinate. — When the soluble suli)hate of roseocobalt is con-
verted into nitrate by double decomposition with baric nitrate, and
chlorplatinate of sodium is added, a salt separates in dark-red mamil-
lary crystalline crusts, which may be regarded as the normal platinum
salt of this series. The salt, like most of its congeners, is much moi-e

OP ARTS AND SCIENCES. 17

soluhle in hot than in cold water, and crystallizes as the solution cools,
though not in well-defined forms. Its formula is —

Co,(NH3),„C]„+2PtCl,+50H.„

as the following analyses show : —

0 9ai8 gr. gave 0-281)'.) gr. platinnm, and 0-08G8 gr. cobalt (by diff.T-
ence) =31-12'^ platinum, and 'J-3'.)«^ cobalt := 40-51 -^Pt-}- Co.
0-3040 gr. gave 0-1241 gr. platinum and cobalt = 40-79%.

Heated to 140°C the salt lost 5-41 <^ water, and was then decomposed
with a slight explosion, so that the whole of the water is not given off
below the temperature of decomposition. The formula requires : —

Calculated. Found.

Platinum, 31-15 31-12

Col.alt, 9-28 9-39

Water, 7-08 5-41

When platinic chloride is added to a solution of chloride of roseoco-
balt, a dull-red crystalline salt in fine needles is formed, readily soluble
in hot water, and crystallizing from the solution unchanged. Of this
salt, —

0-37GG gr. (reduced by zinc and SOJI^) gave 0-1087 gr. platinum and
0-3981 gr. silver = 28-86 f^ platinum and 35-55<^ chlorine.

Tliese results correspond to the formula Co2(NH3)joClg-[-2PtCl^-|-
1201X2, which requires 28-72% platinum, and 3G-04% chlorine.
Braun states that by adding platinic clilocide to a solution of a salt of
roseocobalt and free chlorhydric acid, he obtained a dark orange-red
crystalline precipitate, having the formula, as we should now write it,
3.Co2(NH„)jQCl^-|-4.PtCl^. I have never obtained any such salt; and
as Braun's formula is based upon a determination of the sum of the
percentages of platinum and cobalt only, it cannot be regarded as even
probable. Genth and I have stated in the first part of this paper, that
chloride of roseocobalt forms with platinic chloride a salt which we
had not completely examined, but which apj^eared to have the formula
Co2(NH3)ioCl,.-l-3PtCl^-|-80H2. I have not obtained this salt again ;
but the following analyses will serve to show that we had some reason
for believing in its existence : —

0-7593 gr. gave 0-3256 gr. platinum and cobalt = 42-88%.

0'6155 gr. gave 0-3326 gr. platinum and SO^Co = 0-2 182 gr. platinum

and 0-1144 gr. SO^Co = 35-45% platinum and 7-07% cobalt.
0-4809 gr. gave 0-7491 gr. AgCl = 38-50% chlorine.

VOL. XI. (n. s. ii.) 2

18 PROCEEDINGS OF THE AMERICAN ACADEMY

The formula Co^CNHJioClg+SrtCl.+SOH^ requires : —

Calculated.

Found.

Cobalt,

7-08

7-07

Platinum,

35-56

35-45

Chlorine,

38-36

38-50

These analyses were not published in the first part of this paper, be-
cause Genth and I did not succeed in pre^^aring the salt a second time.
] do not myself consider them — in spite of their close agreement with
the formula given — sufficient to establish the existence of the salt in
question. Further researches may be more successful in this respect.
Sidphato-chlorplatlnate. — When chlorplatinate of sodium is added
to a solution of the soluble sulphate of roseocobalt, a beautiful bright-
red crystrdline salt is precipitated, which is but slightly soluble in cold
water, but which may be dissolved in a very large excess of boiling
water with a few drops of free acid, and crystallizes from the solu-
ticm without decomposition. This salt has the formula, —

Co,(NH3),,(SOJX],+PtCl„

as the following analyses show : —

0-4806 gr. gave 0-3476 gr. silver = 23-78^^ chlorine.

0-4-2-21 gr. gave 0-1505 gr. platinum and cobalt :^ 35-65^.

0-1428 gr. of the mixed metals gave 0-0898 gr. platinum = 22-43%

(of the salt), and 13-22^ cobalt (by difference).
0-5219 gr. gave 0-2618 gr. SO.Ba = 20-669/^80,. Salt fused with

COgKNa.

The salt lost no water on being heated to loO^C. The formula re-
quires : —

Calculated.

Found.

Cobalt,

13-24

13-22

Platinum,

22-21

22-43

Chlorine,

23-90

23-78

SO,,

21-55

20-66

A solution of the yellow modification of the sulphate of roseocobalt
already described, gave with chlorplatinate of sodium a beautiful vel-
low crystalline precipitate remarkably insoluble even in hot water.
Tliis salt, after washing and drying in pleno over sulphuric acid, was
analyzed : —

0'4202 gr. ga^^e 01488 gr. platinum and cobalt = 3541 r^.

OF ARTS AND SCIENCES. 19

The formula Co,(NII,),„(SO,),,Cl2+PtCl, re<iuircs 35-4')%. The
very small quantity of the sulphate at my disposal prevented me from
making a more complete analysis ; but there can scarcely be a doubt as
to the constitution of the salt.

Chloro-aurate of Roseocobalt. — Chloro-aurate of sodium produces
in a cold solution of the chloride of roseocobalt a beautiful bright
orange-red crystalline salt, which may be redissolved in hot water, and
recrystallized without sensible decomposition. This salt has the
formula, —

Co,(NIL),,Cl,+2AuCl3+20II„

as appears from the following analyses : —

0-5996 gr. gave 0-3674 gr. gold and SO^Co containing 0-2047 gr.

gold = 10-33^ cobalt and 34-14% gold.
0-8900gr. gave 0-3080 gr. gold = 34-59%, and 1-0013 gr. silver =

36-98% chlorine.

The salt is soluble even in cold water ; the solution has a fine orange-
red color. The formula requires : —

Calculated. Found.

Cobalt, 10-31 10-33

Gold, 34-44 34-37 (mean)

Chlorine, 37-23 36-98

The salt contains two atoms of water, which are not found in the cor-
responding salt of purpureocobalt. It is one of the most beautiful of
the whole series.

Sulphato-chloro-aurate. — Chloro-aurate of sodium gives a beautiful
orange-red crystalline precipitate with soluble sulphate of roseocobalt.
The salt is but slightly soluble in cold water, and may be washed
without sensible loss. It requires much hot water for solution, but
dissolves without decomposition, and separates from the solution on
cooling in fine briglit-red crystals. The formula of this salt is, —

Co,(NH3),o(SO,),Cl,+2AuCl3+40H„
as the following analyses show : —

0-4331 gr. gave 0-1389 gr. gold = 32-07%.

0-3542 gr. gave 0-U73 gr. SO^Ba^z 0-1363 gr. SO^Ba.

Calculated.

Found.

Gold,

32-04

32-07

SO,,

15-62

15-86

20 PROCEEDINGS OF THE AMERICAN ACADEMY

The yellow modification of sulphate of roseocobalt gives with cliloro-
aurate of sodium a precipitate in yellow needles, soluble without de-
composition in boiling water, and crystallizing from the solution
unchanged. In this salt, —
0-19o2 gr. gave 0-0494 gr. SO,Co = 9-G3%.
0-2657 gr. gave 0-0856 gr. gold and 0.1866 gr. silver = 32-25r^ gold

and 23-11^ chlorine.
The formula, Co2(NH„)io(SOj2Cl2+2AuCl3+40H„ requires : —

Calculated. Found.

Cobalt, 9-59 9-03

Gold, 32-04 32-25

Chlorine, 23-09 23-11

Chloro-hydrargyrate of Roseocobalt. — Under the head of purpureo-
cobalt I have described two salts having respectively the formulas
Co,(NH3),„Cl6+6HgCl2, and Co,(NH3),„Cl,+4HgCl2. The six-atom
salt was first described and analyzed by Claudet,* and afterward by
Carstanjen, f who also first described the six-atom salts with four and
twelve molecules of water of crystallization. I find that the six-atom
salts are always formed when chloride of mercury and sodium,
HgCl^Na2, is added to a solution of chloride or of sulphate of roseoco-
balt, but that the resulting salt always contains four atoms of water of
crystallization, while the anhydrous salt, Co^(NH.5),„Cl,.,-|-6HgCl„ is
foimed when an excess of the mercuric salt is added to a solution of
chloride of purpureocobalt. On re-solution and recrystallization,
each salt separates unchanged, so that the hydrous salt does not appear
to be merely a hydrated form of the other. The salt Co.,(Nn,),nCl(;-}-
GIIgCl2-|-4()H2 crystallizes in lilac-red prismatic forms, which are
much more soluble than the anhydrous salt. Of this compound (from
Co,(NH3),„Cl,+20H,),-

1-7840 gr. gave 1-1522 gr. HgClj^ 54-86<|^ mercury.
1-4373 gr. gave 1-2721 gr. silver =29-09'^ chlorine.
0-8430 gr. gave 0-1205 gr. SO,,Co= 5-43% cobalt.
0-3731 gr. (from Co,(NH8)w(SO,)3+5aq) gave 0-2373 gr. IlgS =
54-84''^ mercury.

The formula requires : -^

Calculated.

Found.

Cobalt, 5-37

5-43

Mercury, 54-57

54-86 54-84

Chlorine, 29-05

• 29-09

* Phil. Mag. II. p. 253.

t De Comiubiis ammoniaco-cobalti

cis. BerUn, 18G1.

OF ARTS AND SCIENCES. 21

Basic Oxalo-sulphate . — This salt, which in the first part of this
paper was assigned to the purpureocobalt series, belongs, as I think,
more probably with the salts of roseocobalt, being formed directly
from the sulphate of that base. This view compels us to admit the
existence of a basic series of roseo-sjilts, to which, however, I can see
no reasonable objection. The formula of the oxalo-sulphate may now
be written,

Co,(NH3),„.0.(C,OJ.(SO,)+70II,.

Acid Oxalo-sulphate. — The acid oxalo-sulphate, described in the
same paper, may be written,

Co,(NH3),„(C,0,),(SA)+30H„

and would then be a dioxalo-disulphate. Its structural formula upon
this view would be

O

Co,

NH3-NH,-0-^^^^2
NH;3-NH3-NH3 Q

NH3-NH3-O (.Q

This formula agrees satisfactorily with the results of the analyses, and
with the fact that the acid reaction is not very strong. On the other
hand, it is at least possible that the salt may contain two atoms less of
hydrogen. In this case the formula would be

Co,(NH3),„(CA)(SO,),+C,HA+20H3.

If the first view be adopted, the formation of the salt by boiling nor-
mal sulphate of roseocobalt with oxalic acid may be expressed by the
equation : —

Co,(NH3),„(SOj34-3CJI,0, = ^Co,(NH3),„(C,OJ,(S,0,)+
C,H,OJ+OH,+S0,H,.

Upon the second view we should have : —

Co,(NH3),,(SO,)3-f 3C,HA = lCo,(NH3),„(CA)(SO,),+
C,H,0J+-20H,+S0,H,.

The second view appears to me preferable, since we have no inde-
pendent evidence to show that ordinary sulphates ever lose water to
form disulphates, except by the action of heat.

Oxalates. — Genth and I have shown that the neutral oxalate of
roseocobalt has the formula Co2(NH3),(,(C20^)3-|-OH2. I find now
that, as already stated, this salt is sometimes formed as one of the
products of the action of ammonic oxalate upon chloride of purpureo-

Calculated.

Mean.

Found.

12-94

13-03

13-00 13-06

18-42

18-03

18-10 18-03 17-96

4-16

4-25

4-22 4-35 4-19

22 PROCEEDINGS OF THE AMERICAN ACADEMY

cobalt, and also by the action of the alkaline oxalate upon the nitrate
of the same base. When the neutral oxalate is boiled with an excess
of oxalic acid, the solution deposits, on cooling, fine garnet-red crusts of
crystals resembling prehnite in appearance. This salt is the acid
oxalate of roseocobalt, and has the formula, —

Co,(NH3),,(C,OJ3+4C,H,0„
as the following analyses show : * —

1. 0-4897 gr. gave 0-1C73 gr. SO,Co= 13-OOr^ cobalt.

2. 0-3421 gr. gave 0-0447 gr. cobalt = 13-06^ cobalt.

3. 0-8908 gr. gave 0-5913 gr. Co^ and 0-3389 gr. water =: 18-10%

carbon and 4-22% hydrogen.
4 M337 gr. gave 0-74G0 gr. Co^ and 0-4439 gr. water = 18-03%

carbon and 4-35% hydrogen.
5. 0-7397 gr. gave 0-4872 gr. Co^ and 0-2922 gr. water = 17-96%

carbon and 4-19% hydrogen.

Cobalt,
Carbon,
Hydrogen,

The formula appears, when compared with tho«e of the ordinary
double oxalates containing metallic sesquioxides, to be abnormal ; but
the analyses made with carefully recrystallized, pure, and homogene-
ous salt seem to leave no reasonable doubt as to the true constitution.
Oxalo-platino-chlorlde. — When a solution of chlorplatinate of so-
dium, PtCl^Nag, is added to one of the neutral oxalate of roseocobalt,
a fine red crystalline precipitate forms after a short time, which may
be jjurified by a second crystallization. The salt forms small grouped
acicular crystals, which have a rather pale-red color. It is somewhat
easily soluble in cold water. Boiling water dissolves it readily, form-
ing a clear red solution, fi-om wliich the salt crystallizes without de-
composition. The formula of this salt is,

Co,(NH,),„(C,OJ,Cl,+PtCl„
as the following analyses show : —

0-5389 gr. gave 0-1210 gr. platinum and 0-4002 gr. silver = 22-45%

platinum and 24-41 % chlorine.
The formula requires 22-62% platinum and 24-34% chlorine.

* My friend and former pupil, Prof. Sadtler, had the kindness to make
analyses 4 and 6 for me after my own laboratory had been closed. I deemed
them necessary to verify the unexpected formula.

or ARTS AND SCIENCES. 23

Cobalto-nitrite of Roseocohalt. — When a solution of (•ol)alto-iiitrite
of sodium, Co^,(NOJ,.,Na„, in excess of sodic nitrite is added to one of
the soluble sulphate of roseocohalt, heautiful brown-orange prismatic
crystals are thrown down, which are readily soluble in hot water vvitii-
out decomposition. Of these crystals dried in plena ovt-r sulphuric
acid, —

0-2820 gr. gave 0-1822 gr. SO, Co = 24-60% cobalt.

The formula of the anhydrous salt, Co,,(NH3),o(NO,)„+Co,(NO,)„,
requires exactly the percentage found. The solution of this salt gives
with salts of luteocobalt a beautiful crystalline precipitate of the co-
balto-nitrite of that base, Co2(NII,)j,(N03)y-|-Co2(NO.Jj. With salts
of strychnia and brucia, it gives the cobalto-nitrites of those alkaloids.
The preparation of this suit, like that of all similar compounds, is
somewhat uncertain, and often fails entirely in consec^uence of the for-
mation of salts of xanthocobalt by the action of the excess of sodic
nitrite on the sulphate of roseocohalt. By the action of a solution of
cobalto-nitrite of sodium upon chloride of purpureocobalt, Sadtler ob-
tained a yellow crystalline salt much more soluble than the luteocobalt
salt, Co2(NH3)j3(NO.,),.-[-Co^(NOo)5, and to which he assigns the prob-
able formula Co2(NH3),o(N02),4-Co,(NO,),+01l2. Farther study
is needed, however, in the case of this salt. It may be identical with
that described above.

Dickromate of Roseocohalt. — When a solution of potassic dichro-
mate is added to one of nitrate of roseocohalt, a dark red precipitate is
formed, which, after re-solution in water with a few drops of acetic acid,
separates in beautiful red scales with bronze-yellow reflections. This
salt is identical with that formed in Mr. Mills's process for preparing
salts of roseocohalt, to which I have already alluded, and in which I
found five atoms of water of crystallization. When digested at a
gentle heat with a solution of baric nitrate, the salt yields baric chro-
mate and nitrate of roseocohalt only, so that it certainly belongs to this
series, and not to that of i^urpureocobalt.

Sulphite of Roseocohalt. — I obtained the sj^ecimen of this salt
vphich I examined from Dr. Genth who prepared it by boiling chlo-
ride of purpureocobalt with a solution of neutral ammonic sulphite.

The salt was recrystallized from its solution in ammonic carbonate,
and contained only a trace of chlorine. It forms granular brownish-
orange crystals, slightly soluble in cold, and readily decomposed by
hot water. Heated in a tube, it gave off water, ammonia, and amnionic
sulphite. When sulphuric acid is poured upon the sulphite, some sul-

24

PROCEEDINGS OP THE AMERICAN ACADEMY

phurous oxide is given off, but it is only by strong heating that the
whole of the oxide can be expelled. Of this salt : —

0-7132 gr. gave 0-3800 gr. SO^Co = 20-27% cobalt.
1-7094 gr. gave 2-0505 gr. SO,Ba = 32-94% SO^.
1-5422 gr. gave 0-9228 gr. water = 6-G4% hydrogen.
0-8927 gr. gave 183 c.c. nitrogen at 15*^-5 C. and 765-14""° =
24-07%.
Tlie formula Co^j (NH3)jo(S03)3 + 30U^ requires : —

Calculated. Found.

2 20-27 20-27

3 32-98 32-94
10 24-05 24-07
36 G-18 6-64

I have assigned this salt somewhat arbitrarily to the roseocobalt series.
In the absence of any direct evidence on either side, it is of course
equally probable that it belongs to the series of purpureocobalt.
Kiinzel's salt,

Co,(NH,),o(S03)3+Co,(SO,)3+90H„

bears the same relation to the neutral sulpliite which I have de-
scribed which the cobalto-nitrite, Co._,(NH.,)jg(NOJa-l-Coo(N02)c,
bears to the normal nitrite Co2(NH3),„(NOo)e.

The salts known with most certainty to belong to the roseocobalt
series are the following : —

Cobalt,

Sulphurous Oxide,
Nitrogen,
Hydrogen,

Chloride,

Nitrate,

Sulphates «, ^, y,

Acid sulphate,

lodo-sulphates «, ^, y*

Bromo-sulphate,*

Dichromate,

Basic oxalo-sulphate,

Oxalate,

Acid oxalo-bisulphate,

Arid oxalate,
Ferricyanido,

Co,(NH3),oCl,+20H,

Co.,(NlI,)„XNO,),;+20H,

Co,(NH3),„(SO,)3+50H,

Co,(NIl3)„(SO,),+SO,ir,+40H3

Co,(NH,),„(SO,),I,+2()H,

Co.,(NIl3),„(SO,).,Br.,+20II.,

Co;,(NII,),„(Cr.,0;)3+50ri, '

Co,(NII,),„.0.(CA)(«0,)+70IIa

Co.,(NII,),„(C..O,)3+60II.,

Co,(NII,),„(CA)(SOJ,-f-CJIA+
2011^

Co,(NH3),o(CA):.+4C,HA
Co,(NIl3),„Cy«+FeXy„+30H,

* ICrok, loc. cit.

OF ARTS AND SCIENCES. 25

Cobalticyanide, Co,(NIIg),„Cy„-fCo,Cy,+30rij

riatino-chloride, Co^(N H,) ,oClu-|-2 PtCl^+oO 1 1.,

Auro-cliloiide, Co./ N II,) ,„Cl,.-i-2 An Cl,-|-20 1 1,

Ilyarargo-chloride, Co,,( N H,,) i„Cl,-|-C) I IgCI,,-|-401l2

Sidphato-hydrargo-chloride* Cc(,(NH,,),„(sbjX'l,+2IIjrCl,

Sulpliato-chloro-platinate p", ■/, Ccr,(NH.,),„(SOJ._,CI,,-f-PtCl^

Sulphato-chloro-aurato p', 7, C(x,(NH,),„(SO^).^Cl.^-[-40Il2

Oxalo-chlorplatiuate, Co./XII,),„(C,OjX'L+PtCl.,

Cerous double sulphate Co2(NH^),/S0J,+SCeS0,-i-0irj

(Wing),

Ceric double sulphate (Wing), Co,(NH,),„(SOJ ,-}-Ce./SOj,-|-OIIj

Chloro-uitro-platino-chloride,* Co./NIl3),o(NO,),Cl,+2PtCl^
Chloro-nitro-hydrargo-chlonde,*Co,(NH3),„(N03)'8Cl3--f3IIgCl2.

With the data given above before us, we may now comj)are the
piirpureo- and roseo- series more advantageously than has hitherto
been possible. Genth and I at an early period in our investigation
recognized the distinction between these two classes of salts, — a dis-
tinction which has been admitted by some chemists, strongly supported
by Mills t and F. Rose, and summarily rejected by Blomstrand J and
others. I shall omit from the discussion those salts which in the
present state of our knowledge might be classed with either series.
As a basis for the distinction which I uphold, 1 present the following
facts : —

1. Chloride of purpureocobalt, Co/NH3)iqC1(;, cannot be converted

into chloride of roseocobalt, Co2(NH3),qC1„-|-"^C)H2, by recrystal-
lization from water. In other words, it does not unite directly
with water to form a hydrate, the combination always taking
place indirectly, as, for instance, when chloride of purpureocobalt
is dissolved in ammonia water, and the solution poured into
strong cold chlorhydric acid. The same argument applies in
the case of the nitrate of purpureocobalt, which behaves in a
precisely similar manner. Chemistry presents, so far as I have
been able to discover, no single case in which similar relations
exist between a salt and its hydrate.

2. Chloride of roseocobalt, in either concentrated or dilute solution,

loses two atoms of water, and is converted into chloride of pur-

* Krok, loc. cit.

t L. & E. Phil. Mag. (4) xxxv. 245.

t Chemie der Jetztzeit. p. 2y4, note.

26 PROCEEDINGS OF THE AMERICAN ACADEMY

pureocobalt by simple heating. I can recall no single instance
in which a true hydrate behaves in a similar manner. Nitrate of
roseocobalt, when heated in solution with a little free nitric acid,
undergoes a similar conversion into nitrate of purpureocobalt.

3. Sulphate, chromate, oxalate, &c., of roseocobalt in solution yield, by

double decomposition in the cold with baric chloride and nitrate,
salts of roseocobalt only. Is a mere state of hydration trans-
mitted from salt to salt ?

4. According to the determinations of F, Rose,* one part by weight

of chloride of roseocobalt requires at 10° C. 4*8 parts of water for
solution. At the same temperature, one part of chloride of pur-
pureocobalt requires 287 parts of water for solution. Rose re-
marks that the identity of chloride of roseocobalt and chloride of
purpureocobalt can only be maintained by admitting that the
same salt can exist both in the hydrous and anhydrous condition
m a solution at the same temperature, an assumption directly
opposed to the numerous observations of Riidorft' and Wiillner
on the tension of the vapor of aqueous solutions.

5. Solutions of the two chlorides form with the same reagents in

many cases different salts. Thus, chloride of roseocobalt foruis

Co,(NH3)ip,+2PtCl,-|-50H2 with platinic chloride,

Co2(NH3)ioCl6+2AuCl34-20H2 with auro-chloride of sodium,

Co2(NH3)jy(C^O^)3-|-60H^ with ammonic oxalate.

With the same reagents respectively, chloride of purpureocobalt
gives,

Co,(NH3),„Cl,+2PtCl„

Co,(NH3),,Cl,+2AuCl3,

Co,(NH3),„Cl,(C,Oj3.

C. The greater number of the salts of the roseocobalt series contain
water of crystallization. The greater number of the salts of pur-
pureocobalt are anhydrous. If it be replied that this statement
involves a petitio principii, I reply tliat the presence or absence
of water of crystallization is, in most cases at least, coexistent
with other jjroperties tending to establish a clear distinction be-
tween tiie two classes of salts.

* Untersuchungen iiber ammoniakalische Kobalt-Verbindungen. Heidel-
berg, 1871, p. 47.

OF ARTS AND SCIENCES. 27

7. I have rendered it, to say the least, extremely probalHe that tliero
are three distinct modifications of roseocobalt, yielding salts with
similar or identical empirical formulas, but differing in color and
solubility. Is it unreasonable to suppose that there may be a
fourth modification or possible variation in the arrangement of
the atoms constituting the molecule Co.^(NIl3)jo ?

With respect to the few known cases in which salts of roseocobalt
and purpureocobalt yield the same salts by double decomposition with
the same reagents, I have to say that there appears to be no reason
for doubting that in such cases there is a transformation of one modi-
fication of the molecule Co^(NIIg),g to another, since we already
know that such transformation may be effected by heat alone. The
best instances of this transformation occur in the case of the reactions
of the two chlorides with potassic ferricyanide and cobalticyanide
mentioned by Genth and myself.

LUTEOCOBALT.

Rogojski * first noticed the existence of a salt of luteocobalt con-
taining both chlorine and sulphuric oxide, and having a formula which
we should now write Co2(NH.5),2Cl(;-f-Co._,(NH3),,_,(SOj3, but wliich
might also be written Co,(NH3),2(SO,)2Cl+Co,(NH,),.,(SOJCl,.
In examining this salt, Genth and I found that the chloride and sul-
phate are capable of crystallizing together in all proportions. Dana
then showed that the two salts are isomorphous. Genth and I observed
further that mixtures of the chloride and sulphate gave peculiar crys-
talline salts with the chlorides of platinum and mercury. These we
naturally regarded simply as mixtures. Braun afterward obtained a
chloro-chromate which he regarded as a double salt, and which we
should now write Co^(NH.3),2(CrO^)^Cl2. The salt is easily formed
by mixing solutions of one molecule of the chloride and two of the
neutral chromate. As in the case of the cori-esponding salts of roseo-
cobalt, Krok t first showed that definite compounds are formed when
ammoniacal solutions of sulphate of luteocobalt are heated with iodine.
The resulting iodo-sulphate has the formula Co2(NIl3),^,(SO^).,I.,- By
the action of chlorine upon this salt the corresponding chloride is
formed, and this gives well-defined crystalline salts with platinic and

* Compt. Rendus, xxxiv. 186. t Acta Univ. Lund. 1840.

28 PROCEEDINGS OF THE AMERICAN ACADEIMT

mercuric chlorides, which have respectively the formulas Co.,(XH3)j2
(SO,),(HgCl,), and Co,(NH,),,(SOJ,(PtCl,). ^

Chloro-platino-diromate of Luteocuhalt. — When neutral chromate
of luteocobalt is dissolved, and a solution of platinic chloride added,
brown-yellow crystals are obtained, which require a large quantity of
boiling water for solution, and are difficult to purify by recrystallization.
Of this salt : —

0-G567 gr. gave 0-1920 gr. platinum, and 0-6026 gr. silver = 29-23%
platinum, and 30-16% chlorine.

These numbers indicate the formula Co2(NH,)i2(CrO,)Cl,+2PtCl,
-|-o aq., which requires 29-33% platinum, and 31*55% chlorine. I do
not consider the constitution of this salt to be sufficiently established
by my analyses, though there is no a priori improbability in the for-
mula itself.

Oxalo-auro-chloride of Luteocohalt. — When neutral oxalate of luteo-
cobalt is digested with a solution of auro-chloride of sodium, the salt
quickly changes its appearance as regards form and color, and a new
salt is formed, which is readily soluble in boiling water, and crystal-
lizes from the solution in long orange-yellow needles. The formula
of this salt is, —

Co,(XH3),,(C,0,),Cl,+2AuCl3 + 40R„
as appears from the following analyses : —

0-5109 gr. gave 0-2107 gr. gold, and cobalt = 41-24%, and 0-1628
gr. gold = 31-86% gold, and by difference 9-38% cobalt.

The formula Co,(NH3),,(C,0,),Cl,^-2AuCl,+40Il2 requires gold
31-56%, cobalt 9-47%. When neutral oxalate of luteocol):dt is dis-
solved in chlorhydric acid, and auro-chloride of sodium is addud, beau-
tiful yellow granular crystals are formed which contain no oxalic acid.
In this salt, —

0-3042 gr. gave 0-1875 gr. SO^Co+Au containing 0-1043 gr. gold =

34-25%, and 0-0832 gr. SO, Co = 10-41% cobalt.
0-6738 gr. gave 0-7591 gr. silver = 37-03% chlorine.

The formula Co,(NH3)i2 01^+2 AuCl^ requires : —

Calculated.

Found.

Cobalt,

2

10-33

10-41

Gold,

2

34-50

34-25

Chlorine,

12

37-30

37-03

OP ARTS AND SCIENCES. 29

SO tliat the salt is identical with that described by Genth and myself
in the first part of this paper. When platinic chloride is digested with
neutral oxalate of luteocobalt, the salt ehantfes its form and color in so
marked a degree as to leave no reasonable doubt of the formation of a
new salt. On attempting, however, to purify this salt l»y solution in
boiling water and recrystallization, I found that decomposition at
once commenced, carbonic dioxyd being given off in abundance.
There can hardly be a doubt, I tliink, tiiat the salt, Co2(NI-Ig),2(C20j2
Cl.,-|-PtCl^, is at first formed, and subsequently decomposed. Oxa-
late of luteocobalt dissolves in hot oxalic acid, and yields a pale buff
felted mass of crystals of an acid oxalate.

Pyrophosphate. — When sodic pyrophosphate is added to a solution
of luteocobalt, a beautiful crystalline precipitate is formed in talcose
scales with a high lustre, remarkably insoluble in water. Braun, who
first studied this salt, assigns to it the formula, —

3 ( Co, ( N H,),03) +5 P2O,+40OH,

(old style) and suggests that it may be a double salt with the
formula, —

2(Co2(NH3)A-"PO,+80H)+Co2(NH3)P3.3PO,+240H,

in which case it would contain both orthophosphoric and metaphos-
phoric oxides. My analyses have led me to the much simpler for-
mula, —

Co,(NH,)^2.(PA334-60H2,

the constitution of the salt being perfectly analogous to that of the
pyrophosphate of purpureocobalt already described. The salt analyzed
was precipitated from a hot solution of chloride of luteocobalt by a
solution of sodic pyrophosphate, well washed with cold water, and
dried in vacuo over sulphuric acid. Of the crystals,

0-8178 gr. gave 0-4692 gr. by ignition = 57-30% Co,P,0,2.
0-8174 gr. gave 0-4651 gr. by ignition = 56-89% CV.P^O,.,.
0-5879 gr. gave 0-0693 gr. water heated up to 120° C. until the weight

was constant = 11-78%.
0-7515 gr. gave 0-4359 gr. P,,0.Mg2= 43-37% P.O^g.

The water given off up to 120° C. corresponds to five atoms, the cal-
culated percentage being 11-81. The last atom of water is retained
at 140^ C.

30 PROCEEDINGS OF THE AMERICAN ACADEMY

Calculated. Found.

Co^P.Oia, 56-95 57-09 (Mean.)

lONHg-fGOH^+O, 43-05 42-91

100-00 100-00

The formula requires 43-57 f;^ ^fia- Found 43-37%. The analj'sis
was made by fusing the salt with CO.jKNa, and precipitating as
ammoiiio-magnesic phosphate. Iodide of luteocobalt gives the same
salt, and does not yield an iodo-pyrophosphate Lc.P^O-.Ig as might
perhaps have been expected.

Sulphate of Thallium and Luteocobalt. — "When a solution of thal-
lous sulphate containing free sulphuric acid is oxidized by potassic
hypermanganate, a dark brown precipitate is formed which readily
rcdissolves on the application of heat. The clear solution produces in
a solution of sulphate of luteocobalt, after a few minutes, a beautiful
crystalline precipitate of yellow talcose scales which have a peculiar
silky lustre. These crystals are decomposed by washing even with
cold water, a brown powder of thallic hydrate T1(0H)3 being formed.
The decomposition may be prevented by adding sulphuric acid to the
water. Of this salt : —

0-5079 gr. gave 0-3169 gr. = 62-39% sulphates of cobalt and thal-
lium.
0-7421 gr. gave 0-6557 gr. SO,Ba = 36-40% SO,.

In the last analysis, the thallium was first reduced in a solution con-
taining free chlorhydric acid by metallic magnesium, as zinc did not effect
a reduction even after long boiling. The precipitated spongy thal-
lium dissolved completely in the excess of free chlorhydric acid. The
formula of the salt is Co2(NH3),2(SO,),+Tl2.0.(Soi2+50H2, which
requires 36-49% SO, and 61-81% of the mixed sulphates, 2.SO,Co-(-

so;n,.

I did not succeed in obtaining analogous salts with the sulphates of
roseocobalt, xanthocobalt, or croceocobalt. It is remarkable that the
thallic sulphate in this salt is basic. I verified the analysis by a
second determination of SO,, made by decomposing the salt with hot
water, filtering off the thallic hydrate formed, and determining the
SO, in the filtrate by baric chloride. The analysis gave 3G-11%.

Dichromate. — Potassic dichromate precipitates luteocobalt from
concentrated solutions of the nitrate in beautiful orange needles, which
may be redissolved and recrystallized without decomposition. The
salt dissolves rather easily in hot water, but dificrent preparations

OF ARTS AND SCIENCES. 81

appeared to contain different amounts of water of crystullizution. la
one preparation in fine crystals : —

1-3713 gr. gave 0-5952 gr. Cr.fl^ = Gl-G2(/o Cr^^.

The formula Co2(NHJja(Cr20.)3+50Il2 requires Gl-17%.

METAMERIC SALTS.

I have already stated that roseocobalt and xanthocobalt give beauti-
ful crystalline salts with the electro-negative or chlorous radical of
Krdmaun's remarkable series. The formula of the octamin salt may
be written, —

|Co,(NH,),(NO,)j'^Co,(NH3),(NO,),^"orCo,(NIl3),(NO,),+
Co,(NIl3),(NO,)„

while that of the xanthocobalt salt is, —

|Co,(x\H3),„(NO,),nCo,(NH3),(NO,),f, or Co,(NH3),„(NO,),+
2(Co,(NH3),(NO,),).

It will readily be seen that, as already shown, the croceocobalt salt is
empirically

2. Co,(NH3)„(NOJe,
and the xanthocobalt salt

3. Co,(NH3)„(NO,)«,

and consequently that both are metameric with the hexamin nitrite
of Erdmann Co2(NH3)y(NO^)y. I will now show that there are two
other compounds also metameric with Erdmann's salt, and yet per-
fectly distinct in chemical structure and properties.

When potassic nitrite is added to a solution of cobalt containing a
little free acid, a yellow crystalline substance is gradually precipitated,
which is the well-known salt first described by Fischer. The investi-
gations of Professor Sadtler first definitively proved that this salt is
essentially Co.XNOj),.,!^,;' the number of atoms of water of crystalliza-
tion varying with the circumstances under wdiich the salt is formed.
Professor Sadtler has also described and analyzed the corresponding
sodic and ammonic salts. The sodic salt is not immediately precipi-
tated when sodic nitrite is added to an acid solution of cobalt, but in
presence of an excess of the alkaline nitrite remains in solution, giving
a deep orange-colored liquid. I found that this solution gave beauti-
ful crystalline precipitates with salts of luteocobalt and roseocobalt.

32 PROCEEDINGS OP THE AMERICAN ACADEMY

Tliese were first analyzed and described in my laboratory by Sadtler,
who found for the luteocobalt salts the formula, —

Co,(NH3),,(NO,)„+Co_,(NO,),+OH,.

In resuming the study of this subject, I found the method of prepara-
tion at first adopted somewhat uncertain, because the excess of the alka-
line nitrite acts readily upon the cobaltamine, forming other products
not always easj' to sejjarate. The following method gives better re-
sults. One molecule of any soluble salt of the cobaltamine — the
nitrates are to be preferred — is to be dissolved with two molecules of
cobaltic chloride or nitrate, and a little acetic acid. A solution con-
taining as nearly as possible twelve molecules of sodic nitrite is then to
be added. The luteocobalt salt is precipitated almost immediately ;
the corresponding salt of roseocobalt after a short time.

The salt of luteocobalt obtained in this way is a yellow crystalline
body very slightly soluble in cold water, and easily purified by wash-
ing. Boiling water dissolves it in very small quantity, giving a j^ale
yellow solution. I have usually obtained it in rather larger deep
orange granular crystals by adding a solution of the corresponding
much more soluble roseocobaltic salt, Co2(NIJ„)j^,(NO.,)g-|-Co2(N02)g,
to a hot neutral solution of nitrate of luteocobalt. It may also be
formed by adding a solution of Co,,(N02)i;-|-6NaN02 in excess of sodic
nitrite to a solution of luteocobalt, there being in this case less danger
of the formation of other products than with the other cobaltamines.
I find the formula of this salt to be

lCo,(NH3),,nCo,(NO,),,| or Co,(NH3),,(NO,),+Co,(NO,)„

as the following analyses, made with three different preparations,
clearly show : —

0-3312 gr. gave 0-2006 gr. SO, Co = 23-789^ cobalt.
0-3776 gr. gave 0-236'J gr. SO,Co = 23-89% cobalt.
0-1785 gr. gave 0-1115 gr. SO,Co = 23-78% cobalt.

The formula requires 23-79% cobalt for the anh^-drous salt. In
one preparation, however, I obtained a salt in which

0-4291 lost 0-0087 gr. at 125° C. = 2-16.

This would corrcs])ond to Sadtler's formula, which requires 1-78%, if
we consider a part of the water as hygroscopic, or that, as is more proba-
ble, there was a slight decomposition. In the dried salt, —

0-4204 gr. gave 0-2643 gr. SO.Co = 23-93% cobalt.

OF ARTS AND SCIENCES.

33

so that the salt when containing an atom of water of crystal lizalion,
certainly becomes anhydrous a little below 125° C.
The structural formula of the salt is : —

NH,-NIl3-0-N < J]> N
NII3— NIL— O— N <[]> N

Co,

NIL— ML— O-

1

NII3— NIL— O— N < J^> N

NH,

Co,

-NH3— 0— N<^>N
NH3— NH3— 0— N < Q > N

In this case, as in formulating Fischer's salts (p. 17), I have as-
sumed that six units of alfinity of the hexatomic complex, Co^, on the
right, are saturated by six units of affinity of nitrogen, which is of
course equivalent to supposing that a nitrite may be R — N< a, and

not, according to the usual view, 0:^N — OR. It seems to ine that
the first view exhibits more clearly the mutual relations of the am-
monia and nitroxyl compounds of cobalt, and the existence of such
intermediate compounds as the salts of Erdmann's series. But it is
also possible that, while the alkaline nitrites have the structural for-
mula, 0 = N — OM, very stable compounds, like Co.^(NO^)j2K,., have
the ditTerent structure which I have above assumed. It will be seen that
the difterence corresponds to that between ethylic nitrite, 0 = N — O
C.,H., and the far more stable nitro-ethan a>N — C„H..

^ o (J ^ o

When the luteocobalt salt just described, and which we may more
briefiy express by the formula Co^(NO._,),oLc, is digested with a solu-
tion of thallous nitrate, TINO3, containing a little free nitric acid, the
yellow salt soon becomes red, and finally assumes a fine scarlet tint,
while the supernatant liquid becomes yellow, and contains nitrate ( f
luteocobalt. After washing with hot water and drying, a fine crystal-
line scarlet salt of thallium is obtained, which has the formuhi,

Co,(NO,),;n,+20H„

as the following analyses show : —

0'3964 gr. gave 0*3724 gr. sulphates of cobalt and thallium =

93-94%.
0-9879 gr. gave 0-0034 gr. water at 102° C.=zO-34%, 0-010 gr. at

130^-135'' C.= 1-02%, and 0-0318 gr. at 150* C.=: 3-229^.

VOL. XI. (x. S. II.) 3

34 PROCEEDINGS OF THE AMERICAN ACADEMY

The formula requires 94-39% of the mixed sulphates 2SO^Co-)-
3S0^Tl„ and 1'8G% water. The salt is partially decomposed above
140^ C.

The thallium salt is very slightly soluble even in boiling water.
Its formation is expressed by the equation, —

Co,(NO,),,Lc-h6TlN03 = Co,(NO,)j,Tl,+Le(N03)«.

It may also be prepared directly by adding a solution of a salt of cobaltic
nitrate or sulphate to a hot solution of thallous nitrate containing a
slight excess of free acid, and then adding a solution of sodic nitrite?
Tlie salt prepared in this manner, however, is apt to contain a little of
the corresponding sodium salt. The thallium salt is a valuable re-
agent in investigations on the cobalt compounds which contain nitroxyl.
IS'Oj. since, taken in connection with the characteristic silver salt of
Erdmann's series, it enables us to recognize and distinguish compounds
which contain Co.,(N02),2 from those which contain Cn2(XH„)^(N02)s,
which is otherwise by no means easy.

The relationship of the luteocobalt salt above described to tlie otlier
metameric salts of the series may be expressed as follows : —

\ Co,(NH,),J \ Co,(NO,),,^ = •2.Co,(NH,),(XO,)«,

the salt having the same atomic weight as the octamin salt already
described represented by the formula, —

|Co,(NH3)3(NO,),nCo,(NH3),(NO,)J.

Ammonia-cohalt-nitrite of Luteocobalt. — A solution of nitrate of
luteocobalt gives with one of Erdmann's salt of potassium, Co2(NH.5)^
(NO.,)jjK„ a fine granular orange-yellow precipitate, whiclr is slightly
soluble in cold water, but dissolves in much boiling water, and crystal-
lizes from the solution without change. Its much greater solubility
distinguishes it from the metameric salts containing Coo(NO.^),2. The
constitution of this salt is expressed by the formula,

^Co.,(NIL),j1Co.,(XIL),(XO.,);J3 or C<.,(NIL)„(NO,)„H-
(Co,(XH,),(NO,)j3,

as tlie following analyses show : —

0-3311 gr. gave 0-2077 gr. SO, Co = 23-88 9/^ cobalt.
0-5073 gr. gave 141-5 c.c. nitrogen at 9'^C. and 7(30""" = 33-86^^
nitrogen.

The formula requires 23-79'% cobalt, and 33-879^ nitrogen.

A solulidii of this salt ffives with argentic nitrate the cliaiacteristic

OF ARTS AN- 1) SCIENCES. 35

salt, Co2(XII.,)^(NO^,)^A<.f._, ; it also gives, though soincwli it slii-iizi-hly,
the characteristic reactions of salts #f luteocobalt. Tiir analyst's and
reactions leave no iloubt as to the true constitution of the salt. Its
relations to the other bodies metauieric with it may be s-een fioni the
expression, —

lCo,(\II,),, nCo,(NH3),(NO,),V, = 4 Co,(NII,)„(NO,)«.
It has the same molecular weight as the octamin salt : —

In the metameric series to which I have directed attention, at least
two other members are theoretically possible. Thus we shoulil cer-
tainly expect the reactions and products indicated ijy the eipia-
tions : —

3.Co,(NH3),o(NO,),Cl,+2.Co,(NO,)„Na, = \ Co.^{^ll,),,U
|Co,(NO,),J,+12NaCl.

3.Co,(NH3)3(NO,),Cl,+Co,(NO,)„Na„ = \ Co,{^U,),(NO,\U
|Co2(N02)„f+6NaCI.

The first or xanthocobalt salt would be empirically, 5.Co2(X.Il,)g
(XOo)^, v.'hile the second or croceocobalt salt would be 4.Co.,(NH3)g
(N02)g. I have more than once been fully confident that I had ob-
tained both these salts ; but in the final revision of my work I did not
succeed in obtaining either for analysis, and their existence must
therefore, for the present, remain doubtful. The difficulty in pi-epar-
ing the salts of the Co2(N02)]2 series depends mainly upon the fact
that it is iiidispensable to avoid an excess of sodic nitrite in preparing
the solution of Co2(N02),2Nag in that salt, as the sodic nitrite acts
readily on the new salts formed. The jwssible existence of the aidiy-
drous xanthocobalt salt of the Co2(N02),2 series is, however, shown by
the existence of the compound

lCo2(NIL)„(NO2)2|3lCo2(NO2),2^,+0OIl2,

which I have described with the salts of purpureocobalt, but which, as
already stated, belongs, as its reactions show, to the xanthocobalt sei-ies.
The metameric compounds, the existence of which may be con>id-
ered as fully established, are as follows, denoting ammonia by A, and
NOg by X, for brevity : —

36

PROCEEDINGS OF THE AMERICAN ACADEMY

Octamin salt, ^CooAj,Xj ICojA^X^^ = 2. Co.^A^Xg

Xanthocobalt salt, ^Co^,A,„X^| ^ Co^A^Xg^.^ = 3. Cc\,A,.Xg

Luteo salt «, j^'o^Aj.J ^Co^XjJ = 2. Co^AijXg

Luteosaltp, iCojAj^nCoaA^XJg = 4. CojA^Xq
Erdmann's salt, 1. CogAyXg

The salts of luteocobalt, the formulas of which may be considered as
well established, are as follows : —

Cldoride,

Iodide,

Bromide,

Nitrate,

Sulphate,

Chromate,

Dichromate,

Oxalate,

Carbonate,

Acid carbonate,

Phosphate (Braun),

Pyrophosphate,

Cobalto-uitrite (Sadtler,

Gibbs),
Amnionia-cobalt-nitrite,
Sul|)hato-chloride (Krok),
Sulphato-iodide (Krok),
Chromo-chloride (Braun),
Cobalticyanide,*
Ferrieyanide,*
Chroniicyanide (Braun),
Platino-chloride,
Auro-chloride,
StiUinoso-cldoride (Braun),
IIvlrar<ro-chloride (Krok),
riydrargo-cldoride (Carstan-

S ul phato-hy drargo-chl oride
(Krok).

Co,(NH3)i,Cle

Co,(NH3),Jg

Co,(NH,3)„3rg

Co,(NH3),,(N03)g

Co,(NH3),,(SO,)3+oOH2

Co,(NH„),,(CrOj3+50H2

Co^(N H3),.,(Cr.,0.),+50 rij

Co;(NH3),,'(aO,)3+40H,

Co,(NH3),,(CO,,)3+70H,

Co.,(NH3)i.,(CO..)3+CH.,0,+50H2

Co;(NH3);,(PO,),+80H,'

Co,(NH3)i,.P,Oi34-60H2

Co„(XIl3),2.Co.,(NO.O,.,

Co,(NIl3),,^Co,(Nll3),(NO,),U

Co„(NIl3),.,(80,).,Cl.,4-GOH.,

Co^(NIl3),;(SOJj/

Co.,(NH,)io(CrOJ.,Cl„-|-10Oll3

Co;(x\H3),;Cy«+Co,Cye

Co.,(NnO,.,Cyo+Fe.,Cv6

Co,(NH3),,Cy,+Cr,Cy«

Cc/NFyisCl^+SPtCl.+GOHa

Co,(NIL),Xl,,-i-2AuCl,

Co2(XH,)„"ci,+;JSnC'i,4-SOII,

Co,(NH3),;Cl,+2HgCi,4-30H,

Co,(NIl3),,Cl,+4ngCl,+OIT,

Co,(NIl3),,(SO,),Cl,+2IIgCl,

* The analyses of tlie cobalticyanide ami forricyanide made by Gcnth and
myself correspond better with a formula containing one atom of water of crys-
tallization.

OF ARTS AND SCIENCES. 37

Sulphato-platino-ohloride, Co,(NH3),,(80J,Cl+PtCl,

Cerous double sulplnite

(Winjr), Co,(NII,),,(SO,),+;3SO,Ce+OII,

Ceric double sulpliate (Wing), Co.^(Nll3),^(8Oj8-|-Ce,(80J,4-0ir.,

Ift/pen'odides, Ni/perbromides, S)-c. — When bromine is addcfl to solu-
tions of the salts of roseocobalt, purpureocobalt, and luteocol)alt, yellow
or orange crystalline precipitates are formed which contain bromine in
excess of the quantity of the chlorous element necessary to form a
normal salt. These compounds give off bromine readily on tlrying,
and cannot be obtained pure for analysis. Iodine behaves in u sim-
ilar manner with some of the cobaltamines, but not with all. I have
already described the hyperiodides of the xanthocobalt and croceoco-
balt series, and shall content myf^elf with having established the exist-
ence of this class of compounds which bear a certain resemblance to
the hyperiodides of the higher alkaloids.

FORMATION AND PREPARATION OF THE COBALTAMINES.

In our joint memoir Genth and I confined our attention almost
exclusively to the determination of the constitution of the cobaltamine
salts and to their description, reserving a detailed study of the mode
of formation of these compounds for the second part of our work.
Circumstances prevented for many years a resumption of the subject.
In the mean time the excellent memoir of Dr. Friedrich Rose * has
appeared, and in this the formation of the cobaltamines by the oxida-
tion of ammoniacal solutions of cubaltic salts has been carefully studied.
The memoir contains also the fullest history of the whole subject which
has yet been given. Rose's results may be epitomized as follows:
An ammoniacal solution of cobaltic chloride absorbs oxygen, forming
a brown solution which, after some days, becomes red by loss of oxy-
gen. The red solution can again absorb oxygen and become brown.
When strong chlorhydric acid is added to the brown solution, carl)()iiic
dioxide and chlorine are evolved, while a reddish-yellow precipitate is
formed. This precipitate is a mixture of the chlorides of pnr[inren-,
roseo-, and luteocobalt, of a black salt for which no rational forujula

* Untersuchungen iiber amnioniakalische Kobalt-Verbimlungen. Von Dr.
Friedrich Rose. Heidelberg, 1871.

38 PROCEEDINGS OF THE AMERICAN ACADEMY

has yet been given, and of the two green chlorides. The mother
liquor contains cobaltic chloride, the two green chlorides, Co2(Nn.;)g
C\^-\-20U,, and Co, (N 113)^01^+20112, and traces of all the other
salts.

Rose determined quantitatively the proportions in wliich the differ-
ent salts were formed when different relative quantities of ammonia
and cobaltic chloride were employed. His results do not sustain in
his opinion the view taken by Genth and myself, that in the oxidation
chloride of luteocobalt and an oxy chloride which we should now
write, C().,(NH.,)j„.O.Cl^, are formed. This view, since the publication
of the first part of this memoir, appeared to be strongly supported by
experiments of Blomstrand, which showed that iodo-sulphates of roseo-
cobalt and luteocobalt are formed when a solution of cobaltic sulphate
in strong ammonia-water is heated with iodine. Blomstrand rei)re-
sents the reaction in this case, as regards the formation of the iodo-
sulphate of luteocobalt, by the equation, —

The formation of the corresponding iodo-sulphate of roseocobalt ma}"-
be explained with equal facility. It was natural to expect the similar
reaction expressed by the equation, —

2 Co(NIl3),.Cl,+0 = Co,(NH3)i„.O.Cl,+2NH3;

but Rose's results show that the role of the oxygen is, in most cases at
least, different from that of the iodine, at least Avhen free oxygen is the
oxidizing ngent. Rose failed to determine the nature of the brown
compound which is formed during the oxidation of an ammoniacal
solution of cobaltic chloride, and which is, in his opinion, the source of
all the other chlorides. It is consequently impossible to express the
derivation of these chlorides fi'om their [)rinaitive by means of otjuations.
But with cobaltic nitrate and ammonia the case is different. Fremy
long since showed that in this case the nitrate of " oxycobaltiaque," to
wliich he gives the formula, Co,(NII,,),-.0,.(NO,,,)_,+OII,„ is formed.
Bypassing a rapid current of air through a solution containing cobaltic
nitrate, ammonia, and amnionic nitrate, I obtained an olive-brown
solution, which after twenty-four hours deposited dark olive-green
prisms in abundance. These were dried by pressure between folds of
pa[)er, and then for twelve hours over sulphuric aelu. Of this salt, —

OF ARTS AND SCIENCES. 39

0-5479 gr. gave 0098<l gr. SO^Co = 17-H7r/ cobalt.
0-8183 gr. gave 0-1-459 gr. SO^Co = 17-83% cobalt.
0-4040 gr. gave 0-2170 gr. water = 5-19<y{, hydrogen.
l-00(iO gr. gave 0-4005 gr. water =^ 5-09''^; bydrogeii.
0.4091 gr. gave 118-5 c.c. nitrogen = 2^-97% nitrog(Ui.
0-3035 gr. gave 109-4 c.c. nitrogen = 29-93<y^ nitrogen.

These analyses correspond tolerably well with the emi)irical for-
mula, —

Co(NIl3)A(NO,),+OII„
which requires, —

Calculated. INIean. Found. Freiiiy's formula.

Cobalt, 2 18-55 17-S5 17-83 17-87 19-54

Hydrogen, 34 5-34 5-14 5-19 5-09 5-03

Nitrogen, 14 30-85 29-45 28-97 29-93 32-45

Oxygen, 18 45-28 47-51 43-38

In judging the analyses it must be remembered that the salt cannot be
recrystallized, as it is instantly decomposed by water. By standing
for a long time over sulphuric acid, the salt loses water and some am-
monia. In a salt so dried, —

0-5088 gr. gave 0-2090 gr. SO.Co = 20-12% cobalt.

0-3290 gr. gave 0-0859 gr. NH3 =20-11% ammonia (by boiling

with KHO solution and titrition).
0-4308 gr. gave 0-1124 gr. NHg =20-09% ammonia (by boiling

with KHO solution and titrition).

The undecomposed anhydrous salt would contain 19-00% cobalt, and
would give oft' by boiling with potash 28-33% ammonia. I consider
the true formula of this salt * to be twice as high as that given above,
so that it becomes, ^ —

Co,(NH,),,0,.(NO,),+20H,.

Fremy found very nearly the same percentages of nitrogen and hydro-
gen, but a much higher percentage of cobalt, 2077%. He also found
that the salt is readily decomposed by water with evolution of oxyo-en.
In a single analysis to determine the quantity of oxygen evolved, I
obtained the following results: —

* In a letter to the German Cliemical Society, I have represented tiie nitrate
of oxycobaltiaque as containing four atoms of ammonia to one of cobalt ; but a
careful revision of my analyses leads to the formula given above. Deutsche
Chem. Gesell. Berichte, iv. 790.

40 PROCEEDINGS OF THE AMERICAN ACADEMY

1-4510 gr. gave 59-5 c.c. oxygen at 22*^ C. and 758 """ = 5-25%
oxygen.

This would correspond to one atom of oxygen for the formula given
above. Fremy also determined the amount of oxygen given otF by the
action of dilute sulphuric acid, and obtained as a mean of two analyses
r)-20%. So far as can be judged from the analyses above, the formula
which I have given deserves the preference. On the other hand,
Fremy's formula, which I double for the sake of comparison,

Co,(NH3),„0,(N03),+20H„

is perhaps somewhat simpler, and explains all the known reactions at
least equally well. The corresponding structural formulas may be
written, —

Co,

NH3— NFI3— NO3

N H3— NII3— NHg— NO3

O, C02

N H,— NH3— NH3— NO3

NH3— ^H3— NO3

NH,— NH3— NO,

NII3— NH3— Nri3— N ),

O.,

NH,— N H, — N 1 1 .,— NOg

NIL— N a, —no!

I adopt provisionally the formula which agrees best with the analy-
ses, fully recognizing the possibility that the other may prove correct.
In this connection I may mention that when iodine is added to a solu-
tion containing cobaltic nitrate, ammonic nitrate, and ammonia, an
olive-green crystalline precipitate is thrown down which contains
iodine, and which may prove to be either the iodide corresponding to
the nitrate above discussed, or an iodo-nitrate corresponding to the
oxy-nitrate. The formation of this nitrate may be expressed by the
equation, —

4Co(N03),+24NIl3+20H,+80 = 2.|Co,(NH3),,.0,.(N03) J
+20(N1I,),.

It is remarkable that the action of iodine upon an animoniacal solu-
tion of cobaltic nitrate is not analogous to its action upon an amnioiii-
acal solution of the sulphate. When the nitrate is heated with clilor-
hydric acid, a small quantity of cliloride of purpureocobalt is, as I
find, always formed. We may have the reaction expressed by the
equation : —

Co,(NIL)„0,(N03),+12IICl = Co,(NIl3),„Cl,+4N03lI+
40II,+6C1 ;

but the greater part of the nitrate is decomposed^ The formation of
the chloride of puipureocobalt under the circumstances is, I think, a

OF ARTS AND SCIENCES. 41

strong argumont in favor of douhliiig tin; formula given \>y Fi'cniy, or
at least of regarding the cobalt as hexatoniic in this salt.

The above results appear to me to render it probable that the brown
solution formed by the oxidation of au ammouiacal solution of cobaltio
chloride contains chiefly

Co,(NII,)„,0,.Cl,.

According to Rose, the brown solution gives off oxygen by long
contact with the air, forming the well-known red licpxid whidi yields,
by boiling with sal ammoniac or chlorhydric acid, chloride of purpureo-
cobalt. If we suppose that six atoms of oxygen are given otl" from
two molecules of the oxychloride, the salt, —

Co,(NH3),oOCl„

will remain in solution, and it is easy to see that this, by boiling with
chlorhydric acid or ammonic chloride, will yield chloride of purpureo
cobalt, since we have —

Co,(NH3)j„OCl,+2IICl = Co,(NII,)j,Cl,+OH,.

This is precisely the view taken by Gentli and myself as regards the
nature of the red solution, though we did not trace its origin to the
brown oxychloride. Genth and 1 stated in our paper that tlie yives-
ence of ammonic chloride was not necessary for the formation of
chloride of roseocobalt by the oxidation of an ammoniacal solution of
cobaltic chloride. We did not state, as Rose * appears to have under-
stood us, that it is a matter of indifference whether amnionic cldoride
is present or not. Rose has shown that in the presence of this salt a
much larger relative amount of chloride of purpureocobalt is fornu;d.
Thus, as a mean of eight experiments, he obtained from one hundred
grams cobaltic chloride, oxidized in presence of sal ammoniac, 134" 6
grams chloride of purpureocobalt, and 1 2* 12 grams chloride of luteo-
cobalt. When no sal ammoniac was present, he obtained, as a mean
of eight experiments, 90-66% chloride of purpureocobalt, and 1G"82
grams chloride of luteocobalt. Rose's results in no way disprove the
existence in the oxidized solution, after giving off oxygen to the air, of
the oxychloride Co2(NH.,),|,.O.Cl^ ; and this view, which is perfectly
consistent with the facts, still gives the simplest explanation of them.

Genth and I always obtained the largest relative quantity of luteo-
cobalt when the solution exposed to the air contained cobaltic chloride

* Loc. cit. p. 76.

42 PROCEEDINGS OF THE AMERICAN ACADEMY

and sulphate, ammonia and coarsely powdered amraonic chloride in
large excess. I have obtained the same results in frequent repetitions
of the process. According to Rose, this result is due not to the foima-
tion of a greater amount of luteocobalt salts in consequence of the
presence of sal ammoniac, but to the fact that the precipitation of the
sulphato-chloride, Co^(NIl3)j„_,(SO^).,Cl2, as fast as it is formed, prevents
its further decomposition. Rose's own experiments, cited above, show
that the larger quantity of chloride of luteocobalt was formed, when no
sal ammoniac was present, when only cobaltic chloride was employed.
He sugi^ests that the quantity of luteocobalt formed depends upon the
longer action of a concentrated solution of ammonia upon the oxidized
solution. If this be the case, the luteocobalt must be formed by the
direct oxidation of the solution, and not by the decomposition of the
brown salt, whatever that may prove to be. Yet Rose assumes that all
the other cobaltamines are formed by the decomposition of this brown
salt.

The results of Fremy, in connection with those of Rose, appear to
show that in the oxidation of an ammoniacal solution of cobaltic
chloi'ide at least two browu salts are formed. These are the chloride
of oxy-cobaltia, Co.,(NII.;)j||O^Cl^, and the chloride of fuscocobalt
(octamin oxy-chloride), Co^(NH3)gOCl^, the last named being in rela-
tively small quantity. By the action of chlorhydric acid upon each of
these salts the chlorides of luteocobalt and i)urpureocobalt are formed.
This appears in the case of the octamin salt from the experiments of
Fremy,* SchiiF, f and Braun t ; in the case of the salt of oxy-cohaltia
(tetroxy-decamin), from those of F. Rose. In Rose's ex[)eriments
relatively small quantities of the hexamin and octamin chlorides,
Co2(NH.,)yCl|;, and Co2(NH3),^Cl,;, were always found in the mother
liquor after the precipitation of the chlorides of purpureo- and luteo-
cobalt by chlorhydric acid. It seems at least probable that the octa-
min chloride is formed from the brown oxy-chloride or fuscocobalt
salt of Fremy, since we may with great probability expect the reac-
tion expressed by the equation, —

Co,(NH3),OCl,+2HCl = Co,)NH3),Cl„+OH,.

Rose also obtained in his experiments a nearly black crystalline salt,
the analyses of which, however, did not lead to any rational formida. lie

* Ann. (le Chiinie et de Physique |3] T. xxxv. 280.
t Ann. der Chemie und Pliarniaeie, cxxf. 124, cxxiii. 1.
t Ann. der Chemie und Pharmacie, cxl. ii., p. 60.

OF ARTS AND SCIKNCR^^. 48

compares liis results witli the two t'onuiilas (old style), Co,,Cl|,ON'|,.II|j.,
and Co,,Cl,,OoN,^II^^.. I liiid tliat his analyses agree fairly well willi
the t'orniida, —

Co,(xiy,.o.ci,+Nii,ci.

Thus we have, —

Calculated.

FouikI (mean).

C'ibalt,

2

27-34

2.S-46

Chlorine,

5

40oo

41-r,4

Nitrogen,

7

22-71

23-43

Hydrogen,

22

5-00

5-33

If we suppose that the blaek salt consists at least essentially of
Co^(NII.,),..O.Cl4 the formation of Rose's dark green chloride of dichro-
cobalt is readily explained by the ecpiation. —

Co,(NIL),.O.Cl,4-211Cl = Co.(NII,),ri„+OIL,

The existence of such a double chloride as Co„(NII.,)|..O.Cl4-[-
NH^Cl is in itself not very probable, nor is it easy to see how such a
salt could be dissolved in concentrated sul{)luiric acid, and precipitated
by cldorhydric acid without change. Farther investigations are re-
quired to determine the constitution of the salt definitively.

Terrell * appears to have first shown that salts of the cobaltamines
are formed when powerful oxidizing agents are added to ammoniacal
solutions of cobaltic salts. Terrell employed hypermaiiganates and
hypochlorites ; Brauii.f the hyperoxides of lead and manganese ;
Mills, + iodine, bromine, and potassic dichromate ; Blomstrand, §
iodine and cobaltic sulphate. On repealing these processes, I find that
that of Mills with potassic dichromate is by far the best for preparing
nitrates of roseocobalt and purpureocobalt. Blomstrand's method is
inconvenient upon the large scale in consequence of the insolubility of
the sulphato-iodide of luteocobalt, but answers well on the small scale,
and gives a fine lecture-table experiment. A good method of prepar-
ing the salts of luteocobalt in quantity is still wanting, as the chloride
and nitrate form valuable reagents in various aTialytieal opei-ations.

* Zeitschrift fur Anal Chemie, v. p. 114. t Comptes Rendus, Ixii. p. 139.
X Phil. Mag. (4) xxxv. p. 245. § Cliemio tier Jetztzeit, p. 295.

44

PROCEEDLNGS OF THE AMERICAN ACADEMY

THEORETICAL VIEWS.

Since the appearance of the first j)art of this paper many chemists
have given expression to theoretical views of the constitution of tlie
ammonia-cohalt salts. Of these 1 think it will be necessary to notice
only those in which the atomicity of cobalt is taken into account, the
older theories having passed away with the chemistry of which they
formed a part. So far as I can determine, Frankhuid* first endeav-
ored to reduce the formulas of the cobaltamines to atomistic expres-
sions. In the first edition of his lecture notes he gives for the chlorides
of purpureocobalt and luteocobalt respectively the formulas, —

Co,

NH„(NHja

nh:(nhjci

nh:ci

NH..C1
NH'(NHJC1

nh:,(nh,)ci

Co., ^

' NH.,(NH,)C1
NR,(NHJC1
NH.',(NH,)C1
Nir,(Nri,)Cl
NII"(XIIJC1

[ NIi;(NIljCl

It is easy to see that tlie other series of salts may be formulated in
a similar manner. Franklaud's view was an important step in ad-
vance. It may fairly be objected to it, however, that it involves the
replacement of hydrogen in ammonium by ammonium and by chlorine,
a view which was not new, and which is certainly defensible, but
which has never been generally received by chemists. If we replace
in ammonium, NI[^, one atom of hydrogen by one atom of chlorine,
and another atom of hydrogen by an atom of ammonium, it is difiicult
to see how the new ammonium, NH2(NH^)C1, can possess a suffi-
ciently well-marked chlurous power to unite with the highly zincous
cobalt so as to form an extremely stable compound.

In a paper on the theory of atomicities, f I have given another view
of the constitution of the cobaltamines and of the analogous platin-
amines. If nitrogen be regarded as pentatomic, ammonia will be
diatomic, and any number of atoms of ammonia may be regarded as
constituting a single diatomic whole. Taking the atomicity of cobalt
(Co :^ 59) as 6, two atoms of tlie metal may be supposed to unite to

vi vl

form a complex with eiglit units of affinity, since we have =Co = Co= ;
of these eight units two will be saturated by the diatomic anmionia,

* Lecture Notes, 1st edition, p. 1%. t Am. Journal, Vol. xl^v. Nov. 1807.

OF ARTS AND SCIRNCRS. 45

tho Other six by clilorine, &.c. Upon this view cliloi-idi^ of i)iir|)iirco-
col);ilt becomes (IONII3) = Coj 1 Cl^, and diloiidc <»f hilcoi-olcilt
(12XIIjj)= Co^, I Cl,j. In this manner the old theory of coii|tlft.s or
(•onjii<jjate ammonias may be rationalized and brought into liannoiiy
with modern ideas. Two strong object ions may be uri^ed a<,Minst tiio
tlieory here proposed. The first is that it recpiires us to eon^^ider au
atom of cobalt as hexatomie, while it exhibits in no other compcMunl
an atomieity higher than f.mr. The other objection has, I think,
mnch greater weight. To explain upon this view the cases of isomer-
ism, to which I have myself directed attention, it becomes necessary to
assume that there are at least three allotropic forms of col)alt. — an
assumption wholly unsupporced by any other and independent evi-
dence. On mature consideration I have therefore rejected this theory.
The objection which I have urged against my own view, that it re-
quires us to consider cobalt as hexatomie, with the atomic weiglit 59,
may be avoided by considering the metal as tetratomic, and regarding
the two atoms as united by 6, 8, 10, or 12 atoms of ammonia, so that
the general formula of a normal cobaltamine chloride will be —

CI CI

I I

CI — Co — (nNH,,) _ Co — CI
I " I

CI CI

since n atoms of ammonia will always form a diatomic whole. The
other objection, that the theory obliges us to assume the existence of
several allotropic forms of cobalt, will, however, still remain.

The view which T now adopt is in substance that of Blomstrand,
which affords, as I think, the simplest and most satisfactory explana-
tion of the whole series of ammonia-metallic compounds at present
known, and which, while not free from theoretic ditficiilties, is yet iu
harmony with all the facts.

According to this view, two atoms of tetratomic cobalt are asso-
ciated to form a hexatomie molecule, the six units of affinity being, in
all the cases at present known, in combination with four or six atoms
of ammonia, regarded as a diatomic. Six units of affinity remain, and
may be incompletely saturated by other atoms of ammonia or com-
pletely by chlorous elements or residues. Thus, on Blomstrand's view,
the .chlorides of purjiureocobalt or roseocobalt and luteocobalt have
respectively the formulas, —

46

PROCEEDINGS OF THE AMERICAN ACADEMY

Co.,

CI

NIT— X IT..— CI
Nil,— XH3— Nil— CI
) Nil,— NH— NIL— CI
NII-NII3-CI '
CI

and Co, <

XH.,— CI
js^H.'- NTT— CI
Nil"— nit'— NH..— CI
NH.!— NH.!— NTT.;— CI
NH.!— NH.— CI "
NH.,— Cl

As I have adopted this view throughout, further illustrations will be
unnecessary. The advantages of the theory are, I think, first that it
regards cobalt as tetratomic, and reduces the whole series virtually to
the type of C02O3, or Co^Cl,;, and secondly that i; enables us to explain
the different cases of isomerism without arbitrary assumptions as to
the existence of allotropic forms of cobalt. Thus it is easy to see that
there may well be a difierence between compounds having respectively
the symmetrical structural formulas, —

f NH3— Cl
I NH.,— NH3— Cl
jr.] NH.!— NH.,— Cl

I- '^o, s ]srH _xii^_ci

NH

r CI

NH3— NH,— CI

II. Co, i

NH3-CI

NH3-(;i

N H,— N H„— N TL— CI
N h!!— N 1 1 J— N H3— Cl
NH3— NIT..— Cl
Cl

f Cl
NH„

nh!!

"I- c^^ s;;:-Sn::

Cl

NIT..- NIL

-NIT.,— CI

NH3— CI
Cl

-NH3— NTT3— Cl

IV. Co., y

Cl
Cl
NH3— NH3— NH,— NTT.

NH.,

Cl
Cl

-NH,

-XH._CI
-NH.,— NTI3— NII3— Cl

and that supposing that the six units of affinity of Co^, are qu;ditatively
exactly e(iual, the complex, Co^,(NIT.,),„Cl,;, admits of being arranged
in a great variety of ways. Now since the salts of roseocobalt and ]uu-
pureocobalt resemble each other as regards the types to which they
belong and as eitlier of these types may be fornnilated in a great
variety of ways, it becomes vci-y dillicult to di'tcrmine which strucliiial
fornnda to adopt for the com|)oun(ls of either series.

Thus the salts of roseocobalt and of jxirpureocobalt. nsually at least,
belong eitlier to the types RcX^ and I^•X^., to RcX^Y^ and rcX^\\„

OF ARTS AND SCIKNCKS.

47

or to RcX.^Y^.Z.j. Now the salts of oitlier of tlicse types may Ix' <'(|iially
well referred to either of the striietural formulas jriveu alfovc 'I'd
which of thfin are we to refer salts of rose(Jcol)alt, and to u liicli >alts of
pnri)ureocobalt ?

Blomstraiul gets over tlic dilliciilly in part hy the slioi-t and easy
method of declaring that chloride of roseocobalt is only the hy-
drate of chloride of pnrpnreocohalt. I think I have shown ccn-
cliisivi'ly that this view is wholly untenahle. lint, even if we admit its
correctness, to which of the four structural formulas shall we assign
chloride of ])urpureoct)balt alone, since all four explain its relations to
other chlorides, and its products of replacement equally well ?

The case is the same with tlie other cobaltamines, though in these
we have no isomerisms to explain, in the present state of our
knowledge at least. The dodecamin and octarain series exhibit the
two types LcX^, OcX^, and LcX^Yj, OcX^Yj, with perfect distinctness ;
but in additiou we have in the case of the dodecamin series the type,
LcX.Y.., as, for instance, in the phosphate described by Brauu,
Co2(NHg),^,(P20^)-f-80H2, and perhaps also in the pyrophosphate
Co.,(NH..),2P^Oj.,-{-*jC)H2, though this salt may be referred to the type,
LcX,., if we consider (PjOj.,) as a hexatomic complex. Luteocobait
may therefore be saturated, if I may so speak, by ones as in LcCl,.,
by twos as in Lc(S0^)^l2, and by threes as in Lc(PO^)„. It would
seem as if we in this manner arrive most naturally at the structural
formulas for the dodecamin series, —

Co., i

f a— a— CI
a— a— CI
a— a— CI
a— a— CI
a— a— CI
a— a— CI

Co.,

a — a — O
a—a— O
a — a — 1
a— a— I
a— a— O
a — a-

-O

>S0.,

>S0.,

Co.,

a— a— O )

a— a— O y PO

a—a— O )
f a— a— () )
I a— a— O PO
[ a— a— 0 )

in which the six ammonia groups have equal weights or qualitative
values, so that the six units of affinity of Coj must also be of the same
kind and the same iuten ity. But, if we examine the list of salts of
roseocobalt which I have given, we find that Krok has described a
salt with the f .rn.ula, —

Co,(Nn3),,(N03)3Cl3+3HgCl, ;

48

PROCEEDINGS OF THE AMERICAN ACADEMY

and among the salts of purpureocobalt we find the formula, —

Co,(NH3),„(N03)3CL+Co,(NH,),,(N03)«.

Roseocobalt and purpureocobalt may therefore also form compounds
in which the six units of affinity are saturated by threes. Now since
tliese saks contain only ten atoms of ammonia; and since these can only
be distributed in pairs of different structure, as in formulas I., II.. 111.,
and IV., it follows that we cannot fairly draw the inference that in the
dodecamin series the atoms of ammonia are arranged in six perfectly
equivalent pairs.

Blorastrand gives to chloride of xanthocobalt the structural for-
mula, —

f 0— NO

a —a— CI

a —a— a —CI

a —a— a —CI

a —a— CI

O— NO

Co.,

upon the ground that cobalt unites with O.NO in Fischer's salt
Co.,(N02)i2lVg with peculiar energy. We seem in this way to gain a
Ttov Gt(6 for this series ; and, if we admit the force of the argument, we
must write the formula of chloride of roseocobalt, —

CI

a—

-a-

-Cl

a —

-a-

-a—

-CI

a —

-a-

-a —

-CI

a —

-a-

-CI

CI

C02 <

On the other hand it is a question whether the remarkable stability
of Co.,(NO.,),.,Kg can fiiirly he attributed to any special allinity nf
cobalt for NO.,. We have a complex whole, which we find remark-
ably stable ; but is not this stability the resultant — so to speak — of
the whole structure, just as the strength of an arch resides in the whole
arrangement of its elements, and not in any single one ? The otlur
c )l)alto-nitrites, as, for instance, Sadtler's salts, Co(NO^,)o-|-NaNO^,. and
Co(NO.,)2-|-2NaNO.„ are not remarkably stable, but ratlicr tlie re-
verse. The salts of xanthocobalt are easily decomposed, both by acids
and alkalies. For these reasons it does not seem to me tliat Blom-
s'rand's arrangement of the atoms in these salts deserves any special
preference at present.

Blomstrand's views as to the constitution of the metal-jinunouias

OF ARTS AND SCIENCES. 49

form part of a complete system to the exposition of wliieh lie has
devoted a large work.* I must refer to this work for the arguments
which ho adduces in support of his theory, since no ahstract can do
them full justice. But I may be permitted here to notice one or two
points of fundamental importance.

Blomstrnnd begins with a discussion of the platinamines, our knowl-
edge of which has been so greatly increased by the sph-ndid researches
of Cl^ve. He assigns arbitrarily to the chloride of Keiset's iirst base
the formula, —

u fa-a-Cl
^t la— a-Cl

AVhen chlorine is passed into a solution of this salt, the chloride of
Gros's base is formed, and Blomstrand attributes to it again arbitrarily
the formula, —

CI

a — a — CI

a— a— CI

CI

Pt^

He employs the same mode of formulation in the case of the chlorides
of jReiset's second and Gerhardt's first base ; namely, —

Pt-}'^~S and Pt<

( a — Li

rci

a— Cl
a— CI
Cl

I admit that it seems most natural to attribute to the formula of the

chloride of Reiset's first base the symmetrical fonnula, Pt < ' ^,'

( a — a — K^i

c j^ a a Cl

instead of the unsymmetrical formula, Pt < ' p, ' ; but even if

( f^\

we start from Pt ■< z^,' as from a fixed point, how is it possible to

(a — a — Cl ^ ^

say with certainty that under the action of chlorine there may not be

a re-arrangement of the atoms of ammonia, so that we have for the

chloride of Gros's base the structural formula, —

fa— Cl
'^,. Ja-Cl

a— Cl

which has a higher degree of symmetry, or is, in other words, more
homogeneous than Blomstrand's formula, —

* Chemie der Jetztzeit. Heidelberg, 1869.
VOL. XI. (n. 8. id 4

50

PROCEEDINGS OF THE AMERICAN ACADEMY

Pt ^

rci

a— a— Cl
a—a— CI
Cl

and which explains the formation of the different salts at least equally-
well ? In this case, as in the cases of the platiuainines generall}', we
have precisely the same difficulties which meet us in applying the
theory to the cobaltamines. We reason throughout from perfectly ar-
bitrary fundamental assumptions. Our only fixed points are the atomi-
cities of platinum and cobalt. All else is purely speculative. In the
present state of our knowledge we are not able tq say whether a chain
of atoms of ammonia, like — NH, — NHg — NHg — , has more or less
powerful affinities than the single divalent atom, — NH., — , or even
whether, — NHg — Cl, is more or less chlorous than a single chlorine
atom. But these points are of fundamental importance in the applica-
tion of the theory of atomicities to the metal-ammonias. Certai.nly
the great majority of chemists maintain that there is a perfect equiva-
lence of value in the units of affinity of the different elements, while
admitting that in complex molecules, as in the benzol ring, positional
differences may result from peculiarities of structure.

Blomstrand, on the other hand, maintains not merely that the four
units of affinity in tetratomic platinum are qualitatively different two
by two, but even that it is possible to determine in the case of which
pair the most powerful affinities are exerted. Thus he asserts that
if we write for platinum, —

^c

Pt<^

the two " points of attack," a and b, act differently from c and d.
With logical consistency he extends this view to nitrogen, cobalt, and
carbon, standing, so far at least as carbon is concerned, wholly alone, I
believe, in opinion, the question of a difference between the four units
of affinity in carbon having been long since discussed, and by connuon
consent decided in favor of their perfect equivalence.

While then I write the structural formulas of the chlorides of pur-
pureocobalt and of roseocobalt respectively : —

Co., ■{

a— Cl
a— a— Cl
a— a— Cl
a— a— Cl
a— a— Cl
a— Cl

Co, <

Cl

a— a— Cl

a — a — a — Cl

Chloride of purpureocobalt.

a^a — a — Cl ' ^

a — a — Cl
Cl
Chloride of roseocobalt.

OP ARTS AND SCIENCES. ,01

I expressly admit that the mode of formuhition is iii each case per-
fectly arbitrary.

The more carefully I have studied the siihject, the more full has
become my conviction that in the present state of our knowledge we
cannot assign absolutely definite structural formulas to the platina-
minesand eobaltamines u[)on Blomstrand's theory. While, therefore,!
a(loi)t this theory, I do so because I think tliat with all its defects it
is by far the simplest and most comprehensive yet proposed. But I
regard the particular structural formulas whicii 1 have employed sim-
ply as convenient illustrations, — provisional formulas which the pro-
gress of science may at any time modify.

In my forthcoming work on the metals of the platinum group, I
shall describe a few other salts of the eobaltamines, which are chieiiy
of interest in connection with those metals ; and I hope also to show
that some of the eobaltamines are valuable analytical reagents. In
closing my labors, I wish again to direct the attention of chemists to
the advantages offered by this class of salts in investigations. We
have in croceocobalt, xanthocobalt, and luteocobalt, respectively, dia-
tomic, tetratomic, and hexatomie bases, possessing the important prop-
erty of forming extremely well-defined and highly crystalline salts. I
suggest the employment of these bases as means of detern)ining the
atomicities of relatively chlorous molecules, as, for instance, of the poly-
meric modifications of phosphoric acid, and in other cases in which our
knowledge is still imperfect. The eobaltamines themselves still form
an extensive and most attractive field of labor. W^ith all that has been
done, there is no part of this field which will not yield au abundant
harvest of interesting and theoretically valuable results.

My grateful acknowledgments are due to my assistant, Mr. W. E.
Cutter, who has aided me in the analytical part of my work with most
paiieut and conscientious labor.

Cambbidge, June 8, 1875.

02 PROCEEDINGS OP THE AMERICAN ACADEMY

II.

OX THE SOLAR MOTION IN SPACE AND THE
STELLAR DISTANCES.

(Second Paper.)
By Truman. Hexry Safford.

Ix a previous paper, I have examined some of the older known proper
motions, and shown that they are favorable to the assumption that
the distances of the stars are, upon the average, inversely profjor-
tional to their projjcr motions. We cannot expect that this will be
equally true in all regions of the heavens. It will be necessary, as mate-
rials accumulate for the study of this problem, and other collateral ones,
to pursue the investigation more into detail ; including more stars, and
examining their motions as related to their position on the celestial
sphere, and especially to the apex of solar motion. The present paper
contains such a detailed investigation for an important class of stars.
Those here investigated are the two hundred and fifty whose proper
motions Argelander has discussed in the seventh volume of the Jionn
Observations, l*art L ; I am myself pre^jaring for another purpose a
similar discussion of about one hundred and fifty more, and other ma-
terial of the same kind is soon to be published in great quantities. So
that the present paper is also of use in fixing the form of the discussion.
From the formulte, —

cos / = sin Z> sin d -\- cos D cos 8 cos (« — A) ;
sin ;j cos \p' = — sin D cos d -\- cos D sin d cos {a — ^4) ;
sin y^ sin yj' = • cos D sin (a — A) ;

/J a cos d = /t g sin \p ;
/] 8 =:^ J g cos t/> ;

where

«, 8, the star's right ascension and declination,
/] a, /] 8, its annual proper motion in these co-ordinates,
A, D, the right ascension and declination of the apex of solar mo-
tion assumed known,
y, the star's angular distance from the apex,
xp', the angle of position at the star of the arc of a great circle

directed away fri)m the apex,
%f<, the angle of position of the star's apparent motion,
are calculated the values of the following table.

OF ARTS AND SCIENCES.

I have assumed as before, —

^ = 259''50'8 Z)= 32^29'!.
I noticed, too late for use in this series, that if we put

sin m sin M= sin D ;

sin m cos J/= cos D cos (« — A),

we can more readily use the formula}, which then become

cos X = sin m cos {8 — M);

sin ;{ cos xp' = sin 7/1 sin (d — M) ;

sin X sin xp' = cos D sin (a — A) ^=. cos mi,

53

tan xp' =

cot m

sm X

sm (S — J/)'
cos m
sin <|/'

by tabulating m, iJi^ and log. cot m, log. cos w, or like functionsfwith
the argument a.

In the following table, the stars are indicated by Argelander's num-
bers, and arranged in the order of their annual proper motions, the
largest (Groombridge, 1830) first.

The columns contain in their order the star's number, Argelander's
values of z/ ? and \p (Bonner Beobachtungen, Bd. VII. S. 109-11.')),
and those of xp', xp' — xp, and log. sin /, which I have computed by the
preceding forraulaj.

In order to get an approximate idea of what these stars indicate,
with reference to the relation between distance and annual motion, I
have taken the means of the cosines of xp' — xp in groujis of twenty-
five stars each ; the meanfe of the natural sines of )r are not syste-
matically variable to any great extent throughout the table.

Group.

Value of A s.

Mean (cos (\p' — \p) )

I.

7"053 — 1"171

0.586

II.

1. 103 — 0. 707

0.615

III.

0. 697 — 0. 583

0.468

IV.

0. 582 — 0. 489

0.390

V.

0. 485 — 0. 438

0.587

VI.

0. 435 — 0. 350

0.588

VII.

0. 348 — 0. 201

0.403

VIII.

0. 200 — 0. 249

0.582

IX.

0. 247 — 0. I80

0.502

X.

0. 184 — 0. 079

0.747

General mean

. . . 0.55G

54 PROCEEDINGS OP THE AMERICAN ACADEMY

The mean sine of f^ is about equal to the integral

/!

sin2 X 5 X
divided by the integral

or unity ; hence equal to i ;r =: 0.7854.
r
The value of — ^ will then, from the present series, be roughly
r A s

equal to 0.556 -~ 0.785 = 0.708,

with a probable error of about ± 0.023.

But it will be noticed that in the present group of stars the values of

COS. {\p' — Mj) increase as the proper motions become smaller ; in the

former paper they appeared to decrease; making it still more probable

that the variations in both series arise from the errors of observation,

and the very various regions in which the stars are situated, and not

from any general deviation from constancy in the ratio

r A s

The value of this ratio, from the previous series, was found equal to
0.666 for forty-three groups of the largest proper motions, and to 0.46
for eleven groups of smaller, or in the mean about 0.622 ; the best
of the two values agreeing nearly with the present determination.

This is sufficiently noteworthy, as the stars of the former series
were, on the wliole, those visible to the naked eye, or of the magni-
tudes one to six inclusive ; of the present ones, very few are brighter
than the sixth, and many are of the eighbh and ninth ; so that so far
the phenomena indicate hurdly any dependence upon magnitude. In
a future paper, I shall discuss a considerable number of other notable
proper motions, which I myself have been lately employed in deter-
mining for a catalogue of latitude stars ; and I intend to gradually
accumulate materials for a more minute investigation of the whole
subject, separating the stars according to their magnitudes and the
region of the heavens in which they are situated.

The delicacy of the investigation is very great, owing to the danger
of taking that for stellar motion which is simply the result of the
errors of observation. Of course the old observers had indifferent
instruments ; but as a rule they used them well, if their work had phin
and coherency enougli to be preserved. Bradley's observations
(1755) are still very accurate and indispensable ; Piazzi and Groom-

OF ARTS AND SCIENCES. 55

bridge (1800, 1810) are now old enoui;li to detcrmino many proper
motions; the early work of Struve, liessol, and Argelander (1811-
1830), makes up in accuracy what it lacks in antiquity.

But too many of the modern observers are careless in their compu-
tations, and unsystematic in their plan of work ; so that for many
important stars there are no very late observations, while for many
others a good many indifferent observations can be found and reduced
with considerable trouble. The subject is becoming more and more
chaotic, and will continue to do so, unless observers bind themselves
by more rigid rules not to make observations save with the utmost pre-
cision, the most thorough system, and the most intelligent plan, directed
towards a definite object. Of this fortunately there is good hope, as is
shown in the interest in the great zones planned by Argelander, and
now in progress under the auspices of the international " Astrono-
mische Gesellschaft."

The next step in the discussion will be to include the more numer-
ous proper motions soon to be determined. Of those which have
already been computed, Argelander's older values, Lundahl's, have
already been taken account of in my previous paper. These, with
O. Struve's (which are nearly identical with a portion of Argelander's
and Lundahl's and Main's), will shortly be redetermined in a more
perfect manner, under Struve's and Auwers's direction, by a combi-
nation of Bradley's observations re-reduced with the Pulcova and
Greenwich modern observations. Galloway's southern proper motions
have been re-determined by the Melbourne observations, and those
made at the Cape of Good Hope ; but a careful study of these will be
necessary, as good ancient observations in that region are scarce. Tlie
great northern zones will in a few years furnish many more.

Miidler's proper motions are, as I have befoie stated, rather precari-
ous for some stars ; he has critiiused the ancient observations too hastily.

We are now justified in grouping any certain proper motions into
normal places, taking in each case the total amount of proper motion
as the luiit ; or at least in so classifying stars which are apparently
near each other in the heavens, and not excessively far apart in
amount of A C We may regard it as settled that the star's distances
are inversely proportional upon the whole to their proper motions.

56

PROCEEDINGS OP THE AMERICAN ACADEMY

TABLE OF INDIVIDUAL STARS.

Argelan-

(ier's
number.

A s

^

i'

i'-^

lo? cos

log. sin
X

112

7"053

144°59'

246°43'

101°44'

9..3082 n

9.9604

104

4.748

186 34

240 6

53 32

9.7741

9.9857

105

4.403

282 22

242 24

— 39 58

9.8845

9.9767

2

2.813

82 31

122 11

39 40

9.8864

9.9879

31

2. 3o9

51 54

136 20

84 26

8.9868

9.9193

140

2. 325

128 6

240 49

112 43

9.5868 n

9.8999

49

2.236

126 1

160 51

34 50

9.9142

9.9739

240

2. 093

82 35

• 106 59

24 24

9.9594

9.9448

15(3

2.015

151 14

214 52

63 38

9.6475

9.9546

70

• 1. 968

156 35

211 34

64 59

9.7588

9.9786

81

1.688

247 30

225 11

— 22 19

9.9662

9.99.50

181

1.606

206 2

193 6

—•12 56

9.9888

9.7380

204

1. 537

221 41

114 8

—107 33

9.4793 n

9.7700

7

1.436

90. 19

114 58

24 39

9.9585

9.9479

177

1.433

197 47

203 30

5 43

9.9978

9.7100

89

1.426

249 25

235 0

- 14 25

9.9861

9.9878

78

1.401

254 21

223 47

— 30 34

9.9350

9.9737

247

1. 383

135 58

122 42

— 13 16

9.9882

9.9991

43

1.375

153 49

158 32

4 43

9.9985

9.9980

206

1.333

101 15

143 47

42 32

9.8674

9.9779

161

1.306

247 24

220 12

— 27 12

9.9491

9.8548

192

1.269

197 8

6 23

169 15

9.9923 n

9.7700

76

1.261

302 0

255 10

— 46 50

9.8351

9.8046

187

1. 207

208 54

180 23'

— 28 31

9.9438

9.7013

71

1.171

187 33

213 9

25 36

9.9551

9.9777

157

1.103

296 IB

294 32

— 1 44

9.95598

9.7477

74

• 1.013

164 15

235 31

71 16

9.5067

9.8440

37

0. 997

133 37

149 18

15 41

9.9836

9.9954

120

0.991

174 10

235 54

61 44

9.6754

9.9984

73

0. 969

201 2

216 4

15 2

9.9848

9.9853

133

0.963

1.58 43

254 54

98 11

9.1534 n

9.8860

150

0. 944

294 13

221 11

— 73 2

9.4651

9.9376

203

0. 906

127 39

105 18

— 22 21

9.9660

9.7457

94

0. 891

172 21

237 39

65 18

9.6210

9.9841

137

0.880

285 58

232 44

— 53 14

9.7771

9.9574

211

0.870

86 50

128 2

41 12

9.8765

9.9021

126

0. 868

160 47

232 20

71 33

9.5004

9.9962

127

0. 86 1

281 0

233 7

— 47 53

9.8265

9.9870

218

0. 859

186 42

118 7

— 68 35

9.5625

9.9014

185

0.848

7 49

343 3

— 24 46

9.9581

9.4214

22S

0. 843

86 5

120 22

34 17

9.9171

9.9700

H

0. 816

69 27

124 18

54 51

9.7602

9.9872

85

(1 IHS

178 25

229 27

51 2

9.7986

9.9979

17;^

0.741

162 42

212 28

49 46"

9.8102

9.7166

52

0.733

125 14

169 31

44 17

•

9.8549

9.9ir53

OF ARTS AND SCIENCES.

57

TABLE OF INDIVIDUAL STARS {continued).

Argelan-

(ler's
number.

As

^

^'

^'-^

log. cos

log. sin
X

20

0"730

110<=37'

131053'

21°16'

9.9694

9.9786

129

0. 719

173 34

236 55

63 21

9.0518

9 9584

01

0.719

135 49

183 44

47 55

9.8202

9.9725

1<J8

0. 707

177 43

151 56

— 25 47

9.9545

9.905H

3y

0. 707 "

27 13

104 27

77 14

9.3444

9.0800

221

0.697

240 43

133 37

—107 0

9.4085 n

9.9947

114

0. 690

214 10

250 26

36 10

f.t.'jmr,

9.9400

53

0.688

144 7

171 45

27 38

9.9474

9.9'.)] 3

()5

0.681

121 15

199 10

77 55

9.3208

9.9972

46

0.678

147 46

158 31

10 45

9.9923

9.9748

77

0.669

207 12

219 37

12 25

9.9898

9.9995

111

0.666

247 44

250 3

2 19

9.9996

9.9516

215

0.667

38 40

63 22

24 42

9.95S3

9.8788

63

0.666

185 16

194 7

8 51

9.9948

9.9054

21

0.052

113 18

133 52

20 34

9.9714

9 9844

219

0.643

209 43

68 30

—141 13

9.8918 n

9.8827

110

0.640

273 10

247 51

— 25 19

9.9502

9.9.588

9

0.639

185 45

124 17

— 61 28

9.0792

9.9832

196

0. 6.36

346 27

59 59

73 32

9.4525

9.0490

33

0.626

222 40

143 50

— 78 50

9.2870

9.9838

97

0. 624

158 52

239 14

80 22

9.2236

9.9815

200

0. 623

231 14

54 17

—176 57

9.9994 n

9.7447

12

0. 623

82 9

127 4

44 55

9.8501

9.9805

246

0.619

40 11

112 10

71 59

9.4904

9.9583

212

0.618

39 21

59 6

19 45

9.9736

98765

225

0.604

235 45

97 28

—138 17

9.8730 n

9.9042

145

0.600

244 46

224 40

— 20 6

9.9727

9.9873

207

0.597

63 15

59 59

— 3 16

9.9993

9.8316

210

0.591

46 56

139 1

92 5

8.5005 n

9.9804

238

0.583

76 44

99 12

22 28

9.9057

9.9300

191

0. 582

152 15

5 59

—146 16

9.9199n

9.6935

64

0.582

141 39

252 16

110 37

9.5407 n

9.5224

106

0.577

110 43

239 46

129 3

9.7994 n

9.9885

217

0. 572

175 1

124 48

— 50 13

9.8001

9.9233

60

0.571

179 49

182 9

2 20

9.9996

9.9989

24

0.561

124 1

138 35

14 34

9.9858

9.9826

243

0. 558

101 32

122 18

20 40

9.9708

9.9989

224 ,

0. 556 .

222 52

112 1

—110 51

9.5514 n

9.9267

199

0.547

295 0

98 2

163 2

9.9807 n

9.0564

80

0.546

248 57

240 6

— 8 51

9.9948

9.9044

241

0.542

92 51

122 32

29 41

9.9389

9.9996

59

0. 542

279 8

181 34

— 97 34

9.1195 n

9.9975

117

0.538

174 41

237 44

63 3

9.0503

9 9932

190

0.536

270 0

2 13

92 13

8.5875 n

9.7582

176

0.516

318 14

218 14

—100 0

9.2397 n

9 4943

58

PROCEEDINGS OF THE AMERICAN ACADEMY

TABLE OF INDIVIDUAL STARS (continued).

Argelaii-

der"s
number.

A s

^

i'

f'-^

log. cos

log. sin
X

14

0"516

138°48'

12.5059'

— 12049'

9.9890

9.9555

118

0.514

277 22

237 4

— 40 18

9.8823

9.9965

91

0.512

270 0

306 8

36 8

9.9072

9.9996

184

0.510

266 11

261 48

— 4 23

9.9987

9.8738

2(5

0.509

43 50

131 29

87 39

8:6128

9 9174

69

0. 497

274 2

210 28

— 68 84

9.6485

9.9590

175

0. 493

278 9

337 14

59 5

9.7108

9.7722

162

0. 493

257 35

249 38

— 7 57

9.9958

9 6740

88

0.491

227 19

239 20

12 1

9.9904

9.9629

86

0.489

204 12

234 25

30 13

9.9366

9 9833

220

0.485

110 0

127 8

17 8

9.9808

9.9519

159

0.481

205 23

217 41

12 18

9.9899

9.9157

284

0.480

219 5

115 19

—103 46

9.3765 n

9.9631

113

0.479

167 32

236 36

69 4

9.5530

9.9998

101

0.476

256 7

237 48

— 18 19

9.9774

9.9946

201

0. 473

173 24

98 16

— 75 8

9.4092

9.6907

163

0. 472

153 36

316 22

162 46

9.9801 n

9.8066

125

0.471

221 24

233 7

11 43

9.9909

9.9930

68

0. 469

245 59

204 54

— 41 5

9.8772

9.9498

195

0.468

165 12

142 16

— 22 59

9.9642

9.G846

179

0.466

331 38

846 56

15 18

9.9843

97717

45

0. 466

123 14

159 40

86 26

9.9056

8.9657

23

0- 466

216 37

129 8

— 87 29

8.6426

9.9196

58

0.464

191 54

180 12

— 11 42

9.9909

9.9994

124

0.462

248 47

262 40

18 53

9.9871

9.9039

226

0.461

165 26

125 42

— 39 44

9.8859

9.9911

144

0. 460 ■

2(;2 30

250 12

— 12 18

9.9899

98619 .

141

0, 457

254 31

235 34

— 18 57

0.9758

9.9227

186

0. 455

300 30

351 41

51 11

9.7972

9.6639

99

0.447

254 49

250 8

— 4 46

9.9985

9.9476

80

0.446

105 36

144 14

38 88

9.8927

0.0000

35

0.445

108 11

147 3

38 52

9.8913

9.9882

222

0.441

142 48

131 55

— 10 58

9.9921

9.9925

15

0. 439

283 11

129 58

—153 18

9.9507 n

9.9739

148

0.438

147 26

238 19

90 53

8.1880 n

9.8383

166

0. 435

294 1

312 38

18 37

9.9767

9.7518

108

0. 485

285 34

256 58

— 28 36

9.9435

9 9367

135

0. 434

150 0

233 33

83 33

^.0505

9.9566

233

0. 430

30 12

95 12

65 0

9.6259

9.9200

136

0.417

297 55

258 29

— 39 26

9.8878

9.8707

19

0.414

116 83

117 21

0 48

0.0000

9.9044

128

0. 400

309 53

279 24

— 80 29

9.9854

9.8942

98

0.400

263 50

210 12

— 23 38

9.9620

9.9809

72

0. 3y9

22S 24

214 3

— 14 21 '

9.9862

9.9972

151

0. 398

278 58

224 43

— 49 10

9.8155

9.9085

OF ARTS AND SCIENCES.

59

TABLE OF INDIVIDUAL STARS {continued).

Ariit'lan-

lier's
number.

A s

^

y

^'-^

log. cos
{^' - ^)

log. sia
X

2u;

0"392

69055'

92°28'

22°33'

9 9655

9.8372

75

0. 389

195 11

216 16

21 5

9.9699

9.9998

180

0.388

180 0

300 23

120 23

9.7040 n

9.1846

245

0. 387

92 40

115 47

23 7

9.9636

9 9711

S-2

0.381

205 44

222 0

16 IG

9.9823

9.9794

V22

0. 375

224 2i)

2fl5 11

40 45

9.8794

9 9149

181

0. 372

219 42

231 29

11 47

9.9908

9.9826

142

0.371

164 52

279 1

114 9

9.6119 n

9.8444

235

0. 3i")9

213 34

123 22

— 90 12

7.5429 n

9 9980

18

0. 366

145 0

126 58

— 18 2

9.9781

9.9522

47

0. 363

297 22

160 3

—137 19

9 8664 n

9.9990

221)

0.361

71 2-5

10'.) 23

37 58

9 8967

9.9354

184

0. 360

264 6

348 59

84 53

8.9503

9.7008

4

0. 356

92 35

118 48

26 13

9.9529

9.9680

14y

0. 350

272 18

221 40

— 50 38

9.8023

9.9370

152

0. 348

141 59

292 51

150 52

9.9413)1

9.7904

165

0. 342

164 24

213 5

48 41

9.8197

9.8851

182

0.340

151 38

327 56

176 18

9.9991 n

9.3245

183

0.335

187 30

187 44

0 14

0.0000

9.8587

119

0. 332

256 57

249 59

— 6 58

9.9968

9.9455

167

0.328

297 5

310 29

13 24

9.9880

9.72.33

<J3

0.323

179 29

234 39

55 10

9.7568

9.9969

121

0. 320

274 42

265 23

— 9 19

9.9942

9.9171

5

0. 320

95 21

113 9

17 48

9.9787

9.9464

90

0.319

170 12

235 15

65 3

9.6251

9.9911

178

0.318

207 40

322 41

115 1

9.6262 n

9.5065

62

0. 315

138 44

188 12

49 28

9.8128

9.8759

193

0.314

195 45

170 1

— 25 44

9.0546

9.9348

130

0.314

162 45

230 14

67 29

9.5831

9.9955

51

0.314

200 52

105 39

— 95 13

8.9587 n

9.2918

38

0.314

123 0

147 20

24 20

9.9596

9.9672

237

0.312

187 41

114 38

— 73 3

9.4647

9.9633

239

0.311

273 30

122 43

—150 47

9.9409 n

9.9998

174

0. 310

191 37

338 49

147 12

9.9216 n

9.8057

231

0.310

116 6

124 17

8 11

9.995G

9.9996

208

0. 309

67 48

136 6

08 18

9.5679

9.9438

147

0. 303

230 30

224 47

— 5 43

9 9978

9.9551

172

0. 302

282 44

202 15

— 80 29

9.2184

9.8844

249

0. 298

88 16

105 33

17 17

9.9799

9.9396

248

0. 291

111 58

104 20

— 7 38

9.9961

9.9371

29

0. 290

191 42

136 56

— &4 46

9.7611

9.9444

10

0.286

169 10

122 41

— 46 29

9.8379

9.9741

109

0.285

332 18

253 55

— 78 23

9.3040

9.9435

56

0. 283

165 16

179 0

13 44

9.9874

9.9709

84

0. 282

121 9

244 50

123 41

9.7440 n

9.9082

60

PROCEEDINGS OF THE AMERICAN ACADEMY

TABLE OF INDIVIDUAL STARS {continued).

Argelan-

der's
number.

A s

^

^'

f-'l'

lot?, cos

log. sin
X

197

0"281

200=50'

151°20'

— 49°30'

9 8125

9 9140 ;

55

0.280

115 22

175 30

60 8

9.6972

9.9375

250

0.279

84 51

116 12

31 21

9.9315

9.9668

244

0. 279

137 34

122 19

— 15 15

9.9844

9.9992

28

0, 279

96 48

112 4

15 16

9.9844

9.8152

202

0.277

202 41

137 22

— 65 19

9.6208

9.8560

loy

0.276

281 16

309 56

28 40

9.9432

9.66.30

15t

0. 274

296 27

268 32

— 27 55

9.9463

9.7252

95

0.273

67 4

238 43

171 39

9.9954 n

9.9819

168

0.269

177 10

302 48

125 38

9.7654 n

9.6503

44

0.268

166 39

101 33

— 65 6

9.6243

9.0649

11

0. 267

134 47

123 22

— 11 25

9.9913

9.9668

160

0.266

183 58

227 16

43 18

9.8620

9.8225

67

0.265

207 1

243 1

36 0

9.9080

9.9752

6

0. 262

120 51

116 38

— 4 13

9.9988

9.9581

205

0. 2.58

51 54

59 26

7 32

9.9962

9.8082

34

0. 258

134 48

146 47

11 59

9.9904

9.9928

155

0.252

291 38

267 51

— 23 47

9.9615

9.7221

194

0.249

215 47

163 24

— 52 23

9.7856

9.9061

153

0.249

180 0

225 1

45 1

9.8494

9.8870

139

0.247

238 53

260 38

21 45

9.9680

9.8553

100

0. 247

158 30

240 48

82 18

9.1271

9.9806

132

0.244

80 6

261 50

—178 16

9.9998 n

9.8777

13

0. 243

93 32

125 29

31 57

9.9286

9.9711

36

0.240

94 5

145 5

51 0

9.7989

9.9521

25

0. 240'

180 0

117 27

— 62 33

9.6637

9.8466

27

0 239

178 5

129 3

— 49 2

9.8166

9.8990

170

0.235

297 2

317 51

20 49

9.9707

9.6593

158

0. 235

170 55

288 57

118 2

9.6721 n

9.7295

16

0. 226

113 9

129 32

16 23

9.9820

9.9686

103

0.222

232 29

248 31

16 2

9.9828

9 9548

171

0.213

237 22

202 20

— 35 2

9.9132

9.8860

66

0. 213

185 42

206 16

20 34

9.9714

9.9073

209

0. 209

28 54

86 31

57 37

9.7288

9.7870

06

0. 209

187 29

242 48

55 19

9.7551

9.9663

67

0.204

177 18

206 18

29 0

9.9418

9.9073

123

0. 201

357 49

261 3

— 96 46

9.0712 n

9.9140

57

0. 200

202 49

179 46

— 23 3

9.9639

9 9612

236

0. 197

106 33

123 16

16 43

9.9812

9.9979

87

0. 196

219 56

232 17

12 21

9.9898

9.9979

242

0.191

168 1

122 36

— 45 25

9.8463

9.9990

48

0. 190

102 27

155 23

52 56

9.7801

9.9096

115

0.187

2:^,7 0

238 5

1 5

. 9.9999

9.9917

1S9

0. 185

222 49

178 40

— 44 9

9.8558

9.7411

104

0.185

355 21

279 53

— 76 28

0.3996

9.6460

OF ARTS AND SCIENCES.

Gl

TABLE OF INDIVIDUAL STARS {co„t!m,rd).

Arpclan-

(Ut's
number.

A s

^

^'

f -^

log sin
X

223

0"184

67035'

67°14'

— 0 21

0.0000

9 9023

213

0.184

188 8

119 53

— G8 16

0 568!>

9.8730

r>o

0. 184

157 13

133 67

— 23 16

9 9032

9.5844

232

0. 182

79 45

124 5

44 20

9.8545

9.99W

11(5

0.182

286 59

237 44

— 49 15

9.8148

9.9933

32

0. 179

95 27

142 24

46 67

9.8342

9.9720

5-1

0. 175

323 40

175 18

—148 22

9.9301 n

9.9685

17

0.174

124 43

132 5

7 22

9.9964

9.9847

1

0. 174

223 10

122 11

—100 59

9.2799 n

9.9895

22

0. 163

111 15

133 27

22 12

9.966G

9.9654

83

0.161

219 2

227 57

8 55

9.9947

9.9896

138

0.154

270 0

226 22

— 43 38

9.8596

9.9934

79

0. 154

234 20

223 18

— 11 2

9.9919

9.9974

40

0.150

115 16

151 7

35 51

9.9088

9.9411

214

0.149

112 33

134 34

22 1

9.9671

9.9627

102

0.149

263 26

255 21

— 85

9.9957

9.9365

188

0.143

327 39

359 38

31 59

9.9285

9.4335

227

0. 137

104 55

127 2

22 7

9.9668

9.9993

42

0. 136

156 21

151 10

— 5 11

9.9982

9.8923

146

0.133

286 38

289 3

2 25

9.9996

9.8452

230

0.123

58 3

91 17

33 14

9.9224

9.9156

3

0.108

76 30

123 16

46 46

9.8357

9.9931

143

0.100

306 15

298 51

— 7 24

9.9964

9.8935

92

0.096

288 14

249 30

— 38 44

9.8921

9.9357

41

0.079

139 30

155 7

15 37

9.9837

9.9980

G2 PROCEEDINGS OF THE AMERICAN ACADEMY

III.

ON THE VEILED SOLAR SPOTS.

By L. Trouvelot.

Read by William A. Rogers, Oct. 12, 1375.

It is now pretty well established that the visible surface of the sun
is a gaseous envelope called " the chromosphere ; " mainly composed of
incandescent hydrogen gas, with which are occasionally associated
some metallic vapors usually occupying the lower strata. To all
appearances, the granulations called " rice grains," the faculai and the
protuberances, are phenomena belonging to the chromosphere ; in fact,
they are the chromosphere itself seen under the particular forms and
aspects peculiar to it. Ordinarily this envelope has a thickness of 10"
or lo". This thickness, however, is by no means constant, varying
from day to day within certain narrow limits.

At no time since I have observed the sun, have I seen the chro-
mosphere so tliin and shallow as during the present year, and especially
between June 10 and August 18. I had before quite often observed
local depressions and upheavals of the chromosphere, sometimes ex-
tending over large surfaces, but I had never before observed such a
general subsidence.

So thin was the chromosphere during this period, that it was some-
times very dillicult to obtain its spectrum by placing the slit of the
spectroscope tangent to the limb of the sun. This was especially the
case on the afternoon of August 9.

This unusual thinness of the chromosphere could be easily recognized
without the assistance of the spectroscope. Indeed, the i)henomenon
was even more interesting seen through the telescope, as, with it, the
structure of the photosphere, lying as it does under the envelope of
the chronios])hcre, could be better seen through the thin veil formed
by the greatly attenuated chromospheric gases.

That the gases forming the chromosphere are sometimes thin enough
to become transparent is a phenomenon which I have observed hun-
dreds of times ; as is abundantly proved by the numerous drawings of

OF ARTS AND SCIENCES. C3

protuberances wliirli I liiive inade at tlu- Harvard C'oll(j.'(; ( )l)sirvatory,
in wliidi the limb ut" tlie sun is seen tlirouji;b the base of the protuber-
ances in front of it. In plate X, lijriire 3, there occurs a very striking
instance, where two small prominences are seen through a larger pro-
tuberance nearer the observer.

During this period of general subsidence, the granulations appeared
to be smaller and farther apart than usual, and conseipiently the light-
gray colored background upon which they are seen projected was more
distinct, as it occupied more space than formerly. During this period,
tlie light-giving element would appear to have been less than usual.

I am not aware that the phenomena of which I shall speak in this
comnumicatiou have been before observed ; but I cannot speak posi-
tively on this point, owing perhaps to the somewhat confused nomen-
clature of solar physics.

Ever since I have observed the sun with instruments of a large
aperture, I have noticed that the light-gray colored baekground seen
between the. granulations is by no means uniform, as it is generally
stated to be. On the contrary, it is greatly and strikingly diversified.
Aside from the very small black dots called " pores," patches of a
darker gray are ii-regularly distributed all over the surface of the sun.
But partly owing to the effect of perspective, and partly on account
of the thicker strata of the chromospheric gases through which they
are necessarily seen near the limb, they disapj^ear gradually as they
approach the border.

These dark spots have been so remarkable during the present year,
and so conspicuous during the period of the greatest subsidence of the
chromosphere, that I have availed m^^self of ev'ery favorable opportu-
nity to study them. So strongly were they marked, that when one
had passed the fiekl of view, it could be easily found again among
many others, even after the lapse of several hours. Of the most
striking and complicated, I have made sketches.

In order to be able to coiuit how many of these gray spots could be
seen in different heliographic latitudes, and also to estimate their area
with respect to the whole surface of the sun, Mr. W. A. Rogers,
Assistant at tlie Harvard College Observatory, kindly ruled for
me on glass a reticule of small squares. Though the problem is
apparently a simple one, it nevertheless presented many difficulties ;
partly owing to the minuteness and delicacy of these objects, partly
on account of the unsteadiness of the atmosphere, and partly to the
many defects caused by the great amount of heat concentrated at the
focus of the objective. However, the observations show clearly that,

64 PROCEEDINGS OF THE AMERICAN ACADEMY

though the number of gray spots varies but little in different latitudes,
in general the spots become larger and more com})licated as they
approach the equatorial zones.

The most marked characteristic of the gray spots is their vagueness
of outline. They are never sharply defined like ordinary spots, but
they appear blurred and diffused like an object seen through a mist.
As I shall endeavor to show presently, these objects are really seen
through the chromospheric gases which are spread as a veil over them,
causing this vagueness of outlines. For this reason, I jiropose for them
the name of Veiled Solar Spots.

The veiled solar spots, especially in the lower latitudes, have a
remarkable tendency to assemble into small groups after the manner of
ordinary spots. Sometimes three or four are seen in contact, while
there are comparatively large intervals where none are to be seen. I
have in several instances seen the actual formation into groups of
distinct veiled spots.

The granulations of the chromosphere are seen projected upon the
veiled spots, just as anywhere else, but they are not there so regularly
distributed ; some being closely crowded together, while others are
widely scattered. Small facula^ are often formed in this manner by the
aggregation of several granules into one mass. Once in a while, the
granulations appear as if they were under the power of a propelling
force by which they arrange themselves in files, and sometimes in
capricious figures which are very remarkable.

• In many cases I have observed that the granulations projected
upon the veiled spots have an extraordinary mobility, to be seen
nowhere else, except perhaps in the immediate vicinity of ordinary
spots in full activity. Often their form and position are totally
changed within a few minutes, and sometimes even within a few sec-
onds. This was especially the case June 21. At 8h. 30m. on that
day, I was observing a group of veiled spots not far from the centre
of the sun, when my attention was drawn to the extraordinary mo-
bility of the granulations covering this group. In an instant they
changed their form and position, some crowding together as though
briskly attracting each other, while others would fly apart as if
repelled by an invisible force. Under this tumultuous conflict of
forces, new veiled spots would appear and disappear in an instant,
faculaj would form and vanish ; in. fact, all was in motion and con-
fusion on that particular part of the sun. It was evident that im-
mense forces were in conflict under the chromosphere.

At 2h, Om. P.M., on the same day, several small black spots had

OF ARTS AND SCIENCES. G")

opened tlirongli the chromosplicn' upon the i^ronp of v('ilc<l spots
observed in the nioniiuL:. At Sh. Oin. on the tollo\vin<f nioniini;. the
group of small bhu-k spots was considerably increased, havin;^ cpiitc a
large spot on the [)receding side, followed by twelve; or fifteen smaller
ones. On June 24, this group had attained to its maximum size.
It was then very large and complicated. In fact, it was the largest
group of sun spots observed thus far during the presetit year.

On August 8, I noticed a group of veiled spots a little south of
the sun's centre. The following morning at 7h. Om,, there was at
the same place a small group of half a dozen black spots disposed in a
crescent shape. At 2h. Om. p.m., the black spots had vanished, but
the veiled spots still remained, having retained the characteristic
crescent form of the black spots and many other details observed in
the morning ; and, as a proof that the chromosphere covered this spot,
t/ie granulutions could be j)lainJy seen upon the tv/iole, indicating
clean-ly tJiat this spot was seen through the veil of the chromosphcric
gases.

On August 24, the same phenomenon took place. Just following the
principal spot of the only group then to be seen on the surface of the
sun, there was a fine group of veiled spots. The following day some
bladi spots had made their appearance upon them. On August 27,
the black spots had vanished, but in their place the veiled spots seen
at first still remained, and they continued to be seen there for several
days.

To all appearances, the black spots which I had seen disappear
under the chromospheric gases, and which continued as veiled
spots, were exactly alike and undistinguishable from the many other
veiled spots scattered all over the sun ; and, had I not seen the open-
ing of the photosphere, with the black spots, I could not have had any
idea of the true nature of the veiled spots.

So far, I have oidy spoken of veiled spots observed in the zones
where the ordinary sun spots make usually their appearance ; but, as I
have said, the veiled spots are scattered all over the surface of the
sun.

During this period, I had many occasions to observe very remark-
able and characteristic veiled spots in very high heliographic latitudes
north and south. On July 15, within a few degrees of the north
pole of the sun, I observed a remarkable veiled spot, unusually large
and dark. Upon it were several bright slender facuhii projected in
crest shape to very high altitudes. These faculae appeared to be pre-
cisely like those observed in lower latitudes near ordinary sun spots.

VOL. XI. (N. S. 11.) 5

66 PROCEEDINGS OF THE AMERICAN ACADEMY

Upon this veiled spot could unmistakabh^ be seen a small black spot,
not a pore ; a real opening of both chromosphere and photosphere.

On August 9, I observed another remarkable veiled spot within
about 10° from the north pole, and upon it could be seen three small
black spots.

On August 13, at lib. Oin., I observed a ver_y dark veiled spot
within 6° or 8° from the north pole. It had upon it a group of small
faouhe, so characteristic of the spots of lower latitudes. At 4h. 3(hn.
in the afternoon, this veiled spot was still darker, and upon it, near a
facula, a pretty large black spot was visible.

On August 24, I observed a remarkable veiled spot at about 75°
south latitude.

On September 6, another large group of veiled spots was seen
within lO'* or 15° of the north pole. At lOh. 20m., some faculte had
formed upon it, and two black spots were distinctly visible. At
5h. Om. in the afternoon, this group was still visible.

On September 8, within a few degrees of the north pole, I ob-
served a fine group of two veiled spots, unusually dark and large, and
near one of these spots there was a pretty large and bright facula. Ten
minutes later the dark veiled spots liad vanished, leaving in their place
some bright faculjB. One minute later the veiled spots began to re-
appear, but under another form, to disappear again the next moment.

A little south-west from this last group, but in the same field of
view, was another group of veiled spots apparently in full activity.
Upon it three or four black spots were visible for some seconds.
Upon these veiled spots the granulations had an extraordinary mobil-
ity ; so much so, that I expected at every moment to see a large spot
make its appearance, but in less than a minute the veiled spots and
the black spots had both vanished, and in their place were formed in
an instant, .some very bright facuke.

To all appearances, the v^eiled spots seen in high latitudes differ but
ver}' little from the oi'dinary sun spots of the lower latitudes, except
in regard to magnitude and activity. The difference seems particu-
larly to be that, in the first, the umbra, instead of being freed from the
gases and vajwrs, is partly or wholly choked with them ; while, be-
sides, the chromosphere covers it. The forces which open the photo-
sphere in higli latitudes, it would seem, have not sufficient energy to
repel or dissolve tl)e chromospheric gases ; or, if tliey have, it is in a
very feeble degree, but, even then, the phenomenon is generally of
short duration.

Though I had no means of making accurate measurements of the

OF ARTS AND SCIENCES. 07

position of the spots seen in liinh laliliulcs, the error of my fNtiiu;i-
tiou cannot be very great. In any ease a few dei^rees would certainly
cover it, anil it remains a fact that I liave observed spots at least within
10° of the north pole of the sun. The in)i»ortance of this observation
will appear when it is stated that very few spots have been oi)serveil
outside of the zones lying 40° on either side of the ecjuator. I know
of but two instances on record in which S|)0ts have been observecl
beyond this limit. La Hire observed a spot 70"^ from the equator,
and more recently, in the month of June, 184G, M. Peters observed
at Naples a spot o(J*^ from the e(piator.

It is fnrtiier to be remarked that, according to the conclusions of the
English observers, the solar spots attain higher latitudes during the
years of the maximum niunber of spots, and recede more and more
towards the equator as the minimum is approaching; and it is to be noted
that the present year is precisel}^ or at least very nearly, a minimum
3'-ear. It is doubtless owing to the unusual thinness of the chromo-
sphere during this period that spots have been observed in so high
latitudes this year. It is true that the spots were small, but, never-
theless, they were genuine spots, with all the characteristics of larger
spots.

It is difficult for one who has seen the phenomena which I have
described, to come to any other conclusion than this : that the veiled
spots are breaks or true openings in the photosphere, seen thrcnigh the
imperfectly transparent gases composing the chromosphere, openings
themselves partly or wholly filled by the vapors ejected by the forces
from the interior of the photosphere. If this hypothesis should prove
to be the expression of a fact, then we should expect to find that the
photosphere is perforated by thousands of crevasses either partly or
entirely filled with the vapors and gases from the interior, which can-
not be ejected entirely outside for want of sufficient energy, save for
a comparatively very siBall number situated in the equatorial zones,
where this energy appears maximum, and is able to repel and dissolve
the gases from the interior.

Before the observations of this year, I had arrived at precisely the
same conclusions in regard to the o])enings of the j)hotosphere in all
latitudes, and to the existence of invisible spots concealed by tiie
chromosphere. These conclusions were derived from my observations
with the spectroscope, made at Harvard College Observatory during a
period of thirty-five months. A discussion of these observations is
reserved for a future communication.

Though one can hardly form a settled opinion with regard to the

68 PROCEEDINGS OF THE AMERICAN ACADEMY

cause of tlie general depression of the chromosphere, on account of
the imperfect data, it seems natural, however, to suppose that the
phenomenon is connected in some way with the minimum period of
sun spots. Judging by the great number of veiled spots observed,
and by the myriads of pores seen between the granulations, it would
seem that both the chromosphere and photosphere have been much
thinner than nsual during the present year.

If there are breaks in the photosphere at many points of the sur-
face of the sun, it becomes easy to account for the unusual thinness of
the chromosphere this year, because, as observed by myself and others,
at certain phases of the spots, the chromospheric gases, rushing with
impetuosity into the umbra, go down under the photosphere like gigan-
tic waterfalls, diminishing consequently the thickness of the chromo-
sphere. That this takes place I shall give amjile proof in another
communication.

It seems evident that the chromosphere near a spot is kept off from
falling into the opening by a force from the interior. As soon as this
force decreases in energy, immediately the chromosphere tends to
cover it, and even to precipitate itself through the opening when this
force becomes extinct. The observations show this plainly.

Wlien a spot is decreasing, it is quite common to observe that the
umbra and penumbra appear as if they were seen through a heavy
fall of snow, their surfaces being covered by numerous bright flocculent
granulations surrounded by a kind of bluish fog. In a few instants of
very rare definition, I have been surprised to see faint traces of this floc-
culent appearance upon almost all the spots ; indeed it would seem that
the spots -are rarely free from some faint traces of the chromospheric
gases. Probably the bright flocculent objects observed upon the umbra
and penumbra of spots, are the granulations of the chromosphere dis-
solved to a greater or less degree by the forces emanating from the spots.

Perhaps it may not be idle to remark that, during the period men-
tioned, I have almost every day observed small groups of facuhc in the
polar regions, especially near the north pole of the sun ; while, for the
most part, they have been entirely absent from the equatorial regions,
where they are commonly found.

To conclude, my observations show : —

l'^. That during this year, and especially during the interval from
June 10 to August 18, and to a less degree to September
14, the chromosphere has been notably thinner than usual
upon the entire surface of the sun.

OP ARTS AND SCIENCES. 69

2*^. That the granulations have been smaller and le?s numerous.

3"^. That the light-gray colored background seen between the granules
has been more c{)iis[)icuous and has occupied more space than
usual.

4". That there are spots, which I have named '' veiled spots," which
are seen through the chromosphere which is spread over them
like a veil.

5*'\ That these veiled S|)ots are true openings of the i»hotosphere, like
those of the ordinary spots.

C. That during this period these spots have been larger, darker,
and more numerous than I have before seen them.

7*"^. That the veiled spots are scattered throughout all latitudes, though
more complicated in the regions where the oixlinary spots make
their appearance.

8®. That I have observed s^jots at least within 10° of the north
pole of the sun.

9". That the flocculent objects sometimes seen projected upon the
umbra and penumbra of spots are the remaining portion of the
granulations comj)osing the chromosphere, more or less dis-
solved by the forces emanating from the interior of the photo-
sphere.

Cambridge, October 1, 1875.

70 PROCEEDINGS OF THE AMERICAN ACADEMY

IV.

ON PHOTOGRAPHS OF THE SOLAR SPECTRUM.

By Robert Amory, M.D.

Read, :vray 25, 1875.

. The photographs I now present to the Academy were taken by
the action of sunlight, thrown by a collimating lens (21 inches focal
length) upon one of Mr. Rutherford's ruled speculum plates, contain-
ing 1 2,080 lines to the inch, and reflected therefrom upon an achro-
matic lens of five feet focus ; the image Avas then received upon a
sensitized collodion film. It will be observed that the solar lines are
more numerous than those shown by the photograph-map (herewith
also presented) of Professor J. W. Draper, and published in 1872,
which was taken from a ruled speculum plate containing only 6,480
lines to the inch. One of my photograph plates has been enlarged to
the same scale as that of Professor Draper's, and comprises solar
lines whose wave-lengths, as compared with Angstrom's map, are
between 4,590 and 3,700. I likewise present photographs of the
absorption bands of Ur&nium acetate, in which the three bands can
be distinctly seen, as well also as the solar lines of that portion of the
spectrum.

In the ajiparatus used for these experiments, I would call the atten-
tion of the Academy to the following observed fact: that, if the slit of
the collimator is placed exactly at the principal focus of the collimat-
ing lens, the solar lines are in focus for all the different orders of the
spectrum upon the true are of a circle. If, however, the slit is outside
of the principal focus, these solar lines are in focus on a curve which
is }iot the arc of a circle, but whose radius gradually becomes
shorter in the higher orders. If, again, the slit is inside of the
principal focus, the radius of the curve gradually becomes longer in
the higher orders. The diagram I present may, perhaps, illustrate
this fact more clearly. Any one may verify it by direct experiment.

Moreover, in using a dark chamber of large width between the sen-
sitized film and the lens used for projection of the . image from the
grating, and placing between this projecting lens and the sensitized
film a dia[)hragm which allows only that portion of the spectrum
actually photographed to pass through, I have had no trouble from
diffused light. In my earlier experiments, a dark tube of the same
calibre as the diameter of the projecting lens would always mar the
sensitized plate, on account of the diffused light, no matter how care-
fully the tube was fitted with diaphragms.

OF AllTri AxND SCIENCES. 71

V.

]\ILSCELLANEOUS BOTANICAL CONTRrBUTIONS.
By Asa Ghay.

Presented, Oct. 12, 1875.

TiiK following notes and characters relate mainly to Californi in
botany, the writer having been engaged in the preparation of the
Gamopetalce for Professor Brewer's Botany of California, now print-
ing. Some of the observations are such as could not well be recorded
in that work ; and the characters of ceitain new genera and species
may appropriately be introduced to the botanical world in a continua-
tion of the " Contributions" which have from time to time been com-
municated to the Academy, and published in its Proceedings. My
first note has reference to two plants of the Atlantic United States,
which have long been confounded.

Sedum pusillum Michx. Glauco-pallidum, 1-3-unciale ; foliis
alternis teretiusculis oblongis (lin. 2-3-longis) ; floribus ad summitatera
ramorum laxe cymosis tetrameris ; pedicellis petala alba oblongo-ovata
acutiuscula suba^quantibus ; folliculis elongato-oblongis stylo brevis-
simo snbito apiculatis ; seminibus ovali-oblongis. — On granite rocks ;
Flat Rock near Camdeu, South Carolina, Michaux ; Stone Mountain,
Georgia, "W. M. Canby, 18G9, and A. Gray, 1875. This little plant
I found on Stone JMouotain, in great abundance from the base to near
the summit, in full blossom on the 19th of April last. Fruiting speci-
mens were sparingly collected at the same station in May, 1809, by
;Mr. Canby, who, however, did not distinguish it from Diamorpha
pnsilla Nutt., which accompanies it, but is most abundant towards and
upon the summit of this singular granitic mountain. I cannot learn
that the true Sedum pitsil/um has been elsewhere seen, except, long
ago, by Michaux. But the two are probably associated at other
stations. At least they must be so at Flat Rock. For there Nut tall
collected, in winter, old fruiting specimens of the plant he descrihed in
his Genera Plantarum, p. 110, as "7V//d?a? crjinosa (Sednm jm.silhon
Michx)," and ou p. 293 as " Diamorpha pusilla {Sedum pusillum

72 PROCEEDINGS OF THE AMERICAN ACADEMY

Miflix.)." Until now no one has supposed that there were two plants
in question, because no botanist had been attracted to them by seeing
the two plants in flower together. The specimens in Michaux's herba-
rium are in fruit, or mainly so, but the phrase " flores albi octandri "
is appended to the character in the Flora. Michaux might have col-
lected and confounded the two ; but Professor Bureau, who kindly
compared specimens for me, informs me that the Sedum in the herba-
rium of Michaux is unmixed with Diamorpha. The two plants are
diflTerent enough in aspect as well as in botanical characters. Tlie
Sedum is the larger, earlier to blossom, of a pale and glaucous hue,
and, with its profusion of pure white flowers, is more conspicuous, even
showy ; the pods are abruptly pointed with a very short style, have the
introrse dehiscence proper to the genus, and the seeds are oblong.

The Diamorpua, of barely half the size, and with proportionally wider
leaves, has a dull purplish hue, extending more or less to the flowers ;
the sepals are distinct nearly to tlie base and narrower ; the petals
oval and obtuse ; the ovaries and pods tapering from a broader base
into a subulate style ; the seeds round-oval ; and the cruciform union
of the pods at base and their peculiar dorsal valvular dehiscence,
peculiar to the genus, are as described by Nuttall.

With these two plants was associated another rarity ; viz., the
Arenaria hrevifulia of Nuttall, in full blossom at the same season.
Mr. Canby also collected it, and very naturally took it for Arenaria
glabra Michx., to which, indeed, it is too closely related, but is probably
distinct.

Cleomella oocarpa. Diffusa, spithama^a ad subpedalem ; foliolis
oblongo-linearibus ; racemo saspissime densifloro ; bi'acteis inferioi'ibus
foliis conformibus, superioribus simplicibus ; setulis stipularibus mani-
festis ; staminibus petala superantibus ; ovario apice 3-ovulato ; capsula
ovata lineam longa stylo breviusculo superata stipite (pedicellum
suba^quante) triplo breviore ; seminibus 1-2 hevibus. — Sterile saline
plains of Humboldt County, Nevada, Torrey, A. Gray ; and adobe
hillsides and plains on the borders of the Mesa Verde, South-west
Colorado, T. S. Brandegee, in Haydi^i's Exploration, 1875. This
has been confounded with C. plocasperma, Watson, Bot. King Kxp.
p. 33, which, thus far, has been collected only by I\Ir. Watson and
the Rev. R. Burgess, and has a larger and dilated rhombic pod, on
a stipe wiiich generally little exceeds it in length, more numerous
and laterally inserted ovules, seeds with peculiar marking, hliortcr
stamens. &c.

OF ARTS AND SCIENCES. 73

POLTGALA ACANTIIOCLADA. Fniticulosa, bipnlalis. r;iin<)si>Niiii;i,

Bubciuereo-pubescens, spiiiis gnicililms uniiata ; (oliis liiic.iii-spniliiilati.s
rigidulis (I'm. o— 4 loujiis) ; lloribus subaxillariltiis sparsis alljitlis liii.
2 loiigis pedicello basi bibractrato parum birviuribiis ; aU.s obovatis
sepalis ciBteris dupio majoribus corollaiu adivquantibus ; carina biir-
viter cvmbiformi iiiida dorso uinbunata. — Sides of bkiffs, on the Sail
Juan River, iu the south-easteiu border of Utah, T. S. lirandc-^ce,
in Ilaydeu's Exploration. Resembles P. subspinosa of ANalsoii, l)iit
woody ; the flowers scattered, pale, and less than half the size ; tiiu
free portion of the corolla of Ave short and obtuse lobes nearly equal
in leu>,'th and little longer than the united portion, emarginate ; the keel
not much larger, a conical boss on the upper part of the back ; no
crest. Spines of the brauchlets often compound. No fruit seen.

Glossopetalon Nevadense. Cinereo-puberulum ; foliis ovalibus
e basi squamacea dilatata manifeste stipulifera ; floribus tetrarneris, —
Northern part of Washoe County, Nevada, J. G. Lemmon and E. L.
Case. An interesting addition to an anomalous genus, upon the
affinity of which more liglit may now be thrown. I had noticed the
likeness of the fruit and seed to that of the Staphyleaceous genus
Enscaphis, and I can now bring to view other points, which alto-
gether must exclude it from CelastracecB, and in my opinion refer it to
tlie Sapindacece, suborder Staphyleinece,* notwithstanding the alternate
entire leaves. Mr. Wright's original specimens of G. spinescens show
no clear trace of stipules ; but in fresh ones from Parry's Southern
Utah collection (No. 27), they are evident on vigorous shoots, in the
form of a setaceous-subulate cusp on each side and near the apex of the
deltoid squamaceous base of the leaf. As in analogous cases, they are
wanting to the fascicled leaves. As in the original specimens of G.
spinescens, so in these, altiiough seeds seem to be full-grown and well-
formed, I find not a single developed embryo. If this should prove
to be straight and the albumen wanting, I should refer the genus to
Rosacece near to Purshia ; but I expect it will turn out otherwise.

Petalostemon tenuifolius. Multicaulis e radice pereuni, pubes-
cens, nunc glabratus ; foliis 3-5-foliolatis ; foliolis mox involutis fdi-
formi-linearibus petiolo brevioribus parce glandnlosis ; spicis longius
pedunculatis ex ovata denium cylindricis densitioris ; bracteis ovatis
caudato-aristatis cum calyce sericeo-villosis eglandulosis ; corolla roseo-

* " Staphi/lecE " Benth. & Hook, is only the plural oi Staphylea, and SlajJij/leece
is overchaiged with vowels.

74 TROCEEDINGS OF THE AMERICAN ACADEMY

purpurea, vexillo rotundato-cordato cucullato. — Arkansas, at the cross-
ing of Red River, Dr. Newberry ; New Mexico, Mr. Dieffendorfer
(ex T. C. Porter), J. T. Rothrock. Much branched, apparently a
foot or less in height, bearing numerous spikes on slender peduncles :
leaflets about half an inch long : spikes at first white with the silky
down, in age fulvous.

Galium angulosuai. Fniticosum, patenti-ramosissimum, hispi-
dum ; ramis insiguiter costato-5-7-angulatis ; foliis crebris sublineari-
oblongis fere- eveniis, costa subtus prominula, caulinis 5-7-nis (lin.
3-4 longis), ramulorum 4-6-nis paullo minoribus, ultimis florem brevi-
pedunculatum fulcrantibus conformibus ; corolla flavescente ; fructu
ut videtur carnosulo vel baccato fere lievi. — Guadalupe Island, on
rocky precipices in the middle of the island. Dr. E. Palmer. This
species seemingly belongs to the Relhuninm section ; but only forming
fruit was collected ; its surface is obscurely granulate. The leaves
on the crowded and divaricate branches are as long as the intcrnodes
or longer ; and the ultimate whorl and its internode are just like the
2)receding ones, in which respect it differs much from G. Relbun and
its near allies. The numerous ribs to the stem are remarkable, and
they are visible even on portions that have become woody.

Brickkllia microphylla Gray, var. scabra. Foliis parvulis
rigidioribus papilloso- vel hirtello-scabris ; pappo tautum 16-20-chiBto.
— Rocks, Southern Colorado, Dr. Parry, T. S. Brandegee in llay-
den's Exploration, 1875.

Aplopappus (Ericameria) Palmeri. Fruticosus, 4-pedalis,
pauiculato-raraosissimus ; ramis floridis nuuc virgatis sursum floriferis
nunc in paniculam effusam ramulosam solutis ; foliis filiformibus (pol-
licaribus, fasciculorum brevioribus) parum punctatis ; involucro tnr-
binato, squamis lato-linearibus chartaceis granuloso-subglandulosis
apicem obtusissimum versus fimbriolato-ciliatis ; ligulis 3-4 fiores disci
11-15 hand superantibus ; acheniis breviter linearibus villosulis. —
Tecate Mountains, in Lower California, twenty or thiity miles below
the State boundary. Dr. E. Palmer. Allied to A. laricifolius, «S;c.
Heads only four lines long.

BiGELOViA (Aplodiscus) spathulata. Ramosissima, panci-
pedalis, glabra, parum glutinosa ; ramulis floridis brevibiis foliosis ;
foliis (semiuncialibus) cuneato- seu obovato-spathulatis retusis iiiteger-
rimis coriaceis vix punctatis eveniis, costa obscura ; ca{)itulis corymbosis
(lin. 4-5-longis) 16-floris; involucri turbinati' squamis coriaceis, inti-
mis latiuscule linearibus pallidis, exterioribus seusim brevioribus eras-

OF ARTS AND SCIENCES. 75

siorihus viridiilisciuo, in l)r;icto()las pcilicolli Krevis traiisciuililiiis ; .styli
aitpeiidiciltiis tenui-subulatis parti stiginatifonc latiori a'liuiloiijris ;
acliciiiis soiiceo-villosis subturhinatis, — Near the entrance; of the
TantiUas Groat Canon, in Lower ("alifornia, near the borders of the
State, Dr. E. Pahner. Tliis sin^idarly i'eseiid)les our Aji/opti/t/ms
cuneatus ; but it has no trace of rays ; the leaves arc (U'stituto of
ghitiuous exudation and are obscurely when at all punctate ; tiie scales
of the involucre are not carinate ; the akenes shorter and silky ; and
tlie bristles of the pappus not (as in that plant) clavellate-thickened.
It must stand near to 7i. jVeiuiesii ; but the style-appendages are as
in the Chrysothamnus section.

BiGKLoviA (Chuysotiia^inoi'Sis, post No. 15 revisionis) Engkl-
MANNi. Spithaiua^a et ultra e basi truticosa, fere glabra et viridis ;
foliis crebris angustissime linearibus rigidulis nuicronato-acutatis paten-
tibus (poll. 1-2 longis seiiiilin. ad lineam latis), costa valida; capitulis
sessilibus fastigiatim coryniboso-glonieratis ; involucro oblongo-tur-
bipato lo-20-floro, squamis oblongo-lanceolatis cuspidato-acuminatis,
exterioribus sensim brevioribus baud folioso-appendiculatis ; corollis
5-dentatis ; appendicibus styli breviter crassiuscute subulatis ; acheniis
lineari-oblongis glaberrimis. — Plains of the eastern part of Colorado,
at Hugo Station on the Arkansas Pacific Railroad, Dr. p]ngelmann
and Dr. Parry, 1874 ; H. N. Patterson, 1875.

Pjigelovia Greenei. (Chrysothamnus, * * h- ante No. 19
revisionis.) Pedalis, glaberrima ; foliis angustissinie linearibus
mucronatis minutim remotiuscule hirtello-ciliolatis ; capitulis corym-
boso-fasciculatis angusto-oblongis ; invohicri squamis oblongis niargine
tenuiter scariosis apice subito caudato-acuniinatis ; pappo rigidulo. — ■
Huerfano Plains, southern part of Colorado, Rev. E. L. Greene,
1872.

DiPLOSTEPHiUM CANUM. (ApLOSTEPHiUM, ligulis paucis parvis
stylo suo brevioribus, pappo simplici.) Frutex ramosus, validus, to-
mento implexo dealbatus ; foliis spathulatis vel angusto-oblongis basi
attenuatis subpetiolatis integerrimis plauis e costa valida subreticulato-
venosis ; capitulis laxe cymosis vel subpaniculatis, primariis in dicho-
tomiis sessilibus ; involucro brevi-oblongo crebre tomentoso, squamis
obtusis ; floribus purpurascentibus, radii 4—6, ligula inconsjncua disco
breviore 2-3-dentata; disci 12-20, corollis 5-dentatis, appendicibus
styli brevibus acutiusculis ; acheniis linearibus subcompressis 4-5-
nerviis sericeo-hirtellis ; pappo e setis rigidulis plerunique a^quali-
bus, vel perpaucis exterioribus minimis. — Guadahijje Island, off

76 PROCEEDINGS OF THE AMERICAN ACADEMY

Lower California, Dr. E. Palmer ; who mentions it as " a large
shrub, about four feet high, of rather loose habit, found only ia
the crevices of high rocky cliffs, March 28. Flowers yellow." A
purple hue in the small rays is evident, and the disk-corollas seem
to have turned purplish also, as they are apt to do in the heterochro-
mous Asterinece. The plant agrees so well in habit, and so nearly in.
character, with Diplostephlum of South America that it may fairly
be referred to that genus, some species of which are equall}- destitute
of an outer abbreviated pappus, while some are said to want the ray
altogether. The general aspect is also much that of the Inuleee, an
Old World group ; but the anthers are completely tailless, and the
appendages of the style-branches are manifest, although not strongly
marked internally, the stigmatic lines not ending abruptly. Still
more does it recall some of the South American Vcrnonice in appear-
ance and especially in inflorescence. It seems best not to constitute
genera upon single species with no more salient characters than these,
but a subgeneric distinction may mark its peculiarities. The heads
are barely half an inch long.

Aster Coloradoensis. Mach.eranthera sed pereunis, nanus,
tomentuloso-canescens ; caulibus in caudice lignescente confertis pluri-
mis monoceplialis ; foliis imis spathulatis, summis fere linearibus,
omnibus argute dentatis, dentibus spinuloso-setiferis ; involucri hemi-
sphairici squamis pluriserialibus subulatis laxiusculis ; ligulis 3.')-4:0
linearibus purpureis elongatis ; acheniis brevibus turbinatis creberrime
cauo-villosis. — Colorado Rocky Mountains ; in South Park, on
banks, gravel-bars, or open hills, Canby, Porter, Wolf and Hoth-
rock, Greene ; and San Juan Pass in the soulh-western jtart of the
State, at 12,000 feet, Brandegee. A species several times collected
and passed over as a very dwarf form of A. cauescens, from which it is
wholly distinct. The tufted stems are only 2 or 3 inches high.

Dicokia Brandeoei. Diffusa, pube substrigulosa cinerea ; foliis
lanceolatis obtusis subintegerrimis ; ca[)itulis laxc racemoso-panicnlatis
parvis ; involucri squama interna florem fccniincum fulcrante nnica
cu'tcris hand lonjjiore achenio oblon<;o tur<fido marixine calloso-dcntato
subdimidio breviore. — On the Rio Montezuma de San Juan, near the
south-western corner of Colorado, T. S. Brandegee in Ilayden's Ex-
ploration, 1875. An interesting accession to the genus, rocpiiring
considerable modification of the character, there being only one female
flower ; its broad subtending scale hardly enlarging, thin but not
scarious or colored ; the exserted and naked akene more thick, convex
and angled on the back, developing on the margins only ligid blunt

OF ARTS AND SCIENCES. 77

teeth for the winij ; p;ih';e of tlic rcceptai'lt' only om> or two aiiioiii; tho
male flowers. Filaiiu'iits iiKiiiadriiiJums to tlu; top, as in J), cdtii-s-
ce/is, antl anthers pointless ; (he style ai)ortivt! ami functioiilcss as a
pt)llen-(listributor.

Fij.vxsKiJiA ILICIFOI.IA. Fruticosa, hirsntula; foliis ri^ido-coriaeeis
ohloiijiis vel ovatis basi aurieulata sulianiplexicaulibns pcnnivcniis (.-t
retiiiilato-venulosis grosse ilentatis, dentibns apieeque sa-pius aciiini-
iiato-spinescentibus ; capitulis masculis hand visis, fcemiueis fruciiicris
globosis biloeularibns disptMinis aculeis crebris longis hainatis arniatis,
rostris 2 aenk'is hand lougioribus parum crassioribus. — Great Cafion
of the Tantillas Mountains, noar the northern border of Jjower Cali-
fornia, Dr. P^. Palmer. Flowering branehes very leafy to the sum-
mit, hirsute or his[)id : leaves an inch or two in length, tipped with
a very sharp rigid spine ; fruiting iuvolucre half an inch in diame-
ter, including the slender prickles, which are 2 lines long.

Wykthia coriacea. Pedalis, villoso-pubescens, paucifoliata ;
foliis longe petiolatis coriaceis eximie reticulatis aut lato-ovatis basi
nunc truneata nunc obliqua vel acuta, aut oblongis in petiolum angus-
tatis ; capitulis paucis breviter pedunculatis ; involucro oblongo e
squamis 5-6 oblongis lanceolatisve ligulas aequantibus vel superan-
tibus cum interioribus perpaucis parvulis .sul)paleaceis ; aclieniis
glabris, radii oblongis obcompressis, disci angustioribus prisma-
ticis 4-o-angulatis, omnibus exaristatis. — On the Mesa Grande,
70 miles north-east of San Diego, California, Dr. E. Palmer. A
remarkable dwarf species, with leaves varying from 3. to o inches
long, and sometimes nearly as broad, on petioles 2 to 4 inches
long ; the broader ones with some of the lower and stronger primary
veins or ribs converging to the apex, or running into false veins by
anastomosis. Heads an inch or so in length. Rays 5 to 8 ; ligules
only half an inch long. Pappus of 4 to 6 short ovate or triangular
scales, a little united at base, rather unequal, one or two occasionally
lanceolate or subulate and longer, but awnless.

HixiANTHUS GRACILENTUS. Perenni.s, tripedalis ; caule ramisque
gracilibus fere glabris kevibus ; foliis breviusculis lanceolatis integerri-
mis utrinque hirtello-scabris subcinereis, inferioribus oppositis breviter
petiolatis ; pedunculis paucis gracilibus nudis ; capitulis parvulis ; in-
volucro disco breviore, squamis inappendiculatis oblongo-lanceolatis
acutis gradatim imbricatis hirtello-puberulis ; ligulis 1 2-1 6 elongatis ,
disco fuico-flavescente ; paleis apice deltoideis; achenio glaberrimo com-
planato pappi paleis 2 subulato-aristiformibus (corolla paullo brevi-

78 TROCEEDINGS OF THE AMERICAN ACADEMY

oribus) dimidio breviore. — California, in the mountains 4o miles
north-east of San Diego, Dr. Palmer. Larger leaves 3 inches long,
somewhat triple-nerved ; the upper successively smaller. Disk little
over half an inch iu diameter ; rays from two-thirds to a full inch in
length.

IvA Hayesiana. Frutescens, sti'iguloso-iiuberula ; caule (ad bipe-
dalem et ultra, basi baud viso) erecto denium paniculato-ramoso; foliis
integerrimis obtusis, caulinis oppositis spathulato-oblongis vel sub-
lanceolatis in petiolum attenuatis, ramealibus bractealibusque alternis
ad linearia ; capitulis longe laxiuscule quasi spicatis vel racemosis ;
involucro e squaniis circiter 5 rotundatis discretis imbricatis. — San
Diego County, California; AYarner's Pass, Sutton Hayes (1858);
and Jamuel Valley, south-east of San Diego, Dr. E. Palmer. A well-
marked species, resembling I. clieiranthi folia rather than /. axillaris.
Heads numerous in elongated leaf'y-bracted spikes or racemes, and
these in an ample paniclq ; the ultimate floral leaves or bracts hardly
exceeding the nodding heads. In memory of the estimable discov-
erer, the late Mr. Sutton Hayes, whose specimens, however, were
indeterminable, the heads having all fallen from their short peduncles.

Encklia (Ger^a) viscida. Herbacea, viscido-glaiidulosa ; caule
forte bipedali (basi igiioto) ramis costaque foliorum pilis longis patulis
multi-aiticiilatis barbatis ; foliis ovatis oblongisve plerumque basi auri-
culata vel cordata semiaraj^lexicaulibus subserratis ; capitulis ramulos
breves foliates terminantibus ; involucro extus viscido, sqiiamis extcri-
oribus herbaceo-membranaceis lato-linearibus obtusis parum ina^qua-
libus, intimis scariosis paleis receptaculi similibus ; ligulis nullis ;
coroUisTadii pallide»flavis ; acheniis angusto-cuneatis calloso-marginatis
biaristatis priesertim ad margines albo-villosissimis. — Near Larkens'
Station, on the southern borders of California, 80 miles east of San
Diego, Dr. Palmer. Head nearly three-fourths of an inch long:
akenes 4 or 5 lines long, and their subulate awns 2 or 3 lines. The
habit is that of a Ilalsea, rather than of any of its congeners.

Perityle incana. Suffiutescens, procera, tomento apphuiato
incana: foliis (etiam inferioribus ?) alternis crassiusculis fere trisectis,
segmentis cuueatis 2-3-fidis, lobis pauci-incisis ; capitulis compluribus
in cymam compositam corymbosam nudam conge-tis ; involucro viri-
dulo; ligulis nullis ; appendicibus styli breviusculis acutiusculis ; acheniis
oblongis subturgidis undique villosis ; pappo exaristato e squamollis
plurimis angustissimis basi coroniformi-concretis. — Guadalupe Island,
oil" Lower California, Dr. ¥.. Palmer. On precipices inaccessible to

OF ARTS AND SCIENCES. 79

goats in the interior of the ishuul, couspiciious by its very white fohage
and abuiulaiit golden-yellow blossoms. A remarkable and anomalous
species, but certainly of tills genus, having all the characters. One of
the genuine species already published is rayless. In size (probably
2 or 3 feet high), in the dense touientum, and in the naked dense
corymbs or cymes, this is peculiar. The squamelhe of the pappus
are as long as the breadth of the akene.

IIkmizoxia (Hartmanxia) fkctkscexs. Fruticosa, erecta, ultra
bipedalis, hirsutula, subviscida ; ramis floridis virgatis fastigiatis folio-
sissimis ; foliis liliformibus (poliicaribus, fasciculorum brevioribus)
integerrimis raro 1— 3-lobatis ; capitulis thyrsoideo-racemosis (lin. 3
altis) ; ligulis 8-9 aureis obovato-oblongis 2-3-dentatis iuvolucro glabri-
usculo a?quilongis; disci floribus 10-12 receptaculi convexi paleis
totitlem liuearibus fere discretis circumdatis ; pappo e paleis 5 lineari-
bus vel subulatis finibriato-deiiticulatis. — Rocky precipices in the
interior of Guadalupe Island, off Lower California, Dr. E. Palmer.
Disk-akeues well-formed, but apparently sterile. This and the fol-
lowing are striking additions to the Hurlmannia section of the genus.

Hemizoxia (Hart-MAXXIa) floribcnda. Erecta, glanduloso-
pubescens, forte tripedalis (basi ignota) ; ramis crebris foliosissimis ;
foliis liuearibus obtusis integerrimis (^-^-poliicaribus) ; capitulis ramu-
los terminantibus paniculatis (lin. 3-4 altis) ; involucro creberrime
glanduloso disco breviore ; ligulis plus 20 majusculis biseriatis cuneatis
apice o-lobatis aurautiacis ; H. disci totidem ; receptaculo parum con-
vexo inter disoum et radium paleis linearibus discretis onusto ; acheniis
disci plerumque fertilibus pappo e paleis 5-8 late ovatis obtusissimis
integerrimis dorso margineque hirsutulis coronatis. — California, near
the southern boundary, on the Fort Yuma Road, 80 miles east of
San Diego. Dr. E. Palmer. Belongs to the subdivision which includes
J{. anguslifoUa and H. cui-ymbosa.

Artemisia Palmeri. (^Serlphidium, licet recei)taculum paleis
onustum.) Ut videtur elata et herbacea, cinereo-puberula ; foliis 3-5-
partitis, ramealibus integerrimis lobisque angusto-linearibus elongatis
subtus tomentoso-incanis margine revolutis ; panicula amplissima flori-
buiida ; involucri squamis ovatis subscarioso-membranaceis ; acheniis
immaturis disco epigyno majusculo. — San Diego County, California,
in Jamuel Valley, 20 miles below San Diego, Dr. E. Palmer. Habit
nearly of A. Gcdifornica, but apparently herbaceous througliout. and
with the leaves or lobes broader and flat, a line or more in diameter.

HO PROCEEDINGS OF THE AMERICAN ACADEMY

Heads a line and a half in diameter : flowers all perfect ; most of them
subtended by palea?, the outer ones similar to the involucral scales,
the inner shorter and smaller.

Senecio Palmeui. Suffruticosus, tomento implexo candidissimiis,
ramosissimus ; foliis in ramis floridis confertis oblougo-spathulatis sub-
integerrimis in petiolum sat gracile attenuatis ; pedunculo elongato
undo corymboso-7— 14-cephalo; involucro ecalyculato incano, squamis
20-30 linearibus; ligulis 12-18 ovalibus aureis; acheniis sericeo-inca-
nis. — Abundant through the northern half of the Guadalupe Island,
Lower California. One of the most conspicuous plants, about a yard
high ; the foliage strikingly white, and the flowers bright yellow.
Heads fully half an inch high, many-flowered ; rays 4 lines long.

Pyrrhopappus RoTHROCKri. Gracilis ; caule ultrapedali e radice
fusiformi perenni? simplici vel inferne ramoso folioso mono-oligo-
ceplialo ; foliis linearibus integerrimis vel basim versus parce pinnati-
fido-laciniatis dentatisve ; pedunculo gracili fere nudo ; capitulo
angusto circiter 20-floro ; involucri squamis ex terioribuspaucis sububitis
adpressis ; acheniis rugulosis sursuni scabris ; pap{)0 maturo sordide
albo ! — Fisch's Ranch in Southern Arizona, at 5000 feet altitude,
J. T. Rothrock, in Wheeler's Exploration, 1874.

PALMERELLA, Nov. Gen. Lohellacearum.

Calycis tubus turbinatus, ovario biloculari multiovulato adnatus ;
limbns 5-partitus, lobis angustis Kqualibns. Corollaj tubus liiicari-
elongatus (intiis pubentissimus), omnino saltern superne integer; fauce
nun(iiiam dilatata ; limbo patente valde inivquali, lobis 2 minoiihus
spathulato-linearibus, 3 majoribus oblongis basi connatis. Filamenta
corolla} tubo longissime adnata, dein monadelpha et uno latere saepius
alterius adnata : anthenc oblong;e, 2 setis paucis rigidis ino?qualibus
vertice penicillata?, 3 paullo majores nudie. Cajt. Lobellce. Fructus
maturus liaud visus.

P. DF.r.iLis. Herba glaberrima, gracilis, ultrapedalis, ramosa ;
foliis alteruis tenuibus lineari-lanceolatis integerrimis eglandulosis
sessilibus 2-3-pollicaribus, floralibus sensim diniinutis bracteis racemi
laxi pauci-])hniflori referentibus ; corolhe tubo albido J-pollicari. lobis
l;ete cyaneis, 2 niinoribus, majoribus lineas 3-4 longis. — Great
Caiion of the Tantillas Mountains, near the northern borders of Lower
California, Dr. Edward Palmer, to whom this genus is dedicated in

OF ARTS AND SCIENCES. 81

acknowledgment of his in(lef:itij;:i1)le and fruitful explorations of tlio
botany of the south-western frontiers of the United States, from Ari-
zona to the islands off Lower California, in whiili region he has ac-
complished more than all his predeeessors.

The genus differs from Lobelia in the remarkalde adnation of the
stamens, as well as in the integrity of the corolla tube, at least its upper
portion. It soon splits from the base upwards for a good distance,
and, indeed, before withering the lower part of the corolla i? much
disposed to separate into five claws (liberating also the lower part of
the filaments) ; but this occurs in many species of Lobelia. From
Rhizocephalum, of Weddell, this is distinguished by the habit, the very
dissimilar lobes of the corolla and its narrower throat, and the com-
pletely 2-celled ovary, which probably matui'es numerous miimte
seeds.

SPECULARIA Heister. Although the two sections made by
Alph. De Candolle are untenable, since species of the Old World {S.
falc(ita,{oT instance) have lenticular seeds, and an American one, much
confounded with S. perfoliata^has the valvular openings of the capsule
near the summit, yet the American species may be well distinguished
from the Kuropean, and into two sections, by taking account of the
cleistogamous flowers. These are regulaily pi'oduced in our species,
and not in those of the Old "World. (They have recently been said to
occur sometimes in aS". ttybrida and S. falcata, but 1 have not found
any trace of them.) They were noticed by Linnfcus in the species
known to him, but were wrongly thought to be incomplete and imper-
fect, as Dr. Torrey remarked, when he accurately described them over
half a century ago. They were what we termed precociously fertilized
flowers, of necessity close-fertilized, — a term to which Mr. Darwin
took objection in the instance of Impatiens and Viola, and with reason
if the name stands in the way of recognition of their special adaptation
to close fertilization; and the proper name of "cleistogamous" is
now established. But one of our species of Specularia, as well as the
genus Lespedeza, lends support to our original view, by showing close
fertilized blossoms as if in various stages of arrest of development.
There is a mistake in Dr. Torrey's remark (in Flora of the State of
jS'evv York, 1, p. 429), that Ruiz and Pavon's plate of Campanula
bijiora represents the two kinds of blossoms. It is curious that this
species should have been confounded with our common northern one,
as by Alph. De Candolle in the Prodroraus, and by Mr. Bentham in
his recent notes upon that order in Jour. Linn, Soc. 15, p. 13. The

VOL. XI. (n. 8. II.) ^

82 PROCEEDINGS OF THE AMERICAN ACADEMY

views wliich we here take may be best exhibited in a conspectus of
the American species.*

* SPECULARIiE Americans.

§ 1. CAMPYLOCERA. Flores dimorplii, prjBcoeiores cleistofjami. Capsnla
elongata, valvulis infra-apicalibus deliiseens, sero saltern in i)raecocioribus
ab apice longitudinaliter subdissiliens. Ovarium in floribus cleistogamis
quandoque abortu uniloculare, i)lacenta lateral!. — Cumpylocera Nutt. in Trans.
Ainer. Phil. Soc. n. ser. 8, p. 257 (1843).

1. S. LEPTOC.4KPA. Caule virgato; foiiis lanceolatis; floribus in axillis arete
sessilibus; stiginatibus 2-3 ; ovario in fl. cleistogamis nonnullis abortu unllocu-
lari calycls lobis 3-4 superato ; eapsulis fere cylindricis gracilibus valvulis sub-
apiealibus adscendentibus 1-3 pertusis, praecocioribus saapius decurvatis raro
tortis ; seminibus oblongis. — Campanula leptocar/xi Engelm. in herbariis. Cam-
pylocera leptocarpa & var. glabella Nutt. 1. c. Specnlaria Liiisecoiin'a Buckley in
Proc. Acad. Philad. 1861, p. 460. — Arkansas, Nuttall, Engelniann ; Texas,
Wright, Buckley ; Colorado to tiie Rocky Mountains, Parry, Vasey. As to
the twisting of the capsule on its axis, in the manner of DowniiKjia, mentioned
by Nuttall, it is hardly if at all to be seen in our specimens.

2. S. LiNDHEiMERi Vatke in Linnwa, 38, p. 713. Procerior; caule erectovel
reclinato (1-3-pedali) superne nunc paniculate; foiiis oblongo-lanceolatis imisve
ovalibus ; floribus brevi-pedunculatis vel subsessilibus magis paniculatis ; stig-
matibus loculisque ovarii semper 3-4; calycis lobis etiam in cleistogamis 5 ;
eapsulis angulatis basi angustatis baud curvatis tortisve valvulis 2-3 pauUo
infra apicem pertusis ; seminibus fere orbiculatis. — W. Texas, Lindheimer,
Wright, Buckley. I take this to be the "Camjuinula Coloradoi-nse" Buckley,
1. c, from his character of " stigmas 4-5"- (I have seen only 4), and therefore
have adopted the specific name. The seeds are described as " ellipsoid," of
the preceding species " elliptical." The expanded corollas are an inch in
diameter, about twice the size of those of S. leptocarpa. The capsules appar-
ently are never one-celled, although the partitions separate readily from the
axis, one carrying away the placenta, and there is a tendency to be septicidal.
The perforations, moreover, are by valves that open from above downward,
or by mere ruptures. In many of the cleistogamous flowers, the corolla has
attained considerable development, so as to suggest a gradation between the
two kinds.

§ 2. DYSMICODON Endl. Flores dimorphi, praecociores cleistogami calyco
3-4-lobo, normales serotini, calyce 5-lobo. CapsuJa brevior. aut sub apice
aut infra medium pertusa. Semina lenticularia. — Difsmirodon Nutt. 1. c.
Triodallus Raf., ubi 1 Specnlaria § Triodallus Torr. Fl. N. Y.

3. S. mi'LouA. Caule gracili ad angulos retrorsum serrulato-hirtello vel
subljevi ; foiiis ovatis oblongisve rariter crenulatis, superioribus lanceolatis
flore fulcrato brevioribus ; floribus in axillis solitariis binisve sessilibus ; calycis
lobis in cleistogauiis brevibus ovatis vel subulatis, in normalibus lanccolato-
subulatis elongatis corollam vix adaiquantibus ; eapsulis cylindraceis subfusi-
formibus vix costatis, valvulis infra-apicalibus. — Campanula hiJJora, Ruiz & Pav.

OP ARTS AND SCIENCES. 83

AuCTOSTAiniYLOS AxuKUSoxir. A. tomentoscE alRiiis ; raiuia
gracilioribus setis longis albis hispidis ; I'oliis tiiimitcr coriuoois fere
sessilibus glabris (costa subtiis sctosa exccpta) viri<libus obloiigo-
lauceolatis basi sagittato-cordatis sa'pe spinuloso-serrulalis ; dnipis
viscosissimo-hirtis. — Hills behind Santa Cruz, Califurnia, Dr. C. I..
Anderson, 1873.

HESPERELiEA, Nov. Gen. Oleacearum.

Calyx tetrasepalus, sestivatione imbricativus, deciduus. Petala 4,
spathulata, unguiculata, festivatione apicem versus imbricata, accrescen-
tia, deridua. Stamina 4, hypogyna, petalis alterna: filameiita sul)u-
lata: antlier^ oblongaj, subintrorsaj, mucronata3. Ovarium uvoideum :
ovulis in loculis binis ab apice pendulis : stylus culumnaris : stigma
crassum, bilobum, lobis dorso parura sulcatis. Fructus sine dubio dru-
paceus. — Arbor 3-4-orgyalis, glabra; foliis plerumque oppositis
integei-rimis oblongis coriaceis e costa valida penniveniis ; paniculai
floribundfe ramis pedicellisque brevibus articulatis ; floribus sulpliureis
hermaphroditis nunc ovario imperfecto polygamis.

Hespereljea Palmeri. Guadalupe Island, off Lower California ;
found only in a canon on the eastern side. Leaves 2 inches or more
in length. Sepals oblong, somewhat scale-like and concave, greenish
becoming yellowish. Petals when full grown nearly half an incii long,
pale lemon-colored ; the claw about the length of the sepals and the
filaments. A very marked new genus, of the Oleineous tribe, remark-
able for the wholly distinct and unguiculate petals, with imbricative
aestivation, and the apparently uniformly isomerous stamens.

Fl. Per. 2, p. 55, t. 200, fig. 6. C. Montcvidensis Spreng. Syst. ? ex char.
C Ludoviciana Torr. (ined. ?). C. intermedia Engelra. in jierbariis & ex Nutt.
1. c. Dysmicodon Cali/oniicum & ovatiim, Nutt. 1. C. Specularia ovata Torr.,
Vatke, 1. c. — S. Carolina to Arkansas, Texas, and in California ; also in S.
America. Singularly confounded with the next. It much more resembles 5.
falcata of tiie Old World, winch, however, has longer calyx-lobes, and, so far as
I have seen, homomorphous flowers.

4. S. PERFOLiATA A. DC. Prodr., excl. syn. nonnul. ; Torr. Fl. N. Y. 1,
p. 428, t. 65. Campanula flagellaris HBK. Nov. Gen. 3, t. 265. Di/smirodon
perfoliatum Nutt. 1. c. Subhispida; foliis rotundato-cordatls quasi amplexicaul-
ibus ; capsulis brevioribus basi angustioribus, valvulis infra medium sitis. —
Canada to Texas, Oregon, Mexico, &c. Triodallus rupestris Raf., according to
specimens in herbaria, is a depauperate and diffuse state, in which only the
close-fertilized blossoms are developed.

84 PROCEEDINGS OF THE AMERICAN ACADEMY

Gkntiana NewberkVi. Pxeumonanthe, nana ; foliis radicalibus
rosulatis obovatis vel spathulatis ; caulibtis floridis 2-4 circa innovatio-
nem centralem folia parvula spathulata vel sublanceolata basi connato-
vaginantia (summa florem unicum stipantia) gerentibus ; calycis lobis
lanceolatis oblongisve tubo subrequilongis ; corolla CiBrulescente late
infundibuliformi, appendicibus plicarum bifidis vel subulato-laciniatis
lobis ovatis mucronatis brevioribus ; seminibus ovalibus ala lata cinctis.

— G. calycosa'? Gray in Pacif. R. Rep. 6, p. 86, non Griseb. — Ore-
gon and California, in the Sierra Nevada, from Crater Pass (New-
berry) to Mariposa County, Bolander. Related to G. frigida.
Corolla over an inch long, pale blue, white within, and greenish-
dotted. Flowering stems an inch or two in length.

Gentiana setigera. Pneumonanthe; caulibus sat validis (pe-
dalibus) adscendentibus e caudice crasso foliosis; foliis inferioribus
orbiculato-ovalibus, superioribus obtusissimis, summis 4 florem involu-
crantibus, omnibus basi connato-vaginante ; calycis lobis ovalibus tubo
a?quilongis ; corolla oblongo-campanulata, appendicibus plicarum brevi-
bus parvulis setas capillares 2-3 lobis ovatis fere adasquantes gerentibus.

— Red Mountain, Mendocino County, California, Bolander, No. 840
of Kellogg and Harford's distribution. Leaves 7 to 10 pairs on the
stem, thick, an inch or less in length. Corolla an inch and a half
long, and the blue lobes nearly half an inch long. Forming seeds
orbicular and winged.

Halenia Rothrockii. Annua, ultraspithama^a, laxiflora ; foliis
linearibus ; corolla lutea, calcaribus subulatis divaricatis parum adscen-
dentibus calycis lobos lineares subicquantibus. — Arizona, on Mount
Graham, at 9000 feet, Dr. J. T. Rothrock, in Wheeler's Expedition,
1874.

MiCROCALA QUADRANGULARis Griseb. "Whether this South
American species is indigenous to California would appear uncertain
as to the vicinity of San Francisco. But Dr. Bolander found it
" near Mendocino, under Piniis contorta" where it seems imlikely
to have been brought by the agency of men or cattle. Dr. Engel-
mann indicated to me that the stamens are inserted in the very
sinuses, not below on the tube as figure<l by Progel in the Flora Bra-
siliensis. Then the stigma, as Dr. Engelmaim has also sliown in both
species of the genus, is separable or in age actually divides into two.

Gn.iA Larseni. Eugilia, dcpressa, surculis filiformibus repenti-
bus apice foliatis perennans, pubescens ; folfis omnibus alternis con-
fertis pedatim 5-7-partitis summisve trifidis, lobis lineari-oblongis

f

OF ARTS AND SCIENCES. 85

majoribus subcuneatis 2-3-(i(Iis ; floiil.us inter folia subsessilibus ;
corolla infuiulibuliforiui violacea (soiuipollicari) calyce 2-;5-|)lo loii-
gioro, lobis late ovalihus ; oviilis solitariis. — California, on Lassen's
Teak, J. G. Leinmon and John Larsen, 187o. lIal)iL of llie K<tni-
retia section ; but tbe lobes of tbe leaves and of tlie calyx are not even
mucronate, and tbe flowers are sparse.

GiLiA (IPOMOrsis) Haydeni. Fere glabra, e basi indurata peic n-
iii vel bienui paniculato-raraosissima, pedalis ; foliis linearibus, iniis vix
spatliiilatis parce pinnatilobatisdenlatisve, raniealibus plerisipie minimis
subulatis integerrimis ; panieulis subthyrsoideis floribuiidis calyeibns-
que parum glandulosis ; corolla c.-eruleo-piirpurea graeili infnndibulari-
tubulosa (ultra-semipollicari), tubo lobis suis ovatis ealyeeqne o-4-plo
longiore ; antberis oblongo-sagittatis subsessilibus fauci insertis ; ovarii
loculis 8-9-ovulatis ; seminibus paucis oblongis, tegumento Iiumectato
nee spirillifero nee mucilaginoso ! — Mesa San Juan, soutbern borders
of Colorado or adjacent part of Utali, T. S. Brandegee, in Ilayden's
Exploration of 1875. Dedicated to tbe indefatigable explorer and geo-
logical surveyor, in charge of this and many other successful explora-
tions of our Rocky Mountain regions. Tbe species has the habit and
color of corolla of the Eugilia division, but the long narrow corolla and
bractless pedicels of Ipomopsis.

GiLiA Brandegei. Eugilia, perennis, pube glandulosa fragrante
viscosissima ; caulibus erectis spithamajis vel subpedalibus thyr-
sifloris; foliis circumscriptione linearibus pinnatisectis, segmentis
plurimis sessilibus parvis aut oblongo-linearibus rarius ovalibus inte-
gerrimis aut bipartitis verticillos 3-4-foliolatos simulantibus ; corolla
aurea infundibuliformi-tubulosa calyce cylindraceo semiquinquefido
2-3-plo longiore, fauce parum ampliata, lobis ovalibus brevibus ; ovulis
in loculis paucis. — South-western part of Colorado, in San Juan Gap
on the face of perpendicular cliffs, T. S. Brandegee, in Ilayden's
Exploration, 1875. A showy as well as most remarkable species,
with trumpet-shaped golden-yellow corolla, about an inch long. Leaves
2 or 3 inches, and their divisions only one or two lines in length.
The likeness of this plant in folinge, flowers, and fragrant viscosity to
Polemonium confertum var. melUtum is most striking. That species is
itself sufficiently anomalous in Polemonium, on account of its lengtli-
ened corolla ; but its filaments are really declinate-curved, while they
appear to be not at all so in the present plant. If this character be
relinquished, nothing will be left absolutely to distinguish either
Polemonium or Loeselia.

86 PROCEEDINGS OP THE AMERICAN ACADEMY

LO&SELTA Linn. § Giliopsis. Flores paniculati vel sparsi, ebrac-
teati. Corollas lobi subcuneati, apice eroso-truncati vel subtridentati.
Folia angustissiraa nuda. (Ovula in loculis 8-10. Semina ut in
spec, propriis exalata!)

LcESELiA TENUiFOLiA. E basi frutescente multicaulis, spithamasa
ad pedalem, glabella ; ramis gracilibus apice laxe paucifloris ; foliis
fere acerosis cuspidato-mucronatis integerrimis vel inferio<ibu3 sub-
liuearibiis paiici-pinnatipartitis, lobis subulatis ; calycis lobis subulatis
tubo dimidio brevioribus ; corolla punicea tubuloso-infundibuliformi
(pollicari), tubo lobis 3-4-plo longiore ; genitalibus longius exsertis. —
Northern borders of Lower California, Tantillas Mountains, especially
at the entrance of the Great Cafion, "W. Dunn, E. Palmer. Longer
leaA'es an inch long ; the upper gradually reduced to small subulate
bracts, but none at the base of the calyx. One lobe of the corolla
separated from the others by deeper sinuses ; the long capillary fila-
ments (which are inserted low down on the tube) more or less de-
clined to that side, and their summits a little incurved.

LcESELiA EFFUSA. Spithamaea ad pedalem, e radice annua laxe
ramosissima, glabella ; ramis ramulisque paniculato-floribuudis gracil-
limis rigidulis ; foliis omnibus fere filiformibus mucroue apiculatis
integerrimis (radicalibus evanidis) ; calycis dentibus brevibus latis ;
corolla brevi-infuiidibuliformi purpurea, tubo cah'cem paullo superante
lobis inasqualibus baud longiore; genitalibus (sat declinatis apice incur-
vis) corollam parum excedentibus. — Tantillas Mountains, borders of
Lower California, Dr. E. Palmer. Stem sometimes as if lignescent
at base; but the root plainly annual. Leaves from half to a quarter
of an inch long, or less. Pedicels sometimes as long as the flowers,
mostly shorter than the calyx. Corolla (" pink," but in the dried
specimens violet-purple) barely half an inch long, the limb rather
ample and spreading, one or two lobes rather smaller and more sep-
arated. Capillary stamens inserted low on the tube of the corolla.
Ovules, seeds, &c., as in the preceding.

Except for the declined stamens and some inequality of the corolla,
these two species would be referred to Gilia, the former to the section
Ipomopsis, the latter to Eugilia. But they accord with Lceselin,
except in the total absence of dilated bracts, which, considering the
case of Gilia, cannot be the generic character. The seeds do not
supply a character. These in Loeselia, as remarked in the yet un-
published portion of the Genera Plaiitarum by Bentham and Hooker,
develop mucilage wlieu wet; the mucilage-cells are underneath a

OF ARTS AND SCIENCES. 87

ratluT (inn iicllicle, as in several species oi Gllltt ; moreover, in no
s{)eeie8 that I have examined is tliere any membranaceous marj^in,
still less a wing; the slight bonier which sometimes gives an apixar-
anee of one comes from the drying of the somewhat translucent
nnicilaginoiis coating. The characters which distinguish Gilitt, J'ole-
monium, and Lceselia are by no means as delinite as was supposed
before such connecting forms as these and tlic preceding were known.
But I conclude that these two 2)lants must constitute a section of
Lceselia.

Lachno.stoma hastulatum. Gracillimuni, volubile, pul.c dcnsa
brevi undique cinereum ; foliis parvis (lin. '2-6 lougis et petiolo sub-
aiquilongo) hastatis ; Horibus solitariis fere sessilibus ; sepalis lineari-
bus; corolloe 5-partita3 lobis lato-linearibus tantum puberulis iniu.s
glabrioribus ; corona simplici asclepioidea, nempe e scpiamis 5 cuculli-
formibus apice tridentatis intus ligula brevi subulata auctis ; folliculis
fusiformibus parce molliter muricatis. — Canon Tantillas, within the
northern borders of Lower California, Dr. Palmer. Corolla greenish-
white, only 2 lines long. Follicles nearly 2 inches long.

Thacelia (Eupiiacelia) niYLLOMANiCA. Elata, ramosa, folio-
sissima, pube et brevi molli densa et superne longiore villosa canes-
cens ; foliis pinnatisectis, segmentis 17-2-3 crebris oblongo-linearibus
pinnatifidis, lobis brevibus oblongis nunc pauciden talis ; spicis thyr-
soideo-congestis primum deusis ; floribus sessilibus ; calyce e phyllis aut
omnibus foliaceis piunato-3-5-partitis aut 1-3 lato liuearibus integer-
rimis corolla violacea parum brevioribus ; plicis brevibus latissimis ;
staminibus subexsertis. — Var. interrupta : viridula, pube laxiore ;
foliis teuuioribus, segmentis paucioribus sparsioribus hinc inde ad lobu-
lum reductis, majoribus sinuato- vel crenato-bipinnatilobatis. — A
striking species of the P. tanacetifolia section, perhaps not an annual,
destitute of hispid hairs and of glands, but rather viscid in the inflo-
resceuce ; the dissected foliaceous calyx peculiar. The annular disk is
very conspicuous.

E.MMENANTHE pusiLLA. Exigua, piloso-pubesccDS ; foliis crassi-
usculis oblongo-lanceolatis vel spathulatis integerrimis in petiolum sat
gracilem attenuatis ; racemo 3-7-floro laxo, primario scapiformi ; corolla
minima (alba?) sejmlis linearibus parum spathulato-dilatatis capsula-
que ovoidea obtusissima mutica dimidio breviore ; stylo perbrevi ;
seminibus 10 valde grosseque rugosis Microyenetis. — Western Ne-
vada, at Steamboat Springs, S. Watson (part! of No. 878, early young
plants confounded with Phacelia pusilla) , and in the same district iu

88 PROCEEDINGS OF THE AMERICAN ACADEMY

May, 1875, Lemmon. A congener of E. glaberrima Torr., which
also appears to have a white rather than yellow corolla. Plant 1 to
3 inches high, slender. Leaves 2 to 5 lines long and with petiole of
almost equal length. Peduncle and raceme filiform ; pedicels mostly
shorter than the calyx ; the latter in flower one line, in fruit two lines
long. Very short and small style deciduous from the capsule. Seeds
less than half a line long.

HARPAGONELLA, Nov. Gen. Borraginacearum.

Calyx inequalis obliquus, e sepalis 3 a basi solutis immutatis, 2 alte
connatis in cucullura fructiferum dorso glochidiatum auctis. Corolla
tnbo brevissimo subrotata, lobis ajstivatione imbricatis, fauce fornicibus
obtusis instructa. Stamina brevia, tubo inclusa : antherge minima),
ovatse. Stylus brevis : stigma subcapitatum. Ovarii segmenta sub-
globosa, gynobasi planiusculai affixa, duo abortiva ; ovula in fertilibus
erecta, anatropa, foramine infero. Nuculas 2, collaterales, laeves, ob-
longse vel subclavatoe, ab areola parva adscendentes, una nuda sajpe
iiifertilis, altera major intra cucullum calycinum 6-7-cornutum (corni-
bus undique patentibus setis uncinatis armatis) arete clausa. Semen
nuculge conforme, basifixum : cotyledones ovata), radicula brevi infera
vel ceutripeta. — Herba pusilla, annua, PectocarycB facie ; foliis lineari-
bus, pedunculis sparsis brevibus extra-axillaribus post anthcsiu deflexis,
floribus minimis, corolla alba. (Benth. & Hook. Gen. PI. 2, p. 846,
adhuc ined.)

Harpagonella Palmeri. — Guadalupe Island, off Lower Califor-
nia, 1875, Dr. E. Palmeri A slender and sparingly branched annual,
2 to 5 inches high, cinereous-hirsute. Leaves linear, an inch or less
long, and the floral gradually reduced to bracts a line or two long.
Peduncles in fruit a line long, stout, and strongly recurved. Calyx in
flower barely a line long, 5-parted, except between two of the sepals,
v/hich coalesce to the middle ; below the sinus of the coalesceut divi-
sions is an external tufted appendage, which at length develops into
the soft-spiny horns. Short style slender to the base. Gyuophore
not elevated. The two lobes of the ovary on the side of the flower
next to the three nearly separate and unchanged sepals (which we
may designate the lower side of the flower) are uniformly and early
abortive ; the other portion of the calyx accrescent, and soon gibbous-
involute into a sort of coriaceous burr, of about 2 lines in length, armed
with a few (usually 7) spiny horns, of a line or two in length, wliidi
spread in all directions, and are beset for nearly their whole length

OF ARTS AND SCIENCES. 89

with short aud very stiff backwurdly hooked bristles ; the burr clo.siii;^
on the ventral side, and coni[)letely covering a fertile nutlet : the other
nutlet is free, aud is certainly sometimes fertile, but more comuioidy,
although enlarging, it seems to fail to mature a seed. The adaptive
character of this little plant, viz., tlie transference of the burr-like
apparatus for the dissemination of the seed from pericarp to the calyx,
aud the investment by the latter of only one of the two ripenirig
nutlets, is most remarkable. The habit is that of Pectucaryd, with
which it is associated upon the island ; but the structure is very dif-
erent.

ECIIIDIOCARYA, Nov. Gen. Borraginacearum.

Calyx 5-partitus ; segmentis linearibus, fructiferis lax is. Corolla
infundibuliformis, sub fauce nuda parum constricta, lobis aistivatione
imbricatis. Filamenta brevissima : antheriB oblongai. Ovarii lobi
gynobasi vix elevata; impositi : stylus brevis : stigma didymum. Nu-
culie 4, lataj, ovato-pyramidataj, inermes, subrugoso-muriculatie, dorso
ventroque carinulatte, carina ventrali apice breviter producta, areola
basilari late concava in stipitem longe producta, sti pi tibus infra medium
per paria connexis introrsum apertis gynobasin conicam claudentibus ;
cicatrice lata excava'a post nuculas delapsas in gynobasi relicta.
Semen breve, leviter curvum : cotyledoues latai subplanae. — Ilerba
annua, diffusa ; foliis (oblongo-linearibus) floribusque Eritrichii sect.
Plagiohothridi referentibus, corolla parva alba vel ca^rulescente.
(Char, maxima ex parte e Benth. & Hook. Gen. PI. 2, p. 854, adhuc
ined.).

EcHiDiocARYA Arizonica. — Verde Mesa, Arizona, Dr. Smart.

Convolvulus (Calystegia) occidentalis. Aut glaber, aut
minute pubescens, volubilis ; foliis nunc ovato-triangularihus sinu
profundo angusto nunc lanceolato-hastatis immo lineari-sagittatis, lobis
posticis soepe 1-2-dentatis ; pedunculo elongato intra biacteas ovatas
vel oblongas quandoque bifloro ; corolla alba vel eruhescente, limbo
lato ; stigmatibus fere linearibus. — Common throughout the western
part of California, on and near the coast. The more luxuriant and
broader-leaved forms so much resemble G. sepium that only the shape
of the stigmas surely distinguishes them. But I have never seen C".
septum with a second flower, while this often has two, and rarely even
three from the pair of bracts. The Californian species abundantly
confirm Mr. Bentham's remark in the Flora Australica, that the char-
acters of Cahjstecjia are too artificial, and it may now be added too
transitional, to warrant the adoption of the genus.

90 PROCEEDINGS OF THE AMERICAN ACADEMY

Convolvulus (Calystegia) Californicus Choisy, which is
Cahjstegia suhacauUs Hook. &, Arn., has the same narrow (at most
oblong-linear) stigmas, with very short or merely trailing stems, ob-
scurely if at all hastate and obtuse leaves, and oblong or oval bracts,
very similar to the outer sepals and not surpassing them.

Convolvulus (Calystegia) villosus, the C. n. sp. ? Torr. in
Pacif. R. Rep. 4, p. 127, and Calystegia villosa Kellogg in Proc.
Calif. Acad. 5, p. 17, is an allied species, usually silvery white with
a dense and soft tomentum, trailing or feebly twining, and the leaves
varying from reuiform-hastate to sagittate, the bracts oval or ovate,
and only equalling the calyx, the corolla cream-color. The following,
instead of the calyx-like membranaceo-foliaceous bracts close to the
calyx and enveloping it, has a foliaceous pair at some distance be-
low.

Convolvulus luteolus Gray. Aut glaber, aut pubescens, gra-
cilis, volubilis ; foliis triangulari-hastatis vel sagittatis, lobis nunc bifidis;
pedunculis folio a^quilongis uni- raro bifloris sub flure bracteas 2 line-
ares seu lanceolatas folioformes gerentibus ; sepalis rotundatis ; corolla
pallide lutea pollicari vel longiore. — Ipomcea sagittcefolia Hook. «fe
Arn., Bot. Beechey, jd. 151, licet stigmatibus lineaiibus. Var. ful-
CRATUS. Magis pubescens ; flore foliis hastatis vel sagittatis stipato.
C. Calif or nicus ToYY. Va,cit R. Rep. 4, p. 127, non Choisy. — Cali-
fornia, in various parts of the State, especially in the southern and
western portions ; its bracts from one to four lines long, and about the
same distance below the calyx. The variety, which often much re-
sembles C. villosus, abounds in the foot-hills of the Sierra Nevada,
and has bracteal leaves commonly half an inch long.

CuscuTA salina Engelm. is a new species added to the Califor-
nian flora : it includes C. snbinclusa var. abbreriata, and C. Call-
fornica var. ? squamigera of Engelmann's monograph. It affects
saline soil and Chenopodiaceous plants, especially Saliconiia, and
occurs on the coast from San Francisco Bay to British Columbia.

CIIAM.ESARACHA. Vide Proc. Am. Acad. 10, p. G2. As
Mr. Bentham has justly remarked (Gen. PI. 2, p. 891. ined.), tliis is
better completely separated from the genus Saracha ; and only three
sjiecies are made out, C. Coronoptts, C. sordida, and C. nana.
Saracha acutifolia of Miers, .which is not well described, appears to
be a Physfdis.

SoLANUM Xanti. Pacliystcmomim, Didcnmara, basi sutt^ruticosa
excepta herbaceum, aut subglabrum aut pilis simplicissimis sa^pe

OF ARTS AND SCIKNCES. 91

glandulosis pub '^cens, l-2-iK"(1:vle ; rauiis <,M-:icililnis subflexuosis ; fnliis
inembranaceis ovatis sen ovato-oblonj^is pctiolalis basi sulx-onlatis vcl
subcuneatis nunc iiite<Tris nunc lol)is latcialibns utrin(|nL' auriculatis ;
cymis umbolliforniibus prinunn tcrniinulibns pauci-phirilloris nunc
fui'catis ; pedicellis tilifornnbus ; corolla violacca plano-rolata angulato-
subquinqueloba pollicem dianietro ; calyce 5-lobo, fi-uctifcro erecto sub
bacca (purpurea?) globosa niodice anipliato. — California, tlirougli the
southern and eastern parts of the State, but extending to Sierra
County, J. G. Lemmon, and to Nevada, near Carson, Anderson. It is
named in honor of L. I. Xantus, one of the earlier collectors of the
species. This has been confounded with S. umhclliferuni, Dr. Bige-
low's specimen from Cocornungo having been referred to that species
by Torrey in the Botany of Whipple's Expedition, as was that of
Anderson from Nevada, by Watson in Kiujf's Expedition, l^esides
other marks, the pubescence is notably different (but sometimes almost
wanting), consisting of simple and few-jointed hairs, some of which
are glandular. It is so variable in foliage that the following plant is
probably referable to it.

Var. AVallacei. Majus; ramis junioribus pedunculisque pilis longis
pluri-articulatis viscidis villosis ;• cyma furcata ampliore ; corolla ses-
quipollicera diametro hete violacea. — Island of Catalina, off San
Pedro, California, Wallace. No. 586 of Coulter's Californian coUec
tion, of which my specimen wants the flowers, and which is glabrous
and has cordate leaves, may be a form of this.

SoLANDM UMBELLiFERUM Esch. Tliis Variable species abounds
around San Francisco and in all that part of California. Eschscholtz
described a form with ovate acute leaves, but they are more commonly
obtuse, and the smaller ones inclined to obovate. S. CuUfornicum of
Dunal is this ordinary form, and S. genistoides a depauperate and
small-leaved summer state of the same. The species is well marked
by the somewhat furfuraceous or tomentose pubescence, which, under
a lens, is seen to be composed of repeatedly branching hairs.

COLLINSIA Nutt. This genus is. exceedingly well marked, but
the species are difficult of discrimination. Eleven species may be
distinguished, of which nine are in the Californian flora, and two in
the Mississippi region and eastward.*

* COLLINSIA Nutt.
§ 1. Confertijlorce, pedicellis brevibus vel subnullis. Occidentales.
* Corolla vaUle declinata, fauce saccata subtransversa (in tubum propriiim
quasi liemitropa) vix longiore quam lata : filamenta superiora basi parce bar-
bata : glanilula (rudimentum staniinis quinti) parva, sessiiis.

92 PROCEEDINGS OF THE AMERICAN ACADEMY

TONELLA Nutt. There are two well-marked species. Although
the character of solitary ovules, assigned iu Proc. Am. Acad. 7,
p. 378, holds iu only one of them, yet the form of the corolla — with
rotately expanding lobes and the lower one open, not at all enclos-
ing the stamens and style — appears to mark the genus as a good
one. Moreover, the middle leaves are almost all 3-parted or divided.
The species are : —

1. C. BicoLOR Benth. Calycis lobis acutis ; corollas bicoloris nunc albae
fauce ventricosa valde obliqua, labio superiore quam inferius parum breviore.

— C. heteropliylla Graham, Bot. Mag. t. 8695, foliis imis trifidis. — Chiefly in the
western part of California.

2. C. TiNCTORiA Hartweg in Benth. PI. Hartw. Viscidior ; pedioellis brevi-
oribus vix uUis ; calycis lobis linearibus vel angusto-oblongis sajpius obtusis ;
corollae (ochroleucce, nunc albaj nunc purpureo notats) fauce ventricosissinia
transversa, labio superiore brevissimo, lobis lateralibus intus parce barbatis.

— C. burhata Bosse in Bot. Zeit. 12, p. 905 (1853). C. se/jlevmervla Kellogg
in Proc. Calif. Acad. 2, p. 224, fig. G9. — Mainly in and towards the Sierra
Nevada.

* * Corolla minus declinata, fauce gibbosa obliqua longiore quam lata : caules
humiliores : folia plerumque crenato-dentata, crassiuscula, obtusa.

H- Filamenta pi. m. barbata : labium superius corollae (sub lobis parum callo-
sum) baud cristatura : calycis lobi latiores obtusi.

3. C. BARTSiiEFOLiA Beutli. in DC. Puberula, subglandulosa, vel superne
viscidulo-hirsuta, erecta ; verticillis florum 2-5; corollae labio superiore fauci
obliquo asquilongo, lobis lateralibus emarginatis vel obcordatis ; glandula sessili
elongata porrecta. — C. bicolor var. ? parvijiora Benth. PI. Ilartw. No. 1884.
C. hirsula Kellogg, 1. c. p. 110, fig 84, forma liirsutior. The low transverse
callosity at the junction of the limb of the upper lip of the corolla with the
throat, which is visible in several species, is more evident in this ; it borders a
small hood-like depression.

4. C. CORYMBOSA Herdor, Ind. Sem. Petrop. 1867, & Gartenfl. 1868, t. 668.
Glabra vel subpuberula, decumbens ; foliis carnosulis latioribus ; floribus in
capitulum unicum congestis ; corolla bicolore rectiuscula, labio superiore brevis-
einio, lobis fere obsoletis ; glandula parva complanata stipitata. — Coast of the
northern part of California.

H- -I- Filamenta glabra : corollae labium superius sub lobis fornicato-cristatum :
calycis lobi angustiores acutiusculi ; flores parvuli violacei.

5. C. Greenei Gray, Proc. Am. Acad. 10, p. 75. — Lake Count}', California,
E. L. Greene.

§ 2. LaxiJlorcE, pcdicellis elongatis aut solitariis aut aunbellato-verticillatis.

* Glabrae : folia inferiora saltem radicalia rotunda vel oblonga, pi. m. dcntata :
calycis lobi acuti, fructiferi capsulam superantes.

OF ARTS AND SCIKNCES. 93

1. T. coLLixsioiDRs Niitt. cx Hcnlli. in DC. Prodr. 10, p. ^93
Tenella, sparsiflora ; floribus minimis ; corolla calyce paullo longiore,
lobis posticis et latorulihus subcoiifonnibus obluiiffis al) antico iniillo
latiorc sinubus profuiulioribus magis discretis ; ovarii lociilis uuiovu-
latis. — Collinsia tenella Hi'iith. in DC. Prodr. 1. c. — Oregon, near
ibe coast to Mendocino County, California, Nuttall, K. Hall, IJ(daii-
der, and Kellogg.

2. T. FLORiBDNDA. Vegetior, 1-2 pedalis; racemis floribnndis vir-
gatis e verticillis 3-7-floris ; corolla ampla (lin. 3— i lata) calyce midto'

+- Orientales, laetiflone : folia caulina plerumque ovato-lanceolata : corolla) faiice
valile gibbosa labiis fere dimidio breviore : filamenta suporiora inferno
pi. m. barbata: glandula (in C. verna) subiUata porrecta.

6. C. VERVA Nutt. Corolla bicolore (labio superiore albo, inferiore cierulco)
lobis tantum emarginatis. — New York to Missouri.

7. C. viOLACEA Nutt. Corolla concolore violacea, lobis oboordato-bifidis,
superioribus dimidio minoribus. — Arkansas. Antirrhinum tenellum is more likely
to belong to this than to the preceding .species.

t- •<- Occidentales mediocriflorae : corolla fauce lata ventricoso-saccata limbo
pi. m. breviore : pedicelli flores suba^quantes.

8. C. GHAXDiFLORA Dougl. in Bot. Reg. t. 1107. Floribunda ; foliis florali-
bus lanceolatis linearibusque plerumque 3-7-natis ; verticillis 3-9-floris ; calycis
lobis acuminatissimis ; corolla bicolore (albo-casrulea) maxima declinata, tauce
in tubo fere transversa, lobis parura emarginatis, labio superiore bicalloso ;
filamentis glabris ; glandula sessili capitata. — Nortli-western California to Wash-
ington Territory.

9. C. SPARSIFLORA Fisch. & Meyer. Gracilis, diffusa ; foliis oppositis, florali-
bus superioribus minimis tantum ternatim verticillatis ; pedicellis solitariis
binisve, summis nunc ternis ; calycis lobis ovatis vel deltoideo-lanceolatis acutis ;
corolla vix bicolore, fauce valde obliqua ; filamentis interne hirsutis ; glandula
sessili elongato-subulata. — C. parvijiora var. sparsiflora Benth. in DC. C. soli-
taria Kellogg, 1. c. p. 10. — North-western California.

1- 1- -1- Boreali-occidentales, parvulae, parviflorae : pedicelli floribus longiores :
corolla subconcolor e calyce paullo vel dimidio exserta, fauce oblongo obli-
quo labiis longiore : filamenta glabra : glandula capitata brevi-stipitata.

10. C. PARViFLORA Dougl. in Lindl. Bot. Reg. t. 1802. — C. minima Nutt. in
J.mr. Acad. Philad. 7, p. 47. — From Lake Superior to California and north-
ward.

* * Glandulosa, viscida : folia linearia, radicalia oblanceolata, omnia integcr-
rima : calycis lobi angusti, obtusi, capsula breviores : corolla parvula, Ixte
cajrulea, calyce multo longior : filamenta glabra : glandula sessilis subulala.

11. C. ToRREYi Gray, Proc. 1. c. 7, p. 378. — California, through the higher
region of the Sierra Nevada.

94 PROCEEDINGS OF TEE AMERICAN ACADEMY

longiore ; lal>ii inferioris trisecti lobis 3 fere conformibus obovatis iis
labii superioris bifidi minoribus ; ovarii loculis 3— 4-ovulatis. — Collin-
sia grandiflora Hook. Kew. Jour. Bot. 3, p. 298, non Lindl. Willow
thickets of the Valley of the Kooskooskee, in the western part of
Idaho, Spalding, Geyer. The sessile gland representing the fifth
stamen is at the very base of the corolla ; in the preceding species it is
higher up on the tube and smaller.

Pentstemon barbatds Nutt., var. trichaxder. Ilumilior e
caudice lignescente ; antheris longe parceque laiioso-barbatis ! — S.
AV. Colorado, T. S. Brandegee, in Hayden's Exploration, 1875. Mr.
Brandegee was struck with this as different from P. harbatus in its
growth and aspect ; but I see no character to distingu'sh it from the
var. Torreyi of that variable species, except the long hairs on the an-
thers, and sometimes a few on the filaments. This has not been else-
where met with in the Elmigera section. But it occurs witli such
variability and apparent inconstancy in P. glaher and some allied
species, that it may not be relied on here.

Pentstemon Clevelandi. P. spectabiU quoad folia et inflorescen-
tiam baud dissimilis ; foliis superioribus arete sessilibus nee connatis,
floralibus minimis ; thyrso racemiformi nudo floribundo ; pedicellis
breviter filiformibus ; calycis parvi lobis ovatis capsulam 3-4-plo bi'evi-
oribus ; corolla sanguinea tuhuloso-infundibuliformi (fere pollicari),
fauce paullo ampliata, lobis brevibus rotundatis patentibus ; filameuto
sterili apice dilatato hinc barbato. — Cailon Tantillas iu Lower Cali-
fornia, received from D. Cleveland in flower, and later from Dr.
Palmer in fruit.

MIMULUS Linn. Having had occasion to elaborate tlie species
belonging to the Califoniiau flora, I have thought it best to give a
synoptical view of all the known North American Mifpuli. Some are
difllicult to limit, and the extent of the genus was also uncertain.
There are three or four groups of species, which would necessarily
rank as genera distinct from true Minuihis, if they were not connected
by transitions. Perhaps the most markeil of these is represented by
two dwarf Californian annuals with long filiform tube to the corolla,
and a cartilaginous capsule, the valves of which bear the half-septa
and placentae. One of them was probably the type of the genus
Jiunaiius Benth. in DC. But the tube shortens and broadens in a
long series of species, which at length pass into true Mimidiis, in
which the placenta sometimes partially and rarely completely divides.
Equally peculiar iu habit are the shrubl)y species or forms on which

OF AIMS AND SCIKNCES. 9!)

the uenus DlpJacus Nutt. w:is t'ouiitlod. Jlt-ru the two jihicfiita; are
hardly at all united in the axis, even in the blossom ; which is olher-
wise that of a true Mimiilns. Then there is a low annual species with
short corolla and thin-walleil capsule, but the placenta' dividinj; with
the valves, which is so peculiar in wanting the angles or kcds which
are so conspicuous in Jlinndus that it was referred to a jjcculiar sec-
tion of Herpestis. Altogether it seems necessary to regard the whole
as one polymorphous genus, and to arrange our species as in the
subjoined conspectus.*

* MIMULUS Linn.

§ 1. EUNANUS. (^«nam/s Benth. in DC.) Ilerbae annuiB, plerumquc nanac :
calyx 5-clentatus, 5 angulatus, angulis dentibusque pi. m. plicato-earinatis :
corolla in typicis tiibo gracili elonjiato : stylus superne fjlandiilosus vol piibes-
cens : stigma aut bilnniellatum, aut labiis latis petaloideo-dilatatis connatis
peltatum vel infuiulibulifornie : cajisiila valvis medio septiferis placentas
divisas auferentibus. — Species 11, Californicae, habitu variiu, pube pi. m.
viscida vel glandidosa.

* Capsula cartilaginea, 2-4-sulcata, sero deliiscens, basi obliqua vel gibbosa :
calyx basi gibbosus, ore valde obliquo : corolla purpurea, fauce variegata
vel maculosa,

H- Tubo filiformi longe exserto : flores primarii caule multo longiores. [CEnoe
Gray in PI. Ilartw., & sect, in Bot. Calif.)

1. M. TRicor.OR Lindl. Jour. Hort. Soc. 4, p. 222, "Junio, 1849." Foliis
oblougis vel subliriearibus basi attenuatis sessilibus ; calyce sursum ampliore
(deutibus longioribus) basi paruin gibbo; corollae labiis ajquilongis, lobis con-
similibus ; capsula brevi-ovali seu ovata subcompressa, marginibus anticis et
posticis acutis ; semiuibus obovatis obliquis iis subsequentium multo majoribus.
— Eunanus Cuii/teri Gray ex Bentli. Tl. Ilartw, p. 321), " Augusto, 1849." — It is
well tbat Lindley's name takes precedence, as tliere was a mistake in supposing
that tins species was in Coulter's collection.

Var. ANGDSTATCS. FoUis linearibus parvulis, tubo corollas bipollicari tener-
rimo. — Eunanus Coulteri var. angustatus Gray, Proc. Am. Acad. 7, p. 381.

2. RI. DocGLASii. Poliis ovatis oblongisve in petiolem contractis ; calyce
basi mox valde gibboso ; coroliic labio inferiore abbreviato, superiore amplo
erecto ; capsula lineari seu lineari-oblonga tereti 4-sulcata ; seminibus ovalibus
modo Einiani utrinque apiculatis. — .1/. vnnns var. fi. mihtinijlitriix Hook. & Arn.
Bot. Bcecb. p. 378. Eunanus iJoiifildsii Bcntli. in DC. Prodr. 10, p. 374. The
stigma is sometimes of two very unequal lobes, as described by Bentbani, some-
times of two broad and rounded unequal lobes, sometimes peltate and nearly
circular, as in most of the following.

-- 4- Tubo corollae e calyce parum exserto : flores folia vix superantes.

3. M. LATIFOI.IU8. Spitbamaeus, viscosus ; foliis radicalibus exiguis ovani-
dis, caulinis amplis late ovatis membranaceis basi angustatis subi)etiolatis ;

96 PEOCEEDINGS OF THE AMERICAN ACADEMY

Hedeoma hyssopifolia. (Euhedeoma, ante IT. pi'peritam.) Gla-
bella; canlibus e caudice perenni ramoso erectis gracilibus subpedali-

calyce basi mox valde gibboso ; corollae labio inferiore superiore erecto dimidio
breviore ; capsula lineari-oblonga subcurvata lateribus sulcata ; seniinibus
prajcedentis. — Guadalupe Island, Lower California, Dr. E. Palmer, 1875. A
near relative of the preceding, but caulescent from the first, flowering only from
about tlie fourth node. Leaves about an inch long ; corolla two-thirds of an
inch long, the narrow tube little if at all exceeding tlie longer tooth of the
calyx ; stamens not very unequal ; stigma of two ample ovate-oblong lips,
sometimes united into a funnelform body ; capsule 5 lines long, somewhat lat-
erally compressed, the posterior edge acute, and the anterior not sulcate.

* * Capsula eoriacea vel membranacea, symmetrica : calyx basi aequalis, cam-
panulatus vel breviter oblongus : stigma sajpissime peltatum.

+- Corolla parvula, tubo tenui exserto : calycis dentes subaequales.

4. M. LEPTALECS. Caulc ramoso 1-3-pollicari ; foliis e spathulato oblongis
ad lanceolata vel linearia (parum semipoUicaribus) ; calycis campanulati denti-
bus ovatis seu triangularibus tubo suo multo capsula oblongo ovata obtusa
paullo brevioribus; corolla rubra, tubo filiforrai sursum parum ampliato (lin.
3-5 longo), limbo obliquo (lin. 1^-3 lato). — Gravelly soil, in the Sierra Ne-
vada, California, at 5000 feet and upwards, south of the Yosemite, Miss Dix,
A. Gray, and in Sierra County, Lemmon. A tin}' species. Capsule 2 line.<«
long.

1- M- Corolla majuscula, infundibuliformis, lin. 7-11 longa, tubo proprio e
calyce subfequali vix parumve exserto. Species nimis affines; caule uiuiali
ad spithamaeum.

5. M. BiGELOVii. Foliis oblongis, superioribus ovatis acutis vel acuminatis;
calycis dentibus e basi lata subulatis acutissimis (lin 2 longis) tubo lato-cam-
panulato dimidio brevioribus, anticis minoribus ; corolla fauce cylindracea limbo
amplo rotato-patente ; capsula membranacea. — Eunaniis BigdovH Gray in Pacif.
R. Kep. 4, p. 121. — Southern part of California, and adjacent parts of Xevaiia
to Southern Utah.

G. M. NANUS Hook. & Arn. (var. a. plurlflorua). Foliis obova'tis ovatis ob-
longisve nunc lanceolatis; calj'cis dentibus lato-lanceolatis vel triangularibus
acutis (liiioam longis) tubo quadruplo brevioribus; corolla inmc rubro-purpurea
nunc flava, tubo e calyce parum exserto sensim in fauccm amplam diiatato;
capsula chartacea. — Eunanns Tnlmnvi Benth. I.e. E. Firmoiifi Watson, Rut.
King, p. 22G, non Benth. — California, especially its eastern borders, Nevada,
and through the interior to the eastern borders of Oregon and the western part
of Wyoming. Hooker and Arnott's specific name is retained ; but most of their
characters relate to M. Douglasii.

Var.? BicoLOR (Eunanns bicolor Gray, 1. c. 7, p. 381), fauce corollre subito
obconica intus atro-purpurea, limbo luteo.

7. M. Fri.monti. Foliis angusto-oblongis imisve spathulatis obtusis : calycis
dentibus ovatis obtusis vel acutiusculis fere a'qualibus (vix liiream longis);

OP ARTS AND SCIENCES. 07

bus; foliis intogerrimis norvosis jmrtor iufima ovalia sou ohlouga parva
liiienri-lanceolatis, iloralihus vorticillastris laxe 3-')-ll()ri,s l)n'vii)ril)U3 ;

corolla; riibro-purpurea} tiiho iiicluso sensim in fauccm infiinililmliforinem ain-
pliato. — Etiiianiis Fnmoiili Bc'iitli. 1. c. — Soutliorn part of (.'alifornia.

•»-■*- -1- Corolla mnjuscula, tiibo j)roprio oalyce inn?iiuali obliquo incluso.

•M- Genuini, corolla iiifiindibuliforini.

8. M. Parryi. Glabriusculus, 2-4-pollicaris ; foliis oblongis oblanceolatisve
Liitoiicrrimis (somipoUicaribus) ; caljcis ore valde obliquo, dontibus aculis,
supremo ovato tubo trijjlo breviore, cieteris minoribiis e basi lata subulatis ;
corolla infumlibuliformi (lin. 8 longa) aut flava aut rubro-ptirpurea ; ea])sula
cal yce fere inclusa. — Gravelly hills, near St. George, S. Utah, Parry (coll.
1874, No. 147).

9. M. ToRRETi. Viscido-pubescens, spithamseus ad pedalem ; foliis oblonpis
vel sublanceolatis integerrimis (semi-ultra-pollicaribus) ; calycis ore sat obliquo,
dentibus brevibus latis obtusissimis, supremo majore ; corolla infundibuliformi
(A-J-poUicari) rubro-purpurea ; capsula chartacea. — Eunanus Fremonti Gray in
Pacif. \\. Kep. 6, p. 83, non Benth. — Common in moist grounds along tlie Sierra
Nevada, California, from the northern part of Plumas County (where it was
first collected by Dr. Newberry, in Williamson's Expedition) to Mariposa
County, as also at Donner Lake, &c., by Dr. Torrey, to whose memory it is
deilicated.

++ ++ Ambigui, elatiores, corolla subito ampliata e tubo perbrevi: folia nunc
exserte denticulata, inferiora flores superantia.

10. M. BoLANDERi Gray in Proc. Am. Acad. 7, p. 380. Subpedalis, viscido-
pubescens ; foliis oblongis ; calycis ore valde obliquo, dentibus lanceolatis, supre-
mo (lin. 3 longo) tubo oblongo dimidio breviore; corolla purpurea pollicari ;
capsula fusiformi-subulata subcoriacea. — M. brevipes Gray in Pacif R. Rep. 4,
p. 120, non Benth. — Foot-hills and the lower ranges of the Sierra Nevada,
Bigelow, Bridges, Bolander. Stigma sometimes bilamellate or oblique.

11. M. BREVIPES Benth. Ultrapedalis, viscido-pubescens ; foliis lanceolatis
linearibus imisve oblongis ; calycis dentibus valde inaequalibus e basi lata
acuminatis, supremo tubo late campanulato subdimidio breviore ; corolla latis-
sima flava ; capsula ovata acuminata coriacea. — Only in the south-western part
of California, from San Diego to Santa Barbara.

§2. DIPLACUS Gray. ( Diplacus 'Nutt.) Corolla, calyx (angusto-prismaticus),
stigma, etc., Eumiinnli : placentae axi vix coadunataj : capsida (crasso-co-
riacea) et dehiscentia Eimani. Frutex glutinosus, Californicus, foliis sub-
coriaceis.

12. M. GLUTTNOSDS Wcndl. : — Var. puniceus, var. linearis, & var. br\-
CHYPDS {Diplacus lunjijlorun Nutt.), cum syn. DC. Prodr.

§ 3. EUMIMULUS. {.Vlmulus Linn., Benth. in DC.) Corolla tubo brcvi vel
breviusculo : calyx 5-dentatus, angulis dentibusque plicato-carinatis : stigma
aequaliter bilamellatum : cajisula vix sulcata, valvis ooriaccis vel membraua-

VOL. XI. (X. 8. II.) 7

98 PROCEEDINGS OF THE AMERICAN ACADEMY

calyce angiisto-tubuloso vix hirtello, dentibus setaceis subincurvis,
inferioribus superiora sat superantibus tubo pubero corollee elongatae

cois medio septiferis columnara centralem placentiferam integram vel bifidain
nudantibiis. Herbaj annuse vel surculoso-perennes.

• Orientali-Americani ; foliis peniiinerviis ; corolla violacea, tube subincluso
iauce palato fere clausa.

13. M. RJNGENS Linn. — Canada to Texas.

14. M. ALATUS Solander. — S. New England to Illinois and southward.

* * Occidentales ; corolla nee violacea nee caerulea,

•(- Sesqui-bipollicaris, flamniea vel rosea, ringens : calycis dentes suba;quales :
herbaj perennes : testa serainum opaca laxa. (Erythranthe Spacli.)

15. M. CAHDiNALis Dougl. Corolla coccinea, tubo parum exserto, limbo
obliquo, labio superiori erecto lateribus reflexis, iuferiori lobis reflexis ; stamini-
bus exsertis.

16. M. Lewisii Pursh. Corolla saturate rosea, tubo exserto, lobis patenti-
bus ; staminibus inclusis.

■»- H- Corolla aut poUicnris, aut minor, nunc parva : testa seminum prajter
M. luleuiii tenuis et polita.

•M- Foliosi, glabri vel pubentes, baud villosi.

= Calyx saltern fructifer ore obliquo, dente supremo majore : folia sajpius dila-
tata, aut subito aut insigniter petiolata.

17. M. LUTEUS Linn., cum varietatibus insignioribus, i. e., ai.pixus Gray, in
Proc. Acad. Philad. 1863, p. 71 IM. Tllituiii Kegel, M. cupreus Veitch, etc.), &
var. DEPAUFERATUS (M. iiiicrophi/Hiis Bentli., M. tenellus Nutt. herb.).

18. M. DENTATUS Nutt. in DC. Species sylvestris, Oregana, vix cognita,
inter M. luteum et moschaUnn quasi mecha.

19. M. Jamesii Torr. & Gray, ex Benth. in DC. M. (jlahrato proximus
sed distinctus videtur.

20. M. ALSiNOiDES Dougl., ct var. minimus Benth.

21. M. LACiNiATUs. Annuus.tener, glaber ; caulibus diffusis ; foliis oblongis
vel spathulatis hiciniatopauci-dentatis lobatisve nunc liastatis uninerviis, pe-
tiolo longo filiforini ; floribus minimis ; calyce brevi, fructifero ovato, dente
supremo maximo ; corolla brevi (lin. 2 longa) flava. — California, on the South
Fork of tlie Merced at Clark's Kancli, A. (ir;iy.

= = Calyx ore fere a'quali, dentibus subsiinilibus : Californici, annul, parvuli,

caulibus erectis.

a. Folia onmia petiolnta.

22. M. PuLsiFKR/E. Glanduloso-puberulus, viscidus ; foliis ovato-oblongis
seu ovato-lanceolatis imisve rotimdatis parce dcnticuhiti.s vel intcgerrimis basi
acuta vel cuneata trinervatis pcilunc^ulo a^quilongis ; calycis tubo fructifero
oblongo, dentibus brevissimis ovato-triaugulatis coroliaj luteje dimidio ad-

OF ARTS AND SCIENCES. W

brevioribus. — Arizona, on Mount Grabam at 9000 feet, Aumist, J.
T. llotlirock, in Wheeler's Ex[)l()i-iiti()n. Corolla renmrkuMy lon^ and
exserted for the genus, 7 or 8 lines long, twice the lengtii of tlie calyx ;
upper lip 2-lobed. Leaves crowded, the main ones from !i;ilf to three-
fourths of an inch long, and a line wide ; the parallel veins nmning
towards the apex ; the upper gradually reduced until at length shorter
than the calyx ; the lowest leaves much shorter, broader, and beneath
with strong more or less diverging nerves.

a^quantibus. — California, in the Sierra and Indian Vaile.vs of tiie Sierra Nevada,
Bulander, Mrs. Pulsifer-Ames. Tube of the calyx in fruit 3 or 4 lines long ;
corolla 5 lines long.

h. Folia pra^ter infinm sessilia.

23. M. iNCONSPicuus Gray in Pacif. H. Rep. 4, p. 120. Glaber ; foliis ovatis
integerriniis ; calycis quasi truncati dentibus minimis ; corolla aut lutea aut
rosea.

24. M. BicoLOR Benth. Viscido-pubescens ; foliis lineari-oblongis lanceo-
latisve basi atteuuatis denticulalis vel parce dentatis ; dentibus calycis con-
spicuis triangularibus ; corolla sat loiiga lutea, labio inferiore albo. — M. Prut-
teiiii Durand in Jour. Acad. I'liilad. n. ser. 2, p. 98 (1855). Calyx sa-pius pur-
pureo guttatus.

25. M. RUBKLLUS Gray. Viscido-puberulus vel glabellus ; foliis a spatliulato-
oblongis ad linearia plerumque integerrirnis, iniis latioribus ; calycis oblongi den-
tibus brevibus rotundatis ; corolla calyce aut pauUo aut duplo longiore lutea
rubra vel purpurea. — M. viontioides Gray Proc. Am. Acad. 7, p. 880, pro parte.

Var. LATiFLORUS S. Watson, Bot. King. (M.montioides Gra,y,l. c. pro parte.)
Forma saepius pygmaea, corolla multo majore (nunc semipollicari), tubo longius
exserto, limbo amplo aureo, fauce purpureo guttata.

*+ ++ Foliosi, villosi, visciduli ; foliis omnibus petiolatis membranaceis sat latis
dentatis pi. m. penniveniis ; calyce sequali vel vix obliquo; corolla lutea.

26. M. FLORiBUNDUs Dougl. in Bot. Reg.

27. M. MOSCHATCS Dougl. in Bot. Reg., cum forma longiflora.

++++++ Scaposi vel subscaposi, stolonibus perennantes.

28. M. PRiMULOiDES Benth. Herbula Iteta ; floribus longissime peduncu-
latis aureis.

§4. MIMULOIDES. {Flerpesfls % Mimuloides Benth.) Corolla, stigma, etc.,
Euiitimuli : calyx 5-fidus, campanulatus, nee prismaticus nee carinato-angula-
tus, lobis planis : capsula 1-Amani. Ilerba annua, humilis, pilis longis mollibus
villosa.

29. M. PiLOSus S. Watson, Bot. King Exp. p. 225. Herpestis (}/imnl<>l(l(s)
pilosa Benth. in Comp. Bot. Mag. 2, p. 57, & DC. 1. c. p. 394. — The anilier cells
are barely oblong, not " linear." The stigma is bilamellar, not " entire." And
the plant is surely a Mimulus, although the calyx is peculiar in wanting the
plicate angles.

100 PROCEEDINGS OF THE AMERICAN ACADEMY

Calamixtha Palmeri. Sect. Act'nos : odore et facie Hedeotnce, an-
nua, a basi ramosa, spithamaea, pube molli ; foliis obovatis vel spathulato-
oblongis in petiolum attenuatis integerrimis, floralibus decresceutibus
conformibus ; bracteis minimis subulatis ; verticillastris G-9-floi'is, supe-
rioribus folia floralia ajquantibus ; calyce parce hirsute basi vix gibboso,
fauce villosissima, labiis tubo brevioribus, superiore latiore fructifero
recurvo pateute ; corolla purpurea calyce vix duplo longiore, tubo in-
cluso ; antherae loculis jjarallelis, connectivo baud incrassato. — Guada-
lupe Island, Lower California. " Common in the intex'ior of the island,
not cropped by the goats," Dr. Palmer. Flower only 3 lines long ;
pedicels a line or so in length. Calyx shorter than in C Acinos, in
fruit less declined or ascending. Except for the four fertile stamens
this plant would be referred to Hedeoma. The stamens are too straight
and distant for a Calamintha, but apparently it may be referred to that
polymorphous genus.

PoGOGYNE TENUiFLORA. Glabriuscula, 2-4-ponicaris ; rarais (dura
adsunt) corymbosis ; foliis spathulatis vel obovatis basi petioloque ciliis
setiformibus perpaucis instructis ; bracteis nudis ; calycis puberuli lobis
inajqualibus lineari-lanceolatis corolla? tubo filiformi dimidio brevioribus ;
filameutis sterilibus parvulis glandula cajjitellatis. — Guadalupe Island,
off Lower California, Dr. E. Palmer. Corolla nearly half an inch
long.

Scutellaria nana. Stolonibus filiformibusmoniliformi-tuberiferis
perennans, depressa, cinereo-puberula, foliosa ; foliis obovatis ovatisve
obtusissimis (semipollicaribus) integerrimis brevi-petiolatis flores
brevissime pedicellatos sequantibus ; corolla alba (semipollicari sat
lata), labiis brevibus cequilongis. — N. W. Nevada, in Winnemucca
Valley, near Pyramid Lake, J. G. Lemmon.

Monardella Benth. A study of some new materials, and a revi-
sion of the species for the Botany of California (to which they all
belong), bring to view eleven species, which may be disposed as here
subjoined.*

* MONARDELLA Bentli.

§ 1. Ufacranthce laxljlora, neinpefloribus in capltulo laxiusculo sat niasnis minus
nunicrosis : corolla e calyce lonye exserta : antheraj loculis ovali-oblongis
divaricatis : perennes.

1. M. MACUANTHA. Rhizoniatibtis ropcntibus cJKspitosa, (leprcssa vcl procuui-
bcns, pul)criila vel pubescens ; foliis crassiiisculis ovatis obtiisis (liaml pollicem
longis) glabratis, petioli gracili ; capitulo 10-20-floro ; bracteis iavoluorantibus

OF ARTS AND SCIENCES. 101

EUIOGONUM CIIUYSOOl IMIALUM. {E. KIlKjii \-M\ lil.n'jo/iin/t (hay,

Proc. Am. Acad. 8, p. 1 G I.) J'J. pduci flora aHiiiiiis, diUcrl pi riijoiiiis
aiuvis basi aniuilo ma^is piotiiiiiL'iite articulatis, iuvolucri (k-iilihus
iiiiiuis latis ; foliis paiiUo latioiibiis iucauis E. multicipUis. — Utali,
ill the Wahsatch Mountains, AVatson, and above Spring Lake, Vixvry ;
by the hitter, iu full flower.

GuAYlA BuAXnEGKi. Iiieriuis, sesquipedalis, leviter i"m t'liiaceu-
cinerea ; fuliis spathulalo-liiiearibus ; thecis niiiHiiil)iis llaviduli,, olilato-
orbiculatis quandoipie trialatis basi latissiiiie retusis, alis sulnindidalis ;
ovaiio basilari papuloso. — IlilLsitles, among fragments of cretaceous
sandstone, on the San Juan River, near tiie boundary between Col-
orado and Utah, T. S. Brandegee in Hayden's Exploration, August,
1875. — While pleased with au accession to this genus, and with the
opportunity of associating it with the name of an excellent correspond-
ent who discovered it, I must add that ic does not much strengthen the

ovatis oblongisveobtusis tcnui-nicmljranaceis subscariosis cum calycibus villoso-
pubescentibus ; corolla sesquipoUicari aurnntiacopunicea, tubo calyce duplo
longiore, lobis lanceolatis. — Southern part of California, on tlie Cuiamaca
Mountains and near Julian City, I). Cleveland, E. Palmer. The calyx is three-
fourths or in fruit a full inch long ; the corolla sometimes two inches long. This
would be very ornamental in cultivation.

2. M. NANA. Prsecedenti sat similis, magis hirsuta ; floribus minoribus ;
corolla pallida, tubo pubescente ultra calycem pauUo exserta; bracteis albidis
roseisve. — S. California, in the mountains behind San Diego, 1). Cleveland.
Calj'x barely two-thirds of an inch long; the corolla-tube only a line or two
longer.
§ 2. DensiflorcB et midlijloroe. : calyce i-J-poUicari : antheraj loculis brevioribus

minis divaricatis.

* Perennes, basi nunc lignescentes : corolla incarnata vel purpurea nunc pal-
lidiore tubo calycem parum superante.

••- Pubescens seu villosa, foliis ovatis nunc oblongis.

3. M. VILLOSA Benth., cum varietatibus.

^- -t- Pube minuta canescens vel fere glabra ; foliis angustioribus, venis in-
con spicu is.

4. M. ODORATissiMA Benth. Humilis ; foliis oblongo-lanccolatis brevipoti-
olatis ; bracteis villosis vel ciliatis ; calycis dentibus brevibus triangulari-laii-
ceolatis intus extusque hirsutis. — Also in Oregon.

5. M. LiNOiDES. Pedalis, gracilis, pube iraperceptibili cinerea ; foliis lan-
ceolatis seu linearibus sessilibus imisve oblongo-spatlmlatis; bracteis panira
ciliatis; calycis dentibus angusto-lanceolatis tantum pubesceutibus. — S. Cali-
fornia, in the mountains east of San Diego, Dr. Palmer.

102 PROCEEDINGS OP THE AMERICAN ACADEMY

genus. The small thecae, as far as seen only 3 lines broad, and with
some furfuraceous puberuleuce (but they are far from mature, and
mainly unfertilized), and the papulose cellular ovary too much remind
us of Atriplex (incl. Obione). A. Endolepis of Watson, Rev. Cheuop.,
p. Ill (of which I should like to form a distinct section), has as thin
and complete a sac; but there are two minute teeth at its apex, and
their position, along with the venation, shows that the sac is compressed
laterally, i.e., formed of two flat bracts. I agree with Mr. Watson's
view, that the sac of Grayia is obcompressed, or formed of a pair of
conduplicate bracts, completely united to the very tip ; and on this
character (along with the inferior radicle) the genus actually rests.-
But tiiis view demands the separation from Atriplex of a species which
has always appeared like a stranger in the genus, and which I proj)ose

* * Annuae, minus foliosas ; foliis integerrimis raro undulatis.

t- Corolla (carnea, rosea, vel purpurea) tubo e calyce sat parumve exserto, lobia
linearibus vel lineari-oblongis.

H-t- Brateae muticae, venis plerisque a basi parallelis ; calycis dentibus latius-
culis muticis.

6. M, UNDULATA Beiitb. Glabella ; foliis oblongo-spatliulatis vel fere lineari-
bus obtusis margine undulatis in petiolum attenuatis ; bracteis ovatis obtusis
tenui-niembranaceis vel scariosis nervis simplicibus percursis (nee venulosis)
caljcibusque viilosis ; corolla rosea.

7. M. LANCEOLATA. Vifidis, fere glabra, bracliiato-ramosa ; foliis lanceolatis
vel oblongo-lanceolatis baud undulatis in i)etiolum gracileni attenuatis ; bracteis
fere foliaceis ovatis oblongisve plerunique aeutis inter costas reticulato-venosis j
calycis parum nervosi dentibus intus crebre extus vix liirsutis ; corolla roseo-
l)iirpiirea saipius maoulata. — California, from Plumas to San Diego Co.; not
unoonuuon ; has been confounded both with the jirecediiig and the sncceeding.

8. M. CANDiCANS Benth. PI. Ilartw. p. .330. Pube breyi moUi canescens vel
oinerea, nunc laxe ramosa ; foliis oblongis vel lanceolatis obtusis subito in
petiolum contractis ; bracteis fere scariosis ovatis obtusis, venulis parcis inter
costas reticulatis ; calycis nervosi dentibus intus extusque villosissimis ; corolla
semper brevi pallida.

++ -^ Bractcte cuspidatae, prceter costas validas tenui-scariosas vel hyalinae.

9. M. BuEWEKi Gray, Proc. Am. Acad. 7, p. 386. Habit of Monarda Jistn-
losa.

10. M. DouGLASii Benth.

■t- H- Corolla (alba? ) parva, tubo incluso, lobis brevibus latis : bractese teuui-
scariosae, candidissimaj, 7-9-nerves.

11. M. LEUc ocEPUALA Gray, Proc. Am. Acad. 7, p. 385.

OF ARTS AND SCIENCES. 103

to establish 1)}' itself, between Alrlplex and Groi/ia, iiiidcr tlic name of
its discoverer, Dr. George Suckley, U. S. A., one of tiie luiturulists
of the exploration across the Continent under Governor Stevens.*

APPENDIX.

CHAPMANNIA Torn & Gray. This genus was described from
imperfect materials in the Flora of North America (1, p. 3">r)), taken
up by Mr. Hentham in his paper upon Arachls, and then the character
added to in Fl. N. Amer. 1, p. 692, — all this upon a wrong view as to
two kinds of blossoms, which Mr. Bentham subsequently corrected.
Good specimens, with well developed flowers, are iu Rugel's collection ;
and I have just received others fi'om an esteemed correspondent, Dr.
Feay of Savannah, collected on Pease River, Florida. A few par-
ticulars are added to complete or slightly correct the character as
given in Bentham and Hooker's Genera Plantarum, 1, p. 517, and
to bring out more prominently the differences between it and Stylo-
santhes.

The broadly obovate vexillum and aloe are only slightly unguiculate,
not at all auriculate at base, but the latter nearly as equal-sided as the
former. In anthesis they are widely spreading, and distant from the
carina. The latter is shorter and straight (only in Rugel's specimens
is there an obliquity giving the appearance as of a slight curvature) ;
its two petals are united almost completely into an oval or somewhat
obovate piece, which is not auriculate at base, very obtuse and emar-
ginate at the apex, convolute as if into a tube, one edge slightly over
lapping, or slightly open in full anthesis. The andrcecium is only halt
the length of the carina, which encloses it or, when it opens down the
upper side, allows the anthers to project from towards its base. The

* Subtribus EUROTIE^. Theca, e bracteis pi. m. coiiduplicatis coalitis con
stans, obcompressa, rarissime triptera.

1. Gratia. Theca nuda, intcgerrima, scariosa, orbiculata, plana, sama-
roidea, alato-marginata. Radicula infera. Flores dioici.

2. SccKLEYA. Theca nuda, subhastata, complanata, marginibus herbacco-
cristatis, apice bidentato. Radicula supera. Flores monoici. — S. petiolaris.
Obione Sticklr-yana Torr. Atriplex SufkJcijana Watson, I. c.

3. EuROTiA. Theca villosissima, turgida, nee marginata nee aristata, apice
bifida. Radicula infera. Flores dioici.

4. Ceratocarpus. Theca cuneata, obcompresso-plana, biaristata. Radi-
cula infera. Flores monoici.

104 PROCEEDINGS OP THE AMERICAN ACADEMY

very slender filiform style, however, is longer tlian the carina and pro-
trudes beyond it more or less, even before the flower opens, and con-
tinues exserted. It is evidently a case of proterojiyny. Ahhough
the ten anthers are nearly alike in size ami shape, the alternate ones
are shorter as well as somewhat differently affixed. The ovary is not
" pluri-ovulatum." That is probably a misprint of " 2-3-ovulatam."
At least I find only three ovules ; and, answering to this, the loment is
at most three-jointed. Instead of " subreniform," the seed is obovate
and the radicle is projecting and straight, as described by Mr. Benthani
himself in Linn. Trans. 18, p. 162. There may be a slight inflection,
but it seems to be in the incumbent direction. The stipules, unlike
those of Stylosanthes, are nearly or quite free from the petiole.

OF ARTS AND SCIENCES. IQ-

VI.

BOTANICAL CONTRIBUTIONS.
By Sekeno Watson.
Presented, Oct. 12, 1875.

/ On the Flora of Guadalupe Island, Lower California.

The Island of Guadalupe is in lat. 29" nortli, about one hundred
miles from the coast of Lower California, and two hundred and thirty
west of south from the town of San Diego, which is near the southern
line of California. It is twenty-six miles in length in a north and
south direction, w^ith an average breadth of ten miles, and is traversed
by a mountain ridge, the central peak (Mount Augusta) haviii"- an
elevation of 3900 feet above the level of the sea. From this point
the nearest mainland is visible. The sides of the ridge are exceed-
ingly rough and broken, cut up by numerous deep and rocky canons,
and even the more level surfaces are described as usually covered by
rocks of every size and form. The rocks are volcanic, and several
extinct craters still exist.

The island lies within the great ocean current which flows from the
peninsula of Alaska down our western coast, the continuation of what
is known as the Japanese Gulf-stream, and in the zone of the north-
west trade-winds. Fogs are very prevalent, especially in the winter
months (from November to February), when they are driven by tlie
winds over the crest of the island, covering all the northern end and
filling the upper portions of the canons, while the lower cailons and
the southern extremity of the island remain clear and warm. These
winter winds from the north-west are described as strong and cold,
sometimes extremely so, an instance of which occurred during Decem-
ber, 1874, when ice an inch in thickness was formed in the middle of
the island, accompanied by two inches of snow, which was followed by
hail and five days of cold rain. In summer these winds have less
force, though still brisk and chilly for much of the time ; and the fogs,
instead of being carried over the central ridge, are driven around the
northern end, and by eddy-winds are borne into the lower canons of

106 PROCEEDINGS OF THE AMERICAN ACADEMY

the eastern side, which are thus made cooler than the region above
them. Otherwise the summer months are intensely hot, especially in
the southern portion of the island, and the soil becomes soon every-
where so dry that the effect of the temporary summer fogs upon the
vegetation is slisht. The difference in the seasons, however, at the
two extremities of the island is remarkable, as vegetation at the south-
ern end and in the eastern caiions is at least two months earlier than
in the northern and western portions, and has for the most part
reached its maturity by the close of May, under the then established
heats of summer. The annual amount of actual rainfall is very vari-
able, there being an abundance in some years, in others little or
none.

Guadalupe was early known to the navigators of these seas, but it
was never permanently occujjied. Tliere are evidences of its temporary
occupation by shipwrecked sailors, and it was also long ago stocked
with goats * for the purpose of supplying fresh meat to vessels short of
provisions or suffering from scurvy, and though out of the general
course of travel it has been occasionally visited on tliis account.
Twelve years ago an expelled governor of Lower California took
refuge here with his family, and remained for two years. Soon after-
ward a i^arty of men from the same State lived for some months upon
the island engaged in killing the goats, and during the last ten years it
has been occupied by a California company, by whom it was purchased
for the purpose of raising the Angora goat, and the island is now over-
run by these animals. Several men are kept in continual charge of
them, and regular visits. are made by the vessels of the company.

With this much of preliminary remark upon those conditions wliich
must affect the vegetation of the island, we may pass to the flora itself.
As respects the probable sources from which this flora may have been
derived, it is evident that there has been abundant opportunity for the
introduction of some species by human agency. These should be
especially expected near the usual landing-place upon the eastern
side, excepting such as would be probably distributed through the
island by means of the goats. Those of most recent introduction in
this way would doubtless be Californian ; the older might be from the
nearer peninsula or from other localities. Of other recognized
agencies for the distribution of i)lants, — the winds, ocean cur-

* It is said that tliis was done by Captain Cook, who, however, was never
upon tliis part of the coast. Vancouver passed Hear the island in 1793, but
witliout stopping.

OF ARTS AND SCIENCES. 107

rents, and birds, — iht; jirevaU'iit diii-ctioii of the (irst from (ho
north-wost is iidversc to tin; siiii|i()>iiioii iliat any species of plia-iKj-
ganums plants, at least, would be so introduced. The ocean cur-
rents might be considered as more favorable, and as likely to bring
accessions from the Californian mainland, contributed from the inte-
rior by the Sacramento and other smaller streams. Hut the winds
here again would prove an interposing agency, and by creating a sur-
face drift toward the coast would prevent floating seeds from attaining
any great distance from it. Such as did succeed in reaciiing the island,
and in obtaining and maintaining a foothold upon it, would probably
be wholly Californian. Less certain conclusions might be expected in
regard to the agency of birds, but it appears, from the collection of the
birds of the island made by Dr. Palmer, that they are all in some
measure peculiar to the island itself, ''consisting almost entirely of
familiar forms of the birds of the Western United States, but showing
marked peculiarities, entitling them to recognition as geographical
varieties. Nothing Mexican about them in the slightest degree."* So
that, though they demonstrate a connection between the island and
California, yet they also indicate that that conuection has only been at
a remote period, and that their })articipation in the introduction of
plants must have been slight.

It might therefore be conjectured, if the island were of comparatively
recent formation and always disconnected from the mainland, that its
flora would show a meagre list of species almost wholly Californian.
Or if, on the other hand, it had at some time been connected with the
continent, that then its vegetation would be similar to that of the
adjacent peninsula, unless some counteracting influence should have
been at work, as would seem to be true of the birds.

To show to what extent the flora of Lower California differs from
that of California proper, reference may be made to the list of plants
collected by Xantus at the lower extremity of the peninsula, f as given
by Dr. Gray in the 6th volume of the Proceedings of this Academy.
Of the 1 18 phanerogamic species there enumerated, only six are probably
found even in extreme Southern California, while thirty others raiiTe
northward only as far as Sonora, or eastward through Mexico to New

* Prof. Spencer F. Baird, in letter.

t The Island of Guadahipe is equally distant from San Francisco and Cape
San Lucas, but three degrees of latitude nearer to the latter point; and tiie dif-
ference of latitude between the cape and San Diego is little greater than that
between Guadalupe and San Francisco.

108 PROCEEDINGS OF THE AMERICAN ACADEMY

Mexico or Texas, the remainder being peculiar to the peninsula or ex-
clusively Mexican. The peninsula shares in this difference with
Mexico itself, the type of whose whole flora accords rather with that
of the eastern portion of the continent northward, except so far as
it would necessarily be affected by the more tropical character of the
climate. Of this a good and sufficient illustration is seen in the fact
that of the PhaseoJe<B, a tribe which is well represented in all the
Atlantic States, Texas, Southern New Mexico, Eastern Arizona,
Sonora, Lower California, and all of Mexico southward, not one
species is found within the limits of California, nor in the interior
basin west of the Rocky Mountains.

The only collection that we have of the plants of Guadalupe is that
made by Dr. Edward Palmer during the last season, from February to
INIay, which is probably as complete as was possible, though attended
with much labor and difficulty. He visited all parts of the island,
often finding it necessary to reach places which the goats had found
inaccessible, in order by means of ropes and poles to secure rare speci-
mens of species which appeared to have been elsewhere completely
extirpated. The entire number of species is 131, including 102
exogenous and 8 endogenous, the remaining 21 belonging to the
higher cryptogamic orders, — ferns, mosses, and livervvoits. Omit-
ting a single phcenogamous species (a Heucherct), of which the ma-
terial is insufficient for a satisfactory determination, the remaining

109 maybe divided into five groups : (1) Introduced species, of which
there are twelve ; (2) Those that range fi'om the Pacific to the
Atlantic States, of which, there ai'e nine; (3) Those that are found
throughout California, or at least as far north as San Francisco, num-
bering forty-nine ; (4) Those found only in Southern California,
below Los Angeles, or in Arizona, numbering eighteen ; lastly, those
peculiar to the island itself, of which there are twenty-one.

The twelve species* of whose comparatively recent introduction
there can be little doubt, are all of European origin, and chiefly from
Southern Europe, and are all also found more or less w'idely natural-
ized in California. The original introduction of most is probably due
to the Spaniards, at least upon the mainland, where the extent to
which several have become distributed is something marvellous. The
most remarkable is tlie Alfilaria (Erodium cicufan'u/n), wh'wh, uuWke

* Brossica nigra; Oli<;oinf'rls suhnhita ; Silene Galllca ; Mnlva horealis; Ero-
diiim cicufan'nm ami E. innsrhnUim ; Soiirhiis oleraceus ; 'AmirjaUis arveiisis ; Solunuin
ni(/;'tfn; Chenopodium album ; Acena Jlitua ; Dromus sterilis.

OF ARTS AND SCIENCES. 109

the wild oat (Arena fatiKi), lias not hccn limitfil in its raii^o to tlio
western side of the Sierra Nevada, hut is found through much of tho
inteiior, from New Mexico to "Washiufrton Territory. On Guadalupo
it is found everywhere, and is more abundant tliau any other plant.
Another species of the same genus (E. moschatiim), provided with the
same contrivances for securing the dissemination and planting of its
numerous seeds, occurs less frequently both here and in California;
probably because, reipiiriiig more moisture, it is unable to maintain
itself where the other will Hourish. Another instance is the OUgoineris
suhulata of India, Egypt, and the Canary Islands, found also in South-
ern California, and common eastward ihrougli the valleys of the Fvower
Colorado and of the Gila to the Rio Grande, and in Northern Mtfxico.
It is difficult to account for the wide spread of this plant, if of recent
introduction, through a region so desert and sparsely iidial)iteil.

Besides these twelve species placed in the first group, there are two
others, also found in California, which are considered identical with
South American forms {Specularia hiftora and AmhJyopappm pasiUns),
possibly introduced from Chili or Peru, perhaps indigenous to both
regions. Their presence on Guadalupe would perhaps rather favor
the belief that they are native to our western coast, especially as five
other South American species, or forms of them, occur in the Guada-
lupe flora {Tillcea minima, Gilia pusilla, Plantago Patagonica, Parie-
taria debilis, and JliMcnbergia debilis), which are more or less frequent
in California and eastward in the centre of the continent, and are gen-
erally admitted to be native.

There are, therefore, 97 pha^nogamous plants which may be considered
as indigenous. Of these, nine have a very extended range upon the
mainland;* one (Parietaria debilis) from Southern California across
the continent ; all the rest common throughout California, and ranging
eastward to the Atlantic States. Two of these (Galium Aparine and
Junciis btij'unius) are also European, and two (Plantago Patagonica
and Parietaria debilis) are found widely distributed through South
America.

Far the largest group, as already stated, includes those species, 49
in number, which are common over a large i')art of the State of Cali-
fornia. Many of these extend northward as far as Oregon or Wash-
ington Territory, or eastward through the Great Basin to the Rocky

* Sisi/mbrium canescens ; Silene antirrhina ; Daucus piisillus; Galium Aparine;
Dodficathcon Meadia ; Linaria Canadensis; Plantago Palaijonica ; Parietaria
debilis; Juncus bufouius.

110 PEOCEEDINGS OP THE AMERICAN ACADEMY

Mountains. To these are to be added the eighteen species * of more
limited range upon the nuiinland, confined to Southern California or
Western Arizona ; very few of them, so far as their di.'?tribution is
known, belonging to Lower California or Mexico, and several of rare
occurrence. Among the latter is Crossosoma Californicum, known
previously only from the Island of Santa Catalina, in the Santa Bar-
bara Archipelago, of which genus the one other species is found in the
mountains of Western Arizona. Leptosyne gigantea and StenocJdoe
Callfornica were also known only from the same island, the latter the
only species of the genus ; the former belonging to a small genus con-
fined to Southern California and the region eastward to New Mexico.
It is evident, therefore, that, as regards the species common to the
island and the mainland, the flora may be said to be exclusively Cali-
fornian in its character. Not a single species is found that is peculiar
to Lower California or Mexico. The same alliance is nearly as prom-
inent if we look at the twenty-one new phtenogamous species of the
island. Fifteen of these (a Thysanocarpus, a Sphteralcea, a Lupinus,
a Trifolium, an (EnotJiera, a 3Iegarrliiza. a Galium, a Hemizonia, a
Perityle, a Bceria, a 3Iimuhis, a Pogogyne, a Calaminfha, a Phacelia,
and an Atriphx) all belong to genera largely or exclusively repre-
sented in California and the region east of it, and are mostly closely
allied to the species of that region. The remaining six species include
a Lavatera, a Composite, a Borraginaceous jilant, a species allied to the
Olive, and finally a palm. The Lacatera is interesting as represent-
ing a widely scattered genus, not otherwise found in America, except
as a second species occurs on the more northern island of Anacapa.
The genus belongs chiefly to the region of the Mediterrane^iu, where
fourteen species are native ; two others are confined to the Canary
Islands ; another has been discovered in Central Asia, and still another
in Australia. The new Composite is referred by Dr. Gray to a South
American genus (^Diplostephiuni), not otherwise represented in our
flora, but of which there are eighteen species in the Andes from the
eqnator southward. Of the Borraginaceous and Oleineous species.
Dr. Gray forms new genera; the one (Ilarpagonel/a) allied to the
small genus Pectocarya, of wliii-h there is one Chilian species, and

* Crossosoma Californicum; Lepidium ^[enziesii And lasiocarpum ; Rhus laiiriiia ;
ITosackia ar<joplii/lla ; Lrptosi/ne gii/antea ; Filago Arizoiiica ; Peril i/le Emori/i ; Am-
bh/opappus pusillus ; ifaliicothrix Clevclaiidii ; Aniirrhinnm Niiltallianum and A.
spedosum : Lycium Californicum; Erilrichium aiicjuslifuli'um ; Pinus irisignis ; Cu-
pressus macrocarpa ; Muklenbergia debilis; StenocJUoe Californica.

OF ARTS ANP SCIENCES. Ill

two Californiau, one of these also in tlic i;uailaIii|M' lima; the oilier
(Resperelcea) bearing no close resemblance to any otli.r nii-nibcr of
the Olive family. On the other hand, the i)alni {Jirti/iru (?) et/ii/is),
conspicuous on the island as the only representative of a ti<ipie:il flora,
is probably less nearly related to tin' Central Mexican <;eniis to which
it is provisionally referred than to the genus Livislonu of Australia.
A congener of the Guadalupe species has recently been detected by
Dr. Palmer in the caiions of the Tantillas Mountains, near San Diego.
As respects the cryptogamic vegetation, of the half a do/en ferns all
are frequent in California, one peculiar to the southern part of the
State, another found throughout North America and Europe. Of the
eleven mosses, two are strictly Californian species, seven are common
everywhere in the United States and Europe, and two are European
species which had not previously been detected in America. Of the
four Hepdtlcce, three are Californian, and one is considered new.

Looking now at the relative proportions which the larger orders
bear to each other in this limited flora as compared with* the flora of
the Great Basin (the only at all similar one of which we have the data
for comparison), we find that the proportions which the Compos! la: and
Leguminosce bear to the whole (17 and 7 per cent.) are identical in
both ; while in the next largest orders, the Cniciferce, Scroph ulariacece,
and Gramine(E, the proportions in the two floras are very nearly the
Bame. The most conspicuous discrepancies are the almost entire
absence in Guadalupe of Cyperacece, Polygonacece, Rosacece, and Lilia-
cece, and a less decided preponderance of SolanacecB, Borraginacece, and
HydrophyUacece. These differences are largely due evidently to the
charactei" of the surface of the island, though the want of any repre-
sentatives of the large characteristic western genera, Eriogonum and
Astragalus, is remarkable-
Reference should be made to the plants which by their abundance
and prominence give character to the vegetation. Among these the
"sage-brush" and "grease-woods" of the valleys of the Basin are duly
represented bj-^ an Artemisia and an Atriplex, which share with a
Franseria in covering large tracts, and in protecting the soil and the
smaller annuals from the winds and sun. Trees are numerous over
much of the island, chiefly coniferous : a pine, belonging to a Southern
Californian species, but peculiar in some of its characters ; a juniper,
common in California ; a cypress, similar to and perhaps identical
with a Mexican species which extends into California ; and a small
oak, which is common throughout the State. To these is to be added

112 PROCEEDINGS OF THE AMERICAN ACADEMY

tlie palm, which is frequent in the southern canons, growing to a height
of forty feet, and bearing large clusters of edible fruit.

To conclude, it is apparent, from all that has been said, that this little
flora as a whole is to be considered a part of that of California, as dis-
tinct from the flora of Mexico. It may be inferred also that it has
not been to any great extent derived from California by any existing
process of conveyance and selection, but that it is rather indigenous to
its present locality. Moreover, while it would indicate a connection at
some period between the island and the mainland to the north, yet the
number and character of the peculiar species favor the opinion that
they are rather a remnant of a flora similar to that of California, which
once extended in this direction considerably to the southward of what
is now the limit of that flora upon the mainland. And, finally, the
presence of so many South American types suggests the conjecture
that this, and the similar element which characterizes the flora of
California, may be due to some other connection between these distant
regions than'any which now exists, and even that all the peculiarities
of the western floras of both continents had a common origin in an
ancient flora which prevailed over a wide, now submerged area, and of
whose character they are the partial exponents.

II, List of a Collection of Plants from Giiadahtpe Island, made hy
Dr. Edward Palmer, with his Notes upon them.*

1, Ranunculus hebecarpus. Hook. & Arn. Abundant on warm
slopes in the middle of the island,

2, Crossosoma Californicum, Nutt. A shrub two or three feet
high, in the crevices of cliffs overhanging the canons in the middle of
the island. Only nine were found, out of reach of the goats, and
accessible only by the aid of a rope. In flower, February 10; petals
soon falling ; seed ripe, April 20,

3, EsciisciiOLTZiA Californica, Cham.,var. nvrECOiDES, Gray,
Only at the south end in ravines, and in the middle of the island on
level ground ; apparently not eaten by goats, A form with smaller
flowers has been found on rocky heights in the middle of the island.

* The determinations of the Gamopetahc of the collection were made entirely
by Dr. Asa Gray. The Mnsci were referred to Mr. Thomas P. James, and
the Ilcpatkce to Mr. Austin. Acknowledgment is made, in connection with a
few species, of assistance received from other authgrities. The numbers are
those under which the collection was distributed.

OF ARTS AND SCIENCES. 113

4. Sisymbrium reflexc.m, XiUt. (S. defexum, Ilnrv.) Abun-
dant in the mitltlle and at the south end, in low grounds ; llowers
white.

5. Brassica nigra, Koi-h. In consideruhle quantity in the middle
of the ishmd, in open spots and on the best soil ; oaten by goats.

G. Sisymbrium canescens, Nutt. In great abundance in warm
sheltered localities.

7. LF.riniiM Menziesii, DC. Generally abundant on warm hill-
sides througlioiit the island ; not much eaten by goats, as also the next.

8. Lepidilm lasiocarpum, Xutt. In ravines in the middle of the
island, rarely at the south end.

9. Thysanocarpus erectus, Watson ; new species. (See page
124.) Found only between Jack's Bay on the west side and Mount
Augusta, in clear level spots ; succulent.

10. Oligomeris subulata, Boiss. In deep warm canons and
ravines in the middle of the island, and occasionally at the south end.

11. SiLENE Gallica, Linn. Occurring sparingly in th'e middle of
the island, in level open spots.

12. SiLENE ANTIRRHIXA, Linn. Only in a caiion on the east side,
near the beach.

13. Stellaria nitens, Xutt. Among rocks on hillsides, in the
middle and at the north end.

14. Calaxdrixia Mexziesii, Hook. In moist spots in the open
valleys all over the island, growing in masses ; flowers white to rose-
color or purple, opening at midday. Goats are very fond of this and
the next.

15. Claytoxia perfoliata, Donn. All over the island, in masses
on the shaded side of rocks or logs, or in deep ravines ; flowers pink.

16. Malva BOREALis, Wallm. Only on the richer open spots in
the middle of the island, in dense masses ; goats at first eat only the
young leaves, but in summer devour the whole.

17. Lavatera occidextalis, Watson ; new species. (See page
125.) A conspicuous plant on the cliffs in the middle of the island,
only rarely, and with difficulty, accessible. In flower and immature
fruit ; April.

18. Sph^eralcea srLPHUREA, Watson ; new species. (See page
125.) In large bunches, three feet high, very abundant on rocky
slopes and in the crevices of the highest rocky ridges, from the middle
of the island to the southern end, where it was most frequent ; much
relished by goats ; April to May.

19. Erodium cicutarium, L'ller. Abundant all over the island,

VOL. XI. (n. S. III.) 8

114 PROCEEDINGS OF THE AMERICAN ACADEMY

and the principal food for the goats, covering the rocks ; usually three
or four inches high by August, and producing abundance of seed.

20. Erodium moschatum, L'Her. Middle of the island, less com-
mon than the last, and starting later in the spring. In low places, the
root long, large, and fleshy ; leaves light green, fleshy.

21. Rhamnus crocea, Nutt. A scraggy shrub, five feet high, of
a dense green hue. Only six were found, growing in the crevices of
high cliffs in the middle of the island ; in bloom, April 6.

22. Ceanothus crassifolius, Torr. Of rather loose habit, eight
feet high ; wood very hard. Only three were found alive, at the base
of Mount Augusta.

— . Ceanothus cuneatus, Nutt. A small shrub almost extermi-
nated, three nearly dead specimens alone being seen among rooks in
the middle of the island ; not in bloom.

— . Rhus laurina, Nutt. An irregularly growing shrub, about
four feet high, in the crevices of high rocks ; only four found ; May
20, not in bloom.

— . ViciA EXiGUA, Nutt. Among rocks in the centre of the island,
a single specimen seen ; very small.

23. HosACKiA grandiflora, Benth. Among trees in the middle
of the island ; flowers yellow, changing the second day to bronze-red.

24. HosACKiA arggphylla. Gray. In the crevice of a rock ;
flowers yellow, changing to reddish brown.

25. LuPiNUS NivEUS, Watson; new species. (See page 126.)
Only in the middle of the island, on high cliffs ; one plant in bloom,
March 25.

26. Trifoliuji Palmeri, Watson ; new species. (See page 132.)
Rather abundant in the middle of the island among rocks and trees on
hillsides; flowers whitish with red centre, becoming redder on the
edges.

27. Trifolium microcephalum, Pursh. Very abundant at the
middle and north end of the island ; flowers white or light pink.

28. Trh'OLIUM amplectens, Torr. & Gray. Only on the lii-ach on
the east side of the island, rare ; flowers yellowish while with dark tips.

29. Alchemilla occidentalis, Nutt. Among rocks and sage-
brusii at the north eiul, and also around a spring, where it was much
larger.

— . IIeuchera ? A single plant in the crevice of a rock, not

in bloom.

— . RiBES SANGUiNEUM, Pursh. Only two plants in the damp
shade of cliffs at the north end ; flowers rose-color, becoming white.

OF ARTS AND SCIENCES. 115

30. TiLL.EA MINIMA, ]\riers, & var. ( 7'. fepfoprfa!,/, Bcntli.). In Iar;;o
patches in a few exposed clear sjjots in the niidiUe and at the north eii<l.

31. Epilobium minutum, Lindl., Mo. AV. Barbey. Only at tho
north end, among rocks and sage-brnsh ; flowers purplish white.

— . CEnotiikra GuADALurKNSis, Watson; new species. (See
page 137.) Only two plants were found in a ravine on the east side,
near the beach.

3'J. Mkntzklia dispersa, Watson. In ravines in the middle and
at the south end ; flowers orange, opening after sinidown. (Joats are
not fond of it.

33. MicGARRHizA GuAnALUPENSis, "Watson ; new species. (See
page 138.) In crevices of high rocks in the middle of the island;
flowers white ; fruit green.

— . Sanicdla Menziesii, Hook. & Am. ? Two jjlants only,
without flowers or fruit, in crevices of rocks in the middle of the
island.

34. Daucds pusillus, Michx. Abundant through the middle of
the island, among sage-brush on the sides of canons and in open level
places ; not much relished by goats.

35. Galium Aparine, Linn. Common on warm shady hillsides
in the middle and more rarely at the south end.

36. Galium axgulosum. Gray, Proc. Am. Acad. xi. 74 ; new
species. A single small scrubby plant, in a crevice of a high cliff in
the middle of the island; flowers greenish white ; May 1.

37. MiCROPUS Californicus, Fisch. & Mey. On dry gravelly
slopes in the middle of the island.

38. Filago Arizonica, Gray. On level ground at south end.

39. Diplostephium canum. Gray, Proc. Am. Acad. xi. 75 ;
new species. A large shrub of rather loose habit, some four feet high,
in the crevices of high cliffs ; flowers yellow ; March 28.

40. Franseria bipinnatifida, Nutt. ? One of the most con-
spicuous plants at the south end, especially about .Tack's Ray, growing
in thick roundish clumps about a foot and a half high, on level spots
and among rocks, giving the country a greenish white appearance.
Flower-buds red ; bloom straw-color, flowering at the end of Febi uaiy.
Not relished by goats, but asses are very fond of it.

41. Leptostne gigantf>;a, Kellogg. Only two plants found, in
the crevices of high rocks. Five feet high, branching near the top,
and the branches terminated with bright green leaves and masses of
showy yellow bloom ; May 10.

42. Hemizonia frutescexs, Gray, Proc. Am. Acad. xi. 79 ; new

116 PEOCEEDINGS OF THE AMERICAN ACADEMY

S23ecie?. In the middle of the i>land, only a few small plants among
bushes in the crevices of high rocks. It grows in compact bunches
with abundant yellow bloom ; May 1.

43. Perityle incana, Gray, 1. c. 78 ; new species. Very common
in the middle of the island, in the crevices of high rocks, hanging in
massive bunches of yellow bloom; April, and through the summer.

44. Perityle Emoryi, Torr. Scattered through some of the
canons on the east side; flowers white, showy, blooming abundantly
for three months, commencing in February. Much eaten by goats.

45. B.ERiA Palmeri, Gray, Fl. Calif, ined. ; new species. Abun-
dant in warm low spots in the middle and at the south end ; flowers
showy, gamboge-yellow; February 27.

— . Bahia I.ANATA, Nutt., var. A single plant had escaped the
goats, on a rocky open spot in the middle of the island ; flowers light
orange ; May 10.

46. Amblyopappus pusillus, Hook. & Arn. In low ground at
the southern end.

47. Matricaria discoidea, DC. Around springs in the middle
of the island.

48. Artemisia Californica, Less. In considerable abundance
at the south end, in rocky spots, giving character to the vegetation ;
about a foot and a half high, of rather loose habit. Also in the mid-
dle of the island in crevices of the highest cliffs.

49. Senecio Palmeri, Gray, Proc. Am. Acad. xi. 80 ; a new
species. " White sage;" very abundant on many warm slopes, from
the middle to the north end. About three feet high, of diffuse habit,
a very free and showy bloomer ; beginning to flower early in Febru-
ary and maturing in May, when the air is fllled with its downy seeds.

— . Gnaphalium Sprengelii, Hook. & Arn. With the next.

50. MiCROSERis lineartfolia. Gray. Only in the middle of the
island, on stony ridges; eaten close by goats.

51. Malacotiirix Clkvelandii, Gray. Abundant among rocks
and trees in the middle of the island ; flowers deep yellow.

52. SoNCiius OLERACEUS, Liuu. Very rare, on warm slopes in
the middle of the island.

— . Specularia biflora. Gray. Rare, in the shade of rocks and
sage-brush on hillsides in the middle of the island.

53. GiTiiOPSis specularioides, Nutt. Abundant at the niid<lle
and north end, under sage-brush and dead branches; flowers white,
turning to blue after gathering.

54. Plantago Patagonica, Jacq. In level spots at the south end.

OF ARTS AND SCIENCES. 117

— . Anagallis auvknsis, Linii, Only three plants found iu a
gravelly place near the beach on the east side.

55. DoDECATiiEON Meadia, Linn. Very abundant on moist
rocky slopes at the south end and niidtlle. Goats are very fond of it,
and birds eat the buds and flowers.

— . LiNARiA Canadknsis, Spreng. Hare on the sides of canons
in the middle of the island.

5G. Antiuriiinu.m Nuttallianum, Benth. Kather rare, in dec])
warm canons in the middle of the island ; succulent, with small violet
flowers, white in the centre and dotted with violet; March 21.

57. Antirrhinum spkciosum, Gray. Frequent in the crevices of
high rocks in the middle of the island. Very ornamental, the bright
scarlet flowers continuing all summer.

58. MiMULUS LATiFOLius, Gray, Proc. Am. Acad. xi. 95 ; new
species. Only in the middle, scattered in warm rather moist spots ;
flowers velvety red, yellow at base, with a musky odor.

59. Castilleia f.oliolosa, Hook. & Arn. Only in the middle
of the island, rare, among fallen branches.

60. SoLANUM NIGRU3I, Linn., var. Rare in the middle of the
island and in a canon near the beach on the east side, in rich level
spots ; flowers white or purple ; fruit black.

61. SoLANUM NIGRUM, Linn., var. Douglasii, Gray. Only two
plants in a canon near the beach on the east side ; flowers white,
small.

62. SoLANUM Xanti, Gray, 1. c. 70. Only in the middle of the island.
A very showj^ shrubby plant, in large bunches, about two feet high, in
the crevices of rocks, blooming all the year. Flowers numerous, lilac
or purple ; fruit small, changing from green to yellow, mottled, and at
length very dark plum-color, maturing very slowly.

63. Lycium C'ALiFORNicujr, Nutt. ; Gray in Fl. Calif, ined. At
the extreme south end, on rocky blufi^s, not abundant. A loose shrub,
about two feet high ; flowers creamy white, tinged with lilac.

• 64. NicoTiANA BiGELOVii, AYatsou. Only in a few places in the
centi-e of the island, in open spots and good soil ; flowers greenish
yellow, bronzy below. The leaves stick to the goats' hair and do
much damage.

65. PoGOGYNE TENUiFLORA, Gray, Proc. Am. Acad. xi. 100;
new species. Very rare, among sage-brush, on the eastern side.

66. Calamintha Palmeri, Gray, 1. c. ; new species. Abundant
among trees and sage-brush in the middle of the island ; strong-scented
and not eaten by goats.

118 PROCEEDINGS OP THE AMERICAN ACADEMY

07. Ekitrichium angustifolium, Torr. On level spots at the
south end, anl also near the beach on the eastern side.

68. EuiTKiciiiUM MURicuLATDii, Torr. In warm clear jjlaces in
the canons of the middle of the island,

69. Amsinckia vernicosa, Hook. & Arn. Very abundant on
level ground at the south end ; flowers orange.

69 a. Pectocarya penicillata, DC. With the next.

70. Haupagonella Palmeri, Gray, Proc. Am. Acad. xi. 88;
new genus. Only at the south end, in low valleys ; often prostrate.

71. Phacelia phyllomanica, Gray, 1. c. 87; new species. In
large compact masses in the crevices of high rocks in the middle of
the island ; rare.

72. Same, var. interrupta, Gray, 1. c. Frequent in warm nooks
in rocky ravines in the middle and at south end ; February to May.

73. Ejimenanthe penduliflora, Benth. Rocky ravines in the
middle of the island ; refused by goats, but asses are fond of it.

74. Elltsia citrysanthemifolia, Benth. Abundant under sage-
brush on warm hillsides from the middle to the north end, and also
rarely at the south end ; flowers lilac.

75. Same, with narrower calyx-lobes and larger corolla.

76. Nemophila aurita, Lindl. On warm slopes in the middle of
the island, rarely at the south end ; much relished by goats, like the
last.

77. CoLLOMiA GiLioiDES, Benth., var. glutinosa, Gray. Abun-
dant under brush and in protected places in the middle of the island.

78. GiLiA MULTiCAULis, Benth., var. millefolia, Gray. Very
abundant in similar localities ; flowers blue and showy, or cream-col-
ored with a violet base.

79. GiLiA PUSiLLA, Benth., var. Californica, Gray. Abundant
in similar localities.

80. Convolvulus occidentalis, Gray, Proc. Am. Acad. xi.
89. In the crevices of high rocks, hanging down six feet or more ;
continuing in bloom from March through the summer. A thousand
flowers were seen on a single plant.

81. Hesperel^a Palmeui, Gray, Proc. Am. Acad. xi. 83;
new genus. A rather compact tree, twenty to twenty-flve feet high ;
flowers lemon-color. Only three live trees were found, in a caiion on
the east side ; no young trees .«;een, but many dead ones.

82. MiRAHiLls Califounica, Gray. Of compact branching habit,
growing in crevices in the walls of canons on the east side ; color
lilac-purple.

OP ARTS AND SCIENCES. 119

— . CiiENOrODiUM ALBUAi, Liiiii. Oul}' oiic pluiit Dcar the sea on
the east side.

83. Atiui'LEX Pal:\ieiii, "Watson ; new species. (See pajfellO.)
Only at the south end, in roundish bunches, about a foot and a half
high. One of the three characteristic perennials of the island, much
more frequent than Artemisia Ciilifornica, but scarcely half so abun-
dant as Franseria hipinnatijiiht. In flower at the end of Febriuu'y.

84. Ptkrosteoia drymarioides, Fisch. & Mey. In the shade
of roi'ks in the middle and more rarely at the south end.

85. Piiouadi:ni)KOX Bolleanum, Seem. Near the south end, on
Juniper us and Cupressus, more frequently the former.

8G. IIesperocnide tenella, Torr. In damp shady places, among
high rocks, in the middle of the island.

87. Pahietauia deuilis, Forst. Abundant in similar localities.

88 and 89. Quercus chuysolepis, Liebm. ; fide Dr. Engelmann.
Frequent at the nortli end, and occasionally found in the canons on
both sides of the island. Often large, sometimes forty feet high, and
wide-spreading; timber good and dural)le, though knotty.

90. PiNUS iNSiGNis, Dougl., var. ; fide Dr. Engelmann ; with leaves
in twos. At the north end, at high elevations. Very vigorous and
handsome trees, usually spreading widely, the largest seven and a half
feet in circumference and averaging seventy feet high. The wood is
very knotty and soon decays. At the extreme northern end, facing
Espaza Bay, the trees assume a hedge-like form, owing to the force of
the winds.

91. JuNiPERUS Californica, Carr., fide Dr. Engelmann. All
over the middle of the island and occasionally at the south end, in the
ravines and low valleys, forming groves about fifteen feet high. It is
exceedingly crooked, the timber small but very durable. As soon as
dead the ants take possession of it.

92. Cupressus jiacrocarpa, Hartw. ? A fine widely spreading
tree, though varying much in habit, growing in irregular clusters in the
middle of the island. It averages about forty feet in height. A tree
thirty-eight feet high and seven in circumference numbered 2oG annual
rino-s. The largest is at the head of Landrum's Caiion, twenty-five feet
in circumference, dividing into seven branches at the height of two or
three feet, the main limb at ten feet above the forks being thirteen feet
around. The bark is claret-brown, shining when wet, at length crack-
in" irregularly and curling up in thin plates. An abundance of resin
is exuded, especially as the bark is eaten off by the goats. The wood

120 PROCEEDINGS OF THE AMERICAN ACADEMY

is white, very knotty and liable to crack, when dry impervious to
nails, and decaying rapidly if exposed to wet. Fruit is abundant.

— . Brahea eddlis, Wendland ; new species. (See page 146.)
Frequent in deep warm ravines, from the northern end to Jack's Bay ;
the only thing on the island having a tropical look. It attains a height
of about forty feet, averaging fifteen inches in diameter. Each tree
bears one to four clusters of fruit, four feet in length, and each weigh-
ing forty or fifty pounds. The fruit is eaten by man, goats, birds, and
mice. In flow'er near the end of March.

93. Jdncus bufonius, Linn. From the middle to the north end
of the island, growing abundantly in very springy places and a suie
indication of water ; not much eaten by goats.

94 and 94 a. Avena fatua, Linn., and var. Several small patches
were found in open places and on the best soil.

95. MuHLENBEKGiA DEBiLis, Trin. Identical with Arizona speci-
mens so referred. Growing in abundance on warm slopes in the
middle of the island, more rare at the south end ; not much eaten by
goats till dried in summer.

96. Stenochloe Californica, Nutt. in PI. Gambel. 189, fide
Professor Thtirber. On warm rocky slopes in the middle of the
island ; not very abundant ; very succulent, and the goats are very
fond of it. Known previously only from Nuttall's specimens.

97. Festuca microstaciivs, Nutt. In bunches on warm slopes
and in open places in the middle of the island.

98. Melica imperfecta, Trin. In tufts in the crevices of high
rocks in the middle of the island.

99. Bromus sterilis, Linn. On warm hillsides, sometimes in
large patches as if sown, at the south end and middle,

100. Pell.ea ornithopus. Hook., fide Professor Eaton. Rare,
in the crevices of the highest cliffs.

101. Gymxogramaie triangularis, Kaulf. In similar places in
the middle and at the south end of the island.

102. AsPiDiUM MUNiTUJi, Kaulf. In large bunches ; only two seen
at the northern end in a rooky place inaccessible to goats, and con-
stantly damp from the prevalent fogs.

103. PoLYPODiuM Californicum, Kaulf., fide Professor Eaton.
Abundant at the north end in the cracks of rocks, in damp localities,
sometimes covering large surfaces.

104. PoLYPODiUM ScouLERi, Ilook. Encircling the trunk of a
single oak, in a thick mat of moss and constantly wet by the fogs,

OF ARTS AND SCIENCES. 121

covering the tree with a network of its strong tough roots to the
heiglit of ten feet.

lOo. NoTHOL.ENA NicwBKUuYi, Eaton. Throughout the island
on rocks in dry exposed phices.

106. WeISSIA VIRIUULA, Brid.

107. Ceratodon ruRi'UKEUs, Brid.

108. Barblla RiGiDA, iSchultz, var. pilifera. Not before col-
lected in America.

109. Barbula atrovirens, Smith. Also new to America.

110. Barbula vinealis, Brid.

111. Barbula ruralis, lledw.

112. Orthotriciium Lyellii, Hook.

113. Grimmia pulvinata, Hook. &, Tayl.

114. Grimmia triciiopiiylla, Grev.

115. HyPNUM MYOSUROIDKS, Linn.

. Alsia Californica, Sulliv.

116. Madotheca naviculakis, Nees.

117. FOSSOMBRONIA LONGISETA, Austin.

118. FiMBRiARiA Californica, Austin.

119. FiMBRiARiA Palmeri, Austin, Bulletin Torrey Botanical
Club, 6. 47 ; new species.

III. Descriptions of New Species of Plants, chiefly Galifornian, with
Revisions of certain Genera.

Anemone (Pulsatilla) occidentalis. Alpine, more or less
villous, stout and often tall : leaves large, long-petioled, biternate and
pinnate ; lateral primary divisions nearly sessile ; segments pinnatifid
with narrow laciniately toothed lobes ; involucral leaves similar, nearly
sessile upon the middle of the stem : flower solitary, white or purplish,
an inch broad or more : sepals six or seven : receptacle conical, be-
coming much elongated : tails of the linear-oblong akenes at length an
inch and a half long, reflexed. — A. alpina, Hook. Fl. Bor.-Am. ;
Torr. «fc Gray, Flora ; &c., not Linn. In the mountains, from British
Columbia southward to Mt. Shasta and Lassen's Peak ; perhaps also
the A. alpina of arctic collectors from Kotzebue Sound, &e., of which
specimens are not at hand. It differs from A. alpina of Europe and
tlie Caucasus in its more finely and narrowly dissected leaves, which
have also the primary divisions much more shortly petiolulate, and in
the lengthened receptacle (sometimes an inch and a half long), which
in the other is small and hemispherical.

122 PROCEEDINGS OF THE AMERICAN ACADEMY

Crossosoma Bigelovii. a low shrub, more slender tlian C.
Cah'foi-nicum, and all the parts much smaller : leaves glaucous, three
to six lines long, oblong, somewhat fascicled : pedicels slender, terminat-
ing very short branchlets : petals oblong, three lines long: stamens
about fifteen: carpels 10— 12-ovuled. — C. CaJifunn'cum, Torrey in
Paoif. R. Rep. iv. 63, t. 1, excl. fig. 1, 2. Collected by Dr. Bigelow,
on Lieut. Whipple's Expedition, in canons near the mouth of Bill
Williams River, W. Arizona ; in flower only. The petals are nar-
rower and the stamens and ovules much less numerous than in the
island species. Of tlie latter, fine fruiting specimens were for the first
time obtained by Dr. Palmer on Guadalupe Island ; but the charac-
ters of the embryo, which is found to be nearly as long as the thick
fleshy albumen and strongly curved, with narrowly oblong cotyledons
longer than the radicle, do not confirm the reference of the genus
either to the PcBoniece or to the DUleniacece.

EsCHSCHOLTziA MiNUTiFLORA. Slender, and about a foot high :
flowers very small (three lines or less in diameter), orange; torus
cylindrical, without border : capsule very narrow, an inch and a half
long : seeds nearly smooth, scarcely half a line broad. — E. Califor-
nica, var. tenuifolia, Gray in Bot. Ives's Rep. 5, in part. E. Califor-
nica, var. hypecoides, Watson, Bot. King's Rep. 14. From North-
western Nevada to Arizona and Southern Utah (Parry), apparently
confined to the inner basin. It has smaller and smoother seeds, smaller
flowers, and narrower capsules than any other form.

Arabis Lyallii. Perennial and alpine or subalpine, glabrous
and bright green or glaucous, or somewhat villous below with s{)read-
ing hairs, especially on the margins of the petioles ; rarely more or
less canescent with stellate haii's : stems slender, from a branching base,
two to fifteen inches high, often dwarf: radical leaves oblanceolate, on
slender petioles, acute, entire ; the cauline oblong-lanceolate, clasping
and sagittate at base : petals light pink, about three lines long, twice
longer than the sepals : style none : pods straight, narrow, erect or
ascending, one to three inches long : seeds in two rows, narrowly
winged. — A. Erummondii, var. nipina, AVatson, Bot. King's Rep. 18.
In the mountains from Washington Territory to Mono Pass in the
Sierra Nevada, and eastward to W. W^^oming and Utah. Resem-
bling some forms of A. Enimtnondii, but distinguished by its peren-
nial root.

Auahis rkfanda. Biennial, pubescent with loose branched hairs,
especially below : stem rather stout and ccnirse, two feet high, the
Bpreadiug branches somewhat flexuous : leaves oblanceolate, three or

OF ARTS AND SCIENCES. 123

four iiiflios lonji, obtuse, coarsely sinuute-toothed, attenuate to a hroad
petiole ; tiiose on the branches narrower and acutish : calyx pubescent,
a line and a iialf long or less, a little shorter than the pinkish petals :
pods souu'wliat pubescent, ascending, falcate, three inches long and a
line wide: style very short: jjceds in one row, broadly wingcid. —
Yoseniite Valley, n, 4881 Bolander. A strongly marked species.

Arabis Breweki. Perennial, cespitose, canesceut with a dense
stellate pubescence and villous above with spreading nearly siinj)le
hairs: stems sim|)le from a branching base, two to ten inches high :
radical leaves spatulate, au inch long or less, !;hortly petiolcd, entire ;
the cauline ovate-oblong, sessile but not sagittate, acute : petals <leep
rose-color, from one to four lines long, twice longer than the pur{)lish
sepals : |)ods spreading or recurved, about two inches long, a line
"nide : style none : seeds in one or two rows, nari-owly winged. — In
the Coast Ranges from Mt. Diablo (Hrewer, Bolander) to Lake
County (Greene) and Mendocino Comity (Bolander). Most like
A. arcnata. Gray, of the Sierra Nevada and mountains of S. Califor-
nia, which is a taller species, with larger flowers, longer pods, and
different pubescence, the leaves mostly toothed and the cauline ones
sagittate.

Smeloavskia (?) Fremontii. a dwarf alpine perennial, pubes-
cent with scattered short spreading hairs, the branching somewhat
woody base covered with a few remnants of old leaves : stems two to
four inches high : leaves less than half an inch long, pinnate with one
to three pairs of linear leaflets, which are strongly nerved and slightly
revolute : sepals glabrous, broad, less than a line long ; petals white,
twice longer: immature pods two to three lines long, somewhat ob-
compressed, obtuse at base and scarcely attenuate above, beaked with
a short thick style ; valves faintly nerved : seeds small, ten or more in
each cell ; cotyledons obliquely incumbent. — Collected by Fremont
on hills near Klamath Lake, and by Lemmon in the northern Sierra
Nevada. It much resembles *S'. calycina in habit, but the characters
of the fruit do not fully accord with those of the genus.

Lyrocarpa Palmeri. Pod reniform-obcordate, rounded at the
base, four or five lines wide, broader than high : cells 2-seeded, the
upper seed horizontal, the lower pendulous : petals linear, purplish,
six lines long, twice longer than the calyx. — It otherwise resembles
the original L. Coulteri, Hook. & Harv. The peculiarities of the
fruit require a modification of the received generic chai'acter. Fi-om
the Big Gallon of the Tantillas Mountains, below San Diego ; col-
lected by Dr. Edward Palmer.

124 PROCEEDINGS OF THE AMERICAN ACADEMY

Thysanocarpus erectus. Smooth and leafy : leaves oblong to
oWanceolate, au inch or two long, aui-icled at base, somewhat sinuate-
dentate : flowers purple or rose-colored : fruiting jiedicels erect : pod
minutely pubescent, the wing of the fruit (still immature) without
indication of nervation or perforation : style very short — Collected by
Dr. E. Palmer on tlie western side of Guadalupe Island. Distin-
guished especially by its erect pedicels.

Frankenia Palmeri. a rather slender ditfuse shrub, a foot
high, with short straight divaricate branchlets : leaves numerous, fas-
cicled, a line or two long, thick and strongly revolute so as to be
nearly terete, canescent with a white papillose and furfuraceous en-
crustation : calyx a line and a half long : petals linear, a little exserted :
stamens four : style bifid : capsule 2-seeded. — Lower California, upon
the gulf side. Dr. E. Palmer.

SiLENE Palmeri. Puberulent with short spreading hairs, glan-
dular above : stems a foot high, slender, from a branching base : leaves
oblanceohite, an inch long : flowers purplish, on slender pedicels, in an
open panicle : calyx four lines long ; teeth short : petals vei"y nai'row,
half an inch long ; blade 4-parted with linear entire or bifid lobes ;
appendages linear ; claw not auricled, and with the filaments veiy vil-
lous : styles and stamens much exserted : ca})sule oblong, exceeding the
calyx ; stipe scarcely a line long : seeds tubercular, not created. — In
the Cuyamaca Mountains, San Diego County ; Dr. Edward Palmer,
August, 1875.

Calandrixia Breweri. Much resembling G. 3Ienziesii, from
which it is distinguished by its divaricately spreading or deflexed pedi-
cels ; by a longer conical blunt capsule, 4 to 5 lines long, and exceed-
ing the triangular-ovate sepals ; and by the rather smaller (half a line
broad) seeds, which are more strongly tuberculate, and not shining. —
C. Meaziesii, var. macrocarpa, Gray in Proc. Am. Acad. ^3. 102.
Collected by Professor W. H. Brewer, in the Santa Inez ^Mountains,
near Santa Barbara ; the only specimens are a foot tall or more, with
elongated racemes.

LAVATiiKA occidentalis. A closc shrub, three or four feet
liigh, leafy at the ends of the short branches: leaves stellatt-piihcru-
lent, round-cordate, T-lobed to the middle, three to five inches broad,
on long petioles; lobes acutish, coarsely toothed: flowers axillary,
solitary, on short deHexed pedicels: calyx over au inch long, twice
longer than the involucre, cleft to the middle into broad foliaceous
lobes : jietals narrowly s{)atulate with a broad naked claw, emarginate,
two inches long, straw-colored witli violet stripes : fruit halt' an inch

OF ARTS AND SCIENCES. 125

broad, finely pubescent ; carpels six to ten, about equalling the short
conical summit of the axis. — Collected by Dr. K. PaluKsr on the
cliffs of Guadalupe Island. An interesting discovery as confirming
the Ameiican habitat of the genus.

jMalvastuum Coulteri. Perennial, somewhat pubescent, with
slender branches : leaves small, ovate or somewhat cordate, 3-o-lobed,
acutely toothed, equalling or exceeding the slender petioles ; flowers
small, in a rather loose raceme : calyx-lobes acuminate : petals rose-
colored, 4 or 5 lines long : carpels rounded, less than a line in diameter,
with a thin horizontal oblong projection inward at base, very strongly
reticulated, pubescent below. — Collected probably in South-eastern
California by Coulter (n. 1)6), and in the valley of the Gila by Schott,
on the Mexican Boundary survey. Very peculiar in the character of
its carpels.

Sph.kkalcea suLriiuuEA. Perennial, resembling S. Emoryi in
habit, but more tomentose, and the inflorescence usually much more
paniculate and diffuse : leaves ovate, two to four inches long, exceed-
ing the petioles, more or less distinctly 3-5-lobed, acutish, crenately
toothed, cordate to abruptly cuneate at base: flowers su]i)hur-yellow or
whitish, usually tinged with pink : calyx two or three lines long, Avith
broad acute lobes : petals twice longer, villous at the base of the claw :
fruit globose ; carpels semicircular, a line and a half long, reticulate on
the sides. — On Guadalupe Island, Dr. E. Palmer ; growing abun-
dantly among rocks, in large bunches three feet high.

Abutilon Newberryi. Woody at base, often four to five feet
high, densely tomentose ; branches short and stout : leaves thick,
oblong-lanceolate, acutish, cordate at base, one or two inches long, on
short petioles : pedicels fascicled in the axils, much shorter than the
leaves : flowers deep yellow, three lines long : carpels about eight,
somewhat membranaceous, three lines long, narrower but rounded
above, 2-valved to the base, 3-seeded. — Sphceralcea incona, Gray,
Bot. Ives's Exp. 8. At Canebrake Caiion on the Lower Colorado by
Newberry, on the Lower Gila by Emory, and in the Big Caiion of the
Tantillas Mountains, below San Diego, by Palmer.

Tribulus Californicus. Small, hoary-pubescent and hairy :
leaflets about six pairs, oblong-elliptical, two or three lines long :
flowers yellow, very small, the petals little longer than the narrow
sepals : fruit deeply o-lobed, two lines or less in diameter, short-
beaked ; the carpels with four or five stout obtuse tubercles upon the
back ; pedicels shorter than the leaves. — Collected by Dr. E. Palmer,
in Lower California (1870), on the eastern side of the peninsula.

126 PROCEEDINGS OF THE AMERICAN ACADEMY

Adolpiiia Californica. a shrub of rigid and compact habit,
about two feet high ; the branches terete, with spreading spiny
branchlets, puberulent : leaves orbicular to oblong-ovate, one or two
lines long, mucronate or often retuse, abruptly attenuate to a slender
petiole : flowers greenish, on pedicels about equalling the leaves ;
petals rather deeply hooded : fruit two lines in diameter ; the short
style deciduous from the very base. — A. infesta, Torrey, Bot. Mex.
Bound. 45, in part. At Solidad and Chollas Valley, near San Diego,
and near Monterey ; collected by Parry, Cleveland, and Palmer.
The more eastern A. infesta, Meisner, is distinguished by its larger
linear or oblong-lanceolate leaves, attenuate to a short petiole ; petals
less deeply hooded ; and longer style, jointed above the base, and leav-
ing the capsule apiculate.

Thermopsis Californica. Woolly -tomentose throughout: stip-
ules lanceolate ; leaflets obovate to oblanceolate, 1 or 2 inches long,
acute or obtuse, equally tomentose on both sides : bracts mostly ovate,
broad and clasping at base : pod on a short glabrous stipe, very
pubescent, linear, 6-8-ovuled ; mature fruit not known. — T. macro-
pliyJla, Torrey, Pacif. R. liep. 4. 81 ; &c. T. fahacea, Torrey, Bot.
Mex. Bound. 58. Marin and Napa counties, California, and probably
southward. T. macrophylla, H. & A., is distinguished by its villous
spreading pubescence, its large leaves glabrous above, and broad 4-5-
seeded jjod. The more northern and eastern species, T. montana,
Nutt. (usually leferred to T. fahacea, DC), is much more glabrous,
the linear pods 10-12-seeded.

LuriNUs NiVEL'S. White throughout with a short dense tomen-
tum, without villousness : stems a foot high, branching, leafy : leaflets
nine, broadly oblanceolate, acutish, an inch long or more, shorter than
the petioles : flowers subverticillate, in a shortly peduncled loose raceme ;
pedicels two or three lines long; bracts short, deciduous: calyx-lips
equal ; the lower narrow, nearly entire ; the upper bifid : ))etals
equal, broad, all naked, four or five lines long, deep blue, the banner
greenish yellow in the centre : pod 5-ovuled. — Collected by Dr. E.
Palmer, on Guadalupe Island, on rocks. Allied to L. lencophi/Ilns.

Lupin us Giiayi. A span high, densely hoary-tomentose through-
out, usually with some silky hairs : leaflets five to nine, cuneate-oblong
or oblanceolate, obtuse or acutish, shorter than the petioles : racemes
peduncled, sliort and loosely flowercl, with rather slender pedicels a line
or two long ; bracts subulate, equalling the calyx, deciduous : flowers
subverticillate, light blue, rather large (six to s'even lines long), with
broad wings and broad naked banner ; keel ciliate : pod 5-6-seeded,

OF ARTS AND SCIENCES. 127

an inch lung or more. — In tlic Siorni Nevada; near Clark's Ranch,
]\Iariposa Co., Dr. Asa Gray; Indian Valley, Plumas Co., Mrs. M.
E. Pulsitcr Ames. With the lari^e Howers and loose racenu! of L.
onuifKS, hut otherwise more nearly allied to the L. Iciiro/i/ti/llns group.

LuPiNUS ONUSTUS. A span high or less, with a decumhent and
somewhat Wdody base, rather sparingly silky-villous : leaflets five to
eight, oblanceolate, acute or acutish, glabrous above;, about an inch long,
the petioles two or three times longer: flowers deep liluc, small (four
lines long), scattei'ed in a loose short and shortly pcduudcil raceme;
bracts short, deciduous ; {)edicels slender : calyx sligiiily gibbous : ban-
ner naked ; keel strongly filiate : pod lialf an iiicili broad, an inch and
a half long, G-ovulcd : seeds brown, over three lines broad. — Indian
Valley, Plumas Co., by Mrs. M. E. Pulsifer Ames ; Sierra County,
Lemmon. Most nearly resembling L. parviflorus on a reduced
scale, but very distinct in its fruit.

Trifolium (Lupinaster) Leiimoni.* Dwarf and cespitose,
alpine, sparingly appressed-pubescent, the short rather slender stems
from a stout thick perennial root : stipules ovate, acuminate, toothed ;

* We give the following revision of the North American species of tliis
genus : —

§ 1. Leaflets 5 to 7 : heads not invohicrate, terminal and axillary : flowers ses-
sile : calyx-teetii fihform, plumose : low or dwarf perennials. — Western
species.

1. T. MEGACEPHALTiM, Nutt. Stout, somewhat villous : stipules ovate-ob-
long; leaflets obtuse, nearly an inch long : flowers in very large spicate heads :
pod smooth, 6-ovuled. — North-eastern California and Northern Nevada to Wasii-
ington Territory.

2. T. Andersonii, Gray. Cespitose, densely villous : stipules lanceolate ;
leaflets smaller, acute, nearly entire : flowers smaller, umbellate : pod tomen-
tose, about 5-ovuIed. — Proc. Am. Acad. G. 522. North-eastern California and
Northern Nevada.

3. T. Lemmoni, Watson. See above.

§ 2. Leaflets 3 : heads not involucrate, terminal : perennial or biennial.
* Flowers on slender pedicels, large. — Eastern species.

4. T. REFLEXDM, L. Not stoloniferous : leaflets obovatc to cuneate-oblong :
flowers numerous, umbellate on the summit of the peduncle: pod stipitate,
4 ovuled. — T. jiJati/ce/ihalum, Bisch. in Linnaea, 14. 132 (Litt-Bericht.). From
Canada West to Florida and Texas.

5. T. STOLOXiFERUM, Muhl. Stoloniferous : leaflets broadly obovate, re-
tuse : flowers fewer, on an evident rhachis : pod nearly sessile, 2-ovuled. — Ohio
and Kentucky to Missouri.

128 PROCEEDINGS OF THE AMERICAN ACADEMY

leaflets three to five, thick, obovate, obtuse, coarsely toothed, half an
inch long or less : peduncles mostly terminal, equalling the leaves :
flowers numerous, silicate upon a short rhachis (only two lines long),

* * Flowers sessile or nearly so. — Western species.

•*- Caulescent, often tall.

-t-f More or less pubescent : calyx-teeth very narrow, much longer than the tube,
plumose or luiiry : stipules lanceolate, acuminate.

6. T. ERiocEPHALDM, Nutt. Usuallv spreading-vlllous : leaflets oblong :
flowers in dense ovate heads, at length reflexed : teeth filiform, lax, very plu-
mose : ovary hairy. — N. California to Oregon and Idaho.

7. T. PLUMOsuM, Dougl. Somewhat appressed-villous : leaflets elongated,
narrowly oblong to linear : heads oblong or ovate ; flowers not reflexed : teeth
straight, plumose : ovary smooth. — Oregon, Idaho.

8. T. LONG I PES, Nutt. Stem usually glabrous : leaflets shorter, narrowly
oblong, mostly very acute : heads ovate, smaller and looser : teeth straight, more
or less hairy. — Var. latifolium. Hook. Often low : leaflets broader : flowers
pedicellate in loose heads. — From the Rocky IMountains to the Pacific.

++ ++ Glabrous throughout : calyx-teeth subulate, rigid, contorted, twice longer
than the tube : flowers sessile : stipules lanceolate, acuminate.

9. T. ALTissiMUM, Dougl. Stout : leaflets narrowly oblanceolate, acute. —
Oregon, Idaho.

++++++ Glabrous throughout : calyx-teeth straight, scarcely longer than the
tube : stipules mostly ovate, acute, entire : flowers on very short pedicels,
at length reflexed.

10. T. Bkckwithii, Brewer, ined. Stout : leaflets oblong to oblanceolate,
obtuse or acute, 1 or 2 inches long, coarsely veined and toothed : flowers 7 to 9
lines long, in dense globose heads : teeth linear-subulate : ovary 2-0-ovuled. —
T. altlssimum, Torr. & Gray, Pacif. R. Rep. 2. 120. N. E. California to S. Idaho.

11. T. King 1 1, Watson. Smaller and more slender : leaflets usually narrow
and acuminate: flowers 4 to 7 lines long, in looser heads. — Bot. King's Rep.
59. T. Ilaydeni, Porter, Ilayden's Rep. 1871, 480. N. E. California to Mon-
tana and Utah.

12. T. BoLANDERi, Gra}'. Cespitose, decumbent : leaflets small, brond and
obtuse, very finely reticulated, slightly serrulate : flowers few, 3 or 4 lines long :
teeth lanceolate, scarcely as long as the tube : ovules 2. — Proc. Am. Acad. 7.
335. Yosemite Vallej'.

■*- t- Dwarf, cespitose, acaulescent or nearlj' so. — Rocky Mountains to Utah.

++ Glabrous: flowers large : ovary smooth, linear, 8-ovuled.

13. T. NANUM, Torr. Leaflets small, oblanceolate, serrulate : flowers 1 to 3,
6 to 9 lines long : calyx-teeth broad, acute.

14. T. Brandegei, Watson. See p. 132.

OF ARTS AND SCIENCES. 129

very small (so far as known) : calyx villous, two lines long, tlif lililbrni
plumose teeth exceeding the puri)lish petals : banner deeply hooded :
ovary smooth, 2-ovuled. — From Lassen's Peak, by J. G. Lenmion,

++ *-* Pubescent: flowers small: ovary obovate, densely villous, 2-ovuleil, at
length exserted from tlie calyx.

15. T. GYMNocARiH)x, Nutt. Leaflets ovate-oblong to oblanceolate : flowers
3 to 5 lines long, in rallier close heads. — T. subcaulescens, Gray, Bot. Ives's
Kep. 10.

§ 8. Leaflets 3: heads not involucrate, axillary or rarely terminal : annuals.

* Pubescent : heads mostly terminal : flowers sessile, not reflexed : calyx-teeth
long-filiform, very plumose : ovules 2. — Western.

IG. T. Macr.«;i, H. & A. Flowers dark-purple, 3 lines long, in dense ovate
long-peduncled heads. — Var. DicnOTOMCM, Brewer. Taller and stouter, with
larger flowers : corolla more conspicuous, tipped with white. 7\ dichntommn,
H. & A. — From the Columbia River to vS. California. The typical Chilian
form appears to have nearly sessile heads and stouter calyx-teeth.

« * Mostly glabrous : heads axillary, small : flowers shortly pedicellate, at
length reflexed : calyx-teeth subulate or short.

•4- Calyx-teeth subulate: ovules 2. — Western species. (T. depauperatum might
be looked lor here.)

17. T. ciLiATCM, Nutt. Glabrous : leaflets obtuse or retuse : calyx cani-
panulate ; teeth lanceolate, rigid, the scarious margin rough-ciliate. — PI. Gam-
bel. 152. T. ciliolaium, Benth. PI. Ilartw. 304. From the Columbia to S.
California.

18. T. GRACiLENTUM, Torr. & Gray. Slender : peduncles rarely villous
with spreading hairs : leaflets retuse : heads rather dense : calyx canipanulate ;
teeth subulate, equalling the corolla. — T. denudatiim, Nutt. PI. Gambel. 152,
t. 24. From the Columbia to S. California.

19. T. BiFiDUM, Gray. Leaflets narrow, deeply notched or cleft, the
sides sparingly toothed or entire : otherwise as the last. — Proc. Am. Acad.
6. 522.

20. T. AMABiLE, HBK. Similar to T. fjrocilentum, but more decumbent,
pubescent : calyx-teeth linear-setaceous, somewhat villous. — Mexico and West-
ern South America.

21. T. Breweri, Watson. See p. 132.

22. T. Palmeri, Watson. See p. 132.

•t- •<- Ovules 4 or more: low, decumbent: leaflets obcordate or obovate. —
Eastern species.

23. T. Carolixianum, Michx. More or less pubescent : corolla 2 lines
long, scarcely exceeding the green subulate calyx-teeth. — Pennsylvania to
Florida and Texas.

24. T. AMPHiANTucM, Torr. & Gray. Stoloniferous, very slender, nearly
glabrous : flowers few, 4 lines long : calyx-teeth slender, much shorter, equalling

VOL. XI. (N. S. III.) 9

180 PROCEEDINGS OF THE AMERICAN ACADEMY

1875, The few specimens are imperfect, only a few jjerhaps unde-
veloped flowers remaining on the receptacles.

Trifolium Brandegei. Dwarf, perennial, cespitose and acau-

tlie tube : small solitary fertile flowers often borne under ground. — Louisiana
to Texas.

25. T. Bejariense, Morieand. Slightly hairy: calyx licrbaceon«, unequally
lobed, nearly equalling the corolla ; upper tooth nearly distinct, narrow ; tlie
rest broad, acute, reticulated : standard and wings broad, toothed, 3 lines long.
— PI. Nouv. 2, t. 2. T. macrocalyx, Hook. Ic. Pi. t. 275. Texas.

§ 4. Leaflets 3 : heads subtended by a mostly monophyllous usually many-cleft
involucre, axillary : flowers in whorls, sessile or nearly so, not reflexed.

* Low or dwarf perennials, acaulescent or nearly so : flowers rather large :
involucre parted, son)ewhat scarious. — Rocky Mountains.

26. T. Parry I, Gray. Glabrous, often stout : leaflets oblong to oblanceo-
late: flowers large, in close heads: bracts 5 to 7, oblong, obtuse : calyx-teeth
broadly subulate, equalling the tube. — Am. Jour. Sci. 2. 33. 409.

27. T. DASYPHYLLL'M, Torr. & Gray. Cespitose, silky : leaflets linear-lan-
ceolate, entire: bracts very small, unequal, lanceolate : teeth linear, mucii longer
than the tube.

28. T. Anuinum, Nutt. Cespitose, silky : leaflets cuneate-oblong, entire :
involucre of 2 broadly stipuled 3-foliolate leaves : teeth subulate, nearly equal-
ling the smaller flowers. — Watson, Bot. King's Rep. 00, t. 8.

* * Slender annuals : corolla not becoming inflated. — AYestern.

1- Involucre not membranaceous, deeply lobed : lobes laciniately and sharply
toothed.

29. T. iNVOLUCRATUJt, Willd. Glabrous : leaflets mostly oblanceolate, acute
at each end : flowers i inch long, in close heads : teeth thin, long and narrow,
entire: ovules several. — T. Wormskioldii, Lelim. T. Jhnhrialum, Lindl. T.
spinuloDum, Dougl. From British America to jNIexico.

Var. HETEKODON. Hcads mostly larger and leaflets broader : some of the
teeth setaceously cleft. — T. keterodun, Torr. «&. Gray. Washington Territory to
New Mexico.

30. T. TKiDENTATUM, Lindl. Smooth or glandiilar-puberulent : leaflets
linear to narrowly lanceolate : flowers 6 to 8 lines long in close heads : teetii
rigid, rather abruptly narrowed from a broad base into the spinulose apex,
entire or shortly tootiied : ovules 2. — T. iiiroliicrattim, Torr. & Gray. T. ciricu-
lare & /'olj/ii/ii/lliim, Nutt. From Washington Territory to S. California.

Var. <>HTUsiFLOHL'.M. Stoutcr, often glandular: leaflets usually broader and
heads large : teeth entire. — T. olitusijlorum, llook. Central California.

Var. MELANANTiiiiM. Smootli, often low: flowers smaller, dark-purple:
teeth entire or toothed. — T. indananthum, Ilook. & Am. T. varkyatum, fi.,
Torr. & Gray. S. California to Arizona.

31. T. PAfciFi,OKUM, Nutt. Smooth, very slender : involucre small: flowers
little exceeding the calyx, rather few : teetli rigid, setosely acuminate, entire. —

OF ARTS AND SCIENCES. 131

lescent, glabrous, tlie inflorescence slightly villous ; stij)ules scarious ;
leaflets ellij)tic-ol)long, thin, acutish, entire, a half to an inch long :
peduncles about equalling the leaves : flowers spicate in a loose naked
head, pur[)lish, seven lines long : calyx-teeth lanceolate, acuminate, a
little longer than the canipanuhite tube : ovary stipitate, T-ovuled. —
On the uorth-western border of New Mexico; collected by T. S.
Brandegee, on Hayden's Survey. A strongly marked and peculiar
species.

Tkifolium Brewkki. Annual, very slender and diffuse, some-
what pubescent throughout, a span high or more : stipules lanceolate,
short ; leaflets obcordate 'or obovate, rarely oblong, toothed or serru-

T. variegatum, Nutt. T. oUganthum, Steud. Washington Territory to S. Cali-
fornia and Utah.

32. T. MONANTHUM, Gray. Often villous, small, very slender : involucre
very small : flowers 1 to 4, much exceeding the short calyx : teeth thin, shortly
acuminate. — Proc. Am. Acad. G. 528. Sierra Nevada.

t- t- Involucre membranaceous, at least at base, less deeply lobcd ; lobes entire
or serrate.

33. T. MiCROCEPHALUM, Pursh. Villous : heads small : lobes of involucre
acuminate, 3-nerved, entire: calyx-teeth long-subulate, with broad scarious mar-
gin. — Washington Territory to S. California, and N. Nevada.

84. T. MiCRODON, H. & A. Villous: involucre broader; lobes 3toothed :
calyx smooth, angled ; teeth rigid, triangular, acute, with a narrow serrulate
scarious margin. — Washington Territory to San Francisco; Chili.

35. T. CYATHiFERtTM, Lindl. Smooth : heads larger : involucre very broad ;
lobes sliort, toothed, many-nerved : calyx-teeth setosely many-branched. — From
the Columbia River to N. California and N. Nevada.

* * * Slender annuals : standard becoming conspicuously inflated. — Cali-
fornia.

•*- Heads mostly large : involucre conspicuous.

36. T. BARBiGERCM, Torr. Somewhat villous : involucre shortly lobed,
setaceously many-toothed : calyx-teeth filiform, plumose, sometimes 2-3-parted.
— Pacif. R. Rep. 4. 79. Monterey to Mendocino County.

37. T. FtrCATUM, Lindl. Smooth, stout : stipules large and scarious : heads
large : involucre deeply lobed or parted ; lobes entire, acuminate : teeth nar-
rowly subulate, entire or 2-3-cIeft. — T. Gamhellii, Nutt. PI. Ganib. 151.

H- -I- Heads small, few-flowered : involucre small or none : calyx-teeth narrowly
subulate : small.

38. T. DEPADPERATUM, Desvaux. Involucre a very small toothed or trun-
cate often scarious ring. — T. stenophijllum, Nutt. 1. c. Also Chilian.

39. T. AMPLECTEKS, Torr. & Gray. Involucre 4-5-parted or cleft, the seg-
ments oblong, usually obtuse, entire or nearly so, equalling the calyx. — T.
diver sifoUum, Nutt. 1. c. 152.

132 PROCEEDINGS OF THE AMERICAN ACADEMY

late, three to nine lines long : flowers few, in axillary naked very
loose heads, nearly white, two to four lines long, on slender pedicels
often half as long, at length reflexed : calyx very narrow, the slender
teetli much shorter than the corolla. — In the Sierra Nevada, from
the Yosemite Valley, at Clark's, to Sierra County, from several coliec-
lors. Of the T. gracilentum group, which is otherwise confined chiefly
to the Coast Ranges.

Trifoliu:m Palmeri. A glabrous and diffuse annual, the stems
ascending, about a foot high or less : stipules elongated, narrowly
acuminate ; leaflets oblong to narrowly lanceolate, acute or acutish at
each end, serrulate, a half to an inch long : peduncles axillary : heads
naked, 10-20-flowered; flowers sessile, at length reHexed : calyx three
lines long, deeply cleft into narrow acuminate entire lobes : petals
purplish, scarcely exceeding the calyx : i)od 2-seeded. — Guadalupe
Island ; Dr. E. Palmer.

Dalea Californica. Shrubby, with the leaves and younger
branches canescent with a fine appressed pubescence : glands mostly
obscure, but upon the peduncles sometimes prominent and prickle-
like : leaflets one or two pairs, linear-oblong, not two lines long, decur-
rent upon the short rhachis : flowers on short pedicels in a loose
raceme, purple, four lines long : calyx half as long, finely pubescent,
the ovate acute teeth shorter than the tube : ovules two. — Known as
yet only from scanty specimens recently collected by Dr. Parry in the
San Bernardino Mountains, California. It adds another to a group of
more or less woody or shrubby species, which may be separated as a
section Xylodalea, characterized by having the claws of the petals
adnate to the stamineal tube only at the very base, the flowers spread-
ing or reflexed, mostly in loose spikes or racemes, and the ovules in a
favf of the species four or six. It includes a dozen species, some
with calyx very pubescent and teeth mostly slender (Z). scopana
Gray ; D. frutescens, Gray ; D. Emoryi^ Gray ; D. arborescens, Torr. ;
D. pnhjadenia, Torr. ; D. amoena, Watson), others with the calyx spar-
ingly pubescent and broadly toothed (Z). Fremontii, Torr. ; D. Gali-
foritica, Watson ; D. Jolinsoni, Watson ; D. Kingii, Watson ; D.
Sc/iOttii, Torr.; and D. spinosa, Gray). The species D. arffi/reea,
D. Parryi, and D. leucostachys are intermediate between this section
and the true Daleas. The genus Asngrcea of Baillon, founded on
J), spinosa and characterized by the several ovules and sim[)le leaves,
can hardly be maintained, as D. Schottii likewise has simple leaves
but only two ovules, while in D. scoparia at least the ovules are
four.

OF ARTS AND SCIENCES. 133

Latiiyuus Nevadensis.* Sk'iulci', usually a spau lii^^li, liuily
pubesceut or nearly glabrous : stipules semi -sagittate, the lobes nar-
rowly acuminate ; leaflets tliiu, two to four pairs, ovate to ovate-

* Tlie North American species of tiiis genus ruay be arrangeil as follows : —

§ 1. Rhachis of the leaves tendril-bearing: peduncles mostly equalling or ex-
ceeding the leaves : pod sessile.

* Annual : racemes 1-2-flowered.

1. L. pusiLLCS, Ell. Glabrous ; stems winged : leaflets 2, narrow : flowers
small, purple : pod linear: seeds minutely tuberculate. — S. Carolina to Texas.

The L. Enfjelmanni, Bischof in Linntea, 14. 182 (Litt.-Bericlit), from near
Fort Gibson, Arkansas, may be distinct. It is described as with oblong leaves,
ciliate stipules, and seeds " rugulosoexsculptis."

* * Perennials : racemes several-flowered.

t- Stipules large, ovate or somewhat semi-hastate with broad lobes : stout and
glabrous, e.xoepting forms of L. marilimus.

2. L. MARiTiMus, Bigel. Stipules broadly ovate, acute: leaflets 6 to 10,
thick, ovate-oblong, obtuse or acutish, 1 or 2 inches long, nearly sessile :
flowers large (9 lines long), purple: calyx-teeth sparingly ciliate. — Seashore,
from New Jersey and Oregon northward, and on the Great Lakes. The high
northern and arctic form is low and more slender, and more or less densely
pubescent.

3. L. POLYPHYLLUS, Nutt. Stipules smaller, triangular, scarcely longer
than broad, acute or acuminate ; leaflets 12 to 20, thin, oblong, distinctly petio-
lulate : otherwise Uke the last. — N. California and Oregon, near the coast.

4. L. ocHROLEUCDS, Hook. Stipules semi-cordate ; leaflets 6 to 8, thin,
ovate, obtuse or acutish : flowers smaller, ochroleucous. — Northern United
States from New England to Washington Territory, and north to Lake Win-
nipeg.

5. L. suLPHUREus, Brewer. Glaucous : stipules semi-cordate or semi-sagit-
tate ; leaflets 6 to 20, oblong-ovate to linear-lanceolate, about an inch long,
acute : flowers sulphur-yellow, 6 lines long. — In the Sierra Nevada.

-t- ■*- Stipules narrower, semi-sagittate, the lobes usually lanceolate, acuminate :
flowers purple or purplish.

++ Leaflets 8 to 12 : peduncles rather many-flowered.

6. L. VENOSus, Muhl. Stout, climbing, usually somewhat downv : stipules
mostly narrow and short ; leaflets oblong-ovate, mostly obtuse, about 2 inches
long : flowers 6 to 8 lines long : calyx densely pubescent to nearly glabrous :
ovary smooth. — Through the Atlantic States to the Saskatchawan, and thence
to Washington Territory.

Var. Californicus. Stems very stout, often strongly winged : stipules
broader ; leaflets acute and narrower : flowers larger. — Sonoma County to
Monterey, California, and in the foothills of the Sierra Nevada ; near water.
Intermediate forms occur.

134 PROCEEDINGS OF THE AMERICAN ACADEMY

oblong, can inch or two long, obtuse or acute ; rhachis rarely developing
a short tendril at the extremity : flowers ochroleucous or sometimes
purplish (?), large (7 to 12 lines long) : calyx-teeth shorter than the

7. L. vESTiTtrs, Nutt. Slender, often tall, usually more or less downj :
stipules narrow, often small ; leaflets ovate-oblong to linear, J to 1 inch long,
acute : flowers pale, 7 to 10 lines long : ovary appressed-pubescent. — L. strictus,
Nutt. Coast Eanges of California, from Sonoma County to San Diego ; very
variable.

•w- ++ Leaflets 4 to 8 : peduncles 2-6-flowered.

8. L. PALtrsTER, Linn. Slender, glabrous Or somewhat pubescent : stem
often winged : stipules mostly narrow, often small ; leaflets narrowly oblong to
linear, acute, an inch or two long : flowers smaller, 6 lines long. — L. Lanszwertii,
Kellogg, Proc. Calif. Acad. 2. 105, fig. 44.

Var. MTRTiFOLius, Gray. Stipules usually broader and larger ; leaflets
ovate to oblong, an inch long or less. — L. venosus, var. S., Torr. & Gray, Fl.
1. 274. L. polyphijlhis, Watson, Bot. King's Rep. 78. — Very variable : found
throughout the northern part of the continent, ranging southward in the moun-
tains to New Mexico, Arizona, and S. California. What appears to be merely a
low form with the tendrils undeveloped is found in the Rocky Mountains and
westward.

§ 2. Rhachis not tendril-bearing or rarely so : pod shortly stipitate.

* Peduncles long, 2-6-flowered.

9. L. LiTTORALis, Eudl. Densely silky-villous : stipules ovate-oblong, acute,
entire ; leaflets 2 to 6, with a small terminal one, cuneate-oblong, 4 to 6 lines
long : flowers purple, 6 to 8 lines long : pod oblong, villous. — On the coast,
from Washington Territory to San Francisco.

10. L. Nkvadensis, Wat«on. See above.

11. L. POLYMORPHUS, Nutt. Usually low, finely pubescent or glabrous,
glaucous: stipules narrowly acuminate; leaflets 6 to 12, thi(;k and strongly
nerved, narrowly oblong, acute, 1 or 2 inches long : flowers very large, purple :
pod 3 or 4 lines broad: funiculus remarkably narrow and hilum short. — New
Mexico and Colorado to Central Arizona.

12. L. OKNATUS, Nutt. Leaves narrower and shorter:' pod somewhat
broader : funiculus broader : otherwise resembling the last. — Mountains of
ColoPiido and Utah.

* * Peduncles very short, 1-flowered.

13. L. ToRREYi, Gray. Very slender, low, sparingly villous : stipules nar-
row ; leaflets thin, 8 to 12, with occasionally a similar terminal one, ovate to
oblong, acute, i inch long: flowers rather small, purplish : pod pubescent. —
Washington Territory to N. California, near the coast.

Species excluded.
L. LINEARIS, Nutt. and others, including L. dissitifotiiis, Nutt., is only a
western form of Vicia Americana, with narrow leaflets, = V. Americana, var.
linearis.

OF ARTS AND SCIENCES. 135

tube: fruit not seen. — L. I'enosiis, var. obovatus, Turrey in racif. 11.
Rep. 4. 77. In the Sierra Nevada, in Calaveras County, where it lias
been collected by Bi^'elow, Brewer (n. 1G02, 1G12), Dr. G. L. Good-
ale, and II. Mann. Other specimens flora the Blue INlouniains, Ore-
gon (-Rev. R. D. Nevius), and from Northern Idaho (Geyer, n. .'512;
L. po/i/morp/iiis, Hook. Jour. Bot. G. 207), are probably the same,
with rather narrower and acuter leaflets.

SornouA Auizonica. An evergreen shrub, somewhat canescent
with short appressed silky hairs : leaflets two or three paii's, nar-
rowly oblong, acutish, about an inch long ; stipules small, subulate :
racemes very short (half an inch long), and few-flowered; bracts de-
ciduous : pedicels bracteolate, about three lines long : calyx narrowed
at base : pods smooth, coriaceous, compressed, reticulated and with
nerve-like margins, three or four inches long, more or less contracted
between the thick oblong (half inch long) seeds ; stipe exceeding the
calyx. — S. speciosa, Torrey in Pacif. R. Rep*. 4. 82. At Cactus
Pass and on White Cliff Creek in W. Arizona, by Dr. Bigelow ;
only fruiting specimens found, January. The pod is thinner and more
compressed than is usual in the genus and the seed less globose.
The more eastern S. speciosa, Benth., has very thick and terete silky
pods, with ovate seeds, and larger obtuse or emarginate cuneate-
obovate or broadly spatulate leaves.

Parkinsonia Torreyana. a small tree, twenty or thirty feet
high, with smooth light green bark ; younger branches and leaves
sparingly pubescent : leaflets two or three pairs in each pinna, oblong,
obtuse, narrower toward the somewhat oblique base, Iwo or three lines
long, glaucous : flowers on long pedicels in racemes terminating the
branches ; pedicels jointed near the middle, the joint not evident until in
fruit : petals appai'ently bright yellow, four lines long ; claw of the
upper petal with a thick prominent gland : ovary glabrous : pod with a
double groove along the broad ventral suture, usually two inches long
or more, 2— 8-seeded, straight or somewhat contracted between the
seeds : seeds very thick. — Cercidium jioridam, Torrey in Pacif. R.
Rep. 5. 360, t. 3. Abundant on the Lower Colorado River and in
the valleys of Western and Southern Arizona, and known as Palo
Verde or Green-barked Acacia. It has been always mistaken for
P. forida (^Cercidium Jloriduin, Benth.), of the Rio Grande Valley,
which has sessile axillary racemes, pods with a narrow acute margin
on the ventral side, thinner'seeds, and somewhat smaller leaflets.

The characters which have been relied upon to sepaiate Cercidium,
Tulasne, from Parkinsonia, do not hold good in regard to our western

136 PROCEEDINGS OF THE AMERICAN ACADEMY

species, and it becomes necessary to unite the two genera. The P.
microphylla of Torrey, from W. Arizona (republished by Benthara
under the same name in Martins' Flora Brazil.), is certainly rightly
referred, the pod being in every respect that of ParAv'nson/a, though the
habit and characters of the flowers are those of Cercidium. Both
genera are alike in the jointed pedicels of the flowers, in the more or
less thickened glandular and pubescent claw of the upper petal, in the
strongly gibbous filament of the corresponding upper stamen, in the
indoubliiig of the style in the bud, and in the more or less oblique
longitudinal veining of the pod. The valvate or slightly imbricate
asstivation of the calyx, the straight or torulose and more or less coria-
ceous pods, and the differences in foliage, cannot be relied upon to dis-
tinguish the genera. In addition to the three species already mentioned
and the eastern P. Texana {^Cercidium Texanum, Gray), there is
perhaps another undescribed species from near Camp Grant in Ari-
zona, and Botteri's n. 994 from Orizaba, Mexico, appears 'also to be
distinct, but the material in both cases is insufficient for a satisfac-
tory description.

Cassia (Chamjesenna) armata. Herbaceous, about three feet
high, minutely puberulent, light green : leaflets two or three pairs,
thick, round-ovate, acutish, a line or two in diameter, the margin
slightly revolute, distant upon an elongated (two inches long) rigid
flattened spinulose rhachis; sti{)ules and glands wanting: flowers in a
short terminal raceme, yellow, on slender pedicels and with rigid
aculeate-tipped bracts : petals two or three lines long : ovary slightly
pubescent; the numerous ovules obliquely transverse: young pod
glabrate, stipitate, linear, acuminate, compressed, the sutures thick
and nerve-like. — A remarkable species, found by Dr. J. G. Cooper in
the mountains of S. California, between Fort Mohave and Cajon
Pass, and also by Lieut. Wheeler in W. Arizona.

Nkillia Torreyi. a small shrub, differing from N. opidifoUa in
its smaller leaves, which are an inch long or often less, its finer pubes-
cence and the leaves sometimes densely white-tomentose beneath, its
fewer and smaller flowers (only half as large) on shorter pedicels, the
fewer (15 or 20) stamens, and especially the densely tomentose
ovaries, which are fewer (usually 1 or 2) and become less inflated. —
Spira-a mono(/yna, Ton-ey, Ann. N. Y. Lye. 2. 194. ^. opii/ifn/id,
var. pauciflorn, Torr. & Gray. In the mountains of Colorado and
westward to Nevada. Very distinct froifi N. opulifob'a. though by
no means always monogynous as originally described, and of interest
as being a strictly American species of this chiefly Asiatic genus.

OF ARTS AND SCIENCES. 137

Sedu.m variegatum. Glabrous, slender; stems simple, from un-
derground rootstocks (?), erect, an inch or two high: radical leaves
none ; cauline lanceolate with a broad base, two lines long or less :
flowers few (three to six) in a close cyme : sepals broadly ovate, acute,
short and purplish : petals twice as long (about two lines), ovate-lan-
ceolate, yellowish with puiple niidvein : stamens 10, included. — A
diminutive species, sent by D. Clevelaiul, from San Diego,

Qi^NOTHKKA (Sphjerostigma) GuADALUPENsis. A low erect
annual (three inches high), branching, finely pubescent: leaves oblan-
ceolate, sessile or the lowest attenuate to a petiole, obtuse or acutish,
obscurely sinuate-toothed, an inch long: fiovvers few, axillary, yellow,
very small : calyx-tube obconical, a line long ; the lobes as long, close
in the bud : capsule oblong-pyramidal, nearly straight, strongly angled,
half an inch long : seeds brown, smooth. — Found by Dr. E. Palmer
on Guadalupe Island ; a peculiar species in the section as respects its
capsule, in which it most resembles (E. andina.

Mkntzklia dispersa. a slender annual, usually about a foot
high ; leaves narrowly lanceolate, sinuate-toothed or sometimes entire,
rarely pinnatifid, the uppermost often ovate: flowers small, mostly ap-
proximate near the ends of the branches; calyx-lobes a line long, little
siiorter than the five spatulate or obovate petals : filaments not dilated :
capsule narrowly linear-clavate, six to nine lines long : seeds very
often in a single row, angular and somewhat rhombohedral, more or less
grooved upon the angles, very nearly smooth, half a line long. — M.
albicaulis, var. integrifolia, Watson, Bot. King's Rep. 114. F'rom
"Washington Territory to Colorado and southward, frequent ; Yose-
mite Valley, Bolander ; Guadalupe Island, Palmer. Much resembling
M. albicaulis, Dough, with which it has been confounded almost from
the first, but wdiich is distinguished by its more pinnatifid leaves and
slightly larger flowers, and especially by its rather strongly tubercu-
late seeds, irregularly angled with obtuse margins. The rarer allied
species M. micrantha differs in its more leafy habit and small ovate
leaves, and in its shorter, broader and few-seeded capsules, the seeds a
line long.

CuouRBiTA PALMATA. Cauesceut with a short rough pubes-
cence, which is appressed upon the leaves ; stems leafy : leaves thick,
cordate, two or thi-ee inches broad, usually exceeding the petioles, pal-
mately o-cleft to the middle with lanceolate acuminate lobes, which are
often obtusely toothed near the base : flowers three inches long, on
stout pedicels : calyx-tul)e an inch long, the lanceolate teeth three
lines long or more : fruit globose ; seeds five lines long, rather smaller

138 PROCEEDINGS OF THE AMERICAN ACADEMY

than in C. digitata. — San Diego County : collected in Cajon Valley
by D. Cleveland, and at Larken's Station near the Jacumba Mountains
by Dr. E. Palmer.

CucuRBiTA Californica, Torrey MS. in herb. Imperfect speci-
mens of tills species were collected by Dr. E. Pickering on the
Wilkes Exploring Expedition, at some locality in the Sacramento
Valley. Tiie foliage is much like that of the last, but the flowers are
smaller, scarcely more than an inch long, exceeding the slender pedi-
cels ; calyx-teeth short and linear.

Megaurhiza Guadalupensis.* Nearly glabrous, the inflores-
cence somewhat pubescent : leaves thin, 3-5-lobed to the middle ;

* MEGARRHIZA, Torrey. The species of this genus have been imperfectly
studied, owintj to want of material, and the only one at all well known has been
the original M. Californica, tlie Echinocijatis fubacm of Xaudin. As already
pointed out by Dr. Gray and Dr. Torrey, the genus is separated from the east-
ern Echinociistis by its thick perennial roots, its large turgid inimarginate seeds,
and its thickened fleshy cotyledons, which remain subterranean in germination,
— characters which hold good in all the species, and may be considered as suf-
ficiently distinctive. The following are the species at present known, the
characters subject to modification as fuller material may require. Considerable
diversity is shown in the internal structure of the fruit, which may perhaps be
found to vary to some extent even in the same species.

1. M. CALiFonN-iCA, Torrey. Nearly glabrous; stems very long: leaves
5-7-lobed, rarely to the middle ; lobes broadly triangular, abrupth' acute : fer-
tile flowers without abortive stamens : ovary globose, densely echinate, 2 celled
(rarely 3-4-celled), the cells 1-2-ovuled; ovules attached to the outer side, the
lower ascending, the upper horizontal : fruit globose or ovoid, two inches long,
beset with stout almost pungent spines (a half to an inch long), 1-4-seeded :
seed obovoid, ten lines long, surrounded lengthwise by a shallow groove or
darker line, the hilum at the end. — Pacif. K. Kep. 6. 74. Echinoci/stis fahacea,
Naudin, Ann. Sci. Nat. 4. 12. 154, t. 9, and IG. 188. Near the coast from Punta
de los Reyes to San Diego.

2. M. Marah. Scabrous or nearly smooth ; stems very long : leaves nearly
as in the last: fertile flowers with abortive stamens : ovary oblojig-ovate, more
or less covered with soft spines, 2-3-celled : ovules 1 to 4 or more in each cell,
ascending or horizontal, attached to the outer side of the cell : fruit ovate-ob-
long, four inches long, somewhat attenuate at each end, more or less beset
with weak spines : seeds horizontally imposed, flattish, suborbicular or irregu-
larly elliptical, an inch in diameter, about half as thick, with an obscure mar-
ginal furrow and prominent lateral hilum. — Marah miiriaitux, Kellogg, Proc.
Cahf. Acad. 1. 38. Near San Francisco Bay, at Bolinas, Saucelito, Alameda,
Redwood, Corte Madera, &c.

3. M. Oregona, Torrey. Much like the last: fertile flowers without abor-
tive stamens : young fruit similar in shape, sparingly muricate with soft spines,

OF ARTS AND SCIENCES. 139

lower lobes quadnuiguhir, tlie upper aciuuiimte, with a few short
teeth : flowers in subsimple racemes, six to eight lines broad ; calyx-
teeth iiliforiu : ovary ovoid, densely covered with short soft spines, on
a slender pedicel an inch long, 2-celled ; ovules one or two in each
cell : fruit ovoid, about two inches long, acute above, somewliat pnljes-
cent, and with scattered short stiff spines, usually 2-seeded : seeds sub-
globose, an inch in diameter, attached to tlie inner side of the cell,
smooth upon the margin. — From Guadalupe Island, by Dr. K. Pal-
mer ; growing on high rocks.

Saniol'la Nkvauexsis. Low, the peduncles mostly from the
base of the stem : leaves ternate with decurrent oblong-ovate 3-5-
lobed divisions, the segments lobed or toothed : involucre pinnatifid
and toothed : rays about o, sometimes branched, about an iuch long in
fruit ; involucels somewhat unilateral, of several oblong acute more or
less united bracts : flowers yellow : fruit sessile, covered with stout
prickles. — lu Plumas County, California ; collected by Mrs. M. E.
P. Ames, and by Lemmon.

CiCUTA BoLANDKRi. Leaves bipinnate ; leaflets narrowly lanceo-
late, narrowly and sharply acuminate, two inches long, very acutely
serrate, the veinlets passing to the sinuses ; lower leaflets petiolulate,
often deeply lobed : involucre of several linear leaflets : fruit two lines
long, nearly orbicular, strongly ribbed and with broad vitta?, wliit-h are
sunk in the channelled seed. — At Suisun, California, in salt-marshes ;
Bolander.

(ExANTHE Californica. Stems succulent: leaves ternate and
bipinnate, the pinnaB nearly sessile ; leaflets approximate, ovate, about
an inch long, acute or acutish, toothed, often lobed at base : involucre

3-4-celled : cells imbricated above each other, 1-seeded : seeds obovoid, ascend-
ing, attached to the outer side of the cell. — Pacif. R. Kep. 6. 74. Common in
Washington Territory and Oregon. The ripe fruit has not been collected.

4. M. MORiCATA. Nearly glabrous and often glaucous ; stems six to eight
feet long : leaves usually smaller, deeply olobed, the divisions broader above
and sliarply toothed or lobed : fertile flowers without abortive stamens, on slen-
der pedicels : ovary oblong, acute at each end, smooth or sparingly nmricate :
fruit nearly globose, an inch in diameter, naked or with a few short weak spines
near the base, 2-celled (or perhaps sometimes 3- or 4-celled), 2-seeded : seed
nearly globose, half an inch in diameter, ascending, attached to the outer side of
the cell near the base, the margin smooth. — Echinocystis muricutn, Kellogg,
Proc. Calif. Acad. 1. 57. On the lower slopes of the Sierra Nevada, in Cala-
veras and Placer Counties.

6. M. GxjADALUPENSis, Watson. See above.

140 PROCEEDINGS OF THE AMERICAN ACADEMY

of one or two linear bracts or none : fruit crowded, oblong, obtuse at
each end ; ribs and commissure very corky : seed somewhat dorsally
compressed, usually angled ; vittai at the angles. — Found in marshes
at Point Lobos and Merced Lake, and southward to San Diego
County. — (E. sannentosa, Xutt., of Washington Territory, differs
esjiecially in its more diffuse leaves, the leaflets acuminate and
smaller.

LiGUSTicuM FiLiciNUM. Rather slender, erect, a foot and a half
high : leaves broadly triangular in outline, ternate, the divisions bipin-
nate, and the segments deeply pinnatifid with linear acute lobes : rays
10 to 15, an inch or two long; involucre none ; involucels of one or
few small linear bracts ; pedicels slender : fruit oblong, three lines
long, with dilated crenate disk but obscure stylophore, strongly ribbed
on the back, the lateral ribs narrow; vittte obscure: seed flattened,
concave on the face, obscurely ridged on the back. — L. apiij'olium,
Watson, Bot. King's Rep. 125. X. scopidorum, Parry in Am. Natu-
ralist, 9. 271. In the Wahsatch and Uintah Mountains (u. 454 Wat-
son ; n. 82 Parry, S. Utah collection), and northward to Wyoming
(n. 121 Parry, N. W. Wyoming collection). Both L. apiifolium, of
Oregon and California, and L. scopidorum, of Colorado, have much
less dissected foliage, and different fruit, which is shorter and more oval,
with conical stylophore, less flattened carpels, and a medial longitudinal
ridge upon the face of the seed. These two species are very similar,
but the latter has the more broadly winged ovate fruit, and the more
depressed seed. There are indications of one or two other species, but
fruit is needed for their confirmation.

Selinum Pacificum. Leaves ternate and bi[)innate, the ovate
acutish segments an inch long, laciniately toothed and lobed : umbels
on stout peduncles, about 15-rayed, with a conspicuous involucre of
two or three lobed and toothed leaflets, an inch long and eipialling the
rays ; involucels of several narrowly linear entire or ^-toothed bracts,
equalling the flowers; pedicels slender: fruit smooth, oblong, three or
four lines long; wings thin, rather narrow ; stylopodium slightly prom-
inent above the disk : vittas conspicuous, very rarely in pairs, the dorsal
ones sunk in the body of the seed. — On the Saucelito hills, near San
Francisco ; Kellogg & Harford, n. 315. This closely resembles a
})lant of Unalaschka, one of the two northwestern and arctic species
which have been referred to the Siberian ConioseUnum Fischeri, but
which are rightly separated from it by Benth. & Hook, in Gen. PL
1. 915. The Alaskan species differs in having narrower and acute
leaflets, the fruit shorter and more ovate (only two lines long), with

OF ARTS AND SCIENCES. 141

often a single prominent calyx-tootli ; stylopodiuni soniewliiit more
prominent, and (in the still immatnre fruit) the vittae obscure and seed
not grooved beneath the dorsal ones.

AxGKLiCA TOMKXTOSA. Very stout, hoary-tomentose throughout
or the stem glabrous : leaves (piiuate and ])ipiMiiate, the leaflets tiiick,
ovate, acute, very ol)li(jue at base, unequally serrate with acntish teeth,
the lower sometimes lobed, two to four inches long : umbels naked,
often dense ; rays one to three inches long : fruit broad-elliptical (three
lines long by two or more broad), the lateral wings thin and the dorsal
acutish : seed thin, flat on the face, channelled on the back under the
solitary vittaj. — In the Coast Ranges from San Fi-ancisco to Men-
docino County ; the only species near the coast.

Cymopteuus GLOiiOSUS. Nearly acaulescent : leaves clustered
upon the very short stem, smooth and glaucous, pinnate or bipinnate
with broadly oblong pinnatifid segments, the ultimate divisions oblong,
obtuse, entire or toothed : involucre and involucels apparently none,
and the rays and pedicels obsolete, the flowers and fruit being in dense
globose heads a half to an inch in diameter: flowers white : fruit three
to four lines long, the thin flat wings a line broad, narrower at base :
vittoe solitary in the intervals, two on the commissure ; seed slightly
concave on the face. — Northern Nevada, collected in the valleys near
Carson City by Stretch and Watson, and in the Goshoot Mountains by
Beckwith. Referred to by Dr. Torrey in Whipple's Report under C.
montanus as an abnormal form, and made a variety of the same species
in Bot. King's Rep. 124, the fruit of the two having been confounded
and the real fruit not examined.

Peuckdanuh IIallii. * Glabrous, shortly caulescent, the elongated

* Tlie western Xorth American species of this confused and rather difficult
genus form a group usually readily recognizable. They are foinid frequenting
hillsides or dry valleys, low-siemmed or acaulescent, with thick fleshy roots, the
stems rarely solitary, involucres wanting; stylophore nearly obsolete, and disk
not dilated. The following characters may serve to distinguish them.

§ 1. Leaves not finely dissected (rarely bipinnate), tlie segments large or broad
or elongated : flowers yellow : calyx-teeth mostly obsolete : fruit glabrous.

* Acaulescent, glabrous : fruit oblong to ovate.

•*- Leaves biternate or ternate-quinate ; leaflets orbicular to lanceolate : involu-
cels none.

1. P. LEiocARPDM, Nutt. Often stout and tall: leaflets thickish, narrowly
lanceolate to ovate, acute, 1 or 2 inches long, entire or often few-toothed at the
apex : rays usually few, elongated : fruit oblong, narrower below, 4 or 5 lines

142 PROCEEDINGS OF THE AMERICAN ACADEMY

peduncles six to fifteen inches high : leaves pinnate, oblong in outline,
the ovate segments half an inch long, deeply toothed or pinnatifid or
pinnate with narrow divisions : involucels small : flowers yellow : calyx-
long, narrowly winged : vittae distinct, solitary, 4 on the commissure. — Wash-
ington Territory and Idaho to the Sacramento.

2. P. NcTTALLii, Watson. Very similar: leaflets orbicular or ovate, ob-
tuse : fruit sliorter and more ovate, very narrowly winged ; vittaj obscure, 3 or 4
in the intervals and 4 to 6 on the commissure. — Bot. Iving's Kep. 128. P. lati-
folium, Nutt. Oregon and N. Nevada.

-*- t- Leaves pinnate or bipinnate; leaflets narrowly linear : involucels present.

3. P. GRAVEOLENS, Watsou, 1. c. Scapc 6 to 18 inches high, a little exceed-
ing the leaves : fruit oblong, 4 or 5 lines long, narrowly margined ; calyx-teeth
evident; vittae about 2 in tlie intervals, 4 on the commissure. — Musetunm teitui-
foliiun. Hook, in Lond. Jour. Bot. 6. 237, not Nutt. Mountains of Utah and
Colorado ; subalpine.

* * Caulescent (often acaulescent in n. 4) : involucels mostly present : vittae
solitary, except in n. 8.

•*- Leaflets linear, entire.

4. P. TRITEKXAT0M, Nutt. Finely puberulent, often tall : leaves blternate
or ternate quinate ; segments acute : fruit oblong, narrower below, 3 or 4 lines
long, very narrowly winged, distinctly ribbed, rarely pubescent ; vittie distinct,

2 on the commissure. — P. leptocarpiun, Nutt., the acaulescent form. Washing-
ton Territory and Idaho to Northern California.

5. P. SIMPLEX, Nutt. Similar : leaves ternate or biternate : fruit orbicular,

3 to 6 lines long, emarginate at each end ; wings broader than the body ; ribs
prominent. — Watson, 1. c. 129. P. tn'lernatam, var. plati/carpum, Torr. in
Stansb. Rep. 389. Montana to N. Arizona.

6. P. AMBiGUUM, Nutt. Glabrous, often low: petioles much dilated at base;
leaves 1-2-pinnate with long linear leaflets, the upper often more dissected :
involucels very small or none : fruit narrowly oblong, 4 lines long, narrowly
winged; 2 vittae on the commissure, broad and thin. — P. Utviijcilitin and P.
abrotaiii/oUum of Nutt. ; P.farinomin and P. tenuissimum of Geyer. Washington
Territory and Oregon to W. Montana; the root much used by the Indians.
There is one other imperfectly known allied acaulescent species in the same
region, and probably more.

•*- +- Leaflets ovate, toothed or sometimes pinnatifid : fruit orbicular or ellipti-
cal : glabrous.

7. P. EuRYPTERA, Gray. Low : leaves ternate ; leaflets broadly cordate,
coarsely toothed, an inch long or less: fruit 5 lines in diameter, emarginate at
each end, broadly winged ; 2 vittje on the commissure. — Proc. Am. Acad.
7. 848. Euri/plcra htcida, Nutt. ; Torrey, Bot. Mex. Bound, t. 27.

8. P. PARViKOLiUM, Torr. & Gray. Low, slender: leaves deltoid in outline,
biternate, 2 inches long ; leaflets ovate, laciniatcly lobeil and toothed or i)innati-

OF ARTS AND SCIENCES. 143

teeth obsolete: fruit "ilahrous, broadly ellii)tical, three liiuis long, the
wing half as broad as the body ; vittie three in the intervals, four or six
on the commissure. — P. nudicdulc. Gray, Proc. Am. Acad. 8. JiHij.
Collected in Northern Oregon by Hall (n. 211).

Peucedanum Parryi. Acaulescent, glabrous : leaves lanceolate
in outline, bi|)innate, the short segments laciniately pinnatilid : [)eduncles
six inches high : involucels small: flowers yellow ; ealyx-ti^cth evident:
fruit oblong, glabrous, four lines long, narrowly winged; ribs liliform ;
vittie undetermined. — P. macrocarpum, Parry, Am. Naturalist, 9. 271.
In Southern Utah, by Parry (u. 85).

Peucedancai Ni:vadensic. Glaucous, puberulent, shortly caules-
cent, the peduncles three to fifteen inches high : leaves compoundly
dissected with small oblong segments : rays often uncciual, an inch or
two long : involucels small, of several linear-lanceolate bractlets, usually

fid : calyx-teeth somewhat prominent : fruit about 3 lines long, broadly winged,
scarcely emarginate ; 4 vittaj on the commissure. — Coast Ranges south of San
Francisco.

9. P. Hallit, Watson. See above.

§ 2. Leaves decompound ; segments narrowly linear ; petioles very brondly
dilated: involucels conspicuous, of usually scariously margined bractlets:
flowers yellow : calyx-teeth obsolete : fruit broadly elliptical, glabrous : caules-
cent, puberulent.

10. P. CARTTiFOLiuu, Torr. & Gray. Shortly caulescent: leaf-segments 4 to
2 inches long : bractlets often lanceolate : fruit 8 or 4 lines long ; ribs obsolete ;
vittffi indistinct, 2 or 3 in the intervals, none on the commissure. — P. muryina-
tum, Benth. PI. Hartw. 312. Central California.

11. P. DTRicuLATUM, Nutt. Morc caulesccnt : leaves more finely divided ;
segments half an inch long or less : bractlets usually much dilated : fruit dis-
tinctly ribbed ; vittje broad, solitary in the intervals, 4 to 6 on the commissure.
— Washington Territory and Idaho to S. California.

§ 3. Leaves ample, very finely dissected with short filiform segments : flowers
yellow : involucels present : calyx-teeth obsolete : fruit glabrous.

* Fruit orbicular or broadly elliptical : acaulescent.

12. P. FCENicuLACEUM, Nutt. Tomcutose, sometimes glabrous : involucels
gamophyllous, 5-7-cIeft : fruit 2 or 3 lines in diameter, winged ; ribs prominent ;
vittfe 1 to 3 in the intervals, 2 to 4 on the commissure. — From the Saskatcha-
wan to Nebraska and the Indian Territory.

13. P. MILLEFOLIUM, Watson. Glabrous, taller : involucels of distinct linear
bractlets : fruit 4 or 5 lines long, 3 or 4 broad, broadly winged : vittae solitary,
2 on the commissure. — Bot. King's Rep. 129. Northern Utali to Washington
Territory.

144 PROCEEDINGS OF THE AMERICAN ACADEMY

dist'nct : flowers white : calyx-teeth obsolete : fruit somewhat pubes-
cent, rounded to ovate,. three to five lines long, two to four wide; ribs
prominent ; vittae two or three in the intervals (sometimes four in the
lateral ones, perhaps sometimes solitary), four to six on the commis-
sure. — 7"*. nudicaule, AVatson, Bot. King's Rep. 130, and others ; not
Nutt. Eastward of the Sierra Nevada froni N. E. California to Souora
and New Mexico.

Aralia Californica. Herbaceous, unarmed and nearly glabrous,
eight to ten feet high, from a deep thickened root : leaves bipinnate,
or the upper pinnate with one or two pairs of leaflets ; leaflets cordate-
ovate, four to eight inches long, shortly acuminate, simply or doubly
serrate with short acute teeth ; terminal leaflets ovate-lanceolate : umbels
in loose terminal and axillary compound or simple racemose panicles,
wdiicli are more or less glandular-tomentose ; rays numerous, four to

* * Fruit oblong : caulescent, glabrous.

14. P. BicoLOR, Watson, 1. c. Stem short ; peduncle elongated : rays few,
very unequal : involucel of a few linear bractlefs : fruit on short pedicels, 5 to 6
lines long, narrowing from near the base, narrowly winged ; ribs filiform ; vittae
obscure. — Wahsatch Mountains.

§ 4. Leaves smaller, much or finely dissected with small segments : flowers
yellow : involucels present : low, acaulescent.

15. P. viLLOScjr, Nutt. More or less densely pubescent : leaves of very
numerous crowded narrow segments : umbels dense in flcjwer : involucels small :
fruit oval, pubescent, 3 or 4 lines long ; vittse several in the intervals. — W.
Nevada to Nebraska and S. Utah.

16. P. Parkti, Watson. See above.

§ 5. Leaves much dissected with small segments : flowers white ; involucels
present : usually low, somewhat caulescent or scarcely so, more or less pubes-
cent.

* Fruit glabrous, oblong or broadly elliptical ; vittiB usually solitary.

17. P. siACROCARPDM, Nutt. Morc or less pubescent : involucels conspicu-
ous, somewhat foliaceous : fruit 4 to 10 lines long, 2 or 3 wide ; calyx-teeth
evident ; ribs filiform ; vitta3 rarely 2 or 3 in the intervals, 2 to 4 on the commis-
sure. — Var. EURYCAuruM, Gray. Fruit broader : leaves rather more coarsely
divided. — Washington Territory to N. California and east to the Saskatciia-
wan ; the variety from Oregon to the Sacramento.

18. P. NcniCAULE, Nutt. Nearlj' glabrous : involucels small : fruit elliptical,
2 or 3 lines long ; calyx-teeth obsolete ; ribs prominent ; vltfa? always solitary,
2 to 4 on the commissure. — Nebraska and N. Colorado to Idaho.

* * Fruit tomentose or puberulent, oval-orbicular j vittae usually several in the
intervals.

OF ARTS AND SCIENCES. 14")

six lines long; involucres of several linear bractlets : flowers a line and
a half to two lines long ; disk and stylopodiuni obsolete ; styles united
to the middle : fruit (still innnature) a line and a half long. — Nortii-
eru California, in shaded mountain ravines and moist places. Much
resembling A. racemosa, but with larger flowers and involucres, and
fewer umbels, larger and with more numerous rays.

CORNUS ToituEYi. A shrub : leaves obovate or oblanceolate,
abruptly acute or shortly acuminate, on rather long slender petioles,
ligliter colored and somewhat pubescent beneath with loose silky haiis :
cyme loose and spreading : fruit white ; stone obovoid, somewhat com-
pressed, acute at base, ridged on the edges, tubercled at the summit,
two and a half to three and a half lines long, — Collected by Dr, Tor-
rey in Central Calitbrnia, but locality not noted. It is very peculiar
in the characters of the fruit.

10. P. DASYCARPUM, Torr. & Gray. Villoiis-tomentose : leaves finely dis-
sected : invohicels of several linear to oval bractlets : fruit often acutisii, tonien-
tose, 4 to 7 lines long; ribs prominent; vittaj usually 3 (rarely solitary) in the
intervals, 4 on the commissure. — P. tomeiUosuin, Benth. PI. ilartvv. 312. Cali-
fornia.

20. P. Nevadense, Watson. See above.

Excluded Species.

P. Newberrti, Watson, Am. Naturalist, 7. 801. Fine fruiting specimens of
this were collected in Southern Utah by Dr. C. C. Parry. Tiie "wing of the
fruit is found to have a thick corky margin, which requires the reference of the
species to Ferula {LejitoUenia, Nutt.), a genus separated by only this character
from Peucedanum. The habit of the plant is very unlike that of our other
species of Ferula.

TiFOEMANNiA TERETiFOLiA, DC, referred to Peucedanum by Benth. & Hook.
As compared with our own species of Peucedanum, and without reference to
foreign forms which may be included in it, tiiis genus appears sufhciently well
marked, differing in the distinct marginal nerve of the wings, in the prominent
conical stylopodium, in the presence of an involucre, and in the very remarkable
habit.

Archemora, DC, another small genus of the Atlantic States reduced to
Peucedanum by the same authorities, though less distinctly marked than the
last, may still conveniently be retained. It differs from the western species in
its tall-stemmed erect aquatic habit, thick and short conical stylopodia with
short spreading styles, the commissural vitta; in part often shorter than tiie
seed, and the iiabit of foliage and inflorescence somewhat peculiar. A. Fendleri,
Gray, of New Mexico and Colorado, is less clearly marked than the two more
eastern species.

VOL. XI. (N. S. III.) 10

146 PROCEEDINGS OF THE AMERICAN ACADEMY

Atriplex Palmert. Stout, shrubby at base, diffusely branched, a
foot or two high, white appressed-scurfy : leaves obovate or oblanceolate,
rounded or acutish at the apex, attenuate to a short petiole, alternate,
entire, a half to one and a half inches long: flowers dioecious, in close
naked panicled spikes : calyx 5-cleft : bracts compressed, cuneate-
orbicnlar, free, the margin above the middle herbaceous and irregularly
laciuiately toothed, in fruit somewhat indurated and convex, a line and
a half broad, the sides rarely sparingly muricate. — Collected by Dr.
E. Palmer on Guadalupe Island. Very nearly allied to A. Nuttallii,
Watson, of Colorado and northward.

Brahka edulis, H. Wendlaiid, in letter. Stem sometimes thirty
feet high and fifteen inches in diameter : leaves flabelliform, to-
mentose on the folded edges when young, three feet long, deeply
parted into numerous (70 to 80) bifid segments which are lacerately
fibrous at the apex ; petiole very stout (an inch broad at the top),
unarmed, somewhat fibrous-pubescent on the upper side, and terminated
by a densely silky-tomentose ligule two inches long: tubular spathes
and mucli-branched sjiadix densely tomentose : flowers sessile, in
clusters of three or more, a line and a half long: calyx 3-parted, shorter
than the thick valvate 3-cleft corolla : filaments broad, adnate below to
the corolla-tube : ovaries oblong, nearly free ; the short styles united :
berry solitary, globose, an inch in diameter when dry, the flesh some-
what fibrous : seed globular, 7 or 8 lines in diameter, smooth : albumen
horny, not ruminate, with a broad and deep ventral cavity filled by the
intruded testa; embryo near the base. — On Guadalupe Island, col-
lected by Dr. E, Palmer ; fruiting clusters four feet long and weighing
40 or 50 pounds. The characters above given differ from those of
Brahea, as described and figured by Martins, especially in the peri-
gynous instead of hypogynous stamens, in the less coherent ovaries and
stigmas, and in the form of the albumen, which in Brahea has a narrow
longitudinal cavity, filled by the testa, extending from the apex nearly
to the base ; the embryo is also doi'sal. In most of these respects it
accords more nearly with Livistona, but with some discrepancies in
other directions.

Bkaiika (?) ARMATA. A sccoud specics very similar in its fruit to
the last, and evidently of the same genus, was recently collected by Dr.
E. Palmer in the Big Cafion of the Tantillas Mountains, about eighty
miles southeastward from San Diego. It is dcsciibed as a tree forty
feet high : the leaves are glaucous, nearly g^labrous even when young,
two and a half feet long, similarly cleft into fewer (30 to 40) entire
segments ; the large ligule glabrous ; petiole a foot and a half long,

OF ARTS AND SCIENCES. 147

somewluvt brown-haiiy on tlie upper side, margined with a continuous
Avliite thickened border which is irreguUirly toothed ; teeth approxi-
mate, broad and thick, three or four lines long, i)()inting upward or
often cleft and pointing both ways: fruit rather smaller.

AVith tliis was found growing a tliird species, which from the foliage
appears to be the same as the palm fouud in San Diego county, and
recently introduced into cultivation under the name oi ''' Jirahea Jila-
metitosa." Its fruit, however, is very diiferent from that of the preced-
ing, much smaller, black and pulpy with a somewhat cruslaceous
integument, the seed very small (three lines long), and the albumen
scarcely at all excavated. It is also peculiar in other respects. The
tree is spoken of as taller and much more handsome than the last.

CvpuirEDiuM OCCIDENTALK. More or less roughly and glan-
dular-pubescent, a foot and a half high, leafy, usually 2-flowered :
leaves ovate, the uppermost broadly lanceolate, acuminate : the
brownish narrowly lanceolate sepals and linear-lanceolate petals
acuminate, nearly two inches long ; lip oblong, an inch long, dull
Avhite, veined with purple : sterile stamen oblong-lanceolate, acute,
yellow dotted with purple. — C. parcijlorum, Hook. Fl. Bor.-Am. 2.
205, in part, and Kevv Jour. Bot. 7. 376. C. passerinum, Gray, Proc.
Am. Acad. 8. 403. In the mountains of California from Santa Cruz
and INIariposa counties northward to the Columbia River. Frequently
collected (Tolmie, Burke, Spalding, n. 334 Geyer, n. 513 Torrey, n.
513 Hall, Bolander, n. 970 Kellogg & Harford, Gray, Nevius), and
very similar in habit to C. parvijiurum.

Cakdamine Gambellii. Perennial, glabrous throughout, erect, a
foot and a half high : leaflets four to six pairs, ovate-oblong to linear,
sessile, entire or sparingly toothed, acute, three to twelve lines long :
flowers white on slender pedicels : petals four lines long, twice longer
than the calyx : pods narrowly linear, ascending, an inch long, equal-
ling the strongly reflexed pedicel ; beak a line long, slender. — Col-
lected by Gambell near Santa Barbara, and recently by Dr. J, T.
Rothrock, of Lieut. G. M. Wheeler's Exploring Expedition, in the
same locality. Resembling G. pratensis. A very similar form, but
somewhat pubescent, has been found by Bourgeau near the city of
Mexico.

Vauquelinia Torreyi. Shrub or small tree: leaves coriaceous,
narrowly lanceolate, acuminate, acute at base and shortly petioled,
acutely serrate, white-tomentose beneath, smooth above, pinnately
nerved with reticulated veinlets, about an inch and a half long: flowers
in small terminal tomentose panicles : petals wliite, oblong : stamens 2o,

148 PROCEEDINGS OF THE AMERICAN ACADEMY

on the margin of the hairy disk ; filaments slender : fruit tomentose, two
lines long ; cells 2-seeded : seeds oblong, terminated above by a wing
as long as the seed. — Spircea Calif o mica, Torr. in Emory's Rep. 140.
V. corpnbosa, Torr. in Bot. Mex. Bound. 64. On the Sierra Verde, near
the southern boundary of Arizona, by Schott on the Mexican Boundary
Survey, and probably the same as that collected previously by Emory on
high mountains near the Gila. The original species, V. corymbosa, Cor-
rea in Humb. & Bonpl. PI. G^quin. 1. 140, t. 40, from Central Mexico,
differs according to the description and figure in its larger and more
deeply serrate nearly glabrous leaves, which are on petioles as long as
the blade and with numerous fine parallel nerves, in its calyx naked
within, and its 15 to 20 stamens. The embryo in the present species
is without albumen, the cotyledons flat, radicle straight and inferior.

PoTENTiLLA Wheeleri. Small and subalpine, decumbent, silky-
villous : stems short, branched and flowering from near the base, leafy :
leaves digitate, 3-5-foliolate ; leaflets cuneate, 3-5-toothed at the rounded
summit, half an inch long or less ; stipules entire or nearly so : lower
flowers axillary : calyx with obtusish bractlets a little smaller than the
lobes : petals obcordate, nearly two lines long, slightly exceeding the
calyx : stamens 20 : carpels 20 : styles filiform. — Collected by Dr.
J. T. Rothrock, in the southern Sierra Nevada, about the head-waters
of Kern River, at 8,200 feet altitude.

HoRKELiA PUUPURASCENS. Pubescent and somewhat villous, six
inches high : leaflets numerous, approximate, 2-4-parted ; segments
oblong to obovate, two or three lines long or less ; flowers few, rather
large, in an open cyme : calyx purplish, about four lines long ; bractlets
small and narrow : petals rose-colored, broadly cuneate-oblong, nearly
equalling the calyx-lobes : stamens 20, in two rows ; the filaments
opposite to the calyx-lobes and bractlets subulate, the alternate ones
filiform : carpels 25, on a nearly naked receptacle. — Collected by Dr.
J. T. Rothrock, on the head-waters of Kern River, at 9,000 feet alti-
tude. An unmistakable Horkelia, but like H. tridentata intermediate
between the typical species and those of Ivesia, leaving it almost im-
possible to preserve the latter genus distinct. Specimens of H. triden-
tata have been recently found with decidedly deltoid filaments, showing
that this character may fail even to be specific.

OP ARTS AND SCIENCES. 149

VII.

SPECIMENS OF MILK FROM THE VICINITY OF

BOSTON.

By S. p. Siiakples, S.B.

Presented, Dec. 14, 1875.

In 1873, Dr. Arthur H. Nichols of this city made a report to the
State Board of Health in regard to adulteration of milk. In this
report, certain analyses of milk made by Prof. J. F. Babcock were
quoted : these specimens were seven in number, and of the following
average composition : —

Specific gravity 1.033

Cream volume, per cent 8 to 9

Total solids, weight per cent 14.55

Sugar, weight per cent 5.08

Ash 86

Water 85.45

These samples were not selected, but were bought from regular deal-
ers who were known to be honest. In view of the fact that the 14.55
is much above the average amount of solids as given by most European
chemists, it becomes a matter of interest to ascertain if the milk pro-
duced in this vicinity is better than the average, or whether this
was a mere accidental occurrence.

During the last summer I had an opportunity of procuring from
Stoneham some twenty specimens of milk. These were brought to
me by my assistant, Arthur Steele, who was present during the milk-
ing of the cows, and who asserts they were not tampered with in any
manner. The milk was produced by cows belonging to ditFerent
owners, the owner's name in each case being given in connection with
the description of the cow.

The method of analysis was as follows : —

For specific gravity one hundred cubic centimetres of the milk were
poured into a flask that held this amount of water at 15 ®5 C, the
temperature was observed by the thermometer, and the milk was
cooled or warmed until it stood at 15 ^b ; it was then weighed. This
same portion of milk was placed in a graduated cylinder, and allowed

1.50 PROCEEDINGS OF THE AMERICAN ACADEMY

to stand in a cool place until next morning, when the amount of
cream was read off. A pipette was then introduced into the cylinder
in such a manner that it reached to the bottom of the vessel, and fifty
centimetres were drawn otf ; this was weighed, and gave the specific
gravity of the skim milk. After weighing, the milk was poured into a
beaker, one or two drops of acetic acid added, the milk gently wanned
until it coagulated, and then allowed to cool again. It was then
thrown on a filter, and the first fifty centimeti'es that ran through were
weiglied as before : this gave the specific gravity of the whey.

These two last determinations were made because many authors
assert that the specific gravity of skim milk and whey are much more
constant than the specific gravity of whole milk.

Von Baumhauer asserts in his monograph on Dutch cow's milk
that he has been unable to obtain clear filtrates when the eurd was
precipitated with acetic acid. I have rarely found any dilficulty on
this score, when the precaution of heating the milk only a little hotter
than from 40° to 50° C. was taken, provided the milk was allowed to
become cold before it was filtered. If the milk is allowed to cool
completely after coagulation, before it is filtered, it generally filters
without any trouble ; but, if poured on the filter before it becomes cold,
the fat fills the pores of the filter, and it is almost impossible to do any
thing with it.

Ihtul Sulids. Five cubic centimetres were poured into a tared
platinum dish and weighed : this latter precaution is necessarj'^, for a
pipette cannot be relied upon to alvva3'^s deliver the same quantity of
milk, as it will deliver more than enough of a poor milk and not
enough of a rich one. This was evaporated to dryness on a water
bath, and then dried for an hour in an oven at the temperature of
105° C. I found that treated in this way the weight became constant
at the end of two and a half to three hours from the time the milk was
placed on the bath.

The dishes used have a considerable influence over this result. The
size I found to work best were about 65 mm. in diameter and 15 mm.
in depth, with the bottom almost perfectly fiat, the sides being nearly
perpendicular, the angle between the sides and the bottom being
rounded. Five centimetres form a layer over the bottom of this
dish but little more than'2mm. thick. "When dry, it does not greatly
exceed one-eighth of this amount, and thus forms a film that is very
readily dried.

Fat. After weighing, the dried film is treated with either benzine
or ether, which in the course of an hour or two completely removes

OF ARTS AND SCIENCES.

l.")!

all the fat; the benzine is deeaiited, a fresh portion pound on and
allowed to stand half an hour; this is poured oil", the disli rinsed with a
little fresh benzine, alh)wed to stand a few minutes until it has all
evaj)orated, again dried in tlie air bath at 10.j°, and weighed ; the loss
gives tilt; fat. The rcjsitlue remaining on the di.^h is of eourse the
solids not flit.

Ash. The dish is then ignited over a Bunsen burner, and again
weighed, the residue in this case being the ash. With a dish of the
size spoken of, all the carbon burns off quickly aud readily, and leaves
the ash perfectly white.

The above determinations are all that are essential to determine the
purity of a sample of milk, and, as will be seen, consume but little
over 100 cc. of milk : 150 cc. are ample for the full analysis as followed.
In order to determine the cheese and sugar, 25 cc. of milk were taken
and diluted with about 50 cc. of water, the mixture was gently warmed,
and a drop or two of acetic acid added with gentle stirring ; it was
allowed to cool and then filtered on a weighed filter, and washed with
about 200 cc. of cold water. The filtrate was made up to 500 cc, and
this solution was titrated with a normal solution of eupric suljjhate
made by dissolving 34.65 grannnes of crystallized eupric suli)hate in
200 cc. of water, adding to this solution a solution made by dissolving
173 grammes of sodio-potassic tartrate in 480 cc. of caustic soda solution
of 1.14 specific gravity. The whole is then made up to a litre; 10 cc.
of this solution were then placed in a flask diluted with 40 cc. of water,
and brought to the boiling point ; the diluted whey was then allowed
to flow into the solution until it no longer gave a brow^n color, when
filtered, acidified with acetic acid and tested with potassic ferrocyanide.
The following table gives the per cent of milk sugar, when 25 cc. of
the milk are taken, and the whey diluted to 500 cc. 10 cc. of the cop-
per solution, which equals .067 grammes of milk sugar, are employed.

PER CENT OF SUGAR.

cc. of

vlioy

0

1

2

3

4

6

6

7

8

9

used.

10

13 40

12 17

1117

10.30

9 57

8.92

8.38

7.91

7.44

7.05

20

6 70

6.39

6.09

5 83

5 58

5 36

5.15

4 96

4.78

4.62 .

30

4.46

4 32

4.19

4.06

3.94

3.83

3 72

3.62

3 53

3.44

40

3.;55

3.27

3.19

3.11

3 04

2.98

2.91

2 85

2.79

2 74

50

2.68

2.63

258

2.Ki

2 48

2.44

2.39

2.35

2 31

2.27

60

2.23

2.19

2.16

2. 13

2.09

2.06

2.03

2.00

1.97

1.94

7>

1!)1

188

1.86

1.84

1.81

1.79

1.76

1.74

1.72

1.69

80

1.67

1.65

163

1.61

1.59

1..57

1.56

154

1.52

1.51

90

1.49

147

146

1.44

1.43

1.41

1.39

1.38

1.37

1.35

100

\.U

1.32

1.31

1.30

1.29

1.28

126

1.25

1.24

1.23

152 PROCEEDINGS OF THE AMERICAN ACADEMY

The curd remaining on the filter is removed from the funnel and
placed on a watch glass, dried at 105", and weighed ; it is then treated
with benzine in a funnel Avhich has a stopper in it, and is covered with
a tiglit fitting watch glass ; one or two soakings serve to completely
remove the fat. It is again dried and weighed. I have not as a rule
found this determination of fat very satisfactory ; it is apt to be too
high, from the great difficulty of drying the greasy curd and filter ;
after the fat is removed, the ca>eine is very easily dried. The object
in tliis set of analysis being rather to endeavor to find a series of con-
stants which might be relied upon for determining the question of
adulteration, no further examination of the caseine was made for ash,
but the portion remaining on the filter after the removal of the fat was
regarded as pure caseine. In all my determinations, I found that
there was invariably a discrepancy between the sums of the caseine,
fat, sugar, and ash, and the total solids as determined by evapora-
tion. This varied from .43 per cent to 1.92 per cent, with an average
of .87 ; this is owing most likely to the albumen of the milk in part,
which is not precipitated by the acetic acid at 4o°— 50° C., and in part
to the solubility of the caseine in acetic acid. As will be seen from
the table annexed, the sugar seems to be the most constant constitu-
ent. The fat varies very much ; the specific gravity is not to be relied
upon. Wanklin's test of solids not fat is departed from in a number
of instances, and the total solids full as low as 11. G4, while according
to the English authorities they should never in pure milk be below
9 per cent for the solids not fat, and 12 per cent for total solids.

In summing up, I must call attention to the remarkably high aver-
age of this milk, 14.49 per cent of total solids, but .06 short of Pro-
fessor Babcock's result, with three times the number of specimens
which he examined. For purposes of comparison, I annex two other
tables, one giving all the average results I have been able to collect
up to the present time, and the other giving the extreme variations
that have been observed.

SPECIMENS EXAMINED.

A. Milk supplied me by a resident of Cambridge, said to be pure Al-

deiney.

B. Milk from an Alderney cow kept by Dr. James R. Kichols for the

supply of his family.

C. Grade cow, Ilerford and Ayrshire. Four years old, hatl hvvn

milking twelve weeks and gave sixteen quarts per day. Feed,

OF ARTS AND SCIENCES. 153

two quarts corn meal and four quarts shorts, with all the upland
hay she would eat.

D. Native cow, eight years old, had been milking three weeks, and

gave eigliteen quarts per day. Feed, three quarts of corn meal
and three quarts of shorts, with hay ; same as C.

E. Native cow, four years old, had been milking fourteen weeks, and

gave eight quarts milk per day. Feed, one quart meal, seven
quarts shorts per day, with hay.

F. Native cow, six years old, had been milking one week, gave six-

teen quarts milk per day. Feed, six quarts shorts per day, and
hay.

Cows C, D, E, and F, were owned by John Steele of Stone-
ham, and the milk was sold.

G. Native cow, ten years old, had been milking six months, gave

seven quarts per day. Feed, four quarts corn meal and meadow
hay.

H. Grade cow, half native, quarter Ayrshire, quarter Jersey, had been
milking fifteen months, gave eight quarts milk per day. Feed,
four quarts of corn meal and four quarts of shorts per day, with
meadow hay.

I. Native cow, four years old, had been milking twelve weeks, gave
thirteen quarts of milk per day. Feed, four quarts of corn meal
and eight quarts of shorts per day, and meadow hay.

J. Native cow, nine years old, had been milking seven and a half
months, gave eleven quarts of milk per day. Feed, six quarts of
meal and eight quarts of shorts and meadow hay.

K. Native cow, nine years old, had been milking four months, gave
fourteen quarts of milk per day. Feed, four quarts of meal and
eight quarts of shorts and meadow hay.

L. Native cow, five years old, had been milking five and one half
months, gave eleven quarts of milk per day. Feed, four quarts of
corn meal and eight quarts of shorts per day, and meadow hay.

M. Native cow, seven years old, had been milking four months, gave
fourteen quarts of milk per day. P'^eed, five quarts of corn meal
and eight quarts of shorts per day, and meadow hay.

N. Grade cow, half native, half Dutch, three years old, had been
milking two weeks, gave fourteen quarts of milk per day. Feed,
two quarts meal, four quarts of shorts, and grass.

Cows G to N were owned by Frank Steele of Stoneham, and
the milk was sold.

154

PROCEEDINGS OF THE AMERICAN ACADEMY

O. Native cow, five years old, had been milking ten weeks, gave five
quarts of milk per day. Feed, one and a half quarts of meal per
day and hay. The first sample of this cow's milk procured was
of such an extraordinary character that two other samples were
afterwards obtained: these did not equal the first, but were rather
better than the average. The cow had been turned out to grass
before the second was obtained. Slie was owned by William
Buckraan of Stoneham, and the milk was used at home.

P. Native cow, eight years old, gave twelve quarts of milk per day.
Feed, one quart of meal, grass and hay. Owned by C. S. Wiley.

Q. Grade cow, native and Devon, nine j'ears old, had been milking
seven weeks, gave nine quarts of milk per day. Feed, grass and
ha}'. Owned by C. Wiley. A second sample of this milk was
obtained a few days afterwards : it had improved somewhat.
The cow had been kept in poor condition all winter, and had not
had grass long enough at the time of the first trial to feel its
beneficial effects. The milk was used at home.

R. Native cow, eight years old, milking one week, gave sixteen quarts
of milk per day. Feed, two quarts of shorts and gi-ass.

S. Jersey cow, five years old, milking six months, gave eight quarts of
milk per day. Feed, one quart of meal and four quarts of shorts.
li and S were owned by E. Thorpe of Stoneham, and the
milk was sold.

Sp. Oit.

LTeain

Total

.SollHs

Cow-

WTiole
ml]k.

Skim
milk.

Whey.

vttl. per
cent.

A»h.

Caseinr

■Sugar.

Fnt.

solids.

not fat.

Water.

A

i.n:',o

16

.63

13.66

86.34

B

l.(t3I

18

.65

3.40

5.29

6.62

15.96

9 34

84.04

C

l.o:j3

1.0,31

Co

.63

2.98

5.40

4.07

14.13

10.06

85.87

D

1 0.i3

1034

1.0.30

11

.72

3.01

5.19

4.10

13 87

9.77

86 13

E

1.031

1 030

1.029

9

.65

3.50

4 81

4.41

13.98

9 57

86.02

F

1027

1.035

1.028

12

.67

3.38

4 47

6.01'

14.99

8.98

85.01

G

1 0.S3

9

.71

4 00

4 99

3,95

15.37

11.42

84.63

H

1.031

1.0.35

1031

11

.79

5.23

4.80

4.36

1,5.61

11.25

84..39

I

1.031

1.031

1.0.30

7

.64

3.46

4.64

4 23

14.18

9.85

85 82

J

1.032

1.0.34

1 02!)

12

74

4.4»

4.63

5.95

16.26

10.31

83.74

K

1.029

1.0.30

1.028

9

.59

3.21

4.82

5.71

14.95

9 24

85.05

L

1.0.33

1.033

1.030

10

.64

3 00

4.80

4.04

14.05

10 01

85.95

M

1.030

1.029

1.028

4

.60

3 59

4.81

3 07

12.63

9.56

87.37

N

1.028

1.0.32

1.029

9.5

.64

4.38

13.81

0.43

86.19

(

1.018

1.0:!0

1.024

54

61

2.35

5.06

1146

19.34

7.88

80 66

o

1.030

1.031

1.020

18

.65

2.91

5.(»9

15 11

10 02

84.89

(

1.028

1 029

1.02f;

12

.tiO

2..34

5.02

6.,32

14.91

859

85.09

P

1 02X

1.031

1028

10

.66

2.57

5.21

4.11

13.43

9..32

86 57

^ 1

1.02S

1 .028

1.02,-)

5

.,57

2.25

4.82

2.71

11.64

8.93

88.36

1 (120

1.031

1.024

5

61

2.67

5.11

4 08

1.3.03

8.94

86.97

R

1.033

1.0.34

1.02(>

5.5

.71

.3.66

4.73

l.Cl

11 91

10.33

S

1.030

1.033

1.02G

11

.74

3.58

5.11

5.69

15.88

10 19

84.12

Av'rages.

1.030

1.032

1.027

( 12.0
\ 10.0

.66

3.27

4.94

\4.86
■l4,.'v!»

14.49

9.66

85.51

Highest.

1.0.33

1.0.35

1.031

54

.79

5.23

5.40*

11.46

19 31

11.42

80.66

Lowest.

1.018

1.028

1020

5

.57

2^25

4.47

161

1164

7.88

88.36

* OniittiiJS tlic loth.

OF ARTS AND SCIENCES.

156

SPECIMENS OF MILK SUSl'EOTED TO BE ADULTERATED.

Wlioli'

(■r,.a,n

lliilk.

VILI. IMT

ci'nt.

A^l,.

Cnnciuo.

.Sugiir.

Fut.

•oll(l».

not flit.

Wiitir.

l.OL'8

7

:51

3.33

11.42

8.09

88.68

].(ii;:t

7

.45

2.94

3..'?6

2 46

9 21

6.7.5

90.79

I.IV.'O

6

.45

:i.n

3.37

2. 20

9.19

6 93

90. Kl

1.021

7

.40

2.77

300

2.00

8.17

6.17

91.83

The last four specimens were all retailed by milk dealers in the
vicinity of Boston, and well serve to indicate the danger of relying ou
any single determination for deciding whether a milk is adulterated or
not. Taking all the determinations as they stand, they leave no douljt
as to the fact that the milk has been watered, yet any one determina-
tion taken separately might be successfully disputed.

The following table, recently compiled by myself from various
sources, is of considerable interest in this connection, as showing the
great variation in this most important product. It will be observed
that the specimens from this vicinity head the list, while those re-
ported by INIr. Vaughan of Providence, R. I., are not far 'behind. I
think that tliis in part may be owing to the use of corn meal as feed,
since this substance is well known as a butter or fat producer.

J. F. Babcock . . Boston

S P Sharpies . . . Boston

Vernnis & Becquerel France

Goppelstoder . . . Switzerland

H. W. Vaughan . . Rliode Island

Lebert France

Letheby Enjifland

Playfajr Scothmd

PhiiKSon England

Chevalier .... France

Waiiklin England

Cameron Ireland

Chevalier & Henry . France

A. Muller .... Sweden

Boussingalt .... France

Haiden

Chandler New York

MacAdam .... England

Voelcker England

Von Baumhauer . . Holland

No. of

Solick.

Not fat.

Caseine.

Ash.

specimens.

8

14.55

.88

22

14.49

961

4.13

.66

46

14.24

9.73

4.86

.65

60

14.13

58

14.08

10.07

4.99

.75

14.00

9.75

5.50

.75

14 00

10.10

4 10

.80

9

13.49

8.61

4.17

.55

13..33

8.46

3.76

2

13.23

10.31

3.98

.78

3

13.12

9.36

4.56

.72

40

13.00

9.00

4.10

12.98

9.75

448

.60

12.85

9.43

3.42

.72

9

12.71

8.80

3.47

.25

12.70

9.70

i.m

.49

1700 qts

12.55

8 72

3.88

.76

66

12.27

9.69

.71

22

12.10

9.15

2.93

.83

162

11.30

8.45

.72

156

PEOCEEDINGS OF THE AMERICAN ACADEMY

The limits of variation as observed by some of tlie above observers
were as follows : —

Total Solids.

Solids not Fat.

Dr. Voelcker . .

Highest. Lowest.

Highest. Lowest.

14.00

9,30

9.88

751

Dr. iSIacAdam

KM

V^.r>1

1123

8.74

Von B.inmhauer .

13.23

10.18

8.93

8 08

Veriiois& Becquerel

19.08

11.70

10.56

7.73

Vautrli<an. . . .

1(!.96

12.85

11.14

8.79

Sharpies ....

19 34

11.64

11.42

7.88

It should be remarked, in this connection, that Dr. Voelcker's results
should be received with a good deal of caution, since he acknowledges
the cows were half starved ; and, further, he refuses to give the methods
employed in his analyses. Von Baurahauer, on the other hand, has
given the fullest information in regard to the methods he emploj'ed,
the feed of the cows, time milking, &c.

The benzine used was the ordinary commercial article distilled from
Pennsylvania petroleum of a specific gravity of about 70° B. Gaso-
line of the specific gravity of 90° B, was at first used ; but it was found
on trial that the heavier article was just as efficient in removing the
fat, and that it left no residue on evaporation, while it was much safer
to have in the laboratory.

OF ARTS AND SCIENCES. 157

VIII.

ON PORTABLE ASTRONOMICAL INSTRUMENTS AND

THEIR USE.

By Truman Henry Saftord.

• Presented, Oct. 12, 1875.

In determining time, latitude, and the azimuth of a meridian-mark,
•which are the principal operations of geodetic astronomy, the only
histrument now much used in America (besides the sextant) is the
jDortable transit, witli added apparatus for speedy reversal, and a mi-
crometer for differences of zenith distance, according to Talcott's
method. A portable transit so constructed affords a speedy deter-
mination of all tliree elements mentioned above ; but its practical
handling is a little difficult to an astronomer used only to large fixed
instruments, and the determination is not always the most economical
in time and labor of observation and reduction.

The present paper is intended to give a few practical hints derived
from actual experience with portable instruments of all grades, from
an ancient transit by a forgotten maker, with an object-glass which
would not come to a focus, up to the latest productions of the best
workshops of America, England, and Russia.

The beginner will do well to practise with an instrument which is
not quite perfect : he thus learns in an exaggerated form uU the faults
to which instruments are liable.

I need not describe these instruments, but will simply refer to
Chauvenet's admirable Manual of Practical and Spherical Astrono-
my, also to the Report of the Coast Survey for 1866. I will
suppose a latitude - and - longitude campaign to be planned. The
first matter to be settled is, what instruments are to be used? If
the work be simply geographical, without special requirements of
extreme precision, like the boundaries established by the United-States
Land Office, and especially if the country be rough and transportation
very difficult, a small transit instrument will suffice. I am inclined to

158 PROCEEDINGS OF THE AMERICAN ACADEMY

think a focal length of 14. to 16 inches, and aperture of the object-
jrlass of 1| inches, are the best dimensions. The frame should be
rather light, but solidly put together; the setting circle plainly divided ;
the striding level delicate ("2" to one division) ; and, above all, the ap-
paratus for illuminating the field as perfect as can be made.

Such an instrument ought to show a star of the sixth magnitude with
full illumination, if the observer's eye be accustomed to not too bright
a light, and especially if he use Mr. Rogers's rulings on glass in
place of spider-lines : indeed, he will hardly fail to do so, for other
reasons. The instrument of this size with which I am acquainted,
belonging to the Canadian government, was planned as an alt-
azimuth by Lindsay Russell, Esq., Deputy Surveyor-General, and
made by Simnis of London. The star X Ursa3 minoris of the 6.7 mag-
nitude could be readily observed with it. It is not too heavy, with all
the attachments, to be carried on a strong man's back ; nor too large
to accompany the observer in a sleeping-car. A somewhat larger tran-
sit, by Temple of Boston, did excellent service on the south boundary
of Wyoming. This has a two-inch aperture, a pretty long focal dis-
tance, but a short axis and a light frame. It looks ill-proportioned,
owing to the length of its telescope ; but has a very excellent object-
glass. Its greatest fault is instability in collimation ; the telescope
tube seems weakly put together ; and the mounting, as I used it, was
unstable too, probably because it was fastened to a plank on a wooden
post.

To mount such an instrument away from civilization requires a
good deal of trouble and e:?pense. Brick is, of course, the best material
for the foundation, but cannot always be obtained ; and, at one of my
stations, the only two brick-masons in town were intoxicated, and the
pier was built by a civil engineer who accompanied me, with a ser-
geant of the United-States Engineers to mix the mortar. At Duluth
the ground itself furnished rough stone in place.

At Santa Fe an unfinished and abandoned State-house furnished a
pier of cut stone. At Fort Union, the sun-dial of the fort, removing
the gnomon, was an excellent pillar for the instrument. Chauvenet's
suggestion to use a tree-stump is impi'actical, on account of the roots :
the instrument is kept in constant tremor by persons walking about.

When circumstances conij)el the use of a wooden post, great care
must be taken to shield it from the sun, and the observations must be
so distributed that the changes in azimuth and level are lu>rmless.
The level requires constant watching, but ought not to be changed
during a group of stars, lest the azimuth be disturbed too. To climi-

OF ARTS AND SCIENCES.

159

nate changes in the hitter, the groups of four or five stars must take
but little time.

All these thnigs considered, it is best to use the ephemcrides of :')2'.)
stars yearly published at Berlin, originally intended for the reduction
of the great zones now in progress. 1 think it altogi'thcr iikily that
this will be eventually the standard time-list for astronomers gener-
ally in this hemisphere : at any rate, these places will be kept accurate
by continual observation for a good many years to come. They include
all stars north of 10° of south declination down to the fourth magnitude,
and a selected list of fainter ones to fill gaps. iNIany of these same
stars are also given in the Connaissance des Temps, the Nautical
Almanac, and the American Ephemeris ; but these latter have not
quite enough of them for rapid work.

To illustrate how azimuth and colliraation are to be determined
and eliminated, I give a scheme of observations actually used at
Pueblo, C. T., May 11, 1873, by Lieut. E. H. Ruffner of the United-
States Elngineers. The scheme was, in general, agreed upon between
him and myself.

Star.

Position of
instrument.

A. R.

Deal.

y Vrsm majoris .

li 47 10

-4-54°24'

0 Virginis . . .

68 45

9 26

4 H. Dracoiiis . .

12 6 19

78 20

7) Vii-CTinis . . .

13 26

0 2

(3 Canura . . .

19 37

39 43

20 Co 111 03 . . .

23 22

21 36

K Draconis . . .

28 7

-^-70 29

y Virginis . . .

35 15

— 0 45

e Ursas majoris .

48 29

+56 id

On comparing this with other similar schemes, it will be noticed that
here are no stars observed below the pole, and but one south of the
equator; in other words, all are as near the zenith as jiracticable.
INIoreover, every pair of consecutive stars include the zenith between
them (this is not absolutely essential, but yet very well), and hence
give a definite value of the clock correction if the collimation be
known.

My own scheme corresponding to the above was as follows : —

160

PROCEEDINGS OP THE AMERICAN ACADEMY

Denver, May 11.

p.. .

Star's name.

Position of
instrument.

A.R.

Decl.

h. m. 8.

1 Ursae majoris . .

I.

11 11 25

32°15'

t Leonis ....

I.

17 19

11 U

A Draconis . . .

I.

23 53

70 2

V Leonis . ...

I.

30 28

— 0 7

3 Draconis . , .

I.

35 25

67 27

X Ursffi majoris

I.

39 22

48 29

y Ursa; majoris

11,

47 10

54 24

0 Virjrinis . . .

11.

58 45

9 26

4 H. Draconis . .

II.

12 6 19

78 20

2 Canum . . .

II.

9 47

41 22

7] Virginis . . .

II.

13 26

0 2

In determining latitude with an instrument of small size, Talcott's
method is subject to some inconveniences, which may sometimes be
better avoided by using Bessel's method ; that is, by establishing the
transit in the prime vertical.

But here the same principle (immediate elimination of azimuth
error) ought to be carried out; that is, the same stars should not, in
general, be used east and \ve.*t of the meridian. Tliis process is Bes-
sel's own, as distinguished from Struve's.

I annex a scheme of observation (from the Report for 1873-74

Star's name.

p rierculis .
6 Lacertas .

0 Andromedae
9 Herculis .
C Andromeda;

1 Andromedie
C I-yra; . .
ij Lyra; . .
fi Andromeda;

6 Lyra; . .

7 CvLrni .

T vVMdronic'da;

V Androineihe

V Cvgni . .
75 C:ygni .
y Andromcdre
16 I'ersei

ff Cygni

E. or W.
transit.

Position
of instru-
ment.

W.

I.

E.

I.

E.

I.

W.

I.

E.

II.

E.

11.

W.

11.

W.

II.

E.

11.

W.

H.

W.

11.

E.

II.

E.

II.

W.

II.

W.

I.

E.

I.

E.

I.

W.

I.

Time of
transit.

20 17
22
43
50

21 19
30
36

56

4

51

1

6

17

85

44

50

56

23

A.R.

17 19 10
22 25 3

22 66 7

17 51 54
0 10 30

23 31 57

18 40 25

19 9 27

0 49 45

19 II 59

20 17 42

1 33 9
1 29 24

29 52 2S

21 35 14

1 56 10

2 42 38
21 12 47

Decl.

37°16'
42 29

41 39
37 li)
37 59

42 34

37 2'J

38 56
37 49
37 55

39 51

39 56

40 46

40 41
42 42

41 43
37 48
S8 52

OF ARTS AND SCIENCES. 161

of the Chief Enfrineer of General Sheridan's staff) which I used for
this purpose at Bismarck, D. T., Oct. 9, 1873. It was my lirst fair
trial of the method. The stars were selected from my catalogue of
981 stars, published in that year by the "War Department, and are all
thoroughly well determined, — an advantage wiiich Bessel's method
has had over Talcott's.

This scheme requires four hours observing. If I recollect rightly, it
was somewhat interfered with by clouds, and would otherwise have
been sooner finished. I was anxious to succeed that evening, as time
pressed ; and I therefore did not attempt to accumulate as many ob-
servations as possible, but preferred to make sure of a few. The
result was sufficiently accurate for geographical purposes, having a
probable error of ± 0"31. The instrument was quite indifferent in
its optical portion. The Land Office at that time required a proba-
ble error of less than 3" ; and does still, so far as I know. There
are Land Office determinations extant which are far more than this
in error.

In more precise latitude and longitude work, the instruments used
have generally 3 inches aperture, and 30 to 36 inches focal length.
Such an instrument should be very solidly built and set up. The one
with which I am most familiar is Brigham Young's, in the Temple yard
at Salt Lake City : it is by Wurdemann, and was originally placed
there at the time of the Coast Survey determination of longitude at
that place. I found it very firm and strong : its level, collimation, and
azimuth errors were constant, though not very small, as the Mormon
astronomers seem not quite expert in adjusting. But I did not for
this reason neglect to make the full number of observations, nor to dis-
tribute them precisely as if I were observing with a smaller and worse
instrument, partly from habit, and partly because the instrument at
Evanston, "W. T., with which I was comparing time, was the instru-
ment by J. H. Temple, mentioned above ; and the observers were ex-
changed in the middle of the series.

There are two essentially different patterns of large portable tran-
sits. The one, the German or Russian, has a prism between the object-
glass and the eye-piece ; and the eye-piece itself is at one end of the
horizontal axis. I have used such instruments only for trials of per-
sonal equation. There is one such at the Harvard College Observatory,
and others were made for the American Transit of Venus expedi-
tions. These transits are very convenient. The level is always upon
the axis. The observer sits in one position between reversals, and has
not the troublesome necessity of bending his body into inconvenient

VOL. XI. (n. S. 111.) 11

162

PROCEEDINGS OF THE AMERICAN ACADEMY

postures. His setting circle is directly before him, his working list at
one side, and liis chronometer or telegraph-key at the other. But he
is liable to a troublesome personal equation ; and I am told that the
collimation cannot easily be made steady, owing to the great prism
between objective and ocular. The instruments are also very costly ;
so that, in this country, a construction is preferred which is nearer
like the ordinary observatory transit. Here the prismatic or diagonal
eye-piece takes the pla,ce of the " broken telescope," as the other con-
struction is technically called in German. The observer has to change
position, and is liable to a variety of petty annoyances thence arising.
Upon the whole, I think one construction is as good as the other for
practical purposes.

The distribution of stars to be observed for time may often be im-
proved by employing one star within 10° of the pole to every group
of four or five time-stars. The latter will then be predominately south
of the zenith, but not exclusively so. Where the instrument is known
to be very firm and solidly mounted, and has a reversing apparatus,
the collimation may be determined by the pole-stars alone. The
double-group for Denver, as previously given, would be modified by
introducing the polars 39 Cephei Hevelii and 6 Ursae minoris Bode,
as follows : —

Star's name.

A.R.

Decl.

68 UrsJB majoris ....
39 Cephei II. sub-polo . .
X Urste majoris

b. m. s.
11 23 38
23 27 47
11 39 22

+43052'
86 37
48 29

INSTRUMENT REVERSED.

Star's name.

A.R.

Decl.

P Virginis

7 Ursae majoris )

0 Virginis > as before

2 Canum )

6 Ursae minoris B

11 44 6

12 14 23

2 29
88 24

OF ARTS AND SCIENCES.

1G3

The single polar iu the first position (39 Cephei IT.) is proUalily
quite sutlicient to give equal accuracy in azimuth witli the two (P. and
3 Draconis) in the former list, especially as 4 Draconis II. is now
replaced by a close polar. The intervals are now a little closer in
some cases than before, as the instrument is expected to be easier
reversed by a machine, and the lines in the focus to be nearer to-
gether.

Additional tirae-stars may also be inserted, namely : —

Star's name.

A. R.

Decl.

T Leonis

u Virginis

TT Virginis

4 Comae Ber

h. m. B.

11 21 23
11 31 53

11 54 33

12 5 24

3°33'

8 50

7 19

26 35

But this would involve (as indeed the close polars do) much extra
computation.

The fashion in Germany has been, lately, to select a list of stars to
be observed regularly, night after night, at both stations ; thus freeing
the results more exactly from errors in the star-places, and, indeed,
supplying observed right ascensions of great accuracy. This plan
would be excellently well adapted for such observations as those be-
tween Denver and Pueblo, which are not far apart in longitude ; but
in much American work the distances are too great, and the use of the
telegraph-lines too precarious. Good star-places are common enough,
if we have them all collected in a convenient place ; and this is done in
the German catalogue mentioned, and, when that has not enough, in
my own catalogue of 981 stars, which is soon to be doubled in extent,
60 as to include the zone between 10° and 70° of declination, instead
of 30° to 60° only.

The young observer should by no means fail to accustom himself to
the eye-and-ear method of observing. It is, as Leverrier has remarked,
a better discipline than the chronographic. It is somewhat less accu-
rate : but one who can use it skilfully can always adapt himself to a
chronograph with ease ; and, on the other hand, if the chronograph
breaks down, or any trouble with it occurs where help cannot be got,
the eye-and-ear observer is more independent than the mere chronog-
raphist. For this reason, I have never allowed a pupil to use a
chronograph till he had mastered the elementary practice of the other

164 PROCEEDINGS OF THE AMERICAN ACADEMY

method. In my own experience at Chicago upon the great zones I
had uo chronograph, but did not find that a serious drawback. Arge-
lander was on this point ultra-conservative ; but I do not think there
are many observers by the new method whose work I would take in
exchange for his by the older. The temptation with mechanical
methods of observing is to undertake more work than can be reduced ;>
which is a bad practice.

In determination of time, Dollen has suggested using the transit in
the vertical of Polaris. I have often used this method on a first
night's work, but, when the chronometer error is roughly known, can
never resist the temptation to bring the instrument at once pretty
close to the meridian. The pupil should be thoroughly practised in
the minutiae of this process ; for I have seen even a good observer
badly vexed with it, when an instrument new to him, especially a poor
one, was employed.

In the determination of latitude by Talcott's method, I think a de-
vice of Mr. Rogers is likely to be useful. He replaces the micrometer
by a system of parallel lines oblique to the meridian, so that each star
must pass two sets of three each in its transit. The lines are very
beautifully and exactly ruled by his process, and they save the time
required to turn the micrometer screw. If this has to be moved
largely, a star might often be lost ; which is the more troublesome, as
in doubtful weather, when there are flying clouds, the pairs are often
spoilt by losing one of the stars. It is quite probable that Mr. Rog-
ers's improvement will enable us to go farther from the centre of the
field, and thus help the choice of star-places.

The stars should always be so chosen that the positive and negative
distances from the centre of the field [^ (tJ-|-5') — (jr] may pretty
nearly balance, so as to give the means of determining the micrometer-
values from the latitude observations themselves ; otherwise the
resulting latitudes could not be as accurate as the star-places and
observations would permit.

The foreign astronomers use Talcott's method very little. Their
objection to it is, that the star-places must necessarily be worse than
for Bessel's or Struve's, or for the employment of a vertical circle
or portable meridian circle. These latter instruments, however, are
not used in America, principally because our methods were formed
independently of the modern Germans, partly because we have no very
good dividing-engines, and because they are too delicate to stand
transportation over our frightful ^Yestern roads. On the other hand,
Talcott's method has greatly helped our astronomers by furnishing a

OF ARTS AND SCIENCES.

105

definite aim for their meridian observations and compilations of star-
catalogues, and will thus contribute largely to the knowledge of stellar
proper motions, as I shall show elsewhere. I may here say, that the
probable error of a star's declination, as compiled from the best authori-
ties, can be so estimated, classified according to the quantity and good-
ness of the materials, and allowing enough to cover all defects.

Class of Star.

Probable Error
of Declination.

A A.
A.
B.
C.

0"18
0 28
0 43
0 70

Within 30° of the zenith, there are now stars enough of the
classes AA, A, and B, for any American latitude, using Talcott's
method ; and the probable error of declination of a single pair of stars
will vary from 0". 13 to 0".31. Allowing, then, a p. e. of 0". 43 to each
observation, we have the final probable error of latitude from a pair of
stars, observed thrice, —

= \J 0^.

0.432
132 + -— or

y o.ai'J

+

0.432;

that is, from ± 0".28 to ± 0".40 ; which only requires from eight to
sixteen (say twelve) pairs to give a probable error of 0".l.

Moreover, observations now in progress, both general and special,
will in a year or two raise all the stars of the British Association's cata-
logue now classed as C (within our latitude-limits) to the class B,
and will doubtless transfer many of this class to a higher. On the
other hand, the portable meridian circle, or the prime vertical transit,
needs only stars of the two highest classes, and, if other practical
difficulties do not intervene, can probably secure this same degree
of accuracy with fewer observations ; not necessarily, however, with a
less amount of time and trouble. I am inclined to think that the
extravagant praises of Talcott's method to which our officials give
utterance are about balanced by the steady adherence of the French
and Germans to the other way, and that the practical difference
between them is one rather of habit than essential. It is quite certain
that both give excellent results.

166 PROCEEDINGS OF THE AMERICAN ACADEMY

The reduction of the observations for time and latitude is simple
enough, and the methods are given in the ordinary books. Some discre-
tion, however, is desirable in applying them.

The application of least squares to time reductions is considered by
Struve often unnecessary ; nor is it generally practised in Germany
and Russia. Where it is applied, weights should be given to the ob-
servations depending upon the star's declinations. I am inclined, in
case the observations are fairly complete, and depend on about the
same number of wires, to consider the expression

as a fair representation of the probable error in different declinations.
Hence the weight will be expressed by

2

" ~ 1 + sec 52,

that at the equator being taken as unity. If azimuth, collimation, and
clock-error, or rather small corrections of their adopted values, are the
unknown quantities, their co-efficients, multiplied by y/ co, will be

^ V^ = sin (cp-d) sec 8 t/ZZHZ =sin (cf-8) J '^

Y 1 4" sec 0^ » 1 + cos 0 ^

CsT^ = J !

^ Vl-fcosfi2

-j- sec d

and their required squares and products

A^ (0 = sin 2 (g) — 5) C^(o
AC oi = sin ( qp — d) C- a

1 -j- cos 0-
Aco = sin (qp — d) Ceo
2

C(o =

sec S -f- C08 8
2

^ — 1 + sec 82.

I have tabulated the values of C'-w, Cw, and «, together with their
logarithms, according to these formuliB, and give them in Table I. For
any station, the preparation of A'-m, A Coo, AXo, is at once very simple.

Tlie best results are not obtained from poor observations by cooking

OF ARTS AND SCIENCES. 1G7

them, but by letting them pass for what they are worth. Of course, au
observation must now and then be rejected. Argelander's method was
to scrutinize doubtful cases with much care, adopting or rejecting them,
and giving the results of both methods. His experience in his own
line was so great, that he rarely missed assigning the probable cause
for any large discrepancy, whether it arose from errors in reading off
mistakes in wires, miscounting time, or imperfect hearing by the
recorder, where one was employed, as in the Ilistoire Celeste ; and, if
he was at fault, he would suspend judgment on the case, and note it
down for further observation. In geographical work, where the
observer must finish each problem in a given time, and is compara-
tively thrown upon his own resources for little repairs to his instru-
ments, and the means of avoiding their occasional great defects, natural
or acquired, he must proceed with double caution in making his obser-
vations, checking them in every way, and making enough to get his re-
sult in spite of any abnormal discrepancies. This is the great advantage
of simplicity in the field-work, and reliance upon the star-catalogues
(which can always be improved afterwards), for what they will give.

The reduction of latitude observations by the zenith telescope needs
but little remark. The process is a simple one : the usual form (see
United-States Coast Survey Report for 1866) unnecessarily compli-
cated.

The half-sum of declinations of the two stars can be at once com-
puted ; first, the mean value for the beginning of the year, ^ (^j-f- ^2)'
and then the half-sum of apparent declinations for the date : thus from

8'^ = 8^-\- Aa\ + Bb'., -f Cc'a -\- Dd'^ \- xii\
it follows that

H5', + 5g = H5: + 5,)

«'i + "^2
2

That a'p a'2, and the rest, are oidy given by their logarithms, is no
objection to the use of this formula. The computer has simply to employ

168 PROCEEDINGS OF THE AMERICAN ACADEMY

the Gaussian logarithms. The best four-place table I know (J. H.
Traugott Muller's, 2d edition, Halle, 1860) has them in excellent shape
for this purpose. The micrometrical and refraction corrections should
be placed in one column, and computed together by a small table of
the value of one division or its logarithm, as affected by refraction at
various altitudes. A very trifling correction from the usual table is
necessary in Rocky Mountain work, as the barometer may stand at 23
or 24 inches instead of 30.

The form of reduction which I suggest will be found in Lieut.
Wheeler's report on the geographical positions of Cheyenne and
Colorado Springs.

In my catalogue of 981 stars, the logarithms of a' b' c' cV are given
for 1875, and will serve for some years to come. The trifle of error
introduced by their use after the lapse of a few years can best be
corrected by selecting some few stars, and computing their reductions
to mean place, say for 1975, thus getting the correction for 100 years ;
or by differential formulae. These will be

da' Secular variation

H 100

dh' da ,15 .

-77 :^ — cos « -r- ^ — aa'— sm 1"
dt dt n

-r- = |_ — tan CO sm 0 — sm a cos oj -^ — cos a sm 0 -—
= — [^\b ad' -\- a c' ivixi 8 -\- \b a' df] sin 1"

dd' . . ^ da , ^ d5 r. - ,■ . c.

-77:= — sm a sm 0 -^ -f- cos a cos 0 -r- = [lo ao' sm 0

a'-

-j- — cos 5] sin 1"

In computing the probable error of the latitude determinations, I
should proceed as follows : —

The stars should be classified, and the probable error of the cata-
logue declination of each class estimated, as suggested above. The
comparison of observations of the same pair will give the probable
error of observation. The mean reciprocal of the number of observa-
tions on each pair should be taken : its reciprocal will give the average
weight of a pair as depending on this circumstance only.

The pairs should now be classified by computing the probable error
to be expected, owing to both causes : those pairs which are once or
twice observed, or whose stars are both doubtful (Class C), will give a
large a priori probable error. These probable errors should now be
compared with the actual ones, to ascertain if any error constant to

OF ARTS AND SCIENCES.

1G9

each pair exists ; which ouglit uot to be, hut is often. The weights to
each pair being now roughly assigned, the observations should be
treated by least scjuares (if they can be improved in this way), con-
sidering the latitude and the value of one micrometer revolution as the
unknown quantities.

A weak point in the zenith telescope is the connection of the level
readings with the actual position of the vertical axis ; arising from
the fact that the level has to be much handled, and to be tilted in
observing. It might be well, therefore, to employ the delicate level
only for the reading off, and have a separate rougher one for the
setting circle ; placing the former in direct connection with the vertical
axis. The instrument ought to be so constructed, that the two delicate
levels used for time and latitude respectively could replace one another ;
saving one spare level, or else diminishing the chance of loss from
their breakage. Some of the earliest as well as of the latest meridian
and equal altitude instruments are reversed by a machine, instead of
being turned around a vertical axis. I think this is an improvement in
solidity, if not in rapidity of observing.

I will give, as an example of a method of discussing latitude obser-
vations, the latitude of Colorado Spi'ings as observed by Dr. Kampf.
(See Lieut. Wheeler's Report on Cheyenne and Colorado Springs,
pp. 70ff.) The stars are taken either from my catalogue of 981 stars,
or computed by myself on similar principles : the quantities z/(p are here
added from a completer discussion of the declinations than given in the
Report.

PAIRS ONCE OBSERVED.

Pairs

A <f>

^

Class of

Probable error.

Probable error.

No.

stars.

(1)

(2)

1

+0"76

38°49'4.S"21

BA

-t:0"49

4

41.22

AB

—0.49

8

H-0. 90

40.59

AB

±0. 49

9

—0.20

41.22

BA

--0.49

10

—0.20

40.84

AB

--0.49

11

+0.25

40.05

AA

J-0.46

12

40.08

CA

—0. 57

13

—1.68

41. 23

AB

±0. 49
m i0"60

±0"60

lean 41. 06

All these observations except those of pair 4 were taken on one day,
August 2d, on which a constant difference of about — 0".7 from the final

170

PROCEEDINGS OF THE AMERICAN ACADEMY

result is exhibited, save for the first pair. The probable errors (1) are
derived from the estimated values as derived from the separate stars,
and the probable error of one observation ±0"428 as given by Dr.
Kampf.

PAIRS TWICE OBSERVED.

Pairs

A (j)

Class of

Probable error.

Probable error.

No.

<P

stars.

(1)

(2)

2

— 0"76

38049/41//6O

AC

0"48

3

— 0. 15

41.29

AA

0.35

5

+ 1. 18

41.38

AB

0.39

6

+ 0. 24

41.04

AA

0.35

7

+ 0. 09

40. 90

AA

0.35

14

+ 0.25

41.00

BC

0.45

15

41. 36

AC

0.48

16

— 0.05

43.04

CA

0.48

17

— 0. 40

41.41

AA

0.35

18

+ 0. 25

41.56

CB

0.45

19

+ 0.43

41.75

CA

0.48

20

41.42

BA

0.39

21

41. 25

AA

0.35

22

— 0.10

41.72

AC

0.48

23

+ 0.45

41.67

AC

0.48

24

— 0. 24

41.17

BA

0.39

49

— 0. 10

41.92

AB

0.39

60

0.00

42.52

AA

0.35

±0"323

Mean 41. 56

Mea

n ±0.42

PAIRS THREE TO SIX TIMES OBSERVED.

AVERAGE NUMBER, FOUR.*

Pairs

A (j)

0

Class of

Probable error.

Probable error.

No.

stars.

(1)

(2)

25

— 0''15

38°49'42"04

AA

L0"27

26

+ 0.04

40.91

BB

_

-0. 37

27

+ 0. 90

41.78

AC

_

-0.43

28

— 0.35

41.87

A A

_

^0. 27

29

41.21

BA

_

-0.33

30

— 0.45

40.35

CA

_

-0.43

31

+ 0. 42

42. 38

BA

_

- 0. sa

32

+ 0. 10

42. 36

BC

_

-0.46

33

41.52

BB

_

-0. 37

34

40. 96

BB

J

-0.37

35

42.40

AC

~

EO. 43

* The number of observations now makes but a trifling difference in the prob-
able errors.

OF ARTS AND SCIENCES.

171

Pairs

No.

A <p

'P

Class of
stars.

Probable

error.

(1)

Probable
error.

36

38°59'42"00

BB

±0"37

37

— 0"19

42.02

AA

±0.27

38

— 0.14

42.31

AA

±0.27

39

+ 0.08

41.84

AB

±0.33

40

+ 0.08

41.06

AC

±0.43

41

— 0.46

41.60

AA

±0.27

42

— 0.46

41.27

AA

±0.27

43

— 0.29

41.35

BA

±0.33

41
45

0.
0.

42.69
42. 46

AA

BC

± 0. 27
±0.46

46

— 0.38

40.78

BA

±0.33

47

— 0.91

40.92

BA

±0.33

48

— 0.91

40.12

CA

±0.43

51

+ 0.38

40.99

AA

±0.27

±0.527

38 59 41 63

±0.357

Classifying according to magnitude of probable error (1), —

Class (a). All stars A A more than once observed.
All stars AB more than twice observed.

20 pairs of class (a) 38°59'41''61

PEoflpair(l) ±0.31

(2) ±0.468

Class (y3). All stars AB twice observed.

All stars BB more than twice observed.

8 pairs of class (j3) 38°59'41//41

PEoflpair(l) ±0.38

(2) ±0.28

Class (7) All stars once observed 38°59'41'/46

All stars AC, BC.

23 pairs of class (y)

PEoflpair(l) ±0.46

(2) ±0.605

172

PROCEEDINGS OF THE AMERICAN ACADEMY

The probable errors (1) and (2) do not agree very well, owing to
the small number of observations ; but those denoted by (2) are the
larger, upon the whole, owing to errors constant either for all the ob-
sei-vations of a night, or upon a pair of stars. The three results wUl
be thus : —

Class (a)
„ (7)

38°50'41//61
41.41
41.46

Probable Error.

(1)

J-(y'069
-t- 0.134
J- 0. 096

-to'aoi

i 0. 099
± 0. 126

I think no considerable uncertainty will be left if the stars of Class
(|S) have a weight of | each, and those of Class (j') \ each. This will
give the total probable error for weight 1, a thoroughly good pair suf-
ficiently observed ; as, —

(1)

(2)

From Class (o)
.. (7)

-}-0"31
-J- 0. 33
iO.33

Mean i 0. 32

\- 0'/46
10.24
10.43

20 pairs.
8 „
23 „

61 „

d

-0.41

and the final latitude

88°59'41'/47 ±0^067

including errors of all kinds.

The latitude is manifestly determined with all the precision neces-
sary for an arc of the meridian ; the instrument being of the largest
class, the observer excellent, and the star-places the result of a careful
investigation.

OF ARTS AND SCIENCES.

173

TABLE I.

Decl.

Log. C'u

Log. Co

C-a>

C«

a>

0°

0.0000

0.0000

1.000

1.000

1.000

2

0.0003

0.0000

1.001

l.(M)0

0.9'J9

4

0.0010

0.0(X)0

1.002

1.000

0.998

6

0.0024

0.0000

1.005

1.000

0.995

8

0.0042

0.0000

1.010

1.000

0.9'JO

10

0.0066

9.9y99

1.015

1.000

0.985

12

0.0095

9.9999

1.022

1.000

0.978

14

0.0129

9.9998

1.030

1.000

0.970

16

0.0168

9.9997

1.040

0.999

0.961

18

0.0212

9.9995

1.050

0.999

0.950

20

0.0262

9.9992

1.062

0.998

0.938

22

0.0316

9.9988

1.075

0.997

0.925

24

0.0375

9.9982

1.090

0.996

0.910

26

0.0439

9.9975

1.106

0.994

0.894

28

0.0507

9.9966

1.124

0.992

0.876

30

0.0580

9.9955

1.143

0.990

0.857

32

0.0657

9.9941

1.163

0.987

0.837

84

0.0738

9.9924

1.185

0.983

0.815

36

0.0824

9.9903

1.209

0.978

0.791

38

0.0912

9.9878

1.234

0.972

0.766

40

0.1005

9.9848

1.260

0.965

0.740

42

0.1101

9.9811

1.288

0.958

0.712

44

0.1199

9.9769

1.318

0.948

0.682

46

0.1300

9.9718

1.349

0.937

0.651

48

0.1403

9.9658

1.381

0.924

0.619

50

0.1508

9.9589

1.415

0.910

0.585

62

0.1614

9.9508

1-450

0.893

0.550

54

0.1722

9.9414

1.486

0.874

0.514

56

0.1829

9.9304

1.524

0.852

0.476

58

0.1936

9.9178

1.562

0.827

0.439

60

0.2041

9.9031

1.600

0.800

0.400

62

0.2145

9.8861

1.639

0.769

0.361

64

0.2247

9.8665

1.678

0.734

0.322

66

0.2346

9.8439

1.716

0.698

0.284

68

0.2440

9.8176

1.754

0.657

0246

70

0.2530

9.7870

1.791

0.612

0.209

72

0.2614

9.7514

1.826

0.564

0.174

74

0.2692

9.7096

1.859

0.512

0.141

76

0.2763

9.6600

1.889

0.457

0.111

78

0.2826

9.6005

1.917

0.399

0.083

80

0.2881

9.5278

1.941

0.337

0.0.59

82

0.2927

9.4363

1.962

0.273

0.038

84

0.2963

9.3155

1.978

0.207

0.022

86

0.2989

9.1425

1.990

0.139

0.010

88

0.3005

8.8433

1.998

0.070

0.002

90

0.3010

2.000

0.000

0.000

174 PROCEEDINGS OF THE AMERICAN ACADEMY

IX.

ON SOME PHYSICAL OBSERVATIONS OF THE
PLANET SATURN.

By L. Tkouvelot.
Read by 'Williaii A. Rogers, Dec. 14, 1875.

During the last four years I have had many occasions to observe
the planet Saturn, and to study its physical constitution under very
favorable circumstances. My series of observations extends over more
than a hundred nights, many of which were as good as could possibly
be desired, both for the steadiness of the image, and for the amount of
light.

The observations on which this communication is based were made :
1°. With the fifteen-inch refractor of the Harvard College Observatory,
while I was employed by Professor Winlock in making the sketches
for the series of the astronomical engravings published by him. By
bis kind permission I have availed myself of considerable of the data
thus obtained. 2°. With the twenty-six-inch refractor of the Wash-
ington Observatory while it was still in the hands of Messrs. Alvan
Clark & Sons. 3°. With the six-and-one-quarter-inch refractor of my
own Physical Observatory at Cambridge. During the past summer, I
was honored with an invitation from Admiral C. H. Davis, Superin-
tendent of the Naval Observatory, to visit Washington and make some
sketches with the magnificent instrument of this establishment. I thus
had an excellent opportunity to confirm all my j^revious observations.
The powers used ranged, according to the amount of light and the
steadiness of the atmosphere, from 140 to 700. On good nights,
however, higher powers have been tried, but never with advantage, as
the light lost by the use of high powers is generally of more impor-
tance for good vision than a superior enlargement with a reduced
amount of light.

OF ARTS AND SCIENCES.

175

NiinKM'ons obscrvors, amoii^ whom ixre such einiiioiit astroiiomors as
Sir AVilliaiu and Sir .Toliii Ihrsclu'l, Otto Struvi', Daws, lioiid, &,c.,
have made careful studies of this phinct; and it is not, therefore, to he
expected that ver^' important (hscovcries remain to he made hy hiter
observers. As I have had the op[)ortunity of observing with the same
instrument many of the celestial objects previously studied with so
much success by Professor George P. Bond, it gives me the greatest
pleasure to express my admiration for the accuracy and fidelity of his
observations.

The following diagram, representing the outlines of Saturn and its
rings, will facilitate my explanations, and give clearness to the sub-
ject : —

Fig. 1.

By looking at the rings, attention is at once attracted to a con-
spicuous dark line, apparently concentric with the outer margin of the
rings, and boldly surrounding the planet, and adorning it by its sharp
contrast. This dark line is known as " the principal division of the
rings," and is shown at a, Fig. 1. Owing to the effect of perspective,
it always appears widest at the two extremities of its major axis, on
that portion called " the ansae," as there only, it is seen without fore-
shortening. I have carefully compared the intensity of this dark line
with the sky outside of the rings, and inside of the ansje ; and I have
always found it to be slightly lighter. All my observations also agree
in showing this line as appearing a little narrower on the side farther
from the observer, at c, Fig. 1, than it appears on the opposite side,
at d. This phenomenon could readily be explained by supposing that
the outside margin of the ring (7 is on a plane higher than the ring B,

176

PROCEEDINGS OF THE AMERICAN ACADEMY

and may, consequently, conceal a narrow portion of the dark line. The
assumption of such an hypothesis seems to be fully supported by the
observations, as will be shown hereafter. It is furthermore to bo
remarked, that the outside margin of the ring C has always appeared
to me to be more sharply defined on that part of the ellipse fiirther
from the observer than on the side nearest. The case is the same for
the outer border of the ring A^ which appears sharper on its northern
than on its southern side. In both cases, the northern portion of the
ellipse is limited by the matter composing the surfiice of the rings
on their flat and illuminated side; while for the southern portion
it is seen a little edgeways, and this may account for the vagueness
of its outlines on this side.

Soon after the beginning of my observations, in October, 1872, my
attention was called to a singular appearance not heretofore noticed,
as far as I am aware. Two small, dark, angular forms, r, Fig. 1, were
seen near the summit of the principal division of the rings on the fol-
lowing side, and apparently projected upon the ring B. After an
interval of three hours, no sensible change could be detected in the
position of these forms ; and on the following day they were seen

Fig. 2.

occupying about the same position. This phenomenon could easily be
explained by supposing there were some sort .of protuberances on the
external edge of the ring C, casting their shadow under the oblique
rays of the sun, which occupied then a proper position to answer to this

OF ARTS AND SCIENCES. 177

hypothesis. But, some days later, unothcr of these .>.iii;^iilar foiiiis was
observed 180° from the first, on the preceding side, ats. This at once
overthrew the supposition that they were shadows cast by protuber-
ances existing on the ring C ; since in this case the shadows wduM
have been projected opposite the sun on tlie ring C, and not on the ring
B. Since that time, 1 have rarely observed the planet without seeing
some of these singular appearances, either on one sidt^ or the other, but
generally on both sides. The number of these dark forms is variable.
One, two, three, four, and even five, have been seen at the same moment,
and on the same side. Though these forms are variable, and appear
and disappear, I have never been able to detect in one night any
change of position which could be ascribed to the rotation of the
rings.

The most plausible explanation of the phenomenon which I can con-
ceive is, that the inner margin of the ring B, which forms the outer
limit of the principal division, is irregular, jagged, and deeply indented,
as shown at A, Fig. 2, which represents Saturn as it would appear to
an observer placed above one of its poles.

As Bond speaks of the principal division of the rings as " not being
perfectly elliptical," and as in one instance he has suspected that it
" was narrower in some places," it is to be inferred that he had some
faint glimpses of the phenomenon which I have observed, and which
possibly may be more conspicuous now than twenty years ago.

But the fiact that this phenomenon has not been observed earlier
does not necessarily prove that it had no existence before ; as it is well
known, by those who have had experience with the telescope, that one
may look for a long while at a celestial object, and miss perceiving
what he will readily see when once he is told where to look, and what
to look for. Seeing what is new and unsuspected is quite different
from seeing what has been observed before.

Thougli no noticeable changes in the position of the dark angular
forms cuuld be observed in the course of two or three hours, it does not
follow that the system of rings does not rotate upon an axis, as theory
indicates ; since the supposed indentations seen on the atisa3 would bo
placed in the most unfavorable position for showing their motion, if
they have any, because it would be accomplished almost in a line with
the visual ray, either approaching or receding from the observer.

Next to this division, but much less conspicuous, and to be seen oidy
on very good nights, is a narrow, grayish, and somewhat diffused line,
called " the pencil line," shown at h. Fig. 1. I have never been able
to trace this line all around the planet, as it diminishes very rapidly

VOL. XI. (N. S. III.) 12

178 PROCEEDINGS OF THE AMERICAN ACADEMY

with the foreshortening, and is soon lost. Probably I have never traced
it more than 30° or 40° on each side of the major axis of the rings.
The pencil line has never appeared to me black and well defined, but
rather grayish and diffused. Sometimes I have had the impression that
it was irregular in width and in depth of tint.

These two lines are the only ones I have observed, which could, with
a certain amount of probability, be said to be a separation of the rings ;
though they might just as well be depressions, or dark belts, es{>ecially
the outer one. But the fact tiiat they have been observed on both sur-
faces north and south, apparently corresponding in position, is in favor
of their being real separations of the rings. Though I have repeatedly
endeavored to see the planet through the principal division between d
and e, Fig. 1, I have never seen the faintest traces of it; and I am
not aware that others have been more successful.

If the principal division of the rings is, in fact, what it is said to be, —
viz., a space free from matter, and entirely disconnecting the rings B
and (7, — I do not see why the planet has never been seen through it.
If the planet could be seen through that space, the dark line forming
the principal division would be invisible from d to e, as the bright light
of the planet would shine through in its place, and be undistiiiguishable
from that of the rings. It may be objected that the invisibility of the
planet through the principal division is due to the thickness of the
ring G ; but, in this case, why should the black sky be seen, if the planet
is invisible ?

Besides the two dark gaps or divisions of which I have just spoken,
the rings are subdivided by concentric zones or belts, which reflect light
of different hues and intensity. Though only three of these belts are
conspicuous, I have found by careful examination that there are six
which I can always recognize whenever tlie illumination is good, and
the image steady. These zones are represented on the diagram. Fig. 1,
at A, B, C, D, E, F. On several occasions, I have had a pretty dis-
tinct impression of seeing the whole surface, from C to E inclusive,
grooved, as it were, by numerous narrow concentric belts. These im-
pressioHo may have been illusory, as they were almost instantaneous ;
but I have since learned by experience, that, after all, rapid impressions
are not so much to be discarded, as, quite often, even nidre fugitive
impressions have proved in the end to be real. A striking instance
in my own experience may be worth recording. This Summer I
made a study of the Ilorse-shoe Nebula in Sagittarius with my
6|-inch refractor. During the course of my observations, I was
much annoyed by what appeared to me as faint ghost-like reticulated

OF ARTS AND SCIENCES. 179

shadows projected upon the iiebuhi. I at iirst thought I Imd h;ft the
reticule of squares ruled on glass in the eye-piece ; but having convinced
myself that this was not so, and the same appearance again presenting
itself, I wiped my eye, but with no better result. As I experienced the
same thing on other nights, I paid no more attention to it, thinking the
trouble was in my sight. Some time afterwards, wliile in Washington,
I had an opportunity of studying the same nebula with tin; great
twenty-six-inch refractor of the Naval Observatory. I was not a little
surprised* to see that the ghost-like reticule which I wanted so much to
rub out of my eye while at home, was caused by dark channels in the
nebula itself, which is divided on the preceding side by bright luminous
patches, separated by dark intervals.

In order of brightness, the zones or belts composing the system of
rings run as follows : C, Z), B, E, A, F; C being by far the brightest,
and F by fiir the darkest. The zones A and B have a bluish cast, or
light slate-color; Cis of a bright luminous white; D is shghtly gray-
ish ; ^ is at little darker ; while F, which is very dark, is tinged with
bluish purple.

A is separated from B by the pencil line ; B from C by the principal
division ; while the others do not show any separation whatever, and
are only limited by the contrast of their different colors and shades, and
seem to be in immediate contact. However, the different zones do not
terminate abruptly where they come in contact, but seem somewhat
blended into each other. This is especially the case between E and
F. Though at that point the contrast between the two internal rings
is verj' great, yet it is impossible to see any line of division, so much
do they mingle at their point of contact.

On good nights, I have often observed on that part of the rings A, B,
and C, seen on the ansse, an unmistakable mottled or cloudy appearance
such as is represented on Plate 1. This appearance was always more
characteristic and better seen on the ring G, especially near its outer
margin, close to the principal division. It would seem, as has been
already remarked, that the ring (7 is on a higher level than that of the
rest of tlie rings, and that the cloudy appearances observed there form
by their accumulation some kind of protuberances of different heights
and breadths. The bright spots resembling satellites, so often observed
by Bond in 1848, when the plane of the rings was parallel with that
of the ecliptic, were probably caused by the crests of some protuber-
ances similar to those now seen on the ansae. The form of the shadow
thrown by the planet on tlie rings on Nov. 30, 1874, as shown at x.
Fig. 1, seems also to agree with this hypothesis. The curious and deep

180 PROCEEDINGS OF THE AMERICAN ACADEMY

indentation of the shadow at x, in that part where it is projected on the
outer border of the ring C, is perfectly exphiined on the supposition
that this part of the ring is on a higher leveL The same shadow,
as it appeared projected on the rings B and A, also clearly indicates that
the plane of these zones is on a lower level.

In order to find tlie shape of tlie surface of the rings from the obser-
vation of the form of the shadow thrown by the planet, I have experi-
mented on a miniature representation of Saturn, illuminated by a lamp
occupying the position of the sun, while my eye occupied the position
of the earth. By successive trials in altering the shape of the minia-
ture rings, I have soon found what must be the form of the rings in
order to give to the shadow tlie same appearance which liad been
observed on the planet ; and the result agrees with the explanation
already given.

From the form of the shadow as it has appeared at different times
during the last four years, and from the experiment just mentioned, it
seems pretty clear to me, that, from the inner margin of the dusky ring
I*", the thickness gradually increases until it reaches the extreme border
of the ring C, where it gently decreases, as indicated by the rounding
of the shadow at this point ; after which it sinks perpendicularly down,
until it comes even with the general level of the rings B and A. The
slightly curved appearance of the shadow of the planet during the
present year, with its concavity turned towards its globe, also supports
this hypothesis.

Though, in general, the level of the ring C is always higher than
that of tlie rest of the system, it does not seem, however, to be uni-
form and permanent, but varies, either by the rotation of the rings
upon an axis, or by some local changes in the cloud-forms themselves;
as in several instances I have observed quite rapid and striking changes
taking place during the course of one evening in the indentation of the
shadow shown at x, Fig. 1. Sometimes the indentation appeared to
increase, indicating a higher level ; and sometimes to decrease, indicat-
ing a lower level.

That the thickness of thfe rings is increasing from the interior margin
of the dusky ring to the outer border of tlie bright ring (7, seems to be
corroborated by the phenomena which I have observed on the dusky
ring, and of which I shall speak presently.

On all favorable occasions, I have made careful searches on the dusky
ring for the divisions suspected by Bond ; but I never had the faintest
glimpses of them. The dusky ring appears 'to me to be continuous,
though it is certainly not of the same thickness throughout. Whatever

OF ARTS AND SCIENCES. 181

may be tlie material of wliich this ring is composed, it is quite rarefied ;
and it becomes more and more so as it ap|)roa('hes its inner margin.
There, it seems to be composed of discrete particles, each of which
reriects the light separately; aud, by applying high powers to telescopes
of large aperture, I have had the impression that the supposed par-
ticles were more widely separated by the increase of magnifying jiower.
I do not pretend to have seen distinct and isolated particles in the
dusky ring; but by instants my impressions have been so decided, that
it seemed as if oidy a little more favorable conditions were retpiired to
enable me to see separate corpuscles of matter. Tiie appearance was
somewhat like fine particles of dust floating in a ray of light traversing
a dark chamber.

The inner border of the dusky ring, notwithstanding its dark ap-
pearance, is sharply defined on the dark sky within the ansai ; but
it loses this sharpness of outline in that part which is seen projected
upon the disk of the planet. There it appears very diffused aud ill
defined.

The inner border of the dusky ring, as seen within the ansae, forms a
part of a perfect ellipse concentric with the other rings ; but these
graceful curves are remarkably and quite abruptly distorted where
they enter upon the disk of the planet at m and jo, Fig. 1. At these
points, they are seen turning up rapidly, describing a short curve ; after
which they continue parallel with the curves of the other rings until
tliey meet at h. If the ellipse described within the ansie should cross
the planet without any deflection, it would be seen along the dotted
line. Fig. 1, and pass through n ; while, on the contrary, it is seen
above at h.

I was quite surprised, at first, by this singular phenomenon ; but I at
last satisfied myself with the following explanation : If we conceive the
dusky ring to be made up either of vapors or of numerous small inde-
pendent solid bodies, and, moreover, if we conceive the thickness of
this ring as increasing from its interior margin to its outer limit, we
shall have an easy explanation of tiie observed phenomena. Wiien
the matter composing this ring, whether solid or gaseous, is seen pro-
jected upon the disk of the planet brilliantly illuminated, it will be
lost, and will individually disappear, absorbed by the irradiation of the
bright light surrounding it, and it will remain visible only at that part
where it forms a stratum thick enough to overpower the eflTect of
irradiation.

The fact that the distortion of the inner margin of the duskv riiio- is
not abrupt at m and p, where it enters upon the disk, but i.« gradual,

182 PROCEEDINGS OF THE AMERICAN ACADEMY

seems to prove that the planet is less luminous on its border than else-
where, providing the above explanation holds good ; and this may be
owing to the absorption caused by an atmosphere surrounding the
planet.

Bond has represented the limb of the globe of Saturn as seen through
the whole width of the dusky ring. In this he agrees with all pre-
vious observers. All the drawings of Saturn represent the limb of tliis
jilanet as plainly and equally visible throughout tlie dusky ring, becom-
ing invisible only where it enters under tlie internal margin of the ring
E. In Bond's memoir, it is positively stated that Mr. Tuttle saw the
limb of the planet through the whole width of the dusky ring. If
these observations are correct, — as without doubt they are, — the solid
particles, vapors or gases, composing this ring, must have luidergone
some changes of position since Bond's time ; as by using tlie same
instrument, and even one of almost double the aperture, I have not
been able to confirm these observations.

During the last four years, I have never been able to see the limb of
the planet Saturn under the dusky ring, beyond the middle of its
width. As it enters under it at m and p, it remains quite distinct for
a short distance : but, as it advances farther in, it diminishes gradually ;
and it entirely vanishes at about the middle, at u and v ; as if the matter
composing the dusky ring was more dense or thicker towards its outer
border. This observation has been so carefully made, and so many
times repeated, the phenomenon has been so distinctly seen, that there
is not the least doubt in my mind as to its reality. Therefore it seems
pretty certain that changes have lately taken place in the distribution
of the matter composing the dusky ring.

As already shown, the substance composing the dusky ring does not
seem to be uniformly distributed ; but seems moreover to be agglome-
rated here and there into denser masses, which I have often recognized
upon that part of the dusky ring crossing the planet between u and
V. These supposed agglomerations appeared as dark masses, inter-
cepting the light of the planet. This phenomenon could not be attrib-
uted to dark markings on the planet, seen through the dusky ring ;
since there are no markings so dark and so small on Saturn. Neither
could they be produced by the dark bands sometimes surrounding the
globe of Saturn, as some traces would have been detected on the edge
of the dusky ring, since these bands are usually wider than the trans-
parent part of the dusky ring.

Of the planet itself I have little to say. It has certainly a mottled
or cloudy appearance, like Jupiter. The clouds of Saturn are more

OF ARTS AND SCIENCES. 183

finely divided, like certiiin forms of the cirri clouds of our own atmos-
phere. The cloudy appearance of Siituni, of course, is not so easily
seen as that of Jupiter. It always rc(]uires a good steady iiiglit to
see it.

I have never seen the planet striped vk-ith a large number of parallel
bands, such as some ob-ervers have described. Three or four form the
extreme limit. Nor have I seen the bauds so conspicuously marked,
so regular, so distinct in outline, and so dark ; the equatorial band
being always by far the most conspicuous, while the others were barely
perceptible. The equatorial belt has always appeared to me to be
sliglitly liiigi'd wMth a delicate carmine red, very much like the equa-
torial belt of Jupiter ; only the pink color of the former is much fainter.
In no instance could I compare the color of this band to " brick red,"
as it is commonly described.

Like the equatorial belt of Jupiter, that of Saturn is variable in
width, and changes its form as well as its position. It is usually com-
posed of two grayish irregular bands, forming its limits north and south,
between which are seen flocculent pinkish cloud-forms.

The general color of the planet differs from that of the rings, in
being of a slight warm brown in which there is a yellowish tinge.
The contrast of color with the rings is better seen by the use of very
high powers.

To conclude: my observations show, —

I. That the inner margin of the ring B, limiting the outer border
of the principal division, has shown on the ansie some singular
dark angular forms ; which may be attributed to an irregular
and jagged conformation of the inner boi'der of the ring B,
either permanent or temporary.
II. That the surface of the rings A, B and (7, has shown a mottled
or cloudy appearance on the ansae during the last four
years.

III. That the thickness of the system of rings is increasing from the

inner margin of the dusky ring to the outer border of the
ring C, as proved by the form of the shadow of the planet
thrown upon the rings.

IV. That the cloud-forms seen near the outer border of the ring G

attain different heights, and change their relative position,
either by the rotation of the rings upon an axis, or by some
local cause ; as indicated by the rapid changes in the inden-
tation of the shadow of the planet.

184 PROCEEDINGS OF THE AMERICAN ACADEMY

V. That the inner portion of the dusky ring disappears in the
light of the planet at that part which is projected upon its
disk.

VI. Tliat the planet is less luminous near its limb than in the more
central parts, the light diminishing gradually in approaching
the border.

VII. That the dusky ring is not transparent throughout, contrary to
all the observations made hitherto ; and that it grows more
dense as it recedes from the planet ; so that, at about the
middle of its width, the limb of the planet ceases entirely to
be seen through it.
VIII. And, finally, that the matter composing the dusky ring is
agglomerated here and there into small masses, which almost
totally prevent the light of the planet from reaching the eye of
the observer.

Cambridge, Dec. 1, 1875.

OF ARTS AND SCIENCES. 185

X.

THE COMPANIONS OF PROCYON.

[Communicated bi/ Rear-Admiral C. 11. Davis, Superintendent of the Naval Obser-
valorij, Waskinyton.]

Kead, Feb. 9, 187G.

The discovery in 18G2, by Mr. Alvan G. Clark, of a companion of
Siriiis very near the place indicated by the tlieory proposed b>' Bessel
to account for the variable proper motion of this star, naturally leil
astronomers to an examination of Procyon, a star which also has a
variable proper motion. On March 19, 1873, a companion of Procyon
was discovered by Mr. Otto Struve, Director of the Pulkowa Observa-
tory, near the place indicated by the theory of Professor Anwers.

As soon as the 26-inch refractor of the Naval Observatory was
ready for use, Professors Newcomb and Holden began an examina-
tion of Procyon, which has been continued, on convenient occasions, to
the present time.

Struve's companion has not been seen by either of these astrono-
mers ; nor, indeed, by any one who has examined the star through our
instrument. Another companion, however, was soon suspected ; and
the existence of this and other companions has now been so well
established that an account of the examination of this star will be
interesting.

EXAMINATION OF PROCYON FOR THE DETECTION OF STRUVE'S

COMPANION.

{Extracts from Observing Bools.)

(1) 1873. Nor. 29. Procyon carefully examinecl, and all sinall stars within 2'

mapped down. Str0ve's companion not seen. Seeing
very good, except possibly a slight haze. Observer:
Newcomb.

(2) 1873. Dec. 30. Examined Procyon. Struve's companion not seen. New-

comb.

(3) 1874. Jan. 2. Procyon's distant companion measured. Struve's com-

panion not seen. Newcomb.

18G

PROCEEDINGS OF THE AMERICAN ACADEMY

(4) 1874. Jan. 8. 13 h. 30 m. Procyon: examined carefully for about 20 min-

utes, — distant companion plain. Seeing good, and rays
round star quiet : no small companion. Holden.

(5) 1874. Jan. 14. 10 h. Very good seeing at times: ... no near companion to

Procyon. Holden.

(6) „ Jan. 25. Seeing very excellent : ... no near companion to Proc^/on.

Holden.

(7) „ Feb. 5. Procyon. Good seeing. Struve's companion not seen.

Newcomb and Holden.

Suspected a companion fol/oicing more distant tban com-
panion to Sirius. Position angle 76° or 77°, by rough

■ sketcli. (See observations of Nov. 12, 25, and 20.)
Holden.

(8) „ Feb. 14. Procyon : poor image. Holden.

(9) „ Feb. 21. Gh. 15m. to7h. Procyon: distant companion plain. Procyon

unsteady, and poor seeing : no suspicion of near com-
panion. Holden.

(10) „ Mar. 11. Procyon; no near companion. Holden.

(11) „ Mar. 20. 7 h. 30 m. Procyon: image good. Struve's companion not

seen. G. W. Hough, Newcomb, and Holden.

(12) „ Mar. 21. 7 h. 30 m. Procyon : no near companion. Holden.

(13) „ May 18. About 8h. Procyon ; no near companion. C. H. F. Peters.

(14) „ May 26. Procyon: aperture reduced to 15 inches. Image poor: no

near companion. Newcomb.

(15) „ Oct. 15. 17 ii. Siriiis : companion better seen with afuTture reduced

to 22 inches. — Procyon : aperture 22 inches. Struve's

companion not found. Definition fine.
17 h. 44 m. Distant companion can still be bisected with

ease in -the increasing daylight.
17 h. 47 m. Bisection difficult, but companion plainly seen

away from wire.
17 h. 51 m. Companion cannot be certainly seen at all. I

am surprised at its sudden disappearance in the daylight.

Newcomb.
[The sun was about 6° below the horizon at 17 h. 50 m.]

(16) „ Nov. 7. Cambridgeport, Massachusetts. Using the McCormick

telescope; aperture, 26^- inches. Seeing rcry good. Pro-
cyon ; no trace of Struve's companion. Alvan Cl.vrk,
G. Clark, and A. G. Clark.

(17) „ Nov. 12. Procyon: seeing about the same as at Cambridgeport

(Nov. 7]. No sign of Struve's companion. Observation
doubtful of a small companion 10" off, marked in drawing
position angle = 68° from sketch. Alvan G. Clark,
Avith 26-inch refractor at Washington.

(18) „ Nov. 25. 14 h. 30 m. to 15 h. 10 m. Pror^/on ; seeing not jwy good.

Struve's comi)anion not seen. Small companion sus-
pected, [p = 47° from sketch.]

OP ARTS AND SCIENCES. 187

15 h. 20 m. Reduced aperture to 22 inches ; no better see-
ing. HOLDEN.

(19) 1874. Nov. 2G. 15 h. Procyon : full aperture. I see distincti}' tlie same

companion that I saw last night. Position about 'J0°
more tlian old companion, [p = ■42" from this estimate.]
Seeing ;((;;/t(■^ Planetary disc to Proci/oii. 15 h. '60 m. to
45 m. : reduced aperture to 22 inches. Sudden scud of
cloud and haze : saw the small companion but ouce.

HOLDEN.

Besides the above recorded observations, the companion has been
looked for and not found on various occasions at the Naval Observa-
tory by Professors Hall, Eastman, and Peters ; and by Professor
Peters at the Melbourne Observatory with the four-foot reflector
under very good conditions.

On Jan. 12, 1876, Procyon was examined under exceptionally
fine circumstances by Professor J. C. Watson and Professor Hoideu.
No trace of Struve's companion was seen ; but both observers inde-
pendently discovered others of which they at once, and without con-
sultation, made sketches which agreed in showing certainly three small
companions quite within 10" of distance, and between 0° and 90° of
position angle ; and one was suspected by Professor tlolden some-
where between the old companion and Procyon. Designating these
in the order of position angle by 1, 2, 3, and 4, the sketches agreed in
making 2 the brightest of the three, and also the most distant, while
1 and 3 were nearly of equal brightness and of equal distance (less
than the distance of 2). The following is a transcript from the Ob-
serving Book : —

(20) Procyon and neighboring stars : coincidence of wires 64 r. 14 approxi-

mately. Telescope west of pier ; eye-piece, 400 A.
Reading for Position. Reading for Distance.

231.6 63.488

p = IQo s = 6" 63.592

J. C. "Watson.

200 63.31

208 63.40

p = 34° s = T'.Q E. S. HoLDEN.

Telescope east of pier. Eye-piece 400.

209.6 65.12

p = 32° 8 = 9'/.7 J. C. Watsov.

208 65.02 eye-piece 400.

p = 340 S = 8.8 _ E. S. IIOLDEN.

188 PROCEEDINGS OF THE AMERICAN ACADEMY

No signs of 2's companion: image fine. At about 11 Ii. Procyon examined
by Professor J. C. Watson, and Holden. Where Ah'an G. Clark found a
companion (see Observing Book, Nor. 12, 1874), wliich was verified by llolden
(1874, Nov. 25 and Nov. 20), Professors Watson and Holden found tlirce.
One of tliese is somewiiat brigliter than tlie other two (see sketclies I. and II.),
an(i tiiis was first seen by Professor Watson (i.e., on Jan. 12), while Holdex
saw tiie precedliKj one; and, finally, all tliree were well seen, and tlie first seen
was measured in botli positions of the instrument east and west of the pier, by
both observers. The seeing was extremely fine, and these images were well
and steadily seen for about two hours (till Vd h.). In the sketches, a is the old
companion, p = 312° [s = 42"].

SUMMARY.

( p = 10° s = 6." : J. C. W.

Telescope W. ^ p = 38 s = 7. 9 : E. S. H.

( p = 34 ... : J. C. W.

„ , -^ ( p = 32° s = 9."7 : J. C. W.

Telescope E. j J _ 34 s = 8. 8 : E. S. H.

Holden suspects a 4th comjianion somewhere about p = 320° — 330°. It
should be noted further that 400 and 400 A are different eye-pieces, and that
these satellites were seen in all parts of the field of view, and in all positions of
the eye-piece.

(21) New companions to Procyon : 1876, Jan. 20. The seeing is not good.
Reading for position angle :

214° Holden p = 28°
224 Peters p = 18
212 Watson p = 30

189° Peters p = 53°
188 Watson- p = 54

242° Peters p = 0°

Saw the brightest of the throe companions without difficulty and quite
steadily, and caught occasional glimpses of one of the others. 1). P. Toud.

Neither Peters, Watson, nor Holden see 0.2's companion.

(22) Companions of Procyon : 1870, Jan. 21. 10 h. 11 m. Examined
Procyon witli power 400. Imnges generally blurred and flaring.
Irregular whiffs of wind. During occasional moments caught quite
distant glinipses of one or two comi)anions about p 45° greater than
old companion, but too unsteady to meitsure. [p = 357°j Nkw-

CO.MU.

OF ARTS AND SCIENCES.

189

About 11 P.M. saw, by slii'M'-'^cs only, two of tlie close companions of Pro-
cyon ; viz.. that neiirest in angle of jHJsition to tlie old coini)anion anil tlie mid-
dle one. Prooyon too much blurred to attempt any measurements. C. II. F.

PliTERS.

At 11 h. cannot be certain of seeing any thing in the place of the new com-
panions, although there is at times something which looks like a companion.
Images not good. Hall.

1876, Jan. 25. 10 h. '2 m. Procyon examined with powers 400 A, 400,
600 A, and single lens 500. I cannot see the new companions or Struve's.
Distant companion seen steadily with all powers, but best with 400 A and 500.
IIall.

(23) Procyon, 1876, Jan. 25. 10 h. 30 m. The nev/ companion, i.e., the
brightest of the three, suspected strongly, and a reading for position
taken. Image of Procyon very poor, p = 37.° 0. IIoldkn.

RECAPITULATION.

It seems to be established by the preceding observations that there
is no companion to be seen in the position indicated by Struve.
Collecting all estimates and measures of other suspected companions
in a table, and adding a supposed identification of them with one of
the four satellites suspected by Watson and Holden on January 12,
we have the following : —

Date of the
Observation.

Position
of the

Distance
of the

Supposed
identi-

Observer.

Companion.

Companion.

fication.

1874. Feb. 5

7fi=::

s>10"

1

Holdev.

Nov. 12

68

10 est

?

A. G. Clark.

» 25

47

about 10

3

Holden.

,. 26

42

„ 10

3

HOLDEX.

1876. Jan. 12

10

6

1

J. C. Watson.

»

38

7.9

2

HOLDKN.

84

2

J. C. Watson.

,1 9, ,,

32

9.7

2

J. C. Watson.

34

8.8

2

Holden.

yy t> )y

320°-330° ?

about 10

4

IIOLDEN.

„ 20

28°

„ 10

2

Holden.

18

„ 10

1?

Peters.

30

„ 10

2

Watson.

53

„ 10

3

Peters.

54

„ 10

8

Watson.

0

„ 10

1

Petehs.

!,' ',', 21

357 (est)

„ 10

1

Newcomb.

,, 25

37

„ 10

2

Holden.

190 PROCEEDINGS OF THE AMERICAN ACADEMY

The three companions about which no doubt is entertained are,^

1.

p = about 10°

s = 6"

2.

p = 36o

s = 8"8

3.

p = about 50°

s < 10"

It is quite possible that there may be one or two more. It is easy
to understand why these have not been seen before, as the early ex-
aminations were principally for the purpose of detecting the existence
of Struve's companion, and as the very finest atmospheric conditions
are required for their certain detection. It is believed, however, that
even in ordinarily good seeing two can be seen.

OF ARTS AND SCIENCES. 191

XT.

NOTES ON MAGNETIC DISTRIBUTION.

By Henry A. Rowland.
Presented, Juno 9, 1875.

In two papers which have recently appeared on this snbject, by Mr.
Sears (Amer. Jour, of Science, July, 1874), and Mr. Jaccjues (Pres.
Amer. Acad, of Sciences, 1875, n. 445), a method is used for deter-
mining magnetic distribution, founded on induced currents, in which
results contrary to those published by M. Jamin have been found. It
does not seem to have been noticed that the method then used does
not give what we ordinarily mean by magnetic distribution. In mathe-
matical language, they have measured the surftice integral of magnetic
induction across the section of the bar instead of along a given length
of its surface* M. Jamin's method gives a result depending on the
so-called surface density of the magnetism, which is nearly proportional
to the surface integral of the magnetic induction along a given leuo'th
of the bar. Hence the discrepancy between the different I'esults.

Had the experiments of Mr. Sears and Mr. Jacques been made by
sliding the helix inch by inch along the bars, their results would have
confirmed those of M. Jamin. Four or five years ago, I made a large
number of experiments in this way, which I am now rewi'iting for pub-
lication, and where the whole matter will be made clear. At present, I
will give the following method of converting one into the other.

Let Q be the surface integral of magnetic induction across the section

of the rod, and let Qe be that along one inch of the rod : then Qe cc -j-

X being the distance along the road. Hence, M. Jamin's results
depend on the rate of variation of the magnetization of the rod, while
those of Mr. Sears and Mr. Jacques depend on the magnetization.

In conclusion, let me heartily agree with Mr. Jacques's remarks
about M. Jamin's conclusions from his experiments. Such experi-

* Meavill's Electricity and Magnetism. Art. 402.

192 PROCEEDINGS OF THE AMERICAN ACADEMY

ments as these give no data whatever for a physical theory of magnet-
ism, and can all he deduced from the ordinary mathematical theory,
which is independent of phj^sical hypothesis, combined with what is
known with regard to the magnetizing function of iron. This will be
shown in the paper I am rewriting.

It seems to me that M. Jamin's method is very defective ; and I
know of no method of experimenting, which is theoretically without
objection except that of induced currents, and this I have used in all
my experiments on magnetic distribution for the last four or five years,
and have developed into a system capable of giving results in absolute
measure. Mr. Jacques is to be congratulated on pointing out these
errors in M. Jamin's conclusions.

Teot, June 7, 1875.

OP ARTS AND SCIENCES. 193

XII.

ON THE METHOD OF LEAST SQUARES.

Bt Truman Henry Safford.
Presented, Oct. 12, 1875.

The method of least squares with the theory of errors of observa-
tion upon which it depends forms the foundation of modern practical
astronomy, and is largely used in subjects akin to astronomy, as
geodesy and physics : the object of the present note is to assist in
their practical application, both in planning and reducing series of
observations.

Legendre first seems to have published the method of least squares,
mainly as a convenient and pretty method of computation. Gauss
soon after showed that it was the same in principle as the ordinary
method of taking the arithmetical means, in the simpler cases to
which that is applicable ; and that either method presupposes a distri-
bution of the errors of observation', such that the probability of larger
errors is less than that of smaller ; and proportional to the function

where A is an error of observation, and h a factor which reduces all
systems of such errors to be comparable with each other.

Of course the probability of an error of observation exactly equal to
a given amount, no hair more nor less, is infinitesimal ; and the definite
integral

denotes the probability that there will be errors between the limits A
and Aj; while the total probability of all the errors of observation
denoted by unity will be equal to

VOL. xr. (n. 8. III.) 13

194 PROCEEDINGS OF THE AMERICAN ACADEMY

Shortly after this investigation of Gauss, Bessel examined long series
of observations, to see whether the Jaw of distribution of errors thus
indicated was a true one : he found that it was approximately so. His
tables and some results are m the Fundamenta Astronomia^ : from
these it appears that the definite integral above mentioned does rep-
resent the actual distribution of errors with striking exactness ; but
that there is generally a surplus of perhaps 1 to 3 per cent of the larger
errors.

I may here mention that the least favorable series quoted by Bessel
— Bradley's declinations — are now in process of re-reduction by Prof.
Auwers, of Berlin, and that his results in part are in my hands for
another purpose. The larger discrepancies which Bessel's own reduc-
tion left in them will probably be found to disappear in the newer
calculations, and seem to arise from variations in the zero point of the
quadrant.

A few years after Bessel's results were published. Gauss wrote his
Theoria Conibinationis Observatiouum. In this he takes the ground,
from the beginning, that

e ^

does represent the probability of error, and mentions casually that it
is only an approximation.

About 1838, Bessel published his last paper upon this subject.
It seems to be little known in this country, but is extremely im-
portant.

He shows that the law of error will be that mentioned with greater
approximation, the nearer the following conditions are complied
with.

First, that the sources of error are very numerous.

Second, that they give rise to errors of equal average magnitude.

He then points out that the first condition always holds good, by an
enumeration of the known sources of error ; and that in good observa-
tions the second condition has always a tendency to maintain itself,
because if any one source of error is sensibly 'more intluential than the
rest, it will be detected and put away, or at least its etfeot diminished
by a proper arrangement of tlie work.

The main object of this paper is to give the rules for good observing
derived from tiiis theory : I have tested thom in two long series of
observations, one made at Cambridge from 1862 to 18G6, the other at
Chicago from 1868 to 1871. The first series is of right-ascensions of
the principal stars, about 500 in number, each observed at least eight

OF ARTS AND SCIENCES. 195

times, and many from thirty to forty times. The second series is a
portion of the great zone observations now going on under tiie charge
of the Astronomische Gesellschaft of Leipzig. The rules for tliis
series were formulated by Argelander.

The sources of error (not mistakes) in astronomical observations are
partly psychological (deficiency of attention), partly psycho-i)liysic:iI (dul-
ness of the senses, time expended in communications through the nerves),
partly instrumental, or depending on temperature, partly optical, depend-
ing on the condition of the atmosphere. Tlie first rule then is that the
observer must keep himself in uniform condition, and therefore be tem-
perate and regular in his life. He must keep his senses constantly
under control. He must have good instruments, well and firmly
mounted : all the parts of the instruments must be solid. The differ-
ent instruments must correspond with each other in their degree of
perfection, and must always be in good repair. Observations must
not be made when the air is uncommonly disturbed, or when the
observer cannot keep himself warm enough to be comfortable, — of
course when it is practicable to make the observations at all under
better circumstances.

The single observations should be uniform ; i. e., on nearly the same
number of wires, with nearly the same number of settings and micro-
scope readings.

Too great fatigue should be avoided by timely pauses, so that, for
instance, the first observations of a night may not be very good, and the
last very bad.

Long series of observations have been greatly damaged by the fol-
lowing causes, among others : —

Large errors of division, much exceeding the errors of setting upon
a star.

The wearing at the centre of a quadrant; and a gradual flexure of the
whole instrument.

Placing a transit instrument in a high tower, which expanded and
contracted by the sun's heat. Too great trust in the fixity of an
instrument. Closely counterpoising a meridian circle, so that,
when observing zones in a hurry, the axis was lifted out of its
bearings.

"Weakness of the telescope tube, and an attempt to improve it by levers
of flexure.

196 PROCEEDINGS OF THE AMERICAN ACADEMY

The wearing of the piv'ots of a transit instrument. Employing a per-
son to note time for the observer proper.

Negligence in determining the zero-points ; too great trust in the Nau-
tical Almanac in comparison with immediate observation.

The employment of two observers of very unequal skill upon the same
work. The employment of a careless or ignorant person to direct
good observers.

In all these cases, some one cause of larger error than is unavoidable
is brought into the work, and manifests itself by larger discrepancies
than the theory of probabilities indicates. In some old series, several
such causes are visible : the effect of tliese is to produce much larger
errors. Now-a-days an observer may be called upon to use an old and
poor instrument upon distant service, and runs the risk of unusual dis-
crepancies thereby.

So far with regard to the errors of single observations : I come now
to the smaller errors of series of observations.

If a star's place is determined hy four observations of equal value, it
will be affected with but one-fourth the sum of all the individual errors ;
and its probable error, the so-called internal probable error, will be but
one-half that of each observation. But there will be new errors intro-
duced, tending to slightly increase this. The skill of the astronomer is
shown in making these as small as possible : first, by giving all the
parts of his instrument as many reversals as he can, without affecting
the stability, reversing his axis end for end, interchanging objective and
ocular ; or else by making his observations more strictly differential.
The former is best, when fewer objects are to be observed ; the latter,
where the mass of work done is more important than its strict inde-
pendence.

Now I wish to notice that the errors of uniform star places will be
more exactly distributed according to the law of probabilities than
those of the single observations from which they are formed. For, in
the first case, the sources of error are more mmierous, and more
exactly uniform in their action ; while the resulting errors are more^
infinitesimal ; provided, that is, due care is taken witli the elimination
of constant error.

On the other hand, if one star be observed twice, and its neighbor, of
just the same importance, twenty times, it will be difficult to bring the
piobable errors of the results under any general rule.

OF ARTS AND SCIENCES. 197

The average rule ia first-class observatories is about this : —

Stars observed en masse, or by zones, should be twice observed, three
times if the two observations disagree much.

Stars observed for ordinary catalogues of objects, interesting as bright
or having proper motions, should ha four times observed, twice in each
of two opposite positions of the instrument. Stars requiring special
accuracy, not of the very first order, should be observed eight or ten
times. For fundamental determinations, it is not so much the number
of single observations that is important, as the number of separate
determinations (in different years) of eight or ten observations apiece ;
and also the number of variations in the position of the instrument
and its parts.

For some months I have been bringing together all available material
for a catalogue of latitude stars for the United States Enjiineers. Tal-
cott's method puts a heavy strain on the catalogue, as it is very simple,
and easily made accurate with a good instrument, but employs quite
small and ill-known stars, for want of well-proportioned pairs enough
at any given time and place.

Hence the British Association Catalogue, which contains stars
enough, was found almost from the day of its publication to be far
from precise. It could hardly be used with a two-inch zenith telescope
in indifferent condition, on the boundary between this country and
Mexico.

In supplying star-places for this purpose from time to time, the
gradual increase of material has been greatly encouraging. But, on
the other hand, there is a troublesome want of uniformity in modern
star-catalogues. To say nothing of unreduced observations, it often
happens that there is much carelessness in settling the zero-points of the
instrument, and the clock- and other corrections ; so that the errors in
these are often larger than those of observations. Moreover, the star-
places used as fundamental are often less accurate than those obtained
by their help ; and the various flexures and errors of division, and the
variations, in clock-rate, are neglected or ill-determined.

As a result, it becomes very difficult to assign the proper weights to
the separate determinations, and to settle upon those w^hich are to be
excluded. The simplest rule would be to exclude certain doubtful
catalogues altogether ; but unfortunately they are sometimes indispen-
sable, where the star is wanted, and no other authority of the same
epoch is at hand.

198 PROCEEDINGS OF THE AMERICAN ACADEMY

Great assistance has been obtained by noting all the doubtful cases,
and requesting their re-observation at the United States Naval Obser-
vatory, or re-observing them myself, when other duties would permit ;
but this is a matter which requires time. I might here mention that
the future progress of sidereal astronomy proper will be greatly fur-
thered by continually watching stars of doubtful proper motion until
their motions are decided ; and that the next few years will very greatly
increase the necessity of so doing.

It is, therefore, very necessary that the system of co-operation among
the astronomers of different countries, which has lately begun, should
extend much wider than it has, or at least that every observer should
strive to regulate his work by the uniform principles which guide the
best ones, and also to do that which is most necessary for the general
good. Fortunately, the making good observations, and reducing them
well, requires chiefly industry, system, and order, and is not very
dependent upon the capacity to appreciate the highest flights of mathe-
matical genins.

The one thing needful for good observations is, in a word, disci-
pline.

In computing probable errors, I generally use the sums of the dis-
crepancies, not the sums of their squares. The formula is. —

£ = 0.840 ./— 7 X

^ m{m — n)

where ^e denotes the sum of the errors, £ the probable error of a
single one, jn their number, ?^ the number of unknown quantities.
The little table annexed contains

V'w (m — n)

31 =

0.845

so that

with the arguments m and n. I have extended it only so far as I
habitually use it ; beyond these limits, it is better to calculate by loga-
rithms.

In the cah'ulations above-mentioned, I have used two little devices
for shortening the solution by least squares, which are best illustrated
by the same example.

OF ARTS AND SCIENCES.

199

The star Piazzi xv. 17G, has the following determinations of its
declination, reduced to the movable planes of 1875, by Bessel's pre-
cession and proper systematic corrections : —

Authority.

Declination.

Ep.

\Vt.

Piazzi & Lalande .

Taylor

Armagh ....
Quetelet ....

14oi0'51"l
47.7
46.9
44.2

1798
1H35
1842
1865

H
1

1
f

The equations to be solved by least squares will be : —

x—0.77y = d".l Wt=:H

x — 0A0y = 5.7 1

X — 0.33 ij = A.2 1

a;_0.10y = 2.2 f

Taking the mean by weights, we have x — 0.461 y = G".09, which is

the final determination of a; — 0.46 1 y.

Hence,

0.3093/==: — 3".01

0.061?/ = — 0.39
0.131y = — 1.19
0.361 y = — 3.89

with the same weights as before. Solving these equations by least
squares (a very easy process), that is, multiplying each by its coeffi-
cient of y and its weight, we get —

0.142 ,y=—l ".39
0.0045/ = — 0.02
0.017 2/ = — 0.16
0.097y = — 1.05

0.260 2/ = — 2. 62
hence x = 6".09 -f 0.461 X — 10.08= 1".44

Adding

y = —10"M

since the declination for 1875 was 14°10'42'' -|- x, and the proper
motions in one hundred years y; I took for y in round numbers — 10"
and brought up the declinations with its help as follows : —

200

PROCEEDINGS OF THE AMERICAN ACADEMY

Wt.

Pi. & Lai. .

T

Arm. . . .

Q

14°10'43"4
43.7
43.6
43.2

H
1
1
1

> strictly 43"44, see above.

Means 43. 48
Adopted 43. 5

The other process combines Taylor and Armagh into one place ;
thus, —

Authority.

Epoch.

Declination.

AVt.

(1)
(3)

Pi. & Lai.
T. & Arm.
Q-

1798

1838.5

1805

14°10'51'a
47.3
44.2

2
i

A theorem of Jacobi's tells us to multiply the result of any com-
bination of the two unknown quantities by the square of its deter-
minaut, and add all together, and divide by the sum of the squares of
the multipliers ; thus, —

Combination.

p. M.

Result
for one.

Square of Det.
X product of wts.

(1) (3)

(2) (3)

— 0"103
—0. 0'J4
—0. 117

672 X H X 1
40.52 X H X 2
26.5^X2 Xi

=5051
=4920
=1053

520.3
462.5
123.2

11024

IIOO.O

final mean— 0".1003.

Using — C'.IO as before, and bringing up we get

Pi. & Lai.
T. & Arm.
Q. . .

43"4
43. 65
43.2 ■

14oi0'43. 48 as before.

OP ARTS AND SCIENCES.
V «( {ill — n)

201

Table of J/=

0.«164

H=l

n = 2

m =3

2 90

2.05

4

4.10

3.35

6

6.29

4.58

6

6.48

5.79

7

7.67

7.00

8

8.85

8.19

y

10.04

9.39

10

11.22

10.58

11

12.41

11.77

12

13.59

12.96

13

14.77

14.14

14

15.96

1533

15

17.14

16.52

16

18.83

17.70

17

19.51

18.89

18

20.69

20.07

19

21.87

21.26

20

23.05

22.44

202 PROCEEDINGS OF THE AMERICAN ACADEMY

XIII.

BRIEF CONTRIBUTIONS FROM THE PHYSICAL LABO-
RATORY OF HARVARD COLLEGE.

BY JOHN TROWBRIDGE.

No. IV. — ON THE EFFECT OF THIN PLATES OF IRON USED AS
ARMATURES TO ELECTRO-MAGNETS.

Preseuted, Feb. 9, 1876.

In a paper presented to the Academy, April 13, 1875, 1 showed that
the application of armatures to two strait electro-magnets, which
formed the primary circuit of a Ruhmkorf coil, more than doubled the
strength of the induction current produced by breaking the primary
circuit. When, however, the circuit of the secondary coil was not
closed, and a spark was allowed to jump across the interval between
its poles, the striking distance of the spark, and its power to charge a
condenser, did not seem to be notably increased by the applications of
armatures to the electro-magnets of the primary circuit. My experi-
ments, at that time, were made with solid iron cores ; and I now
resume these experiments with bundles of fine iron wires in place of
the solid iron cores. The mechanical difficulty of making the ends of
the bundles of fine wires constituting the cores plane surfaces was
overcome by dipping them in melted solder, and then filing the
surfaces. In this way, I had no difficulty in applying the armatures so
that they should lie upon a plane surface.

The resistance of each of the two induction coils covering the two
strait electro-magnets was 6000 ohms, and that of each of the strait
electro-magnets .34 of an ohm. The diameter of the bundles of tine
iron wires constituting the cores was 5 cm., and the length of the
electro-magnets was 28 cm. Condensers of various sizes were placed
in the primary circuit: the results given in this paper were obtained
by the use of a condenser of about one Farad. The method of experi-
menting was to charge a condenser of ^ of a Farad by means of a
spark one millimetre in length, and then to' discharge this condenser
through a galvanometer. If we express the quantity of electricity

OF ARTS AND SCIENCES.

203

received by the condenser by Q, the electro-motive force and the
Civpacity of the condenser by E and C, we have Q = EG. We also

have Q^z"^ sin .V qp, where n is tlie reduction factor of the galva-

noraeter, t the time of vibration of tiie magnet, and (p the arc through
which it swings under tlie effect of tlie charge. Knowing the re(bic-
tion factor of my galvanometer, I had thus the means of reducing my
re.<ults to absolute measure. But I speedily found that the relative
results obtained by the proportions

Q: Q' = sin ^ (f : sm ^ cp' = E : E'

would present the points of this investigation in a manner as valuable
as if the results had been reduced to absolute magnetic measure.
My first experiments were made with solid armatures.

TABLE I.

Without armatures.

With armatures.

80

90

70

80

90

100

60

70

70

85

80

90

Mean 75

86

In this table, the numbers are the deflections of the reflecting gal-
vanometer expressed in millimetres. In this case, tlie gain by the use
of the armatures was trifling, being only about 14 per cent. These
results were obtained by charging the condenser of ^ of a Farad, by
sparks one millimetre in length.

On a closed secondary circuit, however, a gain of one hundred per
cent was clearly shown in the strength of the induced current pro-
duced by breaking the primary circuit. The question of how to make
this great increase in the strength of the induced current by the
employment of armatures manifest in the spark became an interesting
one. It seemed at first as if the application of armatures, by maintain-
ing the temporary magnetization of the iron cores, would be detrimental
rather than otherwise.

I next tried the effect of bundles of thin iron plates, which were

204

PROCEEDINGS OF THE AMERICAN ACADEMY

placed as armatures upon both poles of the electro-magnets, thus
making a magnet of a horse-shoe form. On charging the condenser,
I found a very great increase in quantity, which was manifested by the
swing of the galvanometer needle, the indications being entirely off
the scale. Table II. shows the results obtained by the use of iron
plates 55 of an inch in thickness, twenty in number, constituting each
armature.

TABLE II.

Without plates.

With plates.

80

400

70

380

90

370

60

400

70

370

80

400

Mean 75

Mean 385.6

Here a gain of four hundred per cent was manifested by the use of
the thin plates.

Tlte next step was to ascertain how many plates were necessary to
obtain the maximum effect. The difficulty of obtaining plates of the
same homogeneity made it impossible to obtain smooth curves. To
this difficulty was added that of breaking the primary circuit in a
regular manner.

If the results of Table III. are plotted, it will be seen that the
increase within small limits is very nearly proportional to the number
of thin plates, which were ^^j of an inch in thickness.

TABLE IIL

No. of

Deflections

No. of

Deflections

plates.

of galv.

plates.

ot galv.

1

11

0

15

2

12

7

15.5

3

13

8

16

4

18

0

. 18

5

14

10

■ 18.6

OF ARTS AND SCIENCES.

205

On increasing tlie number of plates, a point was reached where
there was no additional effect. The best result was obtained where
the mass of the armatures was approximately equal to that of the
cores of the electro-magnets. Plates of -^ of an inch in thickness
were also used ; but no advantage resulted in their employment, over
those of T^^ of an inch. It would seem that the thin plates followed
the same law as that of the bundle of line iron wires which constitute
the cores of induction coils of the present day, and that only a
moderate degree of discontinuity in the mass of iron submitted to
magnetic influence is necessary to prevent the formation of currents
of induction which prolong the magnetism of the cores, and prevent
the quick demagnetization necessary to produce intense currents of
induction. The eflfect of insulating the thin plates with thin dielectrics,
like paper, was also tried with no gain in effect. There appeared to
be a slight gain by placing the plates edgewise on the poles of the
electro-magnets, instead of allowing them to repose on their flat sides.
This was doubtless due to better contact of the metallic surfaces.

Since the above results proved conclusively a very great gain in
quantity and electro-motive force by the application of thin plates as
armatures, I next measured the striking distance of the spark.
Table IV. gives the results which are the mean of many trials.

TABLE IV.

Without armatures.

With armatures.

15 cm.

14 „

15 „

Mean 14.6

32 cm.
30 „
32 „

31.3

A curious fact came up in this connection. The lengthening of the
spark was not shown when the spark leaped directly between the poles
of the induction coil. The increase in quantity and electro-motive force
was only made manifest to the eye by the employment of condensers
in the secondary circuit. The results in Table IV. were obtained by
tlie employment of a Leyden jar of large capacity. The increase in
the quantity and electro-motive force was not only shown by the
increased length of the spark, but also by its increase in volume and
its loud snap. Tiie spark consisted of a thick central bolt, surrounded

206 PROCEEDINGS OF THE AMERICAN ACADEMY

by curious thin detached sparks. An attempt was made to measure
the increase of light in Geissk't tubes by Vierodt's photometi'ic appa-
ratus, but it was found too inexact for this purpose, if, indeed, there
was any increase of light, which certainly remains to be proved. I
know of no results which bear upon the relation of the increase of
light to the increase of electro-motive force of tlie induction spark.

Without condensers in the secondary circuit, liowever, the increased
electro-motive force of the spark was shown by its greater constancy
in leaping over a given resistance of air.

The results of this investigation can be thus summed up : —

1. The application of thin plates of iron as armatures to two strait

electro-magnets increases between four and five times the strength
of the spark produced by the surrounding secondary coils.

2. The length of the spark is doubled, which is only shown by the use

of a condenser in the secondary circuit.

3. The results show that it would be more economical to construct

induction coils consisting of two strait electro-magnets constituting
the primary circuit, and two fine coils constituting the secondary
circuit, witli the use of tiiin plates of iron as armatures to the
electro-magnets, than to distribute the same amount of wire on
one strait electro-magnet, as in the common form of llulimkorf
coil.

NO. v. — ON THE SO-CALLED ETHERIC FORCE.

Articles have appeared in various newspapers during the past few
weeks, calling the attention of the public to the evidences of a new
force discovered by Mr. Edison, of Newark, N.J., which he has
termed the Etheric Force. The New York " Tribune " of December .
9th contains a letter from Dr. G. M. Beard, which details some experi-
ments which he has tried ; and in the same letter Dr. Beard invites
the attention of scientific men to the alleged new phenomena.

Evidence of the force is obtained in the following manner : A bar
of cadmium or other metal — cadmium having the preference — is
placed upon the poles of a strong horse-shoe electro-magnet, in the
same manner that a soft iron armature is usually placed ; an insulated
wire is connected with the bar of cadmium ; and when the circuit in
which the electro-magnet is placed is rapidly interrupted, either by a
key or a vibrating armature, sparks appear at the end of the wire con-
nected with the bar of cadmium. It is claimed that tlie kind of elec-
tricity thus evolved does not answer to the usual tests of static

OF ARTS AND SCIENCES. 207

electricity ; that tliere is no evidence of any polarity ; tliat the force
passes through ordinary insulators hettcr than electricity of hi^fli
tension ; that no physiological effects are manifested when tlie dis-
charge is received by the hnnian body, and that it is impossible to
charge a Leyden jar or to affect a sensitive electrometer or mirror gal-
vaiionietcr by this force. The spark, it is c-laimed, differs from that
of ordinary electricity of high tension, in that it recjuires contact of the
end of the wire conducting it with a metal or carbon point presented
to it. The best sparks were obtained by rubbing a fine iron wire
against a rusty ffle or stove-pipe. Dr. Beard found that a galvano-
scopic frog gave no evidence of the existence of the force, although
a spark was received after the passage of the force through the frog.
I\Ir. Edison passed the force through iodized paper for three hours,
and no effect was produced. He also took the wire connected with
the apparatus out of doors, ran it along the ground and in a ditch on a
rainy night, and brought it upstairs several rods from the battery, and
the spark was seen by himself and Dr. Heard, at the terminal of the
carbon point connected with the wire.

The apparatus which I used to produce the phenomenon was a
strong electro-magnet, the limbs of which were six inches long, and
were covered with large bobbins of coarse wire, having a resistance
each of .70 of an ohm. Bars of iron, steel, and brass, were used as
armatures to evolve the force ; a copper wire was connected with the
bar of metal at various places, sometimes at the end and sometimes
in the middle ; and the end of this wire was tested by one of Sir Wil-
liam Thomson's cpuidrant electrometers, by his most delicate mirror
galvanometer, and by the carbon points advised by Dr. Beard in his
letter which we have referred to at the opening of this article.

The electrometer immediately showed a slight tension on the sur-
face of the bar of metal, which constituted the armature of the electro-
magnet. By the method of multiplication, the swing of the needle was
increased, so as to give uiunistakable indications of polarity ; the
directions of the indication being in opposite directions at making and
breaking the circuit of the electro-magnet.

It was evident that the want of polarity noticed by Mr. Edison was
due to the rapid alternating nature of the induction currents produced
in the bar of cadmium. That this so-called etheric force was nothing
but a phenomenon of induction seemed evident at first sight ; but one
would hardly have predicted that currents of sufficient intensity could
have been created in this way to produce a spark. The phenomenon
possesses, however, considerable interest, which seems to have been

208 PROCEEDINGS OP THE AMERICAN ACADEMY

overlooked by those who have given explanations of the phenomenon
based upon the ordinary laws of induction. Faraday early showed
that, if a copper disc be rotated between the poles of a strong electro-
magnet, currents of considerable strength could be drawn from it by
connecting one end of a wire with the axis of the disc, and the other
with its periphery. It has never been shown, to the writer's knowl-
edge, that by suddenly making and breaking the circuit of the electro-
magnet a degree of static induction could be produced in a copper
disc sufficient to produce a spark. It will be readily seen that making
and breaking the circuit of the electro-magnet is equivalent to cutting
the lines of force of the magnetic field by quick rotation ; and therefore
the phenomenon possesses an interest, because it sujjplies a break
in the literature of the subject.

NO. VI. — ON A NEW FORM OF MIRROR GALVANOMETER.

The want of graduated circles for galvanometers is often seriously
felt in Physical Laboratories. The method of reading the deflections
of the needle by the reflection of a spot of light from a minute con-
cave mirror over a scale, or by the reflection of a scale in a plane
mirror attached to the swinging magnet, are methods of great delicacy.

In certain cases, it is difficult to obtain suitable mirrors. I present the
following method of reading the deflections of a galvanometer needle,
without the aid of minute mirrors either plane or concave, which are
usually attached to the magnet. In this method, the mirror is station-
ary, while the magnet moves. I have applied the method to Helm-
holtz's modification of Gangain's galvanometer. In the line passing
through the pivot or line of suspension of the needle, not nece.ssarily
above the centre of the needle, but somewhere in a line passing
through its centre, and perpendicular to its length, an ordinary plane
mirror is placed. A piece of looking-glass will answer. Tlie silvering
of the upper half of the strip of looking-glass is removed, and a fine
scale is etched upon it ; or for rough purposes a paper millimetre
scale is pasted upon the unsilvered portion.

It will be i-eadily seen that for small deflections with a magnet pro-
vided with the ordinary long aluminum pointers, tipped at the ends
with a small vertical point, if the eye be placed so that the vertical
point and its image in the mirror are in the same line that the projec-
tion of the arc of the circle of which the needle with its pointers con-
stitutes the diameter, can be read along the scale placed upon the
mirror.

OF ARTS AND SCIENCES. 209

For small angles, this projection is very nearly equal to the arc
itself, for it is the sine of it; and if R is half the length of the needle
with its pointer, and M the projection on the mirror, then the angle

. -^,( . m

oc r= sin or sni « = — .

R ^i

This method obviates the difficulty of placing a plane mirror upon a
magnet, so that it shall be perpendicular to it, and also in a vertical
position in order that the image of a scale reflected from it can be seen
in a telescope, which is often a troublesome adjustment. It is true
that long pointers are needed, in order to magnify the indications of
the needle ; but a telescope pointed with a micrometer can be used,
which, after focusing on the vertical point at the end of the aluminum
pointer, one can focus on the deflection, and then read the fractions of
a division with extreme accuracy. In this case, very long pointers are
not necessary. The placing of the mirror perpendicular to the magnet
is an adjustment very easily made, for the pointer should coincide with
its image at the centre of suspension. A table of natural tangents is
therefore not necessary with this form of galvanometer.

VOL. XI. (n. S. III.) 14

210 PROCEEDINGS OF THE AMERICAN ACADEMY

XIV.

ON THE SOLAR MOTION AND THE STELLAR DIS-
TANCES.

By Truman Henry Saffokd.

(Third Paper.)
Presented, Oct. 12, 1875.

In previous papers, I have given investigations of this subject, based
upon proper motions determined by others. In the present, I give
the f6rmula3 and tables necessary for the farther prosecution of the
subject, in a form slightly different from the ordinary one. In view of
previous investigations by Madler and Kovalski, it will be necessary
to inquire very minutely into the proper motions whose annudl amount
is about 0."1. The more swiftly moving stars (as we see them) have
been investigated by Argelander and other astronomers, and will be
carefully tested : some of them, it is possible, will show a motion not
directly proportional to the time, not only because the great circle in
which the star appears to move does not meet the successive meridi-
ans at angles varying in the manner in which this hypothesis would
require, but also because we are nearing or receding from them, rela-
tively considered. Thus the terms depending on squares and products
of proper motion, which Mr. G. W. Hill has, I believe, first introduced,
which are the result of the varied relation between the star's apparent
motion and any set of Jixed planes, will not perhaps be the only terms
of this kind ; so that in such investigations I prefer to omit them and
determine by observation the total amount of these terms, following iu
this matter the example set by Bessel.

But the proper motions between 0''.1 and 0".2 are susceptible in
many cases (not yet studied) of accurate determination from observa-
tions now extant ; and in many other cases a ftiw additional observa-
tions will be sufficient, so that the work immediately needed is to
select from the whole mass such stars of this chvss as are adapted to
either method of treatment. »

OF ARTS AND SCIENCES. 211

The same is true in a greater or less degree of the stars whose an-
nual proper motions are less than 0".l. If these are Bradley's stars,
the new reduction by Professor Auwers, and redeterminations at
Pulcova and Greenwich, will be sulRcient for the present ; but, if not,
80 wide a tield for minute criticism is thus opened, that I suspect the
only cases at present worth testing will be those in which special
accuracy is to be expected ; as in the vicinity of the north pole, where
the ear^y observations of W. Struve afford the best possible means of
comparison, in addition to the standard places of Groombridj,^e.

In what follows, I give first the precession-constants and formuUxj ;
and next an auxiliary table for the computation of the relations be-
tween the star's proper motion and the solar motion supposed directed
to the point whose AR. is 259°50'.8 and Decl. -f 32°29M.

The computation of the most probable proper motion involves : first
the reduction of all observations with proper systematic corrections to
a fixed epoch by precession, next the assignment of weights and estab-
lishment of conditional equations, and lastly their solution ; but when
the proper motion is large, or the star near the pole, either the geomet-
rical formula? must be used, or a preliminary proper motion employed
to compute the terms of secular variation depending on it. In volume
IV. Part I. of the Annals of Harvard College Observatory (also
included in Volume VITI. of the Memoirs of this Academy, New
Series), I have given some examples of a still more rigid treatment
of such cases.

PRECESSION-CONSTANTS AND FORMULA.

Fundamenta Astronomiie, p. 297 (Bessel, I.).
For 1750 + <

m = 45".99592 -\- t 0".000308G4oO
n ~2Q .05039 — t 0 .0000970204

Annales de I'Observatoire Imperiale (Memoires, II. 209).
For 1850 + t^

m (ii) = 46".05912 + 0".00028372 t^
n (v) = 20 .05197 — 0 .00008663 t^

Tabulae Regiomontanae (Bessel II.).
For 1750 + <

m = 46".02824 -f- 1 0".0003086450
w = 20 .06442 — t 0 .0000970204

212 PROCEEDINGS OP THE AMERICAN ACADEMY

Peters, Numerus constans Nutationis, p, (195).
For 1800 + t

m = 46."0623 + 0".0002849 t
n = 20 .0G07 — 0 .00008G3 t

Bessel 11.

Struve. — Peters.

m

15

n

Log. n

m

n

Log. n

1750

46".0282

3.06855

20".0644

1.302427

46".0481

20".0650

1.302439

60

.0313

.06876

.0634

406

.0509

.0642

421

70

.0344

.068'. 6

.0625

385

.0538

.0633

402

80

.0375

.06917

.0615

364

.0566

.0624

388

90

.0406

.06937

.0605

343

.0595

.0616

365

1800

.0437

.06958

.0596

322

.0623

.0607

346

10

.0468

.06978

.0586

301

.0651

.0598

327

20

.0498

.06999

.0576

280

.0680

.0590

309

30

.0529

.07020

.0567

259

.0708

.0581

290

40

.0560

.07040

.0557

238

.0737

.0572

271

60

.0591

.07061

.0547

217

.0765

.0564

253

60

.0622

.07081

.0537

196

.0794

.0555

234

70

.0653

.07102

.0528

175

.0822

.0547

215

80

.0684

.07122

.0518

154

.0851

.0538

197

90

.0715

.07143

.0508

133

.0879

.0529

178

1900

46.0745

3.07164

20.0499

1.302112

46 .0908

20 .0521

1.302159

The formulae for secular variation are, as given by Menten, —
100 ^^^ = A-\-Bian8-\-C tan 8-

100 ^ = J' + j5' tan 8
in which, employing Bessel's constants for 18G0, —

A = o!o020G + 0.00650 sin 2 a = o'.0020G + ^ C
B= [8.4750] cos « + [G.811 n^ sin a
C= [8.1130] sin 2 «

A' = — 0."0097 cos a — 0."4479 sin «
B = [9.2900 w] sin a\

OF ARTS AND SCIENCES. 213"

Menten has tabulated the values of A and A', and the logarithms of
the other quantities for every minute of right ascension. These ex-
pressions do not include the effect either of precession in changing the
apparent amount of projier motion, or of proper motion in changing the
precession ; in other words, they are geometrical secular variations only.
The secular variation of the whole motion, omitting terras of the order
of the squares and products of the proper motions, is obtained by
adding to MentenV formula the terms, —

«'
0.01944 [« tan d cos « 4- — sec 5^ sin a]
'15 -"

— 0.01944. 15 fi sin a

in right ascension and declination respectively ; where /w and ft' are
the annual proper motions, ix expressed in time, fi' in arc of a great
circle.

o

Argelander in his Abo catalogue gives secular variations of preces-
sion only, and includes one half of these terms. Thus for a Draconis,
the geometrical secular variations for 1830, computed by Menten's
formula3 (without allowing for the trifling secular change in the
table), are, —

— o!o3622 and — 0".0299.

The proper -motion terms in the secular variation of the whole
motion, according to the previous formulae, are, —

+ o!oi921 4- 0".0254.

Hence the secular variation of the total motion is, for 1830, —

— 0.01701 and — 0".004o,
not including squares and products of proper motion.

o

The Abo Catalogue has, —

— 0.0265 and — 0".017;

that is, one half the proper-motion terms in the secular variation of
the whole motion, or, in other words, the whole effect of proper motion
in changing the precession, is included.

^Sometimes it is necessary to employ the geometrical formulae : they
are these, according to Carrington, using Bessel's constants, for the
reduction from 1750 -j- t to 1750 -|- t'.

214 PROCEEDINGS OF THE AMERICAN ACADEMY

2 -j- X = 23".0144 {t> —t ) — 0".0115 {V -\- t) — 0".000056 f^
— 0".000210<2

e'—V = 23".0144 {f — 0 + 0".011") {t' + 0 + 0".000210 t"^

-\- o".o()oo56 e

d — 20".0652 {f — 0 — 0'-.000048 <'^ -\~ 0".000048 f

a =r « -j- z -j- ^

COS 8' sin a' = cos 8 sin a

cos 8' cos a' = cos 8 cos « cos d — sin 8 sin d

sin 5' = cos 8 cos a sin ^ -|- sin 5 cos d

a' = a' -\-z' — V
Using Struve's constants, the values become : —

z -\-l=L 23".0311 {f — 0 — 0".0001922 e — 0".0000497 f'

z' — V= 23 .0311 {f — <)-}- 0 .0000497 ^^ _^ 0 .0001922 f^

e =20 .0611 {f — t)-\-0 .0000432 t- — 0 .0000432 ^^

. According to Bessel II., the formulae for the computation of these
quantities are, —

I = 0".17926 t — 0".0002G60394 f

0) = 23°28'18".0 + 0".00000984233 f
1/; = 50".37572 < — 0 .0001217945 <-;

1', (o', and \p', are the same functions of t'.

J (z' — z)= 0".1011804 (<' + 0 + 0".0000002446 {f -f ty

tan h (z '+ z) = ^^i ('•'' + ") tan ^ (xp' — xp)
tan 1 ^ = ^h\(?L±ll tan i («>' + (A

^ cos ^ (zi — z) ^ ^ ' ^

The time is counted from 1750.

According to Struve and Peters, the time is counted from 1800,

and I = 0".15119 t — 0".00024186 f^

w = 23°27'54".45 + 0 .00000735 e

t/j = 50 .3798 t — 0 .0001084 f

\{z' — z) =0 -.075573 {f + t)

+ 0 .0000001626 (<' + /)'

OF ARTS AND SCIENCES.

215

The last formula is quoted from Carrington.

LeVerrier counts his time from 1850, and finds (1 employ here
Bessel's notation), —

J (a,/ -f <w) = 23°27'32"0 -|- 0".00000360 (t^ + t'^)
^ (ifj' — x}j) = 25".1851G (f — 0 — 0".00005440 (t'^ — f)
^ («' — z) = 0 .0739G (f -f <) -j- 0 .000000 IG (f + <)'
X =0 .U7*J0 t — 0 .00024167 f^

TABLE FOR M AND m,

[See page 53 of this Volume.]

a

M

log. sin m

log. cos m

0°

105°45

9.7460

9.9193

2

108.27

9.7525

9.9163

4

1 10.99

9.7598

9.9127

6

113.58

9.7679

9.9086

8

116.05

9.7766

9.9040

10

118 40

9.7857

9.8987

12

120.62

9.7952

9.8928

14

122.71

9.8050

9.8864

16

124.68

9.8150

9.8793

18

126.53

9.8250

9.8715

20

128.26

9.8350

9.8630

22

129.88

9.8450

9.8539

24

131.39

9.8549

9.8440

26

132.80

9.8645

9.8333

28

134.12

9.8740

9.8218

30

135.35

9.8832

9.8095

32

136.50

9.8922

9.7062

34

137.56

9.9009

9.7820

36

138.55

9.9092

9.7668

38

139.47

9.9172

9.7505

40

140.32

9.9249

9.7329

42

141.11

9.9322

9.7141

44

141.84

9.9392

9.6939

46

142.52

9 9458

9.6721

48

143.14

9.9520

9.6486

50

143.71

9.9579

9.6232

52

144.24

9.9683

9.5958

54

144.72

9.9684

9.5658

56

145.15

9.9731

9.5331

58

145.55

9.9774

9.4971

216

PROCEEDINGS OF THE AMERICAN ACADEMY

TABLE FOR M AND m {continued).

a

M

log. sin 7n

log. cos m

m

60

145°90

9.9814

9.4573

73°34

62

146.22

99850

9.4129

75.00

64

146.50

9.9881

9.3628

76.67

66

146.74

9.9909

9.3056

78.34

68

146.95

9.9934

9.2391

80.01

70

147.14

9.9954

9.1598

81.69

72

147.27

9.9971

9.0622

83.37

74

147.38

9.9984

8.9354

85.06

76

147.46

9.9993

8.7546

86.74

78

147.50

9.9998

8.4382

88.43

80

147.51

0.0000

7.3036 n

90.12

82

147.50

9.9998

8.4976 n

91.80

84

147.45

9.9992

8.7842 n

93.49

86

147.37

9.9982

8.9551 n

95.17

88

147.25

9.9969

9.0770 n

96.86

00

147.10

9.9952

9.1716n

98.54

92

146.92

9.9931

9.2488 n

100.21

94

146.71

9.9906

9.3139 n

101.80

96

146.46

9.9877

9.3700 n

103.56

98

146.18

9.9845

9.4193 n

105.22

100

145.86

9.9809

9.4630 n

102

145.50

9.9769

9.5022 n

104

145.10

9.9725

9.5377 n

106

144.66

9.9677

9.5701 n

108

144.17

9.9626

9.6996 n

110

143.64

9.9571

9.0269 n

112

143.06

9.9512

9.6520 n

114

142.43

9.9449

9.6752 n

116

141.75

9.9383

9.6967 n

118

141.01

9.9313

9.7168n

120

140.21

9.9239

9.7354 n

122

139.35

9.9162

9.7528 n

124

138.42

9.9081

9.7690 n

126

137.42

9.8997

9.7840 n

128

136.35

9.8910

9.7981 n

130

135.19

9.8820

9 8112n

132

133.95

9.8727

9-8234 n

134

132.02

9.8632

9^348 n

136

131.19

9.8535

9-8454 n

138

129.66

9.8436

9-8552 n

140

128.03

9.8337

9.8642 n

142

126.28

9.8236

9.8726 n

144

124.42

9.8136

9.8802 n

146

122.43

9.8037

9.-8873 n

148

120.32

9.7939

9.8937 n

OF ARTS AND SCIENCES,

217

TABLE FOR M AND wi (continued).

a

M

Ipg. sin m

log. cos m

150

118°0'.»

9.7844

9.8995 n

152

115.72

9.7754

9.9040 n

154

113.23

9.7668

9.9092 u

156

110.62

9.7688

9.9133 n

158

107.89

9.7516

9.9167 n

160

105.06

9.7452

9.9196 n

162

102.13

9.7398

9.9220 n

164

yu.i2

9.7356

9.9238 n

166

96.03

9.7324

9.9251 n

168

92.92

9.7306

9.9259 n

170

89.79

9.7300

9.9261 n

172

86.65

9.7308

9.9258 n

174

83.53

9.7328

9.9250 n

176

80.47

9.7301

9.9236 n

178

77.47

9.7405

9.9217 n

180

74.55

9.7460

9.9193 n

COS ;f = sin w? cos (8 — 31)

sin ;( cos \p' = sin m sin [8 — M)

sin ^ sin \p' = cos m.

If a exceeds 180°, cos m changes sign, and the supplements of m and
ilf are given in the table with argument a — 180°.

218 PROCEEDINGS OF THE AMERICAN ACADEMY

XV.

CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF
HARVARD COLLEGE.

No. VIII. — ON THE INDUCTION SPARK PRODUCED IN BREAKING
A GALVANIC CIRCUIT BETWEEN THE POLES OF A
MAGNET.

By B. O. Peirce, Jr.

Presented, Feb. 9, 1875.

Becquerel, in the " Journal de Physique," IV. 206, states that
the spark obtained by breaking the current, which circulates through
an electro-magnet between its poles, is entirely a mechanical effect.

To test the accuracy of M. Becquerel's I'esult, I placed in the same
circuit four Grove cells, an electro-magnet of the form used in experi-
ments upon Diamagnetism, and a coil of coarse wire wound around a
bundle of iron wires on a core. Over this coil was slipped an induc-
tion coil of 6000 ohms resistance.

I first experimented Upon the spark given by the induction coil
when the primary circuit was broken between the poles of the electro-
magnet, and then outside of them.

The number of cells in the circuit was varied, and its resistance
was several times changed, in order to vary the circumstances as much
as possible ; and, at each change, a series of observations were taken to
see whether the spark ft'om the induction coil had any greater power
of overcoming resistance when the primary circuit was broken between
the poles of the magnet.

A long series of observations on sparks, which were of all lengths
from 2 1 to 15 mms., justifies the statement that the distance over
which the spark of the induction coil would regularly leap was more
than doubled when the circuit was broken between the poles. The
absolute length of spark obtained depended, of course, on the electro-
motive force in the primary circuit being apparently within certain
limits directly proportional to it. In almost all cases, the length of

OF ARTS AND SCIENCES.

219

spark was increased three or four times ; but iu no one set of observa-
tions was the spark less than doubled in length. These experiments
were rei)eated several times on difleroiit days.

I found great dilliculty in breaking the primary circuit uniformly,
and it was only after a long time that my results became regular.

I tried breaking from the surface of mercury ; but, although the
same relative effects were attained, the actual ert'ect was far inferior
to that obtained when two bright copper wires were separated in
the air.

Rowland has shown that a very powerful electro-magnet is not
needed, in order to obtain good results in studying Diamagnetism. la
order to see whether a small magnet would not do to increase the
length of the spark, a small electro-magnet, capable of supporting per-
haps two kilogrammes, was set up, and a series of observations taken
when the circuit was broken between its poles. In this case, the
length of the spark was just doubled. Might not a rather small horse-
shoe electro-magnet be advantageously placed upon the Ruhmkoitf
coil, so that the primary circuit should be interrupted between its
poles ^

I next put the electro-magnet in one circuit, and broke another cir-
cuit containing the primary of the induction coil between the poles
of the magnet. With this arrangement, two sets of observations were
taken under slightly different circumstances. The results are given
below in the actual space over which it was found that the sparks
would just pass. The words " outside " and " inside " denote that the
primary circuit was broken outside of the poles and between them
respectively.

OutsiJe.

Inside.

2i mm.
3 „

12i mm.
2Q „

Of course the relative increase in the length of the sparks depended
upon the relative strengths of the two currents. When the electro-
magnet is very weak, and the outside current very strong, subsequent
experiments showed that there was little, if any, increase in the length
of the spark.

As a direct means of showing that the extra effect obtained by
breaking between the poles is not mechanical, the following method

220

PROCEEDINGS OP THE AMERICAN ACADEIklY

was employed. The electro-magnet was placed in a circuit with two
Grove cells. To the end of one of the large wires used for breaking
the circuit a very fine wire was fastened, leading to one pole of
a Thomson's Quadrant Electrometer, whose other jiole was put to
earth. Whenever the two large wires were separated, there was of
course a deflection of the electrometer mirror corresponding to the
difference of potential of the poles of the battery ; but, beside this,
there was an increased effect when the circuit was broken between
the poles, that seems to be unaccountable, if we assume the effect to be
mechanical.

When a condenser of about 1 Farad capacity was put into the cir-
cuit, the following deflections were obtained : —

Primary broken
outside.

Primary broken
inside.

21

20.5

22

20

Mean 20.9

27
28
28
27

27.5

When no condenser was used, the deflections were as follows : —

Primary broken

Primary broken

outside.

inside.

20

22.5

19

23.5

20

23.5

20

24.

19.75

23.4

The electro-motive force in the circuit was very small, hardly enough
to render the poles strongly magnetic. With a proper electro-motive
force, we might expect the effects to be more striking.

In order to measure the increase of quantity obtained by breaking
the primary circuit between the poles of the m;\gnet, the electro-mag-
net and the primary of an induction coil were placed in the same

OF ARTS AND SCIENCES.

221

circuit as at first. The poles of the induction coil were connected, the
one directly, the other by means of the spark leaping between two
points with a condenser of J Farad capacity. The poles of the con-
denser were connected with a Tliomson's galvanometer of 5880 ohms
resistance. Each of the following results is the mean of two observa-
tions. The length of spark was the same in both cases.

Primary broken
outside.

Primary broken
inside.

6 cells.
4 „

17.5

12.

21.05
17.

The resistance of the six cells (Bunsen) was greater than the resist-
ance of the primary circuit.

On another day, the same arrangement gave the following result,
where each is a mean of two observations : —

Length of
spark.

Primary broken
outside.

Primary broken
inside.

1 mm.
3 „

22
12

30
23

In a great many cases, where the magnet was quite powerful, it
was not easy to get comparable results. When the primary circuit
was broken between the poles, the spot of light was driven off the
scale ; but, when the primary was broken outside, there was frequently
very little deflection.

At another time, a Thomson's mirror galvanometer of 6 ohms re-
sistance gave, with an arrangement otherwise the same as above, the
following deflections as a mean of twelve observations : —

Outside 12.9

Inside 15.37.

When the electro-magnet was in a separate circuit from the primary
of the induction coil, the following observations were obtained with the
Thomson's galvanometer. Each result is the mean of about twenty
observations.

222

PROCEEDINGS OF THE AMERICAN ACADEMY

Length of
spark.

Priinan' broken
outside.

Primary broken
inside.

1 mm.

2 „

3 „

4 „

21
20
16.5
15.2 ■

35.8
23
19.9
17

All these results were taken, interrupting the primary cirQuit by
separating two copper wires held one in either hand. Practice made
the results then obtained quite accurate. I at first tried breaking from
the surface of mercury ; but, beside the irregularity in the amount of the
deflection, there was a most unaccountable change of polarity every few
moments. I distrusted the evidence of my own senses so much in this
case that I asked several other peojile to observe for me, without pre-
viously telling them any thing of this change of polarity. In each
case, the observer noticed the reversal for himself. The deflection
was almost always in one direction when the circuit was broken
between the poles, and in the other direction when the circuits were
broken outside of the poles. This rule is not, however, absolute.
This reversal of polarity only occurred when copper was used to break
from the surface of the mercury. The separation of iron from iron,
or copper from copper, or iron from mercury, never gave any reversal.
This reversal was best seen with the electrometer.

At several different times, I took a series of observations upon the
deflection, by breaking inside the poles and outside of them when the
distance over which the spark had to leap was varied. The curves
obtained by laying down these deflections were not, as one might sup-
pose, hyperbolas, but were apparently exponential curves, having the
axis of X as an asymptote, but not the axis of y. A series of very
careful observations was taken by observing the deflections when the
distances over which the spark passed were small. The curves ob-
tained by breaking the primary between the poles were similar to those
obtained when the primary was broken outside. Tlie observations
were taken by breaking the primary with the interrupter of one of
Ritchie's induction coils. The sparks passed between two circular
discs of copper 10 cm. in diameter. In the centre of one of the discs
was an almost imperceptible protuberance^ in order to insure the sparks
always passing in the same place. One plate was fixed in a horizon-
tal position ; the other was suspended, by a thin ivory handle perpen-
dicular to its plane, to a glass rod placed in the telescope socket of a

OF ARTS AND SCIENCES.

223

catlietometer. In this way, it was found possible to get tlie j)latL'8
6ensil>ly parallel. The poles of the iiidiiction coil were connected with
a condenser ; one directly, and the other by means of the spark passing
between the two discs. The condenser was then discharged through
a galvanometer. The micrometer screw of the catlietometer reads
easily to the yo\)IT '^^ ^ millimetre, and observations were taken with
its aid at intervals of .0<3U mm. The plates were considered to be in
contact, whenever making the primary circuit gave any deflection in
the galvanometer. The zero thus obtained was quite constant, where-
as it was almost impossible to tell by the eye just at what point the
spark ceased to pass when the circuit was broken. The poles of the
battery were kept apart when not actually in use, and it was supposed
that the electro-motive force remained constant during the time of ob-
servation.

In laying out a curve, it must be remembered that there was a
resistance of GOOO ohms already in the circuit. Each of the following
results i? the mean of a series of closely agreeing observations : —

Separation of
plates in mms.

Deflections.

.050

183

.100

176

.150

164

.200

145

.250

130

.300

136

.350

123

.400

127

.450

120

.500

106

.550

102

.600

97

.650

92

.700

88

.750

90

.800

91

.850

95

.900

96

.950

88

1.

93

1.050

79

1.100

85

1.150

84

1.200

70

1.250

75

1.500

63

1.750

51

2.000

50

2.250

45

2.500

42

224

PROCEEDINGS OF THE AMERICAN ACADEMY

When the sparks passed between the ends of two copper wires,
§ mm. in diameter, carefully filed so as to be parallel, the curves ob-
tained were very regular, but of the same general shape. As an
example, I give the following : —

Dist. over which

the spark leaped

Deflections.

in lunis.

1

90

ii

70

3

55

4

44

5

35.6

6

27

7

20

8

13

9

7

10

2.5

11

1.4

12

.8

Sir "William Thomson has shown, in his paper on the " Electro-motive
Force necessary to produce a Spark," that a greater force per unit of
length is needed for short distances than for long distances. He does
not state in his paper whetl>er he experimented upon the Ruhmkorff
coil or the Holtz Machine. In using the Quadrant Electrometer in
measuring the electro-motive force of the sparks from an induction coil,
it is, of course, necessary to use a small leaping distance from tho
sparks to avoid the return current. At times, I have found that a
greater actual deflection was obtained when the leaping distance was
as great as | mm. than when it was much smaller. May not Sir
William Thomson's results be partly accounted for by induction iu the
same manner ?

Another method of experimenting upon the extra spark obtained
by breaking the circuit between the poles of an electro-magnet gave
excellent results. One of the poles of the induction coil was connected
with the outer coating of a very small Leyden jar; while the other
pole connected with the inside coating through a small interval of air,
to avoid the return current. The inside coating of the jai; was con-
nected by a very fine wire to a thin copper disc, 261 mms. in diameter.
Opposed to the copper disc, at a per[)endicular distance of IGO nims.,
was the end of a short rod, 1 mm. in diameter. Attached to the other
end of the rod was a very fine wire connecting with one pole of the

OF ARTS AND SCIENCES. 225

Quadrant Electrometer. The other pole of the electrometer was con-
nected with the ground. The very One wire leading from the oppos-
lug section of the rod was so arranged that experiment showed no
ludnctive effect from the disc upon it. When the primary circuit was
broken, a spark passed charging the Leyden jar, and consequently the
circular plate. The insulated i.late was consequently charged to some
constant potential F^.

According to Maxwell's Electricity, Vol. I. § 177, and Thomson's
I' Papers," 233, the surface density at any point on a thin circular
msulated plate is —

6 = ; — ^ — ,

2 TT- \/ a- — nil

where a^ is the radius of the plate, and m the distance of the point
from the centre.

If the plate is in the co-ordinate plane x y, we have, —

G =

27r-v/«2 — j^t — ^2

The potential at any point (x, y,z)m space due to this distribution is

J J '^' '"'^^ ^^'^ P^^^^ ^« *^^"- The limits must be so chosen as
to comprehend the whole surface of the disc, and to avoid errors the
pomt {x,y,z) must be opposed to the disc.

V ~ C C~° • I ^^ dy

yi'

At any fixed point {x^,y^, z^), therefore, the potential is proportional to
Fq. It was supposed necessary that the potential of the quadrants
attached to the short rod, which was at a great distance from the elec-
trometer,^ would be proportional to V^. The opposite quadrants were
at potential zero, being connected with the earth ; and since, when the
deflections are small they are proportional to the difference of poten-
tial of the two poles of the instrument, it was supposed that the
deflection of the electrometer needle would be a relative measure
of the potential of the plate.

A great many observations were taken with this apparatus, and the
results agreed with the former ones, not only qualitatively, but very
nearly quantitatively. I select the following series of observations to

VOL. XI. (n. S. III.) 15

226

PROCEEDINGS OF THE AMERICAN ACADEMY

show this. The difference is in this case not so widely apparent,
owino' to the extreme weakness of the current used ; it being at this
time, in order to get small deflections, the weakest used in the whole
of my work.

Primary broken

Primary broken

outside.

inside.

7.5

9.5

10.

9.

7.3

9.4

7.

9.5

8.2

8.5

8.2

9.2

10.6

9.5

9.5 .

8.6

5.2

8.4

10.

9.7

8.8

8.5

8.

9.4

6.5

10.5

9.4

10.9

7.

8.1

9.2

10.

5.3

8.7

10.5

12.

8.3

7.8

8.5

8.4

9.8

10.6

9.9

8.6

Mean 8.4

Mean 9.3

These were taken in sets of ten, with wonderfully close means, not-
withstanding the apparently great probable error.

Another series, with a stronger current, gave as the ratio of the
results 1.364.

The results of the investigation are as follows : —

1. By breaking the primary circuit of an induction coil in a magnetic

field, the length of spark produced by the secondary coil is more-
than doubled in length. An application of this fact to the induc-
tion coil is suggested.

2. The results by the different methods used all show an increase of

electro-motive force when the circuit is broken in a magnetic
field ; and that the effect cannot be purely a nicchanic^al phenome-
non, as M. liecquerel affirms.

OF ARTS AND SCIENCES. 227

3. By bre:ikiiig tlie circuit between mercury and copper in the mag-

netic liolil, a remarkable change of polarity was observed witli
the electrometer.

4. An explanation is offered of the fact noticed by Sir William Thom-

son, that a greater electro-motive force per unit of length is
needed to produce a spark at a short distance than at a long^one.

The subject of this paper was suggested to me by Professor Trow-
bridge, and throughout all my work he has kindly given me his advice
and help.

228 PROCEEDINGS OF THE AMERICAN ACADEMY

XVI.

CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF
HARVARD COLLEGE.

No. IX. — CONDENSERS AND GEISSLER'S TUBES.
Br William P. Wilson.

In the secondary circuit of a RulimkorfF's coil of 6000 ohms resist-
ance was joined a galvanometer, and successively Geissler's tubes con-
taining GO, H, and 0. The galvanometer was constructed from a
Rdhmkorff's coil equal in resistance to the one used in the secondary
circuit. Upon sending a spark through a Geissler's tube of GO, a
deflection of 8 centimetres was given by the galvanometer.

The light was strongest in the centre of the tube ; near the positive
and negative poles of the platinum electrodes it was very feeble.

The color in the middle of the tube shaded into red ; at the ex-
tremities it was a pale bluish-white. The light in the enlarged part
of the tube, approaching the positive pole, was beautifully stratified
with alternate light and dark bands. A condenser, consisting of a
Leyden jar of 60.5 sq. cm. surface, was connected with the opposite
poles of the coil, and a spark again passed through the Geissler's tube.
The galvanometer gave the same deflection of 8 cm. as before, but the
difference in light was very marked. This increase in light did not
show itself in the centre of the tube, but towards the extremities ; both
poles, and especially the positive, becoming much more brilliant. The
dark and light bands seen near the positive pole, before the introduc-
tion of the condenser, now entix-ely disappeared. The Geissler's tube
was removed, and an equal air resistance substituted. This was done
by placing near together, and in line, the broken ends of the wire.
By a micrometer adjustment, these wire points could be made to recede
from or approach eacii other, until the galvanometer gave a deflection
of 8 cm. with the condenser in the circuit. Upon sending a spark
through this air resistance, having previously disconnected the con-
denser, the deflection of the galvanometer was at once increased from
8 to 20 cm. The light did not vary as much as in the Geissler's tube,

OF ARTS AND SCIENCES. 229

but could easily be seen to be brigbter ubeu the comlcnser was in the
circuit. The following is the record of observations upon three gases,
and the equal air resistance, with and without a condenser: —

1. Current passing through Geissler's tube of CO.

With condenser, deflection = 8 cm.
Witliout „ „ =8 era.

With „ light increased.

Witliout ,, „ decreased.

2. Current passing through Geissler's tube of //.

With condenser, deflection = 8 cm.
Without ,, „ =8 cm.

With „ light increased.

Without „ „ decreased.

3. Current passing through Geissler's tube of 0.

With condenser, deflection = 8 cni.
Without „ „ = 8 era.

With „ light increased.

Without „ ,, decreased.

4. Current passmg through air resistance equal to the resistance of Geissler's

tube.

With condenser, deflection = 8 era.

Without „ „ = 26 era.

With „ light increased.
Without „ „ decreased.

Let (7, be the condenser ; S, the entire energy of current which would
produce magnetic effect ; L, that part of the energy expended in light ;
and m, the deflection of the galvanometer. We shall then have in

air : —

Without C, S — L =<t>{m)
With C,S — L^ = <t> (nil)
frt = 3.25 times m^
L <L^

in gas

Without C, S — L^ — tf) (mj)
With C,S — L^ = <p (mg)

In other terms, having an air resistance equal to that of the Geissler's
tube, the introduction of a condenser increased the light, and decreased
the dejlection of the galvanometer. Or replacing the air resistance with

230 PROCEEDINGS OF THE AMERICAN ACADEMY

the Geissler's tube, the introduction of a condenser gave a marked
increase in the light, much more so than in air, but no decrease in the
deflection of the galvanometer.

An attempt was made by Vierodt's method to measure the increase
and decrease of light consequent upon the introduction and withdrawal
of the condenser ; but it was found that the intensity was not sufficient
to obtain any accurate results.

It will thus be seen that the effect on the galvanometer was the
same when any one of the gases was used ; and also that, when the
Geissler's tubes were in the circuit, the condenser might be introduced
or withdrawn with no visible result in the deflection of the galva-
nometer.

With an air resistance the spark was a small one with two bright
points and a dark centre. This spark gave a larger deflection of the
galvanometer, but very little light. When the condenser was intro-
duced into the circuit, the character of the spark was changed at once
to a larger one of even intensity. The light was greatly increased,
and the deflection of the galvanometer correspondingly decreased.
But with the Geissler's tubes in the circuit, the only difference which
could be observed between the sparks when the condenser was intro-
duced or withdrawn was in light. The galvanometer continued to
give the same deflection in both cases.

A Geissler tube, .therefore, affords a test for the presence and action
of a condenser in the secondary circuit of an iuduction coil when a
galvanometer fails to do so.

OF ARTS AND SCIENCES. 231

XVII.

ON VIVIPAROUS ECIIIXI FROM THE KERGUELEN
ISLANDS.

By Alexander Agassiz.

Presented, March 8, 1876.

The function of the deeply sunken petaloid ambulacra of several
genera of Spatangoids, such as Moira, Schizaster, Hemiaster, and the
like, has thus far remained unknown. Philippi, in 184"), while
describing some South American Spatangoids, found in the deeply
sunken posterior ambulacra of Hemiaster cavernosus minute Echini,
which he regarded as the young of the species, though they differed
widely from the adults, and seemed, from their shape and the nature of
their spines, to approach nearer the regular Echini than the Spatan-
goids. The Echini of this genus being but rarely found in collections,
no opportunity occurred of verifying the observations of Philippi.
A somewhat analogous observation was made by Grube, who described
more in detail the young of Auochanus (Echinobrissus), which he
found living under very similar circumstances, in a cavity opening in
the abactinal pole of the specimens. No details of the nature of this
cavity having been as yet published, it is not possible to compare these
two modes of carrying the young in these two genera more closely.

In Spatangoids, with deeply sunken ambulacra, we find, nearly
in all cases, that from the sharp edge of the ambulacra! groove long
spines extend, so as nearly to close the opening of the cavity, entirely
bridging it over, and completely concealing from view the ambulacral
pores. This arrangement has usually been considered in Spatangoids
as a sort of filter to keep foreign particles from affecting the delicate
water tubes, which in the Spatangoids perform more or less the func-
tion of gills. This is undoubtedly the case in several genera ; but in
the case of Hemiaster, and perhaps in other allied genera, the sunken
ambulacral area is used for an entirely different purpose, as was cor-
rectly observed by Philippi, that of sheltering the young.

That the many specimens (eight) found in the two posterior sunken
ambulacral areas are really the young of Hemiaster, is of course only

232

PROCEEDINGS OF THE AMERICAN ACADEMY

probable, from the fact that the genital openings, which are unusually
large, open directly into the upper part of their sunken area ; so that the
eggs (or more probably an imperfectly developed Pluteus, like that of
Echinaster) on escaping from the genital openings would readily find
their way into the artificial cavity formed by the spines which conceal
the presence of the sunken areas.

Unlike many Echini, the ovaries of this genus are small, consist-
ing of compact grape-like clusters of eggs, in very different stages of
development, a few of the eggs only attaining a considerable size
(nearly 1 mm.) and apparently ready to escape into the sunken area, as
soon as the place should be left unoccupied by the preceding brood.
No two of the small Echini were in the same stage of development :
they varied in size from 2 mm. to 3 mm., the smaller specimens having
a somewhat pentagonal outline, with rounded angles ; the larger ones
were more nearly elliptical and cylindrical in shape. In the smaller

Fig. 2.

Fi.£T. 1.

specimens (Fig. 1), the spines were short, straight ; the longest, and
only a few in each interambulacral area, about one-fifth the length
of the axis, while the greater number were mere tubercles, scarcely
rising above the level of the test. In the largest specimens (Fig. 2),

Fio. 1. Young Ilcmiaster, measuring 2 mm., seen from the abactinal pole. a,a,
ambulacral spaces. Tlie peripetalous fasciole is already developed.
„ 2. Somewhat older Ilemiaster, measuring 3 mm., seen from the actinal
side, a, a, ambulacral areas.

OF ARTS AND SCIENCES.

233

many of the spines, nearly equalling the radius of the test, had become
curved and assumed the characteristic appearance of Spatangoid spines.
Seen from below (Fig. 3), the large angular mouth, covered by a thick
membrane, was nearly central, somewhat anterior, the edge of the
mouth ou the level of the test, and a few small indistinct pores (Fig. 4)

Fiff. 3.

Fig. 4.

arranged in parallel lines, showing the position of the future actinal
petal ; the ambulacral areas were occupied by coarse granulation, while
the tubercles of the interambulacral spaces were large with well-
developed crenulation, and already perforated. The interambulacral
areas were already broad, leaving but narrow ambulacral spaces, in
which the short, club-shaped ambulacral tubes could with difficulty be
traced ; they were largest
near the apex, and near the
actinostome (Figs. 4, 5).
Seen from above (Fig. 5),
the most marked feature
of all these young Echini
was the broad fasciole, oc-
cupying so large a part of
the abactinal surface, the
position of the interambu-
lacral area being clearly
marked by the two large

tubercles at the extremity of these areas on the abactinal edge of the
fasciole. The whole fasciole was covered by a coarse granulation.

Fig. 3. Young Hemicaster denuded of spines, seen from the actinal side.

„ 4. Portion of actinal surface of Fig. 3, adjoining actinostome to show
structure of tubercles, a, ambulacral area with pores ; ia, ia, adjoin-
ing interambulacral spaces.

„ 5. Fig. 3, seen from the abactinal side, somewhat more enlarged to show
the position of anal system (a), entirely enclosed by the peripetaluus
fasciole (/), the few ambulacral pores of tlie lateral ambulacra, anc'
the more numerous pores of the odd ambulacrum.

234

PROCEEDINGS OF THE AMERICAN ACADEMY

Fier. 6.

The most striking feature in the structure of these small Echini is
the position of the anal opening (Fig. 5, a). This is nearly in the
central part of the abactinal surface towards the posterior edge, and
entirely surrounded by the fasciole. This fascicle, from its position,
must undoubtedly be the peripetalous fasciole, as it agrees in position
with the same fasciole in Brissopsis, though in the latter genus it does
not enclose the anal opening. In the adult Hemiaster the anal open-
ing is not thus surrounded, an additional example of the little value
we can place upon the position of the anal opening as a systematic
character. The transfer of the anal opening to the exterior of the
fasciole I was not able to trace, all the specimens being too young to
show when it took place. There is no trace in these young stages of
any genital openings, or of genital plates; the ocular plates are

somewhat more prominent than the
other ambulacral plates, one speci-
ally, that of the odd ambulacrum
(see Fig. 5). On opening one of
these young Echini (Fig. G), we
find that, notwithstanding the posi-
tion of the anal opening, the intes-
tine already makes a half circuit
round the edge of the test, and is
attached to the sides by the usual
mesenteries, the actinal extremity of
the alimentary canal towards the an-
terior end being free ; the stone canal also leads nearly vertically
flora the anal o^iening to a terminal interambulacral plate situated
to the right of the odd ambulacrum. The anal opening is large,
pentagonal, separating completely the trivium from the bivium, and
is covered by a large plate having a small opening opposite the left
posterior ambulacrum.

The only other young Spatangoid known, resembling so closely a
regular Echinus, is a young Spatangoid figured by Miiller, while still
in the Pluteus stage, with straight spines similar to these figured here
in the youngest specimen. This was the first indication we had of the
great similarity of the sjjines of the young stage.^ in the regular and
irregular Echini. The presence of an anal opening in the young

Fio. 6. Section of Hemiaster, showing tlie course-of the alimentary canal c',
from the mouth m, to tlic anal system an ; c, the stone canal, extoiuling
from tiie circuhir ring to madreporic body md.

OF ARTS AND SCIENCES. 235

Ilemiaster connected, so to speak, with the abactinal system is a most
interesting feature, as well as the complete separation of the bivium
and trivium, the origin of which among Echini had not been under-
stood. The whole family of Collyritidae, in which this is the normal
state, appear in geological times as an abnormal group, disconnected
entirely, and isolated from all the other Spatangoids, which it precedes
in time, and seeming thus far to have no connection with the Spatan-
goids of later geological periods. Their connection as an embryonic
stage is now clearly shown by the young of Ilemiaster here figured,
as well as the close relationship existing between the regular Echini
and such Spatangoids as CoUyrites, appearing as the earliest geologi-
cal representatives of the Spatangoids. The Collyritidas are, there-
fore, not structurally so far removed as has been generally supjiosed
from the regular Echini.

The earlier development, that preceding the stage when the em-
bryo esca^ies in to the ambulacral area, could of course not be traced
satisfactorily. But enough could be seen of the shape of the embryo
mass to render it highly probable that the development was very
similar to that of other viviparous Echinoderms (Star-fish and Ophiu-
rans), in which the young are carried about by the parents till they
are well advanced star-fishes (Sars, Miiller, Agassiz), or hatched
from the main cavity as well-developed Ophiuridae (Quatrefages,
Schultze, Lyman, Agassiz), and where the plutean development is
passed through in a very imperfect manner, owing to the rudimentary
devolopment of the arras, which take such an extreme degree of
growth in the pelasgic Pluteus of Echini and Ophiurans, traces only of
these arms being found in the younger stages of growth of these vivi-
parous Echinoderms.

The specimens I have had the oi^portunity of examining were col-
lected at the Kerguelen Islands by Dr. J. H. Kidder, the Naturalist
attached to the Transit of Venus Expedition, and were sent to me
for examination by Professor Verrill. He has described the species as
new, under the name of H. cordatus ; but I cannot distinguish it from
Hemiaster cavernosus and H. Australis, which I was led to consider
(from analogy with H. Philippii) to be identical species. It is re-
markable that, in the young stages of both these species, all the ambu-
lacra are but little sunken, and it is only when they have attained a
considerable size that the posterior ones begin to deepen. Philippi con-
sidered this might be a sexual feature. We have not sufficient data to
decide the question, but can only say that up to a certain size, at any
rate, there is no difference in the depth of the ambulacra of males and

236 PROCEEDINGS OP THE AMERICAN ACADEMY

females. See PI. IV., Figs. 4-8, Echini of Hassler Exiiedition. 111.
Cat. Mus. Comp. Zool. No. VIII. I have examined a large number
of a common Spatangoid from our southern coasts (INIoira atropos),
with ambulacra still more deeply sunken than in Hemiaster, in hopes of
finding the young, but thus far without success ; from the eggs of Schi-
zaster canaliferus from the Mediterranean, in which some of the am-
bulacra are also deeply sunken, a pelasgic Pluteus is known to be
developed ; so that in many of the genera with sunken ambulacral
petals the sunken area does not shelter the young in their earliest
stages of development.

OF ARTS AND SCIENCES. 237

XVIII.

ON A POSSIBLE EXPLANATION OF THE METHOD EM-
PLOYED BY NOBERT IN RULING IIIS TEST PLATES.

Bv William A. Rogeks.
Presented, June 9, 1875.

I RECOGNIZE the fact that no explanation of a purely mechanical
process can be regarded as either satisfactory or final, which does not
answer the crucial test of reproduction. I offer to the Acadenay what
I believe may prove to be an explanation of the process followed by
Nobert in ruling his test plates ; the highest baud which has been
resolved under the microscope, reaching 112,600 lines to the inch.
You properly ask me if I can reproduce these rulings. I frankly
answer that I cannot. Indeed, I can hardly hope ever to succeed in
producing lines which combine the wonderful delicacy, uniformity,
and distinctness found in nearly all of Nobert's plates. But I have
reached what I hope may prove to be a useful approximation to
Nobert's results. Beginning with 2000 lines to the inch in 1871, I
have now little difficulty in reaching G0,000, the width of each line
being a little less than one half of the intervening space. Several
of my plates have been correctly counted as far as 80,000 to the inch ;
the observer having no knowledge of the actual number ruled. Two
plates in the possession of Frederick Habirshaw, Esq., of New York,
contain bands proceeding by 10,000 as far as 120,000 to the inch.
The bands of both these plates were correctly counted by Samuel
Wells, Esq., of Boston, as far as 80,000, but beyond that point the
number counted was less than the number ruled. While the lines of
the higher bands seem to be nearly as distinct as Nobert's, they are
by no means as smooth and uniform throughout their whole length.

The theory which I offer to the Academy is wholly the outgrowth
ot my own experience. In the various experiments which I have
made, I have noted the constant recurrence of certain results under
certain conditions, and these results form the basis of my conclusions.
Whether they form a true explanation of Nobert's process is, of course,

238 PROCEEDINGS OF THE AMERICAN ACADEMY

entirely a matter of conjecture. I am well aware of the risk incurred
in offering a theory which can at once be refuted by a single stroke of
the pen. Nobert has well kept the secret of his process. If I have
failed to detect it, it is easy for him to say, " You are wholly mis-
taken." Even if this proves to be the case, the facts developed in the
course of my experiments may possess sufficient interest to warrant
their publication.

The problem is naturally divided into two parts : —

(a). The mechanical operation of moving the plate to be ruled over

given and equal spaces.
(b) . The operation of pi'oducing on glass, lines of varying degrees of

fineness.

If a screw is employed to give the required motion, it woidd seem
at first siglit very easy to reach any desired limit of accuracy. In my
own machine, the head of the screw, which is 11 inches in diameter,
is divided into 100 equal parts. For subdivisions, a microscope is
employed, having an eye-piece micrometer, 100 divisions of which
exactly cover one division of the screw-head. It is therefore easy to
read directly to y^^^^, and by estimation to ^^j^j^^y of a revolution.
Since the pitch of the screw is ^^^ of an inch, these numbers corre-
spond to a motion of ^4ti'o^^ and y^-^j^jj-^ of an inch. By a device
which I shall presently describe, the subdivisions can be carried to
rvii^ovxs of ^ revolution.

But nothing can be farther from the truth than to suppose that,
because this high limit of theoretical accuracy can be reached, there-
fore the lines ruled are separated by spaces accurate within the same
limits. It is difficult to name the lowest limit of deviation from the
truth which it is possible to reach ; but I have long since despaired
of being able to rule, e.g. 100 lines, covering successive revolutions
of the screw which shall contain no errors of any kind, whether in-
dividual or accumulated, greater than ^ootjit iiich. I have availed
myself of every opportunity to measure the ordinary stage microme-
ters furnished by dealers in microscopes, and I find the usual range
of error to be between t^q^jj^ and yo^xity ^^ -''^ inch.

Of course the average error may fall fiir witiiin these limits ; and,
especially when the lines are closely ruled, the individual errors may
seem by comparison insignificant ; but I have been unable to find any
rulings which invariably surpass the limit which I have named. As
an illustration of the limit of accuracy attainable, I give in Tables I.,
II., and III., measurements of an excellent Nobert ditlractiou plate, a

OF ARTS AND SCIENCES. 239

Rutherford UUrractiou pliito, and a plate ruled by uiyself for the pur-
pose of investigating the errors of my screw. The measures were all
made with a f\^ objective, and an eye-piece micrometer, 200 to the inch,
tlie lines of which were about x5ff(T«T o^ ''^^ '"^^ ^^ breadth. Using a B.
ocular, the value of one division was found to be xssiyff o^ ^^ ^"^b*
With this arrangement, it was found easy to measure any given space
to yuJ^y^y of an inch with considerable certainty. To eliminate errors
in the micrometer, the same divisions were used in all comparisons.
In the Nobert plate, the width of the lines is about xgjjj^ of an inch ;
in the Rutherford plate, s^^jj^ of an inch ; and iu my own, 55 J jj^ of
an inch. The space measured was ^^^ of an inch.

Table I. contains the residuals obtained by subtracting the meas-
ure of each space from the mean of all the spaces.

Table II. contains the residuals obtained by subtracting the error
of each space from the error of the next consecutive space.

Table III. contains the periodic errors deduced from Table I.

240

PROCEEDINGS OP THE AMERICAN ACADEMY

TABLE L

RESIDUALS FROM THE MEAN.

Spaces.

I.

Nobert.

II.

Rutherford.

III.
Rogers.

Fraction of incli.

Fraction of inch

Fraction of inch.

1

'^ 21700

1

33800

1

~ 44700

2

1
76000

+ 27600

1
44-00

3

"T" 3S000

1
~ 30700

1
23800

4

1
76000

1
— 101000

1
34500

5

0

1

— 27600

1
34500

6

38000

1

— 43400

1

4T7OO

7

1C900

1
— 33800

1
108600

8

1
21700

1

— 101000

1
~ 380000

9

1
152000

1

+ 307000

' 253000

10

1

3S000

1

+ 101000

' 27200

11

i

50700

1

4- 33800

' 27200

12

+ /

70000

1

— 33800

' 20000

13

+ _ J._
152000

1
+ 307000

' 33100

14

_ 1

7C.000

1
— 101000

' 42200

15

11)000

1

+ 43400

' 67500

16

50700

1
— G0800

+ J^
' 23100

17

_ 1

lodob

1

— 307000

1

108600

18

1

30400

1
— 307000

1

380000

19

_ 1
50700

1
+ 43400

1
34500

20

' 152000

1
+ 43400

1

~ 44700

OF ARTS AND SCIENCES,

241

TABLE II.

CONTIGUOUS ERRORS.

Spaces.

1

2

3

4

5

6

7

8

9
10
11
12
13
U
15
16
17
18
19

I.

Nobert.

Fraction of inch.

1

10900

_L

25300

1
25300

1
76000

1
3S000

1

30400

1

9500

1

25300

1

50700

1

152000

1
30400

1
15200

1
5"0700

1
15200

1
30400

1
13800

1
60700

1
76000

II.
Rutherford.

Fraction of inch

1

15200

1

25300

1

152000

1
21700

1
16900
_ 1
r5200b

1
50700

1

76000

1

152000

1
50700

1
16900

1
30400

1
76000

1
30400

1
25300

1
50700

0
1

76000

III.
Rowrs.

Fraction of inch.

1

50700

1
76000

1

76000

1

50700

1

152000

1
152000

1
38000

1

19000

1

152000

1

38000

1

152000

VOL. XI. (n. 8. III.)

16

242

PROCEEDINGS OF THE AMERICAN ACADEMY

TABLE m.

PERIODIC ERROUS.

Spaces.

I.

Nobert.

II.

Rutherford.

III.

Rogers.

Fraction of inch.

Fraction of inch.

Fraction of inch.

1

~ 21700

1

33«)b

I
44700

2

+ J--
~ 30400

~ 152000

1
22400

3

' 16900

"J" 30400

1
11500

4

' 21700

1

152000

1

8700

5

"f" 21700

' 33800

1

6000

6

"T" 13)^00

~ 152000

1

6000

7

"1 7600

1

1

5700

8

"• 11500

1

30400

1
5600

9

' 12700

1
33800

1
~ 5700

10

"r 10000

1
50700

1

7200

11

">" 30400

1 100300

1
9900

12

21700

1
50700

1

19500

13

19000

1

60800

1

47000

14

25300

1
38000

' 380000

15

10000

1
30400

' 60700

16

' 8000

1

7C000

"T" 15800

17

' ItiOOO

1

60800

4- '

~ 18500

18

1
50700

~ 19500

I'J

1

152000

1

~~ 100300

' 44700

20

0

0

0

OF AllTS AND SCIENCES. 243

It is quite evident that in the throe cases under consideration, there
are numerous acriduntal errors amounting to ^^^inu ^^ '^'^ "'*^'' '^"'^
more, while in the hist case the evidence of periodicity is very decided ;
its value at the maximum point being 75^50 of an inch. An exam-
ination of the values in Tables I. and 11., column III., will show how
easy it is to be misled by a seeming accuracy when only consecutive
spaces are measured. It is only when the errors become maguitied by
successive increments that they attract attention.

The following will be fuuixl a very convenient and accurate method
for measuring directly the magnitude of the periodic errors.

First, a series of equidistant lines is ruled on thick glass, care being
taken to use glass having a plane surface. It is better also to have
the spaces corresjiond to equal parts of a revolution of the screw. On
one side a heavy finding line is ruled. This band is then reproduced
on microscopic cover glass, having a thickness of about y^^ of an inch.
Of course care is taken to use the same part of the screw, and the
same divisions of a revolution as before. By cementing the glasses
together with balsam, face to face, but with the finding lines coinci-
dent and on opposite sides, the periodic errors, if they exist, will
appear under the microscope with twice their real magnitude.

In this way it is easy to measure not only the maximum value, but
the values corresponding to every division of the screw-head. If an
objective of high power is employed, care is necessary to have the
surfaces of both pieces of glass as nearly plane as possible. Much
better results are obtained by using a piece of cover-glass not larger
than jig^ of a square inch.

Mr. John M. Blake, of New Haven, did me the kindness to photo-
graph on cover-glass, the plate whose measures are given in column
III. By reversing the plates, in the way indicated above, he found
almost precisely the same value for the maximum periodic error
deduced above ; viz., ^-^qq of an inch.

In passing, it may be interesting to note that though the lines of
the Rutherford plate are more distinct than those of the Nobert plate,
and though the errors of spacing are considerably less, yet the former
was rejected from the start as an imperfect one, while the latter gives
excellent results, yet both plates will show with about equal distinct-
ness four lines between the components of the magnesium line b. This
is hardly in accordance with the theory that the optical test of paral-
lelism of lines, and of equality of spacing, is far more perfect than the
test of actual measurement. It is evident that the theoretical limit of
accuracy required, in order to produce the solar lines in the greatest

244 PROCEEDINGS OF THE AMERICAN ACADEMY

perfection, has rarely if ever been reached in actual practice. All the
evidence seems to point to the conclusion that the brilliancy of the
spectrum depends as much on the character of the lines, and especially
on the character of the edges, as on the equality of the spacing.

It is obvious, then, that the errors which are to be the most feared,
both on account of their magnitude and the likelihood of their escap-
ing detection, are those which are periodic in their character. To tlio
investigation of the sources of these errors, in my own machine, sev-
eral months of careful study have been given. Without entering into
a detailed account of fruitless experiments, I will give only the conclu-
sion at which I have arrived ; viz., that the periodicity resides, not in
the screw itself, but in the mounting of the screiv. The evidence on
this point seems to be conclusive. In a large number of separate
measurements extending over several weeks, substantially the same
system of values as those given in column III. were found. These
values were also constant for different parts of the screw. Conjectur-
ing that the trouble might arise from unecjual friction between the
screw and the nut at different parts of the revolution, owing to the
want of parallelism, between the screw and the fixed way on the bed
of the machine, a slight movement was given to the adjusting screws,
which clamped the split nut. At once the system of corrections
was wholly changed, not only in value but in sign, and the values now
found, remained constant under every variety of tests applied. After a
few weeks, a slight movement was given to the screws holding the plate
against which the precision screw works as a shoulder. The sign of
the errors was again changed, but their magnitude was very much
reduced, amounting at the maximum to about ^jg^J^jy of an inch.
This system of errors also remained, as long as no further changes
were made.

Having definitely found by these and several other similar experi-
ments that the periodicity was not due to the precision screw itself,
but to the constrained motion caused by unecjual friction between the
nut, the screw, and the ways on which the gravity slide, which carries
the plate to be ruled, is moved, I addressed myself to the task of
removing as far as possible this source of error. Wliile I have not
succeeded with entire satisfaction, the errors of a periodic character
have been so much reduced that those which still remain give no seri-
ous trouble, liy a device to be presently described, these residuals
are overcome by an automatic movement connected with the screw
itself. Omitting an account of many fruitless trials, I describe the
following permanent changes whicli were finally made.

OF ARTS AND SCIENCES. 245

(o) The ways over wliit-li the f:;r:ivity sli<le moves, one of which was
at first A shaped, and the other plane, and hotli of which were per-
manently fixed, were both made /\ shaped and hoth movable. The
ends nearest the point where the bearing of the siiaft of the screw
works against its shoulder, were pivoted. The other ends were made
adjustable with set screws. The precision screw being set in its nor-
mal position, and attaciied to the slide by its nut, the ways are set
parallel with the screw by the motion of the slide upon them.

(b) The nut, which at first was only about one inch long, was-
made four inches in length, being one half the length of the screw.
About equally good results were obtained with a lead and a brass nut.
The lead nut is much the more difficult to make, as a tap cannot be
used. Even when it was cut with a chaser on the lathe, it was found
impossible to get a smooth thread until the very simple remedy of
keeping the interior wet with a strong soap lye was tried.

The nut having been fitted to the screw, the threads were reduced
to a homogeneous system, and at the same time polished, by grinding
with the finest emery. It should be remarked that the screw was
originally finished in this way, using coarser emery at first. The rule
adopted was to grind the screw till all ^tremor perceptible to the touch
in the passage of the nut over the entire length of the screw disap-
peared.

(e) In order to set the screw parallel to the ways in a vertical
direction, a hollow cylinder was firmly attached to the under side of
the gravity slide. The screw, with the nut upon it, and jiassing
through this cylinder was first set in position. The gravity slide
having been firmly clamped down upon the ways, the open space sur-
rounding the nut was then filled with plaster of Paris.

In this way the screw is set in perfect adjustment for one position
of the gravity slide. Practically, it is found to be in good adjustment
for every position upon the ways. But any slight deviation from
adjustment in a horizontal direction is corrected by means of the
adjustable ways, while that in the vertical direction is for the most
part overcome by leaving one end of the precision screw fi-ee.

Good results have also been obtained by using a " free nut." In
this case nice adjustments are unnecessary, as the nut moves freely
upon the screw, pushing the gravity slide before it. If this arrange-
ment is adopted, care should be taken that the nut, if not symmetrical
with respect to the screw, should fall freely in the direction of gravity,
and bear at every point throughout its whole length against whatever
holds it in position while the screw is in action. The most serious

246

PROCEEDINGS OF THE AMERICAN ACADEMY

objection to this arrangement is a certain amount of lost motion, which
seems inevitable.

It is not to be inferred that all periodic errors have been overcome
by the arrangement described above ; but experience has shown that
they have been very much diminished. In fact, I have never succeeded
in ruling but two precisely similar plates, in which there was an exact
coincidence of every line from beginning to end, when examined under
tlie microscope. In one plate of 100 lines, ruled with great care, each
.interval being tt^\,-^ of an inch, there are, according to three indepen-
dent measures made by different persons, 84 cases in which the errors
are less than X(j(jVTyTT of an inch, and the greatest individual error is
?T?;(Jo ^^ '^" "^*^'^ ' ^"^ '^® maximum periodic error varies with the
different observers between jootjo ^"<JVooTTTT ^^ *" inch.

Nobert's bands proceed by increments of 5630 lines to the English
inch. The following table gives the number of lines to the inch in
each band.

Band.

Lines in an inch.

Band.

Lines in an inch.

1

11259

11

675.56

2

16889

12

73186

3

22519

13

78816

4

28148

14

84445

5

33778

15

90075

6

39408

16

9-5705

7

45037

17

101334

8

606G7

18

106964

9

56297

19

112594

10

61926

Ubie are these Lines accurately spaced ?

The ordinary way is to give to the head of the screw, which carries
the plate to be ruled, the desired movement over equal intervals by
means of a ratchet and pall : but this method is open to the two objec-
tions, that one is limited to the number of teeth cut on the disc, or to
an even combination of them ; and, also, that all errors of the gear-
cutter with which the ratchet was originally cut are transferred
directly to the rulings, with the addition of other errors arising from
want of centring, &c.

I have employed for this purpose the following device, which, as far
as I am aware, is new in its application : A rigid arm two feet in

OF ARTS AND SCIENCES. 247

length vibrates xipon a sliaft set exactly in a line with the precision
screw. At one end a magnet, fitted to tlie curvature of tlie head of the
screw, is attached by eight pivots in sucli a way as to give parallel mo-
tion with respect to the arm. The outer portion of the head of the screw
consists of a rim of soft iron, which operates as an armature to draw
the magnet to it when the circuit is completed. The other end of the
arm works between two stops, one of which is adjustable. The action,
then, is this : the circuit being completed, the magnet becomes firmly
attached to the head of the screw, and by the movement of the arm
from one stop to the other, it is carried over a given space. The cir-
cuit being broken, the arm during the reverse movement carries the
magnet with it without disturbing the precision screw. In order to
guard against every possibility of disturbance, a second magnet holds
the head of the screw in place while the first one is moving back to
prepare for the next increment of motion. By varying the distance
between the stops, any desired motion whatever, within certain limits,
can be given to the screw. From repeated experiments, it is found
that about twenty movements of the arm for xttoutt of a revolution
of the screw-head can be made without varying more than one from
this number.

If now the lower stop is replaced by a wheel made to revolve simul-
taneously with the head of the screw, and if to the periphery of this
wheel a curvature is given corresponding to the known errors of the
screw, it is obvious that the screw can be made to correct its own
errors. Thus, if at any point in its revolution the screw gives too
small intervals, the periphery of the wheel must be filed away enough
to increase the space ruled by the amount of the error. I am indebted
to Professor Joseph Winlock, the late Director of Harvard College
Observatory, for the suggestion of this elegant method of overcoming
the residual errors of the screw.

How are Noberfs Lines of Varying Degrees of Fineness ruled on

Glass ?

First of all, the evidence seems quite clear that they are ruled with
a diamond having a knife-edge. In all of the cases which I have
examined the lines start in with a curvature, which is maintained
throughout the whole extent of the band. I have been able to
produce this result only by setting the cutting edge of the diamond
slightly inclined to the direction of the line ruled, and this inclination
seems to give a decided improvement to the character of the lines.

248 PROCEEDINGS OP THE AMERICAN ACADEMY

I assume that Nobert uses a prepared diamond, instead of a natural
crystal. It is everywhere assumed by writers on the subject, that
only the natural crystal possesses perfect cutting qualities. While
this is probably true where a deep cut is wanted for the purpose of
fracture, it does not seem to be true where distinct, smooth, and uni-
form lines are desired. I believe this is also the experience of Mr.
Rutherford, who long ago abandoned the natural crystal, either
unbroken, or broken into chance fragments. A circular point is
objectionable for several reasons, mainly on account of its lack of
durability.

Starting with the theory that Nobert's lines are ruled with a highly
polished knife-edge diamond, I had constructed from my own designs
an apparatus for preparing diamonds in this way.

The machine does not differ from the ordinary tool of the lapidary,
except in two particulars ; but these are vital to success. It is well
known that diamonds can be ground and perfectly polished only in the
direction of the cleavage planes, of which there are twenty -four in
every perfect stone. A skilful diamond-worker will locate the posi-
tion of these planes by simple inspection. I found myself obliged to
employ the more tedious, but not less sure, method of finding them by
a tentative process. The machine was therefore so constructed that
the direction of the cleavage planes could be detected after a few
trials.

Again, it is customary either to press the lap, on which the diamond
dust is placed, up against the diamond, which is set in a rigid holder,
or else to connect the holder to a rigid shaft by means of an interven-
ing flat spring. In either case, the diamond is liable to crumble when
it is reduced to a sharp edge. In the arrangement adopted, the holder
containing the diamond is free in the direction of gravity onJij. This
action is secured by two shafts set at right angles, and connected with
the required supports by three universal joints. B\' weighting the
horizontal arm or by lifting it with a spiral spring, the pressure can be
regulated with great nicety. The lap has a circular movement, while
the frame in which it rests has two motions in a horizontal plane, at
right angles to each other. In order to give a motion in revolution to
the holder, for the purpose of grinding circular points, a Hook joint is
used to connect it with a driving pulley.

It may be proper at this point to offer a few observations, derived
from experience, on the kind and quality of gla^s best suited to receive
delicate lines. I have previously made some remarks before the
Academy on what, for the want of a better term, was described as the

OF ATwIS AND SCIENCES. 249

grain of polished crown-glass. Siibsecjucnt observations have not
entirely confirnietl tlie views expressed at that time. Siill, there does
not seem to be much doul)t but tliat certain kinds of glass are capable
of receiving perfect lines only in one direction. When the lines are
ruled ut an angle with the general direction of the grain, the edges at
once become serrated if they are very fine ; whereas, if they are coarse,
they either become enlarged throughout their whole length, the edges
remaining smooth, or else tljey wholly break up, presenting a very
lagged appearance. If the lines aie as fine as 25,000 or 30,000 to the
inch, this delicately serrated appearance can be detected at once ;
whereas, if the lines are coarse, several days may elapse before the
tension by which the particles seems to be held together, is broken.

Two instances occurring in my own experience may serve to
illustrate this action. In one, while I was examining a set of lines
some days after they were ruled, I was fortunate in seeing two or
three lines enlarge throughout their whole length. From being fine
lines, they became, almost in an instant, very heavy lines, smooth,
black, and of excellent quality every way. The action of breaking
up was just slow enough to enable me to follow it. In the other,
the lines had been ruled about two weeks ; and for protection they
were covered with microscopic glass, closely cemented to the surface.
During my examination, the whole surface became com{)letely broken
up. Such was the force of the explosion that particles of glass xtj^oJT
of an inch in length were driven a distance of yj^ of an inch. In
fact, the debris covered the whole sui'face of the glass under exam-
ination. All the particles presented a curved appearance ; and, with
hardly an exception, the curvature was always in the same direction,
On both of these plates lines were afterwards ruled in an opposite
direction, but without noticeable results.

It may be said that this phenomenon was due to the peculiar action
of the cutting crystal with respect to the surface of the glass ; but in all
subsequent experiments, in which similar but less striking results were
noticed, lines were ruled in both directions at the same time, and
under the same conditions. In the case of a particular importation of
polished crown-glass from Chance &> Sons, the evidence of grain is so
marked and of such constant recurrence that all the large plates have
been cut into slides 3X1 inches, in the direction indicated by the
observations. In general, the direction of the grain can be detected at
once by the appearance of lines as fine as 30,000 to the inch, while
coarse lines may retain their initial character for several days.

The present indications are that the grain is only surface deep, and

250 PROCEEDINGS OF THE AMERICAN ACADEMY

that it is the result of polisliing in one direction. Common window
glass seems to be wholly free from it. Nobert's lines are ruled on
microscopic cover-glass about ooo ^^ ^^ ^'^*^'^ i" thickness. The evi-
dence of grain in this kind of glass is strong; but it is hardly decisive.
In some specimens it is very marked, while in others it seems to be
entirely wanting. Indeed, any conclusions on this subject must be
regarded as only provisional, owing to the extreme ditficulty of sep-
arating the action of the cutting crystal upon the glass from the effect
due to the character of the glass itself. It is, however, safe to say
tiiat in certain kinds of glass the best results can only be obtained by
ruling in a given direction.

In order to rule bauds with lines separated by intervals, e.g. of
^uo 0^ an inch, it is of course necessary to rule single lines whose W'idth
is less than this. Great precaution is requisite here, in order to avoid
optical delusion. Every microscopist is familiar with the phenom-
enon of false lines. To avoid errors from this source, a few single lines
are ruled between two heavy finding lines. They are then filled with
graphite. This precaution is necessary in order to give both visibility
and distinctness to the edges. If the lines are not filled, they may
appear much finer than they really are ; tliat is, the objective being
in focus for the bottom of the furrow may fail to reveal abrasions of
the surface on either side. The graphite of the New York Graphite
Company will easily fill the finest line that can be ruled with a
diamond.

In order to measure the width of the lines, the following plan is
adopted as presenting some advantages over the usual method of esti-
mating it by comparison with the known value of a given division in
the eye-piece micrometer.

First, a single line is ruled, which in the eye-piece apparently ex-
actly covers the line to be measured under the objective. A few trials
will suffice for this purpose. Having found what weight must be
applied to the diamond to produce such a line, the next step is to
ascertain how many lines, exactly like this one, can be ruled within
the space of ^^^ of an inch witli a minimum space between each line.
This will also reciuire a few trials. F'or example, if with a yV objec-
tive and a B ocular, the space jtJ^tj of an inch in the eye-piece corre-
sponds to Tji^o of an inch under the objective, and if it is found that
fifteen lines can be ruled within this space, then the width of the line
under examination is -j-Tjiij^ X tV ^^ v^^nTS^ ^^ ^" '"^'^ » ^ result
which is obviously within the truth, especially if the line in the eye-piece
is made a shade larger than the line under the objective. Tested in

OF ARTS AND SCIENCES. 251

this way, the linos of Nobert's 19th baml are about tko^jju "^ ^" '"*^^^
in width. The photographs made by Dr. Woodward seem to give a
little greater value. The linest lines I have suceeeded in rnling are
about jTr^VoTj ^^ '"* '"'^■'' ^" width. These values are substantially the
same as those given by Dr. Roystou Pigott, as representing the ulti-
mate limit of visibility under the microscope. The smallest angle at
which an object can be distinctly seen is stated by him to be G", while
other writers place it as high as GO", or even 120". Even the smallest
value named is much too large. I will at any time undertake to rule
a single line, ^^J^yi) ^^ ^^ i"^^^ '" breadth, which can be seen at the
distance of seven inches from the eye. This corresponds to an angle
of about 1''. In this case the line is filled with plumbago, but, if it is
reflected from a silvered surface, it can be easily seen at the distance
of eleven inches from the eye. Comparing minute particles of matter
which can be seen under a Tolles -^^ objective with those which can
be measured, in the way indicated above, there is every reason to sup-
pose that the limit of visibility falls beyond ^-^tyVcTiT f^ a" inch. It is
quite possible that the conclusion reached by Sorby, that the microscope
has already reached the limit of its power in separating lines whose
distance apart is equal to one half of a wave length, may be found to
be justified by future observations. It is certain that no lines beyond
Nobert's 19th band have ever been resolved. The great difficulty in
distinguishing true from spurious lines has caused more than one skil-
ful microscopist to doubt whether the resolution has been certainly
carried a. far as that point. But that light is " of too coarse a nature "
to enable us to see particles of matter as small as ^tj^^x7(J ^^ ^"^ inch, is
a conclusion which can be refuted without the slightest difficulty.

How are Nobert's Finest Lines produced'^

In trying to answer this question, I shall give the results of four
distinct lines of investigation. Neither of these furnish conclusive
evidence, but they are all suggestive of possibilities.

I. I have already stated that there is strong evidence that they are
ruled with a diamond having a knife-edge. To this is added a fact
derived from my own experience, and confirmed by a trial of several
months; viz., that ivhen a diamond, having a polished knife-edge, is set
slightly inclined to the direction of the lines ruled, its ruling qualities
improve with use. The diamond with which bands of 50,000 lines to the
inch were first successfully ruled would at first barely rule 10,000. It

252 PROCEEDINGS OF THE AMERICAN ACADEMY

was only after a service of several weeks, its position in the holder mean-
while remaiiiiog unchanged, that the highest limit named was reached.
Four new diamonds have since been mounted with precisely the same
result. It is not to be understood that this remark holds entirely true
for heavy lines, such as are requisite for good diffraction plates. It is
the experience of Rutherford and others, that one of the chief difficul-
ties in producing such plates is the inability to find a diamond which
will do its work equally well throughout the entire process of ruling.
But when only very fine lines are desired, the longer the diamond is
used, the greater the pressure which can be applied without increas-
ing the size of the line. In this way the lines can be made much
more uniform throughout their entire length, than when the diamond
barely touches the surface. One can hardly say that the diamond
sharpens itself by use, but there is some evidence that the wear is
greater on the two faces than on the knife-edge.

When the diamond does its work perfectly, the cut, even of the
finest line, produces a sharp singing sound. My ear has become so
accustomed to this peculiar tone, that I can judge of the quality of the
lines ruled almost as well by sound as by sight. In ruling the highest
bands, this sound can be heard throughout the entire length of every
line. It does not always have exactly the same character, however,
being sometimes much sharper in tone than others.

II. From Mr. Herman, a successful diamond worker of New York,
I learned a fact which was thought to be of sufficient importance to
justify a somewhat difficult experiment. He stated to me that his
experience had shown him that the only really hard points of a dia-
mond are those where the line formed by the intersection of two faces
terminate. His directions, therefore, were to grind the faces to a knife-
edge, exercising great care to leave the natural line of ititersection
untouched as far as possible, and then to grind and poli^^h a ftice
nearly at right angles to this line, stopping just at its extremity. He
assured me that the success of the experiment would depend entirely
upon neither falling short or going beyond this point. Only one dia-
mond has been successfully prepared in this way, and even in this case
it is not quite certain that this requirement has been met. Its perform-
ance is sufficiently good to warrant further experiments.

IH. I am indebted to Mr. D. C. Chapman, of New York, for a
third method of preparing a ruling diamond. It is allowed by all
familiar with the subject, that the natural face of a crystal is harder
than any surface formed by breaking the stone into chance fragments.
By splitting a stone in the direction of a cleavage-plane, forming an

OF ARTS AND SCIENCES. 253

angle of about 40" with this natural face, an exceedingly sharp knife-
edge may be formed, possessing excellent ruling (jualities. Moreover,
in ruling lieavy lines for dittraction i)lates, the cutting-edge retains its
form for a long time. In setting the diamond for ruling, tlie natural
face should be slightly inclined to the surface to be ruled. The Bia-
zilian " bort " seems to give the best and most durable cntting-t'dge.
AVith a diamond prepared in this way, the line formed by the inter-
secting faces being about j\ of au inch in length, I find little trouble
in ruling from 60,000 to 80,000 lines to the inch.

IV. A few months since INIr. R. C. Greenleaf, of Boston, placed in
my hands a Nobert plate which had been entirely spoiled by the
introduction of some kind of fluid between the ruled glass and the slide
on which it was mounted. INIr. Greenleaf requested me to under-
take the restoration of this plate, kindly offering to assume all the risk
of failure. The cover, which had been imperfectly cemented to the
slide with something like opal cement, resisted every attempt at
loosening. As a last resort, two pieces, about -^ of an inch square,
were cut with a diamond from the centre of the cover glass. After
several trials, one of these pieces was cleaned and remounted without
material injury to any of the bands. The 19th is quite as easily re-
volved as in other Nobert plates.

The other piece, being less perfect, was made the subject of a some-
what careful study. Among other experiments, an attempt was made
to fill the lines with graphite ; but it was found impossible to do so.
Even the coarsest lines would not receive and hold it. As I had
never before found any difficulty in filling lines either coarse or fine,
this result, so entirely unexpected, was noted down as one of which
no explanation could be given at that time.

A few weeks afterwards, I succeeded in reducing a black carbon to a
knife-edge. Upon an examination of the first lines ruled with it, two
facts at once engaged my attention. First, the lines were finer and
smoother than any I had ever before ruled. They possessed that
quality of glossy blackness which characterizes nearly all of Nobert's
lines. Moreover, they seemed to stand out more boldly in perspec-
tive than lines ruled with the ordinary diamond. Every one who has
made a study of Nobert's diffraction lines will at once recognize this
boldness of perspective as a characteristic feature. Secondly, I was
equally surprised to find that the lines would not receive and hold
graphite.

As these results were confirmed by further observations, it did not
seem too much to say that possibly the secret of Nobert's success might

254 PROCEEDINGS OF THE AMERICAN ACADEMY

consist in his use of a prepared carbon. The natural stone is entirely
unfit for ruling purposes.

But it appeared subsequently that this conclusion was quite too
hastily formed, as far as the capability of receiving graphite is con-
cerned. During all these observations, the position of the diamond in
its holder remained unchanged ; but it was afterwards found that, by
giving it a certain inclination with respect to the surface of the ruled
plate, it was possible to rule lines, both coarse and fine, which would
receive the graphite in the most perfect manner. In general, however,
lines ruled with a carbon will take the plumbago perfectly but once.
If they are filled and the surface of the glass is afterwards cleaned by
rubbing, it is not possible to fill them equally well again. As the fill-
ing is not disturbed by mounting in balsam, the better way is to clean
the glass thoroughly before ruling, and then mount permanently after
the first filling.

Though the carbon is reduced so perfectly to a true knife-edge that
the intersection of the two faces appear as a line when examined with
an eye-piece of high magnifying power, it is apparent, nevertheless,
that the cutting-edge is composed of distinct and separate crystals;
for in many cases two lines have been ruled at the same time. Gen-
erally one is much coarser than the other. Indeed, by regulating the
pressure, companion lines can be ruled so fine that it is impossible
to see them until they are filled. The setting of th^ diamond to rule
lines of a given kind and quality is simply a question of time and
patience. In one hundred trials, perhaps two or three may give lines
which will receive plumbago, four or five may give double lines, and
one or two may give lines of great delicacy. Great care is neces-
sary in the preservation of the minute cutting crystal when once found.
Notwithstanding the most careful manipulation, it often gives way
without visible cause. In several instances, I have been able to locate
the exact point where it was destroyed.

In general, the best results have been obtained with the prepared
carbon. It is, however, somewhat capricious in its action. The labor
of preparation is also much greater than with tlie African or the
lirazilian diamond. The process of grinding occupies from five to
ten days. That it is much harder than any other kind of diamond is
conclusively shown by the fact that one specimen in my possession
has been used in shaping a jewel weighing 180 carats, with only a
trifling abrasion of its surface.

In conclusion I ought to say, in explanation of the somewhat incom-
plete and fragmentary character of this investigation, that it has been

OF ARTS AND SCIENCES. 255

the gradual outgrowth of experimeuts undertaken for a different pur-
pose. Indeed, whatever has been accomplished thu3 far may be said
to be the result of an unsuccessful search after a spi<ler that would
spin a web suitable for the meridian circle of Harvard College Obser-
vatory. Failing to find suitable " spider lines," an effort was made
to produce on glass, lines of the desired quality and size. This was
finally accomplished by etching with hydrofluoric fumes ; the lines
having been first ruled in a coating formed by dissolving white wax in
gasolene, and uniting the solution by emulsion with liquid gelatine.
The coating thus formed will receive lines as fine as 10,000 to the
inch, while its protecting qualities are sufficient to withstand very
strong fumes. The subsequent experiments detailed in this paper
have occupied my attention from time to time during the past three
years, when not engaged in my regular duties as Assistant iu the
Observatory.

256 PROCEEDINGS OF THE AMERICAN ACADEMY

XIX.
MOUNTAIN SURVEYING.

By Pkofessor E. C. Pickering.
Kead, Jan. 11, 1876.

The difficulties and expense of a topographical survey are always
very great ; and this is particularly the case in a mountainous country,
owing to the short horizontal interval between the contours, their irreg-
ularity, and the labor involved in reaching the more elevated portions.
The objections to the usual trigonometrical methods are, that the
theodolite, or transit, needed to measure the angles, is heavy, liable to
injury when carried over a rough country, and the time required to
measure each angle is considerable. The labor and cost of measuring
a base-line are also very great. Moreover, the accuracy attained is
much greater than is ordinarily needed ; since, as the land is commonly
of little value, there is no need of determining positions with more
accuracy than they can be shown on a map. If the tract of country
is large, a scale greater than ixtwV(TTF» ^^ sttotttj' ^^ rarely used; and,
owing to the unequal expansion and contraction of the paper, long
distances could not be measured with accuracy on such a map much
nearer than within fifty to one hundred metres. Another objection
to the trigonometrical method is, that the work must be carried on
continuously from one base to the other ; and no positions can be deter-
mined except by connection with a base through a series of triangles.
If, however, the latitudes and longitudes of several points are ascer-
tained, each of them may be used as a centre from which the form of
the surrounding country may be determined ; and an error in one will
in no way affect the position of the others. The problem proposed,
therefore, was to devise some instrument which should give approxi-
mately the distance and elevation of a mountain summit or other
object, and which at the same time should be light and not easily
injured. AVith such an instrument, an exploring party, whenever they
camped at a point commanding an extensive view, could, during the

OF ARTS AND SCIENCES. 257

night, (lotcrmine their hUitinle aiul longitude, and, during the day,
locate all prominent visible objects.

To measure small distances, the method of the stadia and telemeter
gives excellent results, but is open to the objection that an assistant is
needed, who must cari'y a graduated pole to each point whose distance
is to be determined. This method also is only applicable to short
distances ; as beyond five hundred, or at most a thousand metres, the
pole appears so small, that its apparent length cannot be determined
with accuracy.

These difficulties are, in a great measure, avoided in the following
instrument. A good traveller's telescope, or spy-glass, is mounted
firmly on a tripod, and a spider-line micrometer or scale of equal
parts is inserted in its eye-piece. In front of the object-glass is
fastened a piece of plane-glass, which may be set at any desired angle,
and clamped firmly. The angle may be roughly measured by a small
ciix'le divided into degrees. The whole is free to turn around the
axis of the telescope. To measure the distance of any object, D,
Fiff. 1, the angular magnitude of the divisions
of the scale in the eje-piece, is first determined

by the usual methods. The telescope is ^ * D •

then mounted at A, and directed towards D, „
taking care to select for it some sharply
defined object, as a rocky crag, the trunk of
a tree, or the edge of a snow-bank. Select a
second object, C, nearly at right angles to Z), ^ *
and turn the glass in front of the telescope Fig. 1.

until the reflection of G in its front surface

shall be in the field at the same time as the image of D transmitted
through the glass. Measure accurately the interval between the two
images with the micrometer. Next measure off a distance AB from
A towards G of one or two hundred metres, and place the telescope at
B. Again measuring the interval between the two images, taking
care not to disturb the mirror, a result will be obtained which will
differ from the previous measurement by the angle ADB. From

this triangle we deduce DB = AB - — j- = AB sin A — ;^^, in which
° sin JJ (fs '

d is the difference in the scale-readings, and s the magnitude of each
division in seconds. A should be taken nearly 90° ; in which case
sin A will very nearly equal unity. Its value may be found with suf-
ficient precision with the divided circle attached to the mirror, or by a
plane-table. The greatest accuracy will be attained when AB has

VOL. XI. (N. s.iii.) 17

258 PROCEEDINGS OF THE AMERICAN ACADEMY

such a value as to make the angle at D neai'ly twice the diameter of
the field. To determine the degree of accuracy attainable with such
an instrument, suppose the diameter of the field of view 1'^, and that
an error of .1' or 6" is committed in the measurement, — a large error,
considering how accurately seconds are determined with the spider-line
micrometer in astronomical work. Sujipose, again, that the object D
is ten thousand metres distant, or 6.21 niiles, and that AB is taken
equal to two hundred metres : the error in question would then equal
only fourteen metres, or forty-six feet, — a quantity quite insensible on
the scale proposed above. Again : if the object is fifty or a hundred
kilometres distant, it is only necessary to increase AB in the same
proportion, and we shall still be able to measure the distance of D
with the same proportionate accuracy, without yet using a base of
inconvenient length. In this way, if the country is daugerous, the
observer may measure the distance of all visible objects without going
far from camp. Comparing this instrument with the stadia, we see
that it has the advantage that it is not necessary to send a man to the
point to be measured, and that the accuracy is the same as if he could
carry a pole one or two hundred metres in length.

Three methods have been employed for the determination of
heights. First, by the barometer. But this involves a visit to every
point to be measured, and, at the best, is very inaccurate. Observa-
tions in Switzerland and California have shown, that with the best
barometers, after applying all the known corrections, and even if each
observation is the mean of thirty, taken once a day for a month at the
same hour, at both the upper and lower stations, there still remains
an uncertain error, amounting sometimes to two per cent of the
whole height. How much greater, then, must be the error of a single
reading, often made without simultaneous observations below, and
with the defects of an aneroid added to the other errors! The most
accurate method of determining a height is by levelling ; but the labor
and expense of this are too great to allow its frequent use in moun-
tainous countries. The third method is that of zenith distances,
which is largely used in the Coast Survey for determining heights.
The altitude is here observed by a large vertical circle, which must be
read witli the utmost precision, since the angle, if the object is distant,
rarely exceeds two or three degrees. It is claimed that at least an
equal degree of accuracy may be attained by the instrument described
below, while the expense of a graduated circle and delicate mounting
is wholly avoided. The principle employed is tliat of the zenith
telescope, so largely employed in determining the latitude. It consists

I

OF ARTS AND SCIENCES. 259

simply of the telescope, described above, turned around its axis 90",
and a delicate level screwed firndy to its tube. To make sure that the
telescope is turned by precisely the right amount, it is well to have a
second level at riu;ht angles to this to render the threads of the mi-
crometer exactly horizontal. The size of the divisions of the level and
of the micrometer must be previously determined; their relative value
being most easily found by directing the telescope towards any distant
object, and slightly inclining it, so that the bubble shall occupy various
positions in the tube. The corresponding positions of the object are
read by the micrometer, and a curve constructed with ordinates ecpial to
these readings, and abscissas to the position of the middle of the l)ubble
of the level. The reading of the micrometer corresponding to a perfectly
level line must next be determined. This may be found by setting the
telescope up at two not very distant points, and reading the height of
each from the other. The mean will give the direction of a horizontal
line ; since the elevation in one case equals the depression in the other.
The direction is, however, best found by observing the height of some
known objects ; since this eliminates various errors, as will be described
below. The height of any object is more readily determined by direct-
ing the telescope towards it, and bringing the bubble nearly to the
centre of the tube. Then read the position of the object by the mi-
crometer ; and, finally, read the exact position of the two ends of the
bubble, taking care not to touch the telescope. These readings may
then be reduced to seconds of altitude, as follows : Call A the required
altitude in seconds, m the reading of the micrometer, m} its reading
when the telescope is directed towards an object at the same height as
its own, and b the mean of the two ends of the bubble of the level.
Again, let s equal the magnitude of each division of the level in
seconds, and I the corresponding magnitude of the level divisions.
Then A =. (m — ?m^) s -{- hi. The elevation in metres or feet is then
found by multiplying the tangent of this angle by the horizontal
distance of the object, and correcting for the curvature of the earth and
for refraction. The fii-st of these corrections may be made with great
precision by the formulas or table given in the Coast-Survey Ileport for
1871, pp. 160 and 169. The second correction is, however, very
irregular, and may, therefore, generally be regarded as nearly propor-
tional to the square of the distance. Since the correction for
curvature is also nearly proportional to the square of the distance, we
may write the elevation A' = Z> tang A -\- m Z)-, in which D is the
horizontal distance, and m a quantity dependent on the condition of
the air. If, therefore, the height of any distant object visible is

260 PROCEEDINGS OF THE AMERICAN ACADEMY

known, it is better to deduce m from its observed altitude, and from
this compute the other elevations. Were it not for the uncertain error
of refraction, this instrument would give results of extreme precision.
Thus an error of 6" in the altitude of a mountain one hundred kilo-
metres distant would only correspond to a difference in height of about
three metres. The uncertainty of refraction is much greater than this,
and far exceeds the instrumental errors, except in a small telescope.
Since, however, this cause of error is present when the theodolite is
used, we see that altitudes can be obtained by this instrument with all
the precision of the best theodolite ; in fact, with all the accuracy of
which the method is capable. Apart from its lightness and cheapness,
it has this great advantage over a theodolite, — that, since the level is
firmly attached to the telescope, there is little liability to error ; while,
as the theodolite measures the angle between the telescope and the
horizontal limb of the instrument, any injury is liable to throw it out
of adjustment. With the instrument as described above, no angles
could be measured gi'eater than the diameter of the field of view.
This ditiiculty may be remedied by attaching another level, slightly
inclined to the first, so that the two fields of view corresponding to a
horizontal position of the two levels shall be nearly tangent to each
other. A third level serves still further to extend the range of the
instrument. Thus, if the field of view is about 2°, angles between 1°
and — 1° may be measured by the first level, between 1° and 3° with
the second, and between — 1° and — S^ with the third. The instru-
ment, in this form, may be called a micrometer-level. One of its
greatest advantages is the rapidity with which elevations may be
measured. There is no difficulty in measuring thirty or forty moun-
tains in this way per hour, without the labor of ascending them ; while
by the barometer it rarely happens that more than one can be
measured in a day, and with the ordinary level the altitude of a
high mountain would be the labor of days or weeks. The rapidity is
also much greater than that of a theodolite ; since no accurate mount-
ing is needed, and a micrometer-scale can be read at least as quickly
as the telescope can be set, so that the entire time of reading the circle
by the vernier is saved.

One of the principal advantages of both the instruments here pro-
posed is, that either may be made out of a telescope such as any
explorer would be likely to carry. By simply adding a mirror in
front, a photographed scale, and three levels,- distances and elevations
may be measured with all the accuracy ordinarily required. This
method may be applied with especial advantage on a mountain-top ;

OP ARTS AND SCIENCES. 261

since the elevations of all other mountains in sight, except those in the
immediate vicinity, may be determined.

The fact is worth notini^, that, even if the error from refraction
could be eliminated, the method of zenith-distances would not equal in
accuracy that of ordinary levelling. For suppose that the sights are
taken at disUmces d, and that the probable error of each is e. If n
sights are taken, or the ilistance travelled is nd, the probable error
will be only ey/yj, since the positive and negative errors will probably
in part neutralize. The error in the method of zenith-distances will,
however, be proportional to the distance, or will be ne. Thus, if sights
are taken every hundred metres with a probable error of 1 mm., the
probable error of the level in ten kilometres will be 10 mms., since
w = 100; while with zenith-distances the error would be 100 mms.
Evidently, therefore, within reasonable limits, to attain the greatest
accuracy with the level, the sights should be as short as possible, — a
fact in accordance with general experience.

Evidently the telescope of a theodolite may be converted into a
micrometer level by inserting in its eye-piece a scale, and attaching
three levels. Small vertical angles, which are those most used in
surveying, can then be measured more accurately than by a vertical
circle. In the same way, a similar attachment may be made to the
telescope of a plane-table ; and the advantage is especially marked in
this case, since an accurate mounting is not needed. A further appli-
cation may then be made ; namely, to determine the distance when the
height is known. Suppose that a distant pond is observed from the top of
a hill. The telescope is directed to various portions of its shore, and
the apparent depression observed. Since every portion must be at an
equal distance below the observer, it is easily shown that the distance
is always inversely proportional to the depression. Accordingly, if
the direction of each part of the shore is marked on the plane-table
sheet by a line, and a distance is laid off on this inversely as the
observed depression, a map of the pond is quickly made. This may
be reduced to its true scale if we know the position of any one point,
or the height of the observer above the water. If the shore is abrupt
or wooded, only the farther edge of the shore can be thus surveyed, or
rather the portion where the actual shore-line is visible. This method
is in fact a form of stadia, in which the measuring-pole is replaced by
the constant vertical distance between the eye and the plane of the water.
The same method may be used for determining the form of an island,
of a coast-line, or of a river winding through a nearly level meadow.
The form of a pond or island may also be obtained in the same way

262 PROCEEDINGS OF THE AMERICAN ACADEMY

from a drawing made by a camera obscura or camera lucida, or from
a photograph ; and has the advantage that it begins to be accurate for
depressions greater than 2° or 3° just where they pass out of the
range of the micrometer-level as described above.

Valuable observations on the changes in the dip and in the refrac-
tion might be made with a large telescope of this form. It is much to
be desired that such observations might be conducted for a period of
years from two such stations as Mount "Washington and Portland.
As the pressure, temperature, and moisture of these points is already
determined by the Signal-Service Department, a small additional
expense would furnish a valuable addition to our knowledge of the
atmospheric refraction.

OF ARTS AND SCIENCES. 203

XX.

HEIGHT AND VELOCITY OF CLOUDS.

By Professor E. C. Pickering.
Presouted, Jan. 11, 187G.

The velocity of the wind at different altitudes is an important
element in Meteorology, and the ordinary methods of measuring it are
far from satisfactory. By the following method, it is believed that the
velocity of the wind at considerable heights may be measured with an
accuracy at least equal, and probably greater, than that of similar
measurements near the surface of the earth. The apparatus consists
simply of two similar camera obscuras formed of tripods covered with
black cloth, and with cosmorama lenses above, which form an image of
objects near the zenith on a sheet of paper placed beneath. A day is
selected when cumuli clouds are crossing the sky, and the two cameras
are placed at any convenient interval, as a hundred metres, in a direc-
tion nearly perpendicular to the direction of the wind. An observer
with a watch is stationed at each camera, and when a cloud enters the
field a signal is given, and each draws a line tangent to the edge of the
cloud and parallel to the direction of the wind every half minute. At
the intermediate quarter minutes, other lines are drawn perpendicular
to these, and also tangent to the cloud. The first series of lines will
be nearly coincident, the second at intervals marking the cloud's
motion. The zenith is now marked on each drawing by suspending a
plumb-line from the centre of each lens, or in some other way, and a
line drawn through it parallel to the direction of the cloud's motion.
It will now be found that the distance of this line from those parallel
to it and tangent to the cloud is different in the two sheets by an
amount equal to the parallax of the cloud, or the angle between the
two cameras as seen from the cloud. The height of the cloud may
then be easily determined, if we know the focal distances of the lenses
and the interval between the cameras, by the jiroportion : Difference
of distances of the two lines : focal length of lenses = interval between
the cameras : required height of cloud. To determine the accuracy of
this method, suppose the interval between the cameras one hundred

264 PROCEEDINGS OP THE AMERICAN ACADEMY

metres, the focal lengths one metre, and the height of the cloud one
kilometre ; then the difference between the distances of the two lines
will be a decimetre. K this distance is measured with an error no
greater than a millimetre, the height will be given wdthin ten metres,
or within one per cent. The velocity per minute is then readily
deduced from the lines perpendicular to the direction of the wind, and
the velocity of the latter may thus be determined within one or two
per cent, a degree of accuracy at least equal to that of the best deter-
minations of tlie velocity of the wind at the earth's surface and much
greater than the degree of uniformity of any ordinary wind. Each
cloud will furnish a measurement at a different height, and a compari-
son with observations at the surface of the earth will readily give the
relative velocities at these various altitudes.

Various other applications of this principle will suggest themselves.
For instance, if the paper is replaced by a sensitive photographic
2:)late, and the cameras directed towards a distant tliunder cloud at
night, an image of each flash may be taken. A great many flashes
may be recorded on each plate, and the corresponding images recog-
nized by their forms. The distances and true dimensions may then be
determined with considerable accuracy. If observations are made at
the same time, of the interval between the flash and the thunder, the
velocity of the sound may be measured, and it may be proved whether,
as has been claimed, the velocity of such an intense sound is far greater
than that of any ordinary noise.

OF ARTS AND SCIENCES. 265

XXI.

CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF
THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY.

VIII. — AN EXPERIMENTAL PROOF OF THE LAW OF INVERSE
SQUARES FOR SOUND.

By William W. Jacqdes.

Presented, May 10, 1876.

Tpiere is every dynamical reason for believing that the intensities
of light, heat, and sound, diminish as the reciprocals of the squares
of the distances from their origins.

That this is true of light and heat has been demonstrated experi-
mentally. The case of sound, however, has only been put to the test
in experiments so crude as not at all to warrant the assumption of the
law on experimental grounds.

The following method (which was suggested by the reading of Pro-
fessor Mayer's paper in the ''American Journal" for January, 1873)
ranks in its degree of accuracy with those which have been applied to
the verification of this law in the cases of light and heat. It depends, '
primarily, on the principle, that, when a particle of air is solicited by
two equal and opposite forces, it will remain at rest.

If two resonators, adjusted so as to resound with equal intensity, be
placed equally distant from an organ-pipe, and connected by tubes
with the two prongs of a fork-shaped tube in such a way that the
sound-wave from one resonator shall arrive at the fork in opposite
phase to that from the other, we shall have this condition ; and, if the
stem of the fork be placed in the ear, no sound will be heard. If, in
place of one of these resonators, we put two, each of the same inten-
sity as the first, both connected with the same prong of the fork, we
may, by moving them farther from the source of sound than was the
single resonator, at the same time altering the length of the tubing so
that the wave from the single one shall arrive at the fork in opposite
phase to that from the pair, produce the same effect of complete inter-
ference. If the law of inverse squares holds true, the distances of the
sinsle resonator from the source of sound should be to the cor-

260 PROCEEDINGS OF THE AMERICAN ACADEMY

responding distance of the pair as 1 : s/^. If three resonators be
opposed to one, the distances should be 1 : V 3 ; if four resonators,
1:V4 or 1:2, &c.

It will be seen that the accuracy of the above method depends
ujjon the following conditions : —

1st, That the resultant wave from the combination of two resonators
has twice the intensity of that coming from one.

2d, That the decrease in intensity of a sound, in passing through a
tube, is inconsiderable.

3d, That the intensity of resonance is proportional to the intensity
of vibration at the mouth of the resonator.

Let us first see the arrangement of the apparatus used, and then
determine how nearly these three conditions are satisfied.

As a source of sound, a Co closed organ-pipe was used, blown by a
stream of air from a large gas-holder having an arrangement for keep-
ing the pressure constant. The pipe was mounted on a small standard,
raised some four feet above the floor, so that the sound-waves pro-
duced might have opjjortunity to diverge equally in all directions. At
a measured distance from the embouchure of the pipe were placed
two resonators, each cylindrical in shape, and capped with a hemi-
sphere at one end, through which ran a tube ^-in. in internal diameter,
and at the other end with a flat plate, in which was a circular aper-
ture of 1.5-inch diameter. The resonators were telescoped, so as to be
readily adjusted for pitch and intensity. From the small tubes of the
pair of resonators pieces of rubber tubing led to the two prongs of a
forked brass tube, in which the waves from the two resonators came
together, and augmented each other. From the stem of the fork
another tube led to one arm of the trombone interference apparatus of
Herschel. The third resonator was placed at an appropriate distance
from the embouchure of the pipe, and so arranged that it could be
moved to or from the iii])e, and, at the same time, one arm of tlie
interference apparatus could be moved to compensate for the change in
phase due to such motion. From the small opening of this resonator
a rabl>er tube extended to the other arm of the interference apparatus ;
and in this tube was insei'ted a bi'ass fork precisely like that used for
the pair of resonators, excepting that one of its arms was stopped, so
that the conditions of reflection for this wave might be as similar as
possible to those from the jiair of resonators. If all these conditions
of reflection be the same, it follows that two resonators give twice as
great an intensity as one placed at the same distance from the source
of sound.

OF ARTS AND SCIENCES. 2G7

The second condition, that the decrease in intensity in passing
through a tube is inconsiderable, is abundantly proved by the experi-
ments of liiot and Regnault in water-pipes. The third condition,
that the intensity of resonance varies directly with the intensity of
vibration of the air just outside of the resonator, seems not to be sus-
ceptible of experimental proof, excepting on the assumption of the
law of inverse squares.

There seems, however, to be no cause for any considerable varia-
tion from this ratio : and if, upon trial, we find that the law does hold,
it is reasonable for us to conclude that the valuation of resonance is
proportional to the intensity ; for it is extremely improbable that there
would be two errors which would exactly counterbalance each other.

The resonators having been adjusted so as to resound with equal
intensity by comparing them two at a time on the interference appa-
ratus, it was only necessary to connect three resonators as described
above, so that the resultant wave should act on the air contained in the
tube which enters the ear. Keej^ing now the pair of resonators in a
constant position, and moving the single resonator and one arm of
the interference apparatus until the resultant sound is at its minimum
intensity, the relative distances should be W2ll.

Below are given several series of readings of the distance of the
single resonator from the source of sound. The first three columns are
the results of experiments made in front of the pipe, the pair of reso-
nators being placed at a distance of 142 cms. from the embouchure.
The resonators were lettered, for convenience, A, B, and C ; and the
three series of readings are the results of opposing successively A to B
and C, B to A and C, and C to A and B. In the last three columns
are given the results of similar measurements behind the pipe, the
embouchure being still taken as the source of sound, and the pair of
resonators being distant 177.5 cms.

At the bottom of the table the means are compared with the calcu-
lated positions of the single resonator.

The mean of the means of the first three columns is 100.3 cm;
which differs from the theoretical by only 0.3 cm. The mean of the
last three is 128.2, giving a difference from theory of 3.2 cm.

An inspection of the following table shows us, that, assuming the
embouchure of the pipe as the source of sound, in front of the pipe
the law of inverse squares holds almost exactly true : behind the pipe
there is a slight difference. Theoretical considerations of the way in
which the sound-waves are given off* fi-om a closed pipe would lead us
to expect an error of this kind. The error due to the experiments

268

PROCEEDINGS OF THE AMERICAN ACADEMY

being conducted in a hall was i^robably inconsiderable, as the hall was
92 feet long and 65 feet wide; and, moreover, the windows were
partially open. It should be remarked, that bringing the resonators
too near the pipe introduced an error of a nature and magnitude which
indicated that for a sound of considerable intensity the resonance
was not proportional to the intensity of sound at the mouth of the
resonator ; but this exception only serves to prove the rule for the
case of moderate intensity.

A opp.

B opp.

C opp.

A opp.

B opp.

C opp.

to B & C.

to A & C.

to A & B.

to B & C.

to A & C.

to A & B.

cm.

cm.

cm.

cm.

cm.

cm.

V9

102

100

128

128

128

100

100

99

120

127

131

100

100

103

129

128

133

101

100

99

129

128

131

99

102

101

125

127

132

99

99

99

127

129

127

100

100

104

125

129

128

101

103

100

127

129

129

100

104

100

126

129

126

98

108

100

129

128

126

101

100

101

128

129

127

99

100

100

128

127

127

99

101

100

128

129

128

100

101

99

128

128

129

98

100

101

128

126

124

100

102

100

132

124

129

Mean =

Mean =

Mean =

Mean =

Mean =

Mean =

99.6

101.0

100.4

128.4

128.5

127.8

Theor. =

Theor. =

Theor. =

Tlieor. =

Theor. =

Theor. =

lOJ.O

100.0

100.0

125.0

125.0

125.0

It is true that these experiments do not furnish an exact proof of
the law of inverse squares for sound ; but we have not an exact proof
of the same law in the cases of light and heat. All that we can say
of any of them, on experimental grounds, is, that they are very
approximately true.

The above experiments show that we may make this assertion for
sound on as valid experimental grounds as for light or heat.

OF ARTS AND SCIENCES. 269

IX. — DIFFRACTION OF SOUND.

By William W. Jacques.

Prcsoiitea, INIay 10, 187C.

The following experiments were made in order to test the po.ssibility
of applying to our atmosphere the principles of Fresnel and Huyghens,
which, in their application to the ether, have been attended with such
fruitful results.

There seems to be no a priori reason why the particles of air, form-
ing, as they do, a medium which, so far as the transmission of wave
motion is concerned, is essentially similar to the ether, should not be
80 acted upon as to produce the interferences known in optical science
as diffraction fringes. The following experiments bear upon this
point.

The apparatus was so arranged, in the first course of experiments,
as to give the best conditions for the study of external fringes, or those
produced outside of the geometric shadow of a sharp edge, on which
sound waves, diverging from a centre, were allowed to fall.

In the second course, similar waves were made to impinge upon an
isolated narrow obstacle, and so to give rise to a system of interior
fringes.

All other phenomena of diffraction may be classed as particular
cases of one or the other of these two kinds.

First series. A board one hundred and fifty centimetres wide was
placed at right angles to, and in contact with, the side of the hall. One
hundred and fifty centimetres from the edge, in a line at right angles to
the plane of the board, was placed a B^ stopped lead organ pipe. On
the other side of the board, a system of co-ordinates was established
by means of light wooden rods, running parallel and perpendicular to
the board ; these rods being divided into centimetres, it became very
easy to locate the points of interference by referring them to these
co-ordinates, and so to trace out the bands of interference.

In order to distinguish these bands, I first tried applying my ear to
different points along one of the rods ; but they were not sufficiently
well marked to make them apparent to the unaided ear. I then
arranged a resonator, of proper size to resound to the pipe, to slide
along the rod ; connecting this, by a piece of firm rubber tubing, with
the canal of my ear. The other ear I filled first with cotton, and then
with putty ; so that it was entirely deaf to all sounds. I was thus en-

270 PROCEEDINGS OP TEE AMERICAN ACADEMY

abled to annul the effect of every sound but that which was re-enforced
by the resonator. Moving now the resonator along the rod, I was able
distinctly to mark points of maximum and of minimum intensity, wliich,
in general, coincided with the positions which these bands should
occupy as calculated by formulte essentially similar to those applied
in the diffraction of light.

In the first experiments, a number of quite serious difficulties were
encountered. Perhaps the most important was that due to the fatigue
of the sense of hearing, in conseipience of which a maximum was
estimated before it actually occurred. By alternately opening and
closing the mouth of the resonator with the finger many times in
quick succession, however, and by taking a reading by first moving the
resonator in one direction, and another by moving it in the other, it
became possible to set it with considerable accuracy, the differences
being, generally, only a few centimetres. Another difficulty was met
with in the shape of a distinct band of interference, seeming to have no
connection whatever with the other bands, and following quite a different
law. Upon tracing it out, however, it was found to be due to an
interference of the direct wave with the wave reflected from the gas-
holder used to blow the pipe. Upon covering the holder with a cloth,
this was very much diminished: and, upon removing the holder, the
interference band disappeared altogether. There seemed to be slight
evidences of nodes and loops formed in the hall, as in an organ pipe ;
these, however, were very indistinct indeed, and were probably not a
source of error. An attempt was made to use the manometric flame
and revolving mirror to determine the points of most comi)lete inter-
ference, but the difference in effect upon the flame was so slight as to
render this method entirely impracticable.

In fact, the phenomena of diffraction can be studied only by the
closest attention with the ear, and the ear is certainly far more delicate
than any instrument of this kind that has ever been constructed. A
very pure note, and one of constant intensity was necessary for the
best results, and these were obtained by blowing the pipe with a
stream of air from a gas-holder, having an arrangement for keeping
the pressure constant.

Second series. The same board was set up near the middle of the
hall. Two hundred centimetres from its middle point, on one side,
was placed the pipe used in the preceding experiments. On the other
side was arranged a system of co-ordinates within the sound shadow.
Tiio method of determining the points of interference was the same as
in the first series ; excepting tliat only the bands of minimum intensity

OF ARTS AND SCIENCES.

271

were noted. The whole iihonomeiiou was less distinctly niarkcfl than
iu the case of a single edge ; and the bands of maxinmni intensity
were not definitely recognizable. It was only with careful attention
that even the bands of mininnun intensity could be discovered.

Below are given tjxbles showing the observeil and theoretical co-
ordinates of the points of interference noted. Table I. is the case of
diffraction from a single edge, and Table II. from a narrow obstacle.

In Table I., the first column gives the distances from the edge of
the board measured perpendicularly to its plane : the second and
third columns give the observed and calculated abscissas corresponding
to these ordinates, for the points of maximum intensity noted ; and
the fourth and fifth columns the corresponding values for the points of
minimum intensity.

In Table II., the first column gives the distances from the middle of
the board ; the second and third, the observed and theoretical ordi-
nates of the first curve of minimum intensity ; and the fourth and fifth
columns, the ordinates of the second curve, — all to the right of the
middle line ; the sixth, seventh, eighth, and ninth give corresponding
values for the two curves to the left of the middle line.

TABLE I.

Distances.

Curve of ^lax. Intens.

Curve of jNIin. Intens.

Obs.

Tlieor.

Obs.

Theor.

cm.
100
150
200

cm.

94

120

142

cm.

88

115

144

cm.
129
196
235

cm.
148
200
250

TABLE IL

Dis-
tances.

Ol)s.

Theor.

Obs.

Theor.

Obs.

Theor.

Obs.

Tlieor.

cm.

cm.

cm.

cm.

cm.

cm.

cm.

cm.

cm.

100

18

19

52

59

17

19

49

59

150

22

25

68

74

21

24

69

74

200

24

30

80

87

24

28

75

89

272 PROCEEDINGS OF THE AMERICAN ACADEMY

The theoretical values in the above tables were obtained by a
grajJiical solution, as the formula?, after undergoing the changes
necessarily made, because of the sound waves being of considerable
magnitude, became quite cumbersome, and extreme accuracy was not
required. The value of 1 was carefully determined and properly
corrected for temperature.

It should be remarked that all of the above experiments were made
in the large hall of the Institute, a room 92' by (So'.

The phenomena of the diffraction of sound are not so distinctly
marked as those of the diffraction of light. An examination of the
tables, which are the results of a most careful series of observations,
show that we are not warranted in accepting them as a basis for such
excellent further work as has been done in the case of light. It is
quite possible, of course, to calculate, from the positions of the fringes,
the values of X and therefore of V ; to determine the temperature of the
room in which the experiments are carried on ; or, given these quan-
tities, to deduce the values of physical quantities which are intimately
connected with the propagation of sound, and to determine acoustic
quantities analogous to those similarly deduced in physical optics : but
the method is difficult, uncertain, requires the use of a large hall,
physical annoyance to the observer, and, above all, is not susceptible of
the desired degree of accuracy.

Their chief value seems to lie in their reactive effect on physical
optics. In acoustics we are sensibly aware that we are dealing with
waves propagated in an . elastic medium. These waves may be felt
and even seen.* Finding similar effects in optics to those here
observed, we immediately refer these similar effects to similar causes,
and so place our explanations of the diffraction of light and of the
various cases of ethereal interference on a much firmer basis. The
experiments show, too, that the principles of Fresnel and Huyghens,
announced for the ether, are also applicable to our atmosphere.

♦ Expts. of Topfer. Pogg. Ann. 1867.

OP ARTS AND SCIENCES. 273

X. — COMPARISON OF PRISMATIC AND DIFFRACTION
SPECTRA.

By Professoii E. C. Pickering.

Presented, June 0, 1S75.

The object of tlie present communication is to affonl a means of
comparing the advantages of the two methods commoidv employed for
producing spectra, by diffraction gratings and by prisms. Two ques-
tions at once present themselves, the comparative length or dispersion,
and the comparative brightness of the spectra. In adopting a standard
of comparison, it is evidently necessary to select an absolute unit,
which shall be wholly independent of the instrument employed, and
defined entirely by the ordinary units of distance and direction. In
comparing the two kinds of spectra, since an observing telescope and
collimator are employed in both, it will be best first to compare the
effect of the prisms and gratings alone, and tlien see how far both are
affected by the telescopes. In the case of a diffraction grating, if i is
the angle of incidence, r the angle of reflection, D the distance between
the lines, ). the wave length, and n the order of the spectrum, these
four quantities must be connected by the relation nl. = D (sin i -f-
sin r). The dispersion or angular deviation of two rays whose wave
length differs by dl is found by differentiating r with regard to I,
recollecting that ^ being constant, its differential equals zero. We

thus obtain 7idX =: D cos rdr, or - = If now the grating; is

' dX D cos r * °

placed at right angles to the observing telescope, as in.Meyerstein's
spectrometer, the dispersion takes the very simple form -, or is inde-
pendent of the angle of incidence and of the wave length, and hence is
uniform throughout, and is simply proportional to the order of the
spectrum, and inversely as the distance between the lines. This
position has the further advantage that it gives a minimum of disper-
sion, and that consequently a slight error in setting is unimportant.

If N is the number of lines per millimetre, or equals — , the dispersion

assumes the still simpler form nN. This, then, forms the proper term
of comparison for diffraction gratings, or the length of any minute
portion of the spectrum will be proportional to its order, and to the
number of lines per millimetre.

VOL. XI. (N. S. III.) 18

274 PROCEEDINGS OF THE AMERICAN ACADEMY

As an example, the grating that Angstrom employed in most of his
measurements contained about 133 lines to the millimetre; and, as he
commonly observed the fifth or sixth spectrum, his dispersion equalled
G65 or 798. The admirable gratings of Mr. Rutherford contain 6480,
8640, 12,960, and 17,280 lines to an inch, or 255, 340, 510, and 680
lines to a millimetre. Accordingly the fifth spectrum of the 8640
grating would have a dispersion of 1700.

The case of refraction is a little more complex. As shown else-
where (Proc. Am. Ai-ad. vii. 478), when a beam of light, having an
index of refraction n, passes through a prism having an angle a, we

shall have the relation —^= — , in which i\ and ,7-2 ai'e the

dn cos i\ cos ?2

angles of refraction after passing the first and second surfaces. For

the position of minimum of deviation, r^ = r^ = ^ a, and in this case

di\, 2 sin i a 2 • tc • i *.i nr\o

— - =z — = - tang ^. It, as is commonly the case, a = 00 ,

dn COS I n

dr^ . -r, , . . dr '^^' , , • 1

^=secz. rJut this gives y' whue we want ,^ wlucn may be ob-
tained by multiplying by -^. The latter may be deduced from Cau-

dA

Ti C fl

chy's formula, ?^ = ^ -[- _ -j- -. Differentiating this equation, ~^=. —

A- \* dk

__ _ — ,and multiplying by ^, gives -^ = ^ tang x \B^ -^j,

or for a 60° prism — :L^ iB ■\- x-) sec ^.

The substances most commonly used for spectroscope prisms are
flint glass and bisulphide of carbon. The indices of refraction of the
first of these varies very greatly with the composition, and that of the
second with the temperature. The lines B, E^ and G are selected as
sliowing the effects of the ends and central portion of the spectrum.
The indices for flint glass are those given by Fraunhofer for the
specimen No. 23, and equal 1.62775, 1.64202, and 1.66028. For the
bisulphide of carbon the temperature of 11°5 C. is employed, and the
indices 1.6207, 1.6465, and 1.6886. These values give for the flint
glass, 7i= .00789 and (7= .000307. The corresponding values for
the bisulphide are, i? = .00614 and C= ,001972, the wave lengths
being expressed in thousandths of a millimetre. F'rom these we may

compute the three values of — for flint crlass to be .0568, .1381, and

.2804; and for bisulphide of carbon, .0818, 12293, and .6073. And
finally multiplying tiiese values by 1000 to change the unit from thou-

OF ARTS AND SCIENCES. 275

sandths of a niilliniotre to inilliinetivs, and l.y ^ gives the followin.r

an '^

values for tlio dispersion of a GO'' flint jjlass prism. For B, 98 ; for E,
242 ; and for G, i>0'^. The correspondii)<r values for a 00° prism filled
with bisulphide of carbon are : for B, 140 ; for E, 404 ; and for C, 1 1 ;i;i.
Comparing these numbers with those given above for difn-action
gratings, we see the superiority of the hitter as regards dispersion,
especially at the red end of the spectrum.

These advantages are, however, in a measure counterbalanced by
the greater loss of light. It is shown elsewhere (Am. Jour. Sci.
xlv.) that in a spectroscope containing ten 60° prisms the loss of light
by reflection would equal 50.9 per cent; so that the transmitted ray
would have an intensity of 49.1, the incident ray being taken as 100.
This would be further reduced by the loss from absorption, but the
amount would vary with the material, the wave length, and the length
of path, or size of prisms. Estimating this loss as one half, still leaves
the intensity of the whole of the spectrum as 25 per cent of the
original beam passing through the slit. In a diffraction spectrum the
light is much less; allowing one half for the light lost in the central
white image, evidently if we have five spectra on each side, the average
amount of light in each cannot exceed five per cent. And even tlfis
must be diminished by the loss due to reflection and absorption in the
case of glass gratings, and to imperfect reflection in the case of
speculum metal or silvered glass.

The discussion of the effect of the collimator *ind observing telescope
on the dispersion involves another consideration ; namely, the size of
the image of the slit. To render this clearer, suppose we are observing
the sodium spectrum, when a small amount of the metal is present.* We
shall then obtain two sharply defined images of the slit separated by an
interval dei)endent on the dispersion. These images may overlap, and
will vary in width as the slit is open or shut, but their distances apart
will not alter. Call w the true width of the slit, W that of its image
as seen througli the telescope, and referred to the distance of distinct

* If much sodium is present, the lines widen and become hazy, and with a
large dispersion both appear again double, owing to tlie absorption of the outer
layer of sodium vapor. Tliis effect is readily obtained by putting a lump of
borax in the flame, wlien at first it gives a bright blaze and shows the four
lines ; presently, however, the light becomes feeble, and the usual double line
IS alone seen. If now an image of the flame is projected on the slit, the spec-
trum of any part of it may be studied, and it will then be found that the central
portion only gives the four lines, the edges giving the usual double line.

276 PROCEEDINGS OF THE AMERICAN ACADEMY

vision, 250 mms., or ten inches. Also call c the focal length of the
collimator, o that of the observing telescope, and e that of a lens

equivalent to the eye-piece. Then W := "''. Again, the dispersioa

ec

or interval between the two images will equal that of the prism or
grating, multiplied by the magnifying power of the observing tele-
scope, or -, and will be quite independent of the collimator,
e

As in the microscope and telescope the highest powers are by no
means those which give the best results, so in the spectroscope the
best effects are not always obtained with the greatest dispersion. In-
creased angular disjjersion is readily obtained by using a high power
with the observing telescope, but the limit is soon reached, since the
apparent width of the slit, and the various distortions, are increased in
the same ratio. Moreover, with a very gi-eat dispersion the light is so
far enfeebled that the spectrum becomes faint and the slit must be
opened wider.

The most satisfactory test of the efficiency of a spectroscope, as of
other optical instruments, is to examine some delicate object and com-
pare the appearance with that obtained with other similar instruments.
Formerly the D line was used for this purpose, which with any but
the smallest instruments is seen to be double. In the solar spectrum
it was soon found that there was a third line between these, and
afterwards several other lines were noticed. The observations of
Professor Cooke (Proc. Am. Acad. viii. 57), however, showed that
most of these lines were due to the aqueous vapor in the earth's
atmosphere, and that their visibility therefore depended very largely
on the condition of the air. The E line is free from this objection ;
and, as it contains many more components, it furnishes a much more
complete test. The following table gives the appearance of the E line
as seen with various instruments. A dash denotes that the line
opposite which it is drawn was visible. When a double line is seen as
single, one of its components only is marked. The lines given in the
map of KirchhofF are shown in the column headed Kir. Those given
by Angstrom are, in like manner, marked Ang. To obtain the lines
seen with various instruments of the largest size, I asked several
friends to draw all the lines they could see with their spectroscopes;
and I take this occasion to express my thanks to them for the
results. Tlie column headed Sh. gives the results obtained by Mr.
Sharpies, with a large spectroscope belonging to Dr. Gibbs, having
six GU° prisms, filled with chemically pure bisulphide of carbon.

OP ARTS AND SCIENCES. 277

The clispersiou, therefore, as shown above, would be about 2400.
Coluiim Am. gives the Hues seen by Dr. Amory, with a diffraction
grating of Mr. Rutherford's, liaving olO lines to a millimetre. As he
emjjloyed the sixth spectrum, the dispersion was 30G0. For the most
recent and complete measurement I am indebted to Professor Young,
who has measured the E line with a very perfect grating by Mv. Ruth-
erford, having oiO lines to the millimetre ruled on silvered glass.
As he used the eighth spectrum, the dispersion was 2720. These
results have been taken as a basis, and the resultant wave lengths
are given in the second column. My own observations are given in
the column marked P., and were made in 18G9 and 1870, with a
spectroscope in which the ligiit traversed each prism twice, giving
a dispersion equivalent to 7, 9, or 11 flint glass prisms. This would
correspond to dispersions of 1700, 2200, and 2G40; but tiie best
results were obtained with the two lower powers. All the observers
used telescopes about a foot and a half iu length.

We have thus four entirely independent maps, as neither observer
had at the time a copy of the work of any of the others. The simi-
larity of the results, with instruments differing so greatly in form and
power, seems to show that we have nearly reached the limit beyond
which an increase of dispersion is uuadvisable ; and as if with our
largest instrument nearly all the lines really present in the spectrum
were visible. It is much to be desired, however, that these lines may
be compared with any other instruments of greater power, if such are
ever constructed. It is only essential that the measurements should be
made before comparii^on with the above results, since with the lines, as
with faint stars, it is much easier to detect them when we know exactly
where to look. Various tests may be selected from these lines for an
instrument of any power. Thus to double the ^ hues, or to show 24
and 26 as two lines, is a good test for a one prism spectroscope of
large size. The five pairs, (27, 28), (29, 30), (31, 32), (35, 36), and
(37, 38), also form an excellent test for any but a verj' large instru-
ment. The great number of double lines in this group, and more
particularly in the B line, and in the electric spectrum of sodium,
seems to prove most conclusively, as in the case of double stars,
some real relation between the two components.

The last two columns give the relative intensity and width of the
lines as estimated by Professor Young. Nos. 2, 16, and 27 are hazy,
and No. 35 is a mere shade. The numbers under the observers' names
give the approximate dispersion employed by each.

278

PROCEEDINGS OF THE AMERICAN ACADEMY

No.

Wave
length.

Kir.
1400

Ang.
800

Sh.
2400

Am.
3060

P.

2000

Y.

2720

In-
tensity.

Width.

1

5260.9

3

2

2

1.3

—

—

—

—

6

3

3

1.8

-!

—

. —

—

1

1

4

2 1

—

3

1.5

5

2.4

—

—

—

5

2.5

6

2.8

—

—

—

1

2 5

7

3.2

—

2.5

1.5

8

3.4

—

"^

6

2

9

4.0

—

2

2

10

4.4

—

—

—

1.5

1

11

4.8

—

—

2

1.5

12

5.0

—

—

—

2

1.5

13

5.1

—

—

2

1.5

14

5.3

—

7

15

5.6

—

16

5.8

—

—

—

7

3 5

17

6.3

—

1

1

18

6.5

—

—

—

1

1

ly

6.6

—

.5

1

20

7.0

■

—

—

1.5

1

21

7.5

—

—

—

2

1.5

22

7.7

—

—

1.5

1

23

8.3

—

.5

1

24

8.7

—

—

—

10

3.5

25

9.0

1

—

■I

.5

2

26

9.5

—

—

—

8

2

27

69.9

f

.7

28

70.3

—

.7

1

29

0.5

—

—

—

1.5

• 1

30

0.7

—

—

1

1

31

12

—

—

—

2

1.5

32

1.6

—

—

2

1.5

33

2.3

—

—

6

2

34

2.5

—

5

1.5

35

3.1

—

1

3

36

3.9

—

—

—

.7

1

37

4.2

—

1.5

1

38

4.4

—

—

—

—

—

2

1.5

o'.t

5.0

—

—

2.5

1

40

5.3

—

—

—

—

—

4

2

SLIT ^b OF
INCH WIDE . S.

ABSORPTION BANDS OF
URANIUM RCETATE SOLUTION

ABSORPTION BANDS OF
CHLOROPKVLL SOLUTION

SOLAR SPECTRUM

SOLAR SPtCTRUM

ABSORPTION BANDS OF
CHLOROPHYLL SOLUTION

10 . RPTION BAN05 0'
SOLUTION Of
PHOTO CHLORlDEWURANiL

/iELiOTYPE.

OF ARTS AND SCIENCES. 279

XXII.

ON PHOTOGRAPHS OF THE SOLAR SPECTRUM.

By Robert Amort, M.D.

Read, May 10, 1876.

In continuation of the experiments first presented to the Academy
a year ago concerning the photography of absorption bands from light;
transmitted through colored solutions, I take pleasure in announcing,
that owing in great part to the assiduous application of my assistant,
Mr. J. H. Hubbard, the lines between F and D of the solar spectrum
have been distinctly impressed upon a sensitized collodion plate. The
plate I now present to the Academy shows these lines unmistakably,
the double line of D being i^erfectly visible. The image is impressed
upon that kind of collodion which is coated ujaon what are known as
the " Stuart -Wortley Plates."

I believe this is the first time that a sharp photographic image of
the D line has ever been exhibited ; though 1 am well aware that
others have reported that they have been able to obtain photographic
effects from the yellow and red rays of the spectrum.

You are probably aware that these are dried plates ; and in addi-
tion to the advantage of using a dry plate, in which the decomposi-
tion may be supposed to continue more favorably than on a wet plate,
which is constantly drying up when exposed, mention may be made of
the probable ingredients used in the dry process. These consist of
bromide of silver, salicine, and uranium, among others ; and it was evi-
dent to us, fi'om certain of our preliminary experiments, that the
glucosides, added to collodion, increased the sensitiveness of the plates
exposed to the green rays. Hence we were induced to use these in
preference to the ordinary dry tannin plates. An exposure of thirty
to forty -five minutes is required in order to obtain a distinct image of
the solar lines in that portion of the spectrum which I have here pre-
sented.

You will observe that the image is brought to a principal focus in the
vicinity of E and b lines ; in fact, that eight of the group of E lines are

280 PROCEEDINGS OF THE AMERICAN ACADEMY

quite easily made out, especially if viewed through a magnifying lens of
low power. It may also be noticed that the two lines of D are quite
sharp, and distinctly visible : possibly the positive impression taken
from the same negative, which is here exhibited, may make these lines
more visible in the dazzling gaslight of this room. I also present
negatives and their positives of the absorption bands of a solution of
uranium acetate, of" uranium chloride, and also of a solution of chloro-
phyll, the latter of two kinds, one of which is obtained from grass,
and the other from green tops of the asparagus-plant.

In conclusion, I will state that we have used the most simple appara-
tus that could be devised, so that we may only lose a small portion of
light, and not complicate the results by too many reflections of the
image submitted to the photographic action. This apparatus consists,
1 st, of the heliostat ; 2d, a mirror arranged in the central axis of the
heliostat to intercept and reflect the beam into a dark room ; 3d, a
slit (width about one-hundredth of an inch) in the shutter of the dark
room ; 4th, a collimating lens at its exact focal distance from the slit ;
5th, a dense glass jirism arranged at the minimum angle of deviation
for the especial line whose image we wish to photograph ; Gth, a com-
mon spectacle lens of forty-two-inches focus ; 7th, the sensitized plate.
Between the prism and the sensitized plate, a square, dark box of
large capacity excludes all other light than that we wish to use.

On the following page will be seen heliotype prints of these bands,
though it should be borne in mind that it is almost impossible to ob-
tain an exact reproduction of details in a positive on paper, unless the
negative be retouched, which for obvious reasons cannot be allowed.
Mr. E. PLdwards very obligingly has devoted much pains to the repro-
duction of these jirints by the heliotype process.

OP ARTS AND SCIENCES.

281

XXTIT.

A NEW FORM OF INDUCTIVE APPARATUS.

Bt Henry P. Bowditcu.

Presented, Oct. 12, 1875.

The inductive apparatus commonly used in physiological laboratories
is the so-called " Sledge Apparatus " of Du-Bois Reymond. In this
instrument, the intensity of the induced current is regulated by varying
the distance between the two coils, their axes being always kept in the
same straight line. By this method, very feeble currents can only be
obtained by separating the coils to a considerable distance, and an in-
strument made to permit this separation has often an inconvenient
length.

In the instrument here presented, and which is figured in the
accompanying wood cut, this ditficulty is obviated by allowing the
secondary coil, as soon as it has been withdrawn enough to be fairly
free of the primary coil, to rotate round a vertical axis. In this way,

the intensity of the induced current may be reduced to any desired
degree, zero being obtained when the coils are at right angles to each
other. The effect of simple rotation of the secondary coil, regarded
by itself, would doubtless be to cause the intensity of the induced
current from that coil to vary in the same proportion with the cosine

282 PROCEEDINGS OF THE AMERICAN ACADEMY

of the angle of rotation. This effect is, however, complicated by the
variation in the distance of the different parts of the two coils from
each other which attends this rotation. It is accordingly found that
the curve which represents the actual variations in intensity (obtained,
according to Fisk's method, by measuring with the galvanometer the
intensity of single induction shocks at every ten degrees of revolution
of the secondary coil *) differs from the curve of cosines in being
slightly convex towards the abscissa just before it reaches that line.

The scale with wliich the instrument is provided indicates the in-
tensity of the induced current at different positions of the secondary
coil, expressed in terms of an arbitrary unit employed in the gradua-
tion of a large " sledge apparatus," in use at the physiological labora-
tory, and similar to the unit adopted in German laboratories for the
graduation of similar instruments.

* See Cyon's Metliodik der physiologischen Experimente, p. 379.

OF AllTS AND SCIENCES. 283

XXIV.

HYDROGKAPIIIC SKETCH OF LAKE TITICACA.

By Alexander Agassiz.
Presented, March 8, 1876.

From the position of Lake Titicaca, its exri^loration promised to
give interesting results in Natural History, judging at least from the
materials collected in lakes situated at great heights. It was there-
fore with considerable disappointment that my companion and myself
after a protracted examination of this great sheet of water examined
our plunder. We had come prepared with all the necessary apparatus
for dredging, for taking observations of temperature and making
soundings ; and, with the facilities placed at my command by the
Peruvian government, we hoped to gather a rich harvest. Mr. Gar-
man spent nearly six weeks in skirting the shores of the lake, stoj)-
ping at all convenient places for making collections of the Fauna of
the lake and of its shores, and for exploring the ancient remains found
on the islands in the lake and at several points in the vicinity of the
shore line. While Mr. Garman was sailing on the lake in a small iron
sloop, the only sailing vessel on the lake, if we except an old flat bot-
tom ferry plying across the Straits of Tiquina, I made two expedi-
tions in the steamers '' Yavari " and "■ Yapura " placed at my disposal
by the Peruvian government, landing at all the noted points where
interesting Lica ruins existed : the islands in the lower lake, the islands
of Coati and of Titicaca, Copacabana, and Tiaguanaco. During these
two expeditions, I crossed the lake longitudinally twice, and ran sev-
eral lines of soundings from shore to shore. The captains of the
government steamers, Capt. F. Guerrero especially, taking the great-
est interest in my proceedings and assisting me in all possible ways,
sparing neither time nor pains to secure proper observations. The first
mate of the " Yavari " was fortunately assisted by a number of P^nglish
sailors, who were devoted in hauling the sounding lines at all times of
the day and during all kinds of weather. The sketch map accompany-
ing this notice is compiled from the map of Thompson and of Pentland,
with such corrections of the shore line as we could make from per-

284 PROCEEDINGS OF THE AMERICAN ACADEMY

sonal examination. The latitude as given by Pentland, 16° S. for
the northern extremity of the Island of Titicaca, is very nearly cor-
rect, Capt. Guerrero and myself having taken several sextant observa-
tions off the northwest point of tlie island, which agreed quite closely
with Pentland's positions. The longitude of Puno, however, as given
by Pentland, 70*^ W., is j^robably not quite correct, and too far to the
eastward. The distance of Puno from the harbor of Mollendo being
only seven minutes in time, as ascertained by telegraph between the
two points, of course this is approximate ; while taking the longitudes
as given on the English admiralty map 73° 39' for Mollendo, as given
by Fitzroy, and 70"^ for Puno, by Pentland, the diiference of longi-
tude is somewhat greater, more than 3°.

Mr. Garman and myself took more than sixty -five soundings, from
which a number were selected to represent the surface of the bottom.
The whole bottom of the lake in its deepest parts, and frequently quite
close to the shore, up to the point at which the myriophyllum and the
totora grow so plentifully in certain localities, is covered by a thick
bed of mud, the finest jjossible greenish black silt. This bed of mud
must have been several feet in thickness, to judge from the ease with
which the heavy sounding leads disappeared in it. It contained but
few fragments of shells, being almost always made up of pure fine
mud. It was only in a small number of localities near the shore, and
away from the mouth of any rivers, that occasional patches of sand
and of shelly or rocky bottom were found. In the lower lake,
however, the bottom was generally sandy, the water having deposited
the bulk of the matter held in suspense before reaching the Straits of
Tiquina. At the time of our visit to the lake, althougli during the
last jjart of the rainy season, when all the rivers pouring into the lake
were very high and turbid with the mud and materials they brought down
from the mountains, yet, a short distance from the shore, the surface
water was remarkably pure and clear. According to an analysis made
by Professor Raimondi of Lima, there is but a mere trace of saline sub-
stances, and not sufficiently large to affect the potability of the water.
Having an outlet to Lake Aullagas through the Desaguadero, there is
no chance for an accumulation of saline matter, while Lake Aullagas
is already, as I am told, somewhat saline, and the sink into which that
pours is quite saline. The unpleasant taste of the lake water near the
shore is due to the immense amount of decayed vegetable matter
abounding in the extensive fields of myriophyllum and of totora,
which line the shores for miles, and which e.xten 1 to a depth of from
six to seven fathoms. The totora fields are most extensive in Puno

OF ARTS AND SCIENCES. 285

Bay and the southern shores of the lower lake. The myriophyllum
^rows very hixuriantly, anil forms an important article of food for the
cattle of the lake shore. It is not an uncommon sii^ht to see tho
cows of Puno wading up to their middle in the water, and diving
boldly in search of their food which they cannot find on the shore.
This habit has as yet produced no apparent effect on these amphibious
cows, although carried on for a good many generations. The fields of
Totora are also the feeding places of the myriads of aquatic birds
which abound along the lake shore, and which are the most charac-
teristic feature of the Fauna of the lake. The fishes and reptiles are
not numerous,* and our collections of the former showed a poverty in
S2>ecies which is most remarkable, and this is also accompanied by a
comparative jioverty in the number of sjiecimens, except in certain
localities. The scarcity of fishes can, however, be readily explained
when we examine the physical condition of the water, which is cer-
tainly not well adapted to them. In the first place, the whole bottom
of the lake, as I have mentioned before, is covered with silt, thus ren-
dering unfit a large part of the area of the lake for the fishes and rep-
tiles, leaving only the shallower bays, a more or less wide belt along
the shore according to the nature of the adjoining country, and the
lower lake, which appears to be the favorite fishing post of the Indians.
This, however, may be due to the greater energy of the Bolivian In-
dians, who are a finer set of men, more willing to work, and in every
way superior to the lazy natives found near Puno and the northern end
of the lake. In the second place, the temperature of the water of the
lake is so high that none of the fishes which abound in the lakes of
our temperate zone are to be found. There are in all only six species
of fishes, Cyprinoids and Siluroids, — a remarkably small number for
a sheet of water as large as Lake Erie. They were all known before.
In the way of reptiles, the most interesting species was a huge frog,
which remained often for hours perfectly quiet on the bottom, sus-
pended on fronds of myriophyllum, apparently too lazy to come up
to the surface to breathe.

The effect of the vertical sun upon the temperature of the water is
very marked, extending to its deepest point, and heating the whole
body of water to such an extent that the greatest difference we ob-
served was in one case, it is true, as high as 6J degrees at a depth
of 103 fathoms; but the usual difference between the surface and

* See Bull M. C. L. Vol. III. No. 11.

286 PROCEEDINGS OF THE AMERICAN ACADEMY

the bottom, even at the greatest depth (154 fathoms), was not more
than from 3 to 4 degrees. The lowest temperature of the bottom
was only 51°, the general temperature varying from 54 to 55^; while
the surface temperature ranged from 53 to 59°, the greater part of
the time 56 to 57° Falir.

We used the ordinary deep-sea thermometer of Miller Casella,
kindly loaned to me by Captain Patterson of the United-States Coast
Survey. As is well known, deep-sea observations show that the effect
of the sun does not extend in the ocean much bej'ond 50 fathoms; but,
in a closed basin like this, at so great an altitude, the effect of the direct
rays of the sun passing through so little atmosphere is very great.
It must be remembered, that, even in the winter months of that re-
gion (the dry season), the sun never goes farther north than 52°, and
that only for a short time ; and that, in the summer months (the rainy
season), it is nearly vertical the greater jiart of the time. The water,
of course, retauis its heat readily, and, even in summer, is but little
cooler than the surrounding air, which becomes ver}' rapidly chilled by
the least cloud interposing between it and the sun. It is a very com-
mon thing for the thermometer to rise or fall eight or nine degrees in
as many minutes from the effect of the sudden appearance or disap-
pearance oi the sun. Ice is said to form only in small quantities
along the shores or shallow places : this is easily imagined when we
take into account the immense body of water which must be cooled,
120 miles long by 30 wide, and an average depth of about 100 fath-
oms ; the surface of the lake, even in winter, receiving a large amount
of heat by absorption, although the air itself is uncomfortably cold.
We find here, as is the case in many other sheets of water com-
paratively isolated, but few S})ecies, and these peculiar to the lake.
We find at this great elevation a condition of things reminding us of
the marine life of arctic regions, — a great abundance of specimens,
with a comparatively small number of species ; the shoals of Orestias
and Siluroids, which are seen in certain localities, agree with the ac-
counts we have of the swarms of fishes and other animals haunting the
arctic realms. Still there are peculiar physical conditions of the bot-
tom of the lake, the immense deposits of mud formed by the settling
of the silt brought down annually by the mountain-streams, the great
elevation of the lake, the high temperature of the water ; all of
which causes should tend to specialize to a remarkable degree the
genera found to thrive in such a condition of things. We find, how-
ever, no such specialization brought about among* the fishes : on the
contrary, their isolation, even while living under such peculiar physical

I

OF ARTS AND SCIKNCRS. 287

ooiiditions, appears to have deprived some of them, at any rate, of
any eapacity for development in the direction of tlieir congeners.
The genus Orestias is closely allied to Fundnlus, one of the most
Avidely distributed of fresh-water genera. The species of the genus
Orestias resemble in a remarkable degree the young of some species
of Fundnlus, and might be considered, without exaggeration, its em-
bryonic type, at a time when the young Fundnlus is remarkable for
its large head, prominent opercula, its large scales resembling plates
along the anterior part of the back and sides. The other genera of
lish found in the lakes are eminently fresh-water, having a great
geographical distribution. The great number of water-birds recalls
to us vividly also the more northern marshy regions, where thousands
of ducks and water-hens abound. The mollusca are all species of
eminently fresh-water genera, showing nothing very special. The
Crustacea, on the other hand, belong mainly to the Orchestiadre, forms
which thus far have not been found in fresh water at all : their near-
est allies are nearly all marine (see Bull M. C. L., vol. iii. No. 16).

Although we have from the researches of several geologists, but of
Darwin mainly, a pretty good general idea of the immense extent of
territory which has been subject to a greater or less elevation along
the whole west coast of South America, from tlie south coast of Ecua-
dor to the eastern coast of Patagonia, this elevation appears to have
culminated in Central Peru. Yet there has been nothing shown which
would lead us to assume such an immense elevation of the land as
12,000 feet. It is very true that Darwin showed the most positive
proof of elevation to a height of about 600 feet ; while terraces,
shingle-beaches, and other more or less distinct traces of the former
level of the sea, he traced to a height of from 1,300-1,500 feet. I
have been able to follow up these traces of elevation somewhat higher,
having found at Tilibiche, at a height of 2,900 feet above the level of
the sea, corals of genera closely allied to those now found living in
the West Indies (see Bull M. C. L., vol. iii. No. 13). These corals
were attached to rocks, in crevasses formed between them, much as
we would find them attached at the present day in the cracks of rocks.
This being near the northern extremity of the nitrate-fields of Peru,
throws considerable light on the probability of these deposits having
been of marine origin. In fact, the geography of the whole of the
west coast of the Andes to the north of Chili seems to point to a
former condition of things such as we now find on the west coast of
Chili. The plains to the southward of Santiago, bounded by the coast
range to the westward, and the Andes to the east, gradually pass to

288 PROCEEDINGS OF THE AMERICAN ACADEMY

the condition of the coast now prevailing at Conception Bay, and south
of it, — the coast range forming the archipelago, the Andes forming the
coast range, and the plains of the more northern regions becoming
changed to bays ; the immense basins succeeding each other towards
the nortli which form the so-called Desert of Atacama, the nitrate-beds,
the llanos of the coast, the jjampas of Peru, through which the rivers
flowing to the west have cut deep valleys with more or less marked
terraces, showing the different periods of ascent in the elevation of the
continent. These plains are everywhere found, either between a
coast range and the base of the eastern talus of the Andes, or ex-
tending fx'om the summit of the shore terrace, if we may so call it,
generally at a height of from 1,200 or 3,000 feet, sloping to the
second terrace, with its base at an average height of from G.OOO—
7,000 feet, and then followed by a second and third more or less
indistinct terrace until we reach the main elevated plateau or basin
which lies between the eastern and western slope of the Andes. All
these basins show more or less distinctly the trace of their former
marine origin ; so that, if we are to judge from the presence of strictly
marine forms, the successive terraces developed on a magnificent scale
on the west coast of the Andes, with the interlying basins, we have
a fair presumption that the elevation of the Andes to their present
height has taken place at a comparatively recent date, and during their
upheaval the present nitrate district and saline deposits were left as
large lagoons during a considerable period, to judge from the great
thickness of the deposits found within their basins, all denoting the
presence of a comparatively quiet inland sea.

Lake Titicaca itself must have, within a comparatively very recent
geological period, formed quite an inland sea. The terraces of its
former shores are everywhere most distinctly to be traced, showing
that its water-level must have had an elevation of 300 or 400 feet at
least higher than its present level. This alone would send its shores
far to the north in the direction of Pucara, forming a narrow arm
reaching up to S. Rosa. Lake Arapa is probably only an outlier of
the ancient lake, as well as several of the small lakes, now at a
considerable distance from the west shore. The immense plain of
Cabanillas, extending north beyond Lampa to Juliaca, onlj'^ 100 or
1 20 feet above the lake at its highest point, was one sheet of water.
The terraces of the former shores are still very distinctly seen. The
eastern shores did not probably differ greatly from the present out-
line, though the peninsula of Achacache was jirobably an island.
The Bay of Puno must have been connected with the plains of Llave,

OF Aims AND SCIKNCKS. 289

and those back of Juli; wiiile i'roiu the lower lake, back of Aygache,
the hUve formed huge inlets or deep bays, now represented only by
till' ncarlv dry river-beds flowinir into the lake at Ayijache. Gorilla,
and CJuajui. The sluggish Desaguadero must have been a strait of
considerable width, with large islands ; and this long lake, connecting
Lake Titicaca with Lake Aullagas, must have equalled in extent the
up{)er lake ; the upper lake, at tliat time, extending across the Isth-
mus of Yunguyu, leaving the Peninsula of Copacabana as a large
island, connected with the lower lake by a broad jiass between the
hills to the west of Copacabana, and those to the west of Yunguyu.
The plains, now laid bare at the northern and western shores of Lake
Titicaca, give us an excellent idea the appearance the whole basin of
the lake would present if entirely dry. The number of lakes and
basins, great and small, which formerly covered the elevated plateau
of the Andes, must have been very great ; but we now find only
here and there a small sheet of water. The former lakes are only
represented by the more or less extensive pampas, forming basins at
great altitudes, showing plainly that the whole of this district is re-
ceiving a much smaller waterfall than in former times, but probably
not Avithin historic times, if we take into considei'ation the position
of some of the most ancient ruins of Bolivia (at Tiahuanaco), which
are only about 75 feet above the present level of the lake. These
ancient basins are thickly covered bj^ huge bunches of rank grass,
from which the llamas, alpacas, and vicunas obtain their only suste-
nance at the immense heights where they seem best to prosper. It
would be an interesting inquiry to ascertain the causes of the differ-
ence in the habitat between the other species of camels and the
llamas, which do not thrive near the sea-coast.

In the lower lake, which is shallow, the temperature of the surface
and that of the bottom varied extremely. From the number of obser-
vations taken, I can only state that it is very local, depending upon
the prevailing wind and the condition of the sky.

The following soundings, taken from those of the upper lake, show
the great uniformity of the temperature of the surface and bottom: —

VOL. XI. (N. S. III.) 19

290

PROCEEDINGS OF THE AMERICAN ACADEMY

Depth.
Fath.

Surface.

Bottom.

Air.

Time.

5

55° F.

550 F.

7.40 A.M.

8

55

53

56°

10.15 A.M.

28

58

53

12.30 A..M.

18

59

64.5

55

4.30 P.M.

12

55

54.9

42

7.10 a.m.

24

56.5

56

53

9 a.m.

33

54.7

64.5

47

12.20 a.m., cloudy.

30

57.5

56.2

58.5

4 p.m., clear.

43

56.7

55

58

10.20 a.m.

47

55.9

54.9

67

11.05 p.m., sun very brig

ht.

66

56.1

54.3

55

11.10 P.M., sunny.

74

57

54.5

60

2.25 P.M., sunny.

82

55.5

51

8 a.m.

85

56

54

43

6 a.m., rainy.

90

56

54

55

1 p.m.

100

5.5.3

54.3

44

7.10 A.M., raining hard.

103

56

51.5

6.15 p.m.

111

57.5

54.9

63

12.20 p.m., clear.

106

57

54.5

112

54.9

54.5

44

7.10 P.M., raining hard.

113

57. 5

55

61

10 A.M., clear.

114

55

116

55

54.6

45

11.14 A.M., raining hard.

124

56.3

56

60

1.09 P.M., sunny.

125

55

54.9

45

8.05 P.M., sunny.

180

56

55

9.10 P.M.

136

57

54

55

10.30 A.M.

132

53

52

149

55.3

54.5

47

11.40 A.M., cloudy.

150

55

54.5

48

10.25 a.m., cloudy.

151

65.4

55

49

12.25 P.M.

154

54

52

8.45 A.M.

The elevation of the lake above the Pacific has been taken from the
surveys of the railroad engineers, obtained while laying the line from
Ai'Ofjuipa to Puno. Professor James Orton inclines to the oi)inic)n
that the wliole basin of Lake Titicaca, with the high plateau to the
westward, is gradually sinking, because the successive observations
made from early times give a gradually diminishing height. Thus
far, the few measurements taken can hardly be more than a chance
coincidence, when we remember the uncertainty and great divergence
attending all measurements of heights taken to within a comparatively
very recent period. The experience of the topographers of the late
geological surveys in the Rocky ^Mountains has been very similar ; and
yet we are hardly prepared for such a sweeping generalization as
the sinking of the greater part of the Rocky Mountains from much

OF ARTS AND SCIENCES. 291

more abundant data tlian those accessible from Lake Titicaca and its
vicinity.

Along the eastern coast of Lake Titicaca, the mountains forming its
former shores nowhere rise to any considerable height. The greatest
elevations arc found along the general line forming the western edge
of the high plateau, to the south of which the lake is situated, from the
Nevados of Tacorara to those east of Moquega, the Pichupichu,
Chachani, Coropuno. A lower nearly parallel range extends about
half-way between the line of the former and the axis of Lake Titi-
caca. This range, however, does not rise to more than 10,000 or 17,000
feet, and, sweeping to the northward at a distance of about one hundred
miles to the north-east of the lake, forms the water-shed between the
rivers leading to the headwaters of the Amazonas and those flowing
into Lake Titicaca, the eastern sides of this great basin being formed
by the northern extension of the huge range which culminates near
the south-eastern shores of Lake Titicaca in the snowy giants of
Guaina Potosi, Mamini, and Mampu. The range runs nearly north-
ward from the head of the Bay of Achacache, forming the southern
boundary of Caravaya on the north, and uniting with the northern
water-shed of the great Titicaca basin. This eastern range of snowy
mountains retreats from the shore of the lake about as far as the
western intermediate range, and forms at the same time the line
between the waters flowing to the Pacific and those belonging to the
basin of the lake. The hills of the peninsula of Copacabana do not
rise more than 800 to 1,000 feet above the level of the lake ; and, to
the south of the lake, low ridges form the dividing-lines of the tor-
rents flowing from the heights between La Paz and Corocoro into
the lower lake. The view from the crest of one of these ridges im-
mediatel)^ to the eastward of Tiahuanaco is truly magnificent ; and the
panorama of snowy heights rising from 8,000 to 10,000 feet above
the level of the lake is one of the most beautiful stretches of mountain-
scenery it has been my fortune to see. Rising as these mountains do
behind the islands of the lower lake as a foreground, with the low
hills beyond Huarina on the opposite shore of the lake at the base of
the snow-line coming down to within a couple of thousand feet of the
shore, we have within a radius of thirty-five miles no less than six or
seven peaks varying from 20,000 to 22,000 feet above the level of the
sea. Looking over the peninsula of Copacabana extends the upper
lake, with its sacred islands hardly visible on the horizon ; while to
the westward extend, as far as the eye can reach, the huge flat-topped
hills, the dividing-ridges between the torrents flowing into the lake,

292 PROCEEDINGS OF THE AMERICAN ACADEMY

which comprise the immense elevated plateau reaching a height of
some 1G,000 feet above the level of the sea, with an endless number
of somewhat higher peaks rising slightly above this general elevation ;
while to the westward of Tialiuanaco the sharjily-cnt outline of the
mountain-chain \vhich formj the div.>ij.^-bou;.dai_) between Bolivia
and Peru shuts out the view in that direction. But while the outline
of many of these chains is most graceful, and the grandeur of the
Nevada de Sorata is not to be forgotten, the barrenness and utter
desolation of the whole scene deprives it of much of its beauty.
There is absolutely nothing green to rest the eye ; the whole country
is dry, arid, stony ; here and there a patch of rank grass, upon which
the vicuiias manage to eke out their existence ; an occasional shrub,
with a stem as large as one's little finger, only left because it has thus
far escaped the eye of the Indian gathering the few shrubs remaining
as the only firewood, which, with characteristic imprudence, he does
not cut down to give it a chance to grow again, but jiulls up roots and
all, to get as much fuel for the present needs as possible.

The accompanying map illustrates the general hydrograj^hy of the
basin of Lake Titicaca.

»77<rT.fv_

So >>v»'(to

OF ARTS AND SCIENCES. 293

XXV.

CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF
HARVARD COLLEGE.

No. X. — DISTRIBUTION OF MAGNETISM ON ARMATURES.

By Harold Whiting.

Presented, May 10, 1876.

The subject of the distribution of magnetism on armatures has not
yet been carefully investigated ; although the change of form of the
curve due to the addition of an armature has been roughly determined.
It appears, that, when an armature is added to one end of a magnet,
some of the magnetism spreads over the nearest part of the armature.
To prove this, and at the same time to get a general idea of the best
way to investigate the subject further, I performed the following pre-
liminary experiment. My ajiparatus consisted of a steel rod, half a
metre long and about a quarter of an inch in diameter, and an iron
rod of the same dimensions ; also a small wooden bobbin wound with
about a hundred and fifty coils of fine insulated wire, and having a
hole in its axis just large enough to allow it to slide freely over the
rods. A paper scale, graduated into centimetres and millimetres, was
attached to each rod. The two ends of the coil of wire were connected
with a very delicate galvanometer. The steel rod was magnetized.

The coil was now slijiped in different parts of the rod, over a dis-
tance of two centimetres each time, and the deflections were noted.
This deflection was made the ordinate of a curve, and the abscissa was
taken equal to the distance of the centre of the coils at the central
point of their motion.

Table I. gives the figures, which are, of course, only relative. The
distances are given in centimetres.

294

PROCEEDINGS OF THE AMERICAN ACADEMY

TABLE I.

SIMPLE MAGNET. PRELIMINARY EXPERIMENT.

Distances
(Cm.).

Deflections.

Distances
(Cm).

Deflections.

0.5

+ 9.6

29.5

— 0.6

2.5

7.8

81.5

1.4

4.5

6 2

37.5

2.45

6.5

5. 1

40.5

4.2

8.5

4.1

42.5

4.9

10.5

'6.7

44.5

6.7

1-2.5

3.0

46.5

8.6

15.5

2.0

48.5

9.0

195

1.1

49.5

10.0

23.5

0.35

1.

25.5

0.23

27.5

0-

1

"Wlien the armature was added, the distribution on the magnet was
as in Table II. a. Here, too, the numbers represent only relative
values. Table II. b gives, in the first column, the distances ; in the
second, the permanent magnetism of the armature (nearly constant
after once touching the magnet) ; in the third column, its magnetism
when the magnet was attached ; in the fourth, the difference of the
second and third ; in the fifth, the value corrected as afterward to be
explained.

TABLE n.

MAGNET AND ARMATURE. PRELIMINARY EXPERIMENT.

a. The Magnet.

Distance.

Deflections.

Distance.

Deflections.

Distance.

Deflections.

0.5

-f-0.1

19.5

+ 1.25

34.5

—1.4

2.5

8.3

22.5

0.6

36.5

2.0

4.5

6.5

24 5

0.4

38.5

2.9

65

6.3

26.5

0.2

40.5

3.2

8.5

4.4

27.5

0.

42.5

4.

10.5

8.7

28.5

—0.2

446

4.5

12.5

2.9

80.5

0.5

46.5

5.

15.5

2.1

32.5

1.0

48.5

5.7

OF ARTS AND SCIENCES.

295

h. The Ahmature.

Distances from

Defltiction tUie

Detlootlon wlion

DirtVrenco of

Corr('(!te<l val-

juncture.

to in'rniiUK'ut
uiagi\ctisui.

bar was added.

last two
columns.

armature.

60.5

+ 0.15

—4.2

— 4.35

—4.28

62 5

— 0.05

a. 7

3.65

3.65

54.5

0.15

2.2

2.05

2.05

56.5

0.2

1.8

1.6

1.6

58.5

0.2

1.2

1.0

1.0

60.5

0.2

1.0

0.8

0.8

6-J.5

0.2

0.75

0.55

0.55

655

0.15

0.6

0.45

0.45

69.5

0.065

0.3

0.24

0.25

74.5

0.045

0.18

0.18

0.18

80.5

4-0.10

0.03

0.13

0.16

84.5

0.17

0.01

0.18

0.14

86.5

0.20

+ 0.08

0.12

0.13

92.5

0.26

0.05

0.11

0.12

97.5

0.20

0.06

0.12

0.11

The last three vahies of the curve of magnet, under a sliould be
corrected so as to read,

Distance.

Deflection.

44.5
46.5

48.5

6.7
5.4
6.4

It is evident from this experiment, 1st, That the magnetism spreads
over the armature.

2d, That the zero point is almost immovable. This was proved
repeatedly with various magnets and armatures ; and even tlie most
delicate test possible — that of testing the change of distribution at
the zero point, when the armature was suddenly removed, by tlie
current induced in a helix — even this failed to show more than the
very slightest change.

3d, That the whole farther end of the magnet is unaffected by the
armature. This was tested and proved in the same way.

4th, That probably the permanent magnetism of the armature should

296 PROCEEDINGS OF THE AMERICAN ACADEMY

be subtracted from the total magnetism of the armature when in con-
tact with the magnet ; and when the two are nearly equal, as a small
error in observation will jiroduce a large relative error in the result,
any small irregularities should be removed from the curve. When,
however, there is any quantity of permanent magnetism at the junc-
ture, and of an opposite sign to that of the magnet, allowance should
be made for a portion of this magnetism spreading over the magnet.
The law by which this happens will be demonstrated by and by. It
is the same, nearly at least, as if the magnet were soft iron. About
half of this magnetism, therefore, spreads over the magnet. Unless
this coimter-distribution be taken into account, it will be absolutely
impossible to obtain accurate results ; for no bar of soft iron used as au
armature will remain free from permanent magnetism, even if it were
perfectly non-magnetic before.

I next investigated the change due to closeness of contact, and
found that a bar with perfectly fiat ends varied in the amount of mag-
netism it drew from a magnet ten to twenty per cent, according to the
means taken to secure jierfect contact of surfaces.

The amount drawn otf varies with the length. Some idea of the
proportion may be given by these numbers. 100 iHiits being the
amount drawn off by a metre bar from a metre magnet, a bar a metre
and a half long would draw off about 135 units; half a metre long,
80 units ; and 9 cm. long, about 30 units. A mass of iron in weight
equal to 116 cm. of iron rod of the size used above draws off about
65 units ; so that the length makes a much greater difference than the
mass. When for a solid rod we substitute a bundle of wires of equal
length and weight, there is no sensible difference in the amount of
magnetism drawn off, as tested by the current induced in a helix.

The old apparatus was now laid aside. The new one dift'ered in
several respects. The bobbin was of brass ; thickness outside, 5i ram. ;
inside, 3 mm.; depth of cut was about 5.^ mm.; and the diameter of
the rods was 12 mm. The magnet and armature had a small hole bOred
in each end, and a small screw was fitted to draw them tightly together.
Tlie surfaces of the ends were nuide perfectly flat in a latlie. Two
clamps served to limit exactly the motion of the bobbin to any distance
(lcsir('(l. The magnets and armature wore placed east and west on a
table about eight metres from the galvanometer, whose deflections
were observed with a telescope. Therefore both the induced mag-
netism of the earth was eliminated, and the magnet had but little effect
upon tlie galvanometer.

OF ARTS AND SCIENCRS.

297

Table III. gives the magnetism of magnet No. 1 reduced to absolute
measure by the following formula: —

Let n = number of coils in helix.

n' = number of eoils in earth inductor.

R = radius of earth inductor in centimetres.

K = the intensity of earth's magnetism I ^ about — ^^tt?,!'

A =. deflection of galvanometer by helix.
£ = deflection of galvanometer by earth inductor.
dL = the distance over which the helix was slipped.
M = the surface magnetism of the bar at the point to be meas-
ured, the unit being that quantity which will produce

unit field at unit distance, then M :=z — — — — - (for all

u n dL

points except very near the ends).

Table III. shows the magnetism of magnet Xo. 1, and armature iu
terms of K.

TABLE III.
a. The Armature.

Distances
from

Permanent
magnetism.

Magnetism
wlien at-
taclied to

Difference
of last two

Values cor-
rected for
contra-dis-

juncture.

magnet.

columns.

tribution.*

98

+4.0

+3.0

+ 1.0

92

4.5

2.97

1.7

81f

5.1

3.8

1.5

71f

6 2

4.5

1.7

61i

7.3

4.9

1.9

61

8.5

5.5

3.0

41

13.9

8.3

6.6

30|

16.3

7.25

9.1

-20%

18.8

0 12

18.7

10|

21.2

—5.3

26.5

+24.0

54

21.2

16.5

37.8

29.5

li

17.0

27.2

44.2

30.5

* That is the distribution of the permanent magnetism of the armature upon
the magnet.

298

PROCEEDINGS OF THE AMERICAN ACADEMY

b. The Magnet.

Distances

Magnetism cor-

Distances

IVragnetism cor-

from

rected for contra

from

rected for contra

juncture.

distribution.*

juncture.

distribution.*

2i

56.

m

45.5

3

57.

m

29.7

5

54.5

39

16.

8

54.

49

0.

lU

53.5

69

—22.

14i

63.

74*

44.

IH

52.

84

67.

16i

60.

94

109.

15*

48.

98

162.

Table IV. gives the distribution for a hollow tube of soft iron (one
metre in length) magnetized by a core of steel wires extending half
way down the tube. The magnetism was obtained by halving the
difference of the two values obtained before and after reversmg the
magnetic core.

TABLE IV.

HOLLOW TUBE AVITH MAGNETIC CORE.

Distances

(Cm.).

Magnetism.

Distances.

Magnetism.

2i

—12.

49i

5.85

lOi

— 6.5

66

4.0

20|

— 1.8

61

2.9

31

+ 1.05

71

1.35

41

4.2

81i

0.52

44

6.5

91^

0.2

46

6.65

Last of all, let us examine the case of two magnets joined by their
opposite poles.

* That is the distribution of tlie permanent magnetism of tlie armature upon
the magnet.

OF ARTS AND SCIENCES.

299

Without going through the process of analysis, let me simply state
what seems to me to he the truth.

Each magnet probably distributes upon the other as much magnet-
ism as it would were a steel bar, without magnetism, in the j)lace of
the other magnet ; and this amount is about one-half or two-thirds the
amount that would be distributed on a bar of soft iron. The result-
ing distribution is simply the algebraic sum of its components.

Table V. gives the magnetism actually observed ; and it is remark-
able, that, if these curves are plotted, the very same line that repre-
sents the theoretical represents also the observed magnetic curve for
this case. I would state that the curves were not chosen to suit the
occasion, but are identical with the curve of the preliminary experi-
ment, where the poor juncture or the shortness of the bur made up
for the superior capacity of the soft iron.

^Miether the theory be true or not, I leave it to be judgf^l. It is at
least useful in eliminating the contra-distribution iuevitable in experi-
menting with soft-iron armatures ; for, if the law holds so nearly in
case of such large values, the error in small values must be inappre-
ciable.

The law is as follows : Find the curve of the armature when a
perfectly non-magnetic bar of soft iron, of lialf the length of the mag-
net, is joined to it ; then subtract algebraically this magnetism from
the observed.

TABLE V.

DISTRIBUTION OF TWO MAGNETS UNITED BY OPPOSITE POLES.

Magnet No. 1.

Magnet No. 2.

Distances
from juncture.

Magnetism.

Distances
from juncture.

Magnetism.

0

10

15

20
30
50
98

+ 20

—29.0

37.0

37.0

31.0

1.5

151.0

0
10

15
20
30
60
98

+ 2.

86.

37.

36.

24.
— 2.5
130.

300 PROCEEDINGS OF THE AMERICAN ACADEMY

In the case of two similar poles being brought together, there is no
perceptible change of distribution : the most delicate experiments
failed to show any. Probably a change does, however, take place ;
but the resulting curve is so like the former curve, that the difFereuce
is imperceptible.

On the theory of the analogy of the magnetic lines of force to elec-
tric currents, these laws will, I think, be nearly, though not com-
pletely, fulfilled.

These laws, if true, and, if not, in so far as they are true, eual>le one
to determine the shape which the curve would assume were the
armature and magnet of one piece of metal ; i.e., if the juncture was
absolutely perfect.

Moreover, the same method enables us to draw the limiting values
for different lengths of armature : for we have only to increase each
abscissa of the curve of the magnet as the total length of magnet and
armature is to tliat of the magnet alone, and to take the half-sum and
half-difference as before, to find the curves on the magnet ; then, draw-
ing a curve in the same manner to represent another magnet of length
of armature joined by a similar pole, the curves on the armature can
thus be determined. We shall see, then, that a soft-iron armature
acts like a steel armature of about double the length. Whetlier this
is due to contra-distribution, or to a superior magnetic ca})acity, I leave
to be determined.

The following experiments were devised to show the change in
magnetic moment due to armatures. The experiments are rough ; but
they give far the best idea of the changes that take place in magnetic
distribution. A magnet was placed ujion the floor at a fixed distance
from the galvanometer-needle, to the east of it, and pointing east and
west. Then an armature was added, and the position of the centre of
the magnet was marked upon the floor. Then the whole combination
was removed to a distance, and the deflection was noted. Then the
combination was brought back, with poles reversed, and was moved
toward the galvanometer till the deflection was equal to the previous
one.

This at once showed the increase of distance between the poles ; for
it must have been equal to tlie distance of the centre of the magnet
from its former position, and the central point must have advanced
half this distance. Having determined the position of the central
point, the magnet alone was now turned ujion it; and tlie ratio of the
deflection of the magnet and armature to that of the magnet alone
showed the chaufie of mairnetic moment.

OF ARTS AND SCIENCES. 301

The centre of the longest armature (150 cm.) advanced 18.25 cm.,
and the moment became lialf as much again. The centre of the
metre armature advanced 14.5 cm., and its moment became a little
over quarter as much again. The moment of the short (50 cm.)
armature was increased one-sixth.

From this the distance of the poles of the magnet from the ends can
be calculated; and it is about 12 cm. AVhen calculated by the vibra-
tions of a comi)ass in two jiositions very near the end, it appeared to
be 5 cm. : the latter method is probably, therefore, inexact, and will
always give the distance too small. It is only at large distances that
the magnetism of one end of a bar can be considered as acting at a
point.

When the magnet was joined to the armature by a short piece of
iron shaped like a U, so that it was parallel to the armature, the pole
ap2iarently retreated about 7 cm., and the moment decreased about
one-tenth. When, however, a second U armature was added to com-
plete the circle, the reduction of magnetic moment was scarcely per-
ceptible, being less than ^ of the total value. This may possibly be
due to poor contact ; but I was unable to obtain any different result,
though I measured the distribution in various Avays. Perhaps, when
the ai'mature is bent round so near the magnet, the resistance of the
air to the line of force is so slight, that the adding of the second arma-
ture affects it but little. This, I think, would be the necessary con-
sequence of the analogy of magnetic force and electric currents.

We see, then, that shunting, so to speak, the poles of a magnet with
a soft-iron bar, diminishes the magnetic moment about one-sixth.

It follows, that, if a stronger magnet be shunted by a weaker one,
the magnetic moment will be dhuinished in some way ^iroportional to
the difference of magnetization. This accounts for the fact that thick
magnets are weaker than an equal weight of thin ones : 1st, because it
is impossible, owing to the difficulty of temjDering evenly, to obtain
the maximum capacity for magnetism in all parts of the bar, and
those parts which are weaker diminish the average magnetism per
weight, and also diminish the strength of the stronger parts, acting
like a shunt ; 2d, because, in the common process of magnetizing a bar
by rubbing the surface, the interior is less magnetized than the out-
side, and the core acts more or less like a shunt of soft iron.

If, however, a solid body is magnetized by a force acting on all parts
alike, it will not act differently from a bundle of wires of equal length
and weight, provided the material be the same. Therefore the bundle

B02 PROCEEDINGS OF THE AMERICAN ACADEMY

of iron wires alluded to above ought to act, as they did, like the solid
bar. Fact and theory agree. T am now prepared to answer a ques-
tion, from which, curiously enough, the whole of the present investi-
gation sprang. I can answer decidedly that there will be no
advantage in substituting a bundle of iron wires or plates for the solid
core of the helix of a magnetic engine; but, as the helix will be
farther off from the core, the induced current will not be increased,
but diminished.

OP ARTS AND SCIENCES. 303

XXVI.

CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF
HARVARD COLLEGE.

XL — CHANGE OF ELECTRICAL RESISTANCE IN WIRES BY
STRETCHING.

By George S. Pink.

Presented, May 10, 1876.

The electrical resistance of a wire of constant section and material
is directly proportional to the length, and inversely proportional to the
area of the cro.ss-section. When the wire is stretched, its thickness or
cross-section, as well as its length, undergoes a change. This investiga-
tion was undertaken to see whether the change in resistance is directly
as the length, and inversely as the cross-section of the wire ; or
whether the copper or the iron, whichever the substance may be, is a
better or a worse conductor.

Let I = original lengtli of the wire.

/j = length at the end of tlie experiment.

r = original radius.

rj = final radius.

R = original resistance of the wire.

i?j = final resistance.

V = volume of wire, — supposed constant.

A = resistance of wire whose length equals its cross-section.

Suppose that X does not alter. On this supposition, let us find the
resultant resistance. We must compare this with the observed resist-
ance to see whether our supposition is right; to see whether I does or
does not alter.

Supposing I does not vary

^ = 4 K = ^.

22

(1)

304 PROCEEDINGS OF THE AMERICAN ACADEMY

The volume being unchanged by the stretching

V ^= -irrH also v = T^r-y^l^

Substitute this value in equation (1), —

From this we mny conclude, tluit, if the original resistance is to the
final resistance in a greater or less ratio than the square of the original
length is to the square of the final lengtli, the stress of the paiticles
does alter the speciKc resistance of the wire. If the ratio of the re-
sistances is greater than the ratio of the squares of the lengths, then
the conductivity of the wire is improved.

In the following experiments I used a Thomson's mirror galva-
nometer with the arrangement of Wheatstone's bridge. I used a
wooden bracket attached to a partition of the wall, about 2.5 metres
from the floor. I put the wire through a hole in this bracket, and kept
it from slipping by driving in a wooden peg. To guard further against
slipping, the wire was wound tightly around a screw near the hole.
Altogether there was from four to ten centimetres of wire that was
not stretched, but whose resistance was taken account of. In the later
experiments, this length was taken account of in calculating the re-
sistances. To the lower end of the wire I bound a ring, and on this
ring were hung the weights. I connerted the ends of the wire with the
box of resistance coils by means of thick wires. The resistance of
these thick wires was found to be .036 ohms.

Experiment 1. — This experiment was made with copper wire .G28
millimetres in diameter. It being tlie first experiment I made, all the
phenomena were not observed. The original and final resistances, and
the original and final lengths, I got pretty carefully ; but I failed to note
the intermediate lengths.

Original length was 1.647 metres.

Final lengtli before breaking 1.857 „

Stretched 21 centimetres.

Ohms.

Original resistance with connections . • 144

Resistance of connecting wires 036

Original resistance 108

Final resistance without connecting wires 134

OF ARTS AND SCIENCES. 305

^ __ 2.71S _ Jl 108 R P

/,- — ";5.45 — -'^6 7^ — 134 — -^^^^ IT^ > V

AVe .sliduKl expect R^ to have been .137. Tlic wire broke under the
weight of 16.3 lbs. The weights I used were in lbs., not grannnes.

But we liave not considered the whole length in considering the
change in length ; but we have considered the whole length in consider-
ing the change in resistance. If we add the same constant to / and /j,
say a, and /j is greater ihan /, then plainly

/2 (/ + «)2

But more th;in a may have been added to /[.

Then, too. if the whole length had been under the stretching
process, 7i*, might have been greater than it was observed to be. So
that the ditfei-ence of .003 ohms might have been made up, had the
whole length been under the stretching process.

In this experiment I measured the final diameter of the wire with
the dividing engine, and found that it varied perceptibly in different
parts ; in one part the mean reading being .593 millimetres, and in
another part .50 millimetres. From the deduction given above, it can
be seen that we need only consider the lengths and the squares of the
lengths. In the following experiments I did not consider the change in
diameters.

Exppi-iment 2: — In this experiment I used thin iron wire. 4, 6, 8,
and 10 lbs. produced no change in the resistance of the wire, tliough
the length increased slightly. Original resistance was 1.053G ohms.
At first, i? was only 1.0584.

10 mm. 7? = 1.068 ohms.

15 „ li = 1.0704 „

20 „ li = 1.1256 „

25 „ A' = 1.1304 „

28 „ 7^ = 1.1404 „

30 „ A' =1.1472 „

T did not observe the changes in length carefully. At tliis time,
2 lbs. was the smallest weight I had. On applying fourteen pounds,
the wire stretched some; but, when I allowed the whole foi'ce to come
on, the wire snapped near a place where it was wound. I applied the
weight again, and the wire snapped near the middle.
VOL. XI. (n. s. hi.) 20

306 PROCEEDINGS OF THE AMERICAN ACADEMY

Length of wire before applying 1-1 lbs 1.633 metres.

Original length 1.58 „

/2 2.496 R 1.0530

7^ — 2.667 — -^^^ Ri — L1472 — ''^^^

R P .

Here — < ,— ; and it would seem that finally iron has been made

a poorer conductor by stretching. As to the intermediate states of the
wire, nothing can be inferred. Later I performed another experiment
with better results. It was with the same kind of wire. It would
seem to show that the conductivity of iron is improved by stretching.
I will call it

Expei iment 2a. — These are the results : —

/

/2

1.696

2.876

1.716

2.944

1.736

3.014

1.766

3.119

r-

-p, = .922

'r

R

R, = -93

R

1.104

1.1064

1.1448

1.178

R /2

"We .should expect i?^ to have been 1,197.

Experiment 3. — In this experiment I used thin copper wire |^
millimetre in diameter. 2 lbs. produced no change in the resistance,
though the length inci'eased 2 centimetres. These are the results: —

/

p

R

1.476

2.1786

.3816

1.5

2.25

.3816

1.566

2.452

.3912

1.576

2.484

.4032

It broke

under weight 4,

o
.o

lbs.

, and I did

not get the tin:

.936

R

= .946

R

ere —

^'1

It seems that the conductivity of the wire is improved.

I used the same kind of wire in another experiment, which T will
call

Experiment 3a. — The wire stretched in all 31 centimetres, and
broke under the full force of 4.3 lbs. The .3 lbs. is the weight of the
iron rin;'.

OF ARTS AND SCIENCES. 307

lo =

I

P

R

1.81

8.276

.4776

1.905

8.629

.5040

1.945

8.788

.5280

1.965

8.822

.5520

1.985

8.94

.5592

= 2.055

/o^

4.223

.6216

2.09

4.368

.624

2.12

4.474

.6264

/2

R

= .769

See the curve representing the resistance in this exjieriment. There
is a great and rapid change in the resistance vvlien the wire has been
stretched 20 centimetres.

n L81_ _ „ ^ R _ 4776

lo' ~ 2.055 — -'"^ To — 6"2r6 "'^^

,.. R I'
Here at this point -p- < tt.

Experiment 4. — In tliis experiment I used thicker copper wire,
with the following results : —

I

i2

R

1.70

2.89

.0636

.1.72

2.958

.0636

1.75

8.07

.0648

1.757

3.086

.0648

1.825

8.327

.0684

1.85

3.48

.0768

1.875

3.515

.078

289
8.5i5 —

.822

R 636

.828

R n

R,> W

I

I tried the same kind of wire again. It stretclied considerably
before there was any change in the resistance. The original length
was 1.65 metres. The final length was 1.82 metres. 23 lbs. broke the
wire before I had time to ob.serve the resistance; but, before api)lying
the last pound, the resistance was .076 ohms. Tlie original resi.stance
was .072.

/2 2.622 R R ^ P

l{' 3.312 •' A'l A\ -^ /j^

Experiment 4b was with the same kind of wire, with these re-
sults : —

308 PROCEEDINGS OF THE AMERICAN ACADEMY

I

1.595

2.544

R

.0648

1.635

.0648

1.6G5

.0648

1.715

.0648

1.765

8.116

.0648

1.855

3.44

.0820

1.945

3.783

.090

2.

4.

.1008

fj := .636

R

= .0.642

R /I
R, > l^

2G lbs. broke the wire.

In all the.se experiments, it is easy to see that the change iu resist-
ance at first is not at all proportional to the increase iu length. At the
close of some of the experiments, the resistance is almost as much as
it ought to be ; and perhaps, if there were no error in ob-servation or
calculation, the resistance at the breaking-point would be as much a-?
the law would make it.

Experiment 5. — Tliis experiment was mmle with copper wire not
so thick as that used in the previous experiment. I measured the
total leno:tli,and tlie changes in Icnijth ; so tliat, although not the whole
length is under th(i stretching process, the resistances given correspond
more exactly to the lengths given.

I r- R

1.71 2.924 .109

1.725 2.965 .1092

1.755 3.08 .1104

1.815 3.294 .1128

1.84 3.385 .1128

1.875 3.516 .114

1.9 3.61 .114

1.91 3.648 .114

1.95 3.8 .1356

1.99 3.98 ass

P R R r^

J- = .738 jr = .791 'F> ri

V ^'1 ^'1 'i

K) lbs. broke the wire. I performed a second experiment with the
.same kind of wire, and with es.sentially the same rc.^^ults.

Experiment G. — I next took German-silver wire. Tiie curve of
observations here will be found to almost coincide with the straight line
representing the law. This experiment is (piite curious when con-
trasted with the others.

OF ARTS AND SCIENCES. 309

/

P

R

1.53

2.84

4.33

1.535

2 856

4.84

1.546

2.387

4.40

1.57

2.465 •

4.577

1.595

2.544

4.728

1.615

2608

4.824

1.C4

2.69

4.987

1.665

2.772

6.112

1.69

2.856

6.22

1.735

3.01

6.609

I'i

.777

R

li,—

.77

Experiment 6a. — Germau-silver wire again.

Original total lengtli 1.70 metres.

Length to be stretched 1.60 ,,

Original total resistance 4.848

Resistance of connecting wires 036

Resistance of 1.70 metres 4.812

Subtract -^^^ of this 283

Resistance of 1.60 metres 4.529

I

1.60

r-

2.56

R

4.529

1.61

2.692

4.641

1.64

2.689

4.733

1.67

2.789

4.9226

1.70

2.89

6.1386

1.77

3.133

5.5226

1.815

3.294

6.813

1.85

3.42

6.0506

1.885

2.591

6.2858

1.99

3.96

6.9626

/2

/7= .646

R

= .650

R /2

R, > 7^

By examining the curve, it will be seen that it very nearly follows
the law, and that the conductivity of the metal is but little altered.

Experiment 7. — This experiment was made with copper wire
No. 18.

Original total length 1.62 metres.

Length to be stretched 1.67

310 PROCEEDINGS OF THE AMERICAN ACADEMY

Ohm.

Original resistance with connecting wires 3000

Resistance of connecting wires 036

Resistance of total length 2G4

Resistance of length not stretched 008

Original resistance of length to be stretched . . . .256

/ /2 R

1.57 2.465 .256

1.58 .256
1.595 .256
1.6 2.56 .256
1.615 2.608 .2608
1.64 2.69 .2728
1.66 2.7556 .2776
1.69 2.856 .2776
1.725 2.9756 .2992
1.76 3.0976 .3016

P 2465 ^ R 256 R_ P

l^ ~ 3097 ~ ■''^^ S^ — 30l6 ~ -^^^ ^1 ^ "^

i?j should have been .322 if the conductivity of the metal had not
been altered.

Experiment 8. — Copper wire No. 22.

Original total length 1.57 metres.

Length to be stretched 1.53 „

Resistance with connecting wires 3048

Resistance of connecting wires 036

Resistance of total length 2G88

Resistance of length not stretched 0068

Resistance of wire to be stretched 2620

1.53 2.341 .262

1.55 2. — .262

1.59 .262
1.62 2.624 .262
1.G55 2.739 .30(>4
1.68 2.822 .3124

li R R ^ P

pf = .829 jr = -841 7T > ,T,

The wire broke under weight of .3.2 lbs.

H^ should have been .3161 if there was no chaiige.
Experiment 8a. — With copper wire of same size.

OF ARTS AND SCIENCES.

311

I

Oriiiinal length \M metres.

LiMifTth to bo stivtc'lied 1.52 „

Ke^istance of whole lengtli 2070 „

liesistaiice of leiijj;!!! not stretclieil 0008 ,,

Resistance of wire to be stretched 2008 „

/ /-' R

1.52 2.3104 .2008

1.54 2.3716 .2008
1.56 2.434 .2020

1.58 2.496 .2020
1.6 2.56 .2836
1.0^ 2.65 .2'J56
1.655 2.706 .298
1.67 2.789 .310

1.69 2.856 .816
1.705 2.i}07 .3256

/2 R

^=.794 ^=.8

Wive broke under 5.2 lbs.

Experiment 9. — Copper loire, the finest yet.

Original total length 1.56

Length to be stretciied 1.52

Original total resistance 780

Resistance of connecting wires, &c 055

/ /•^ n

1.52 2.3104 .725

1.5S5 .725

1.55 2.4025 .725
1.565 2.444 .7298

1.59 2.528 .7538
1.01 2.592 .7766
1.64 2.0896 .8018
1.67 2.789 .8318

1.70 2.89 .8618
1.73 2.993 .8918
1.77 3.133 .9314
1.81 3.276 .971
1.855 3.441 1.000

V- R

r-= .671 7r= -7206

If tbere were no change, i?j should have been 1.08 ohms. The wire
broke under pressure of 2.6 lbs.

From the foregoing experiments, I conclude that the conductivity of
German-silver wire remains unaltered by stretching ; that the con-

312 PROCEEDINGS OF THE AMERICAN ACADEMY.

Hiictivitv of iron wire is perhaps improved, and that the conductivity
of copper wire is improved, that up to a certain point the wire can be
stretched without increasing the resistance, or only increasing the re-
sistance very little; tiiat beyond that point the resistance increases very
rapidlv for a while, and then increases less rapidly. In most cases,
after the wire has been stretched to the point wliere the resistance
ceases to increase rapidly, the resistance appears to increase in such a

IJ ' .
wav, that the ratio -,7 remains almost constant.

It appears, then, that copper wire can be stretched to some
advantage; that, if it is stretched too much, some of tlie advantage
gained is lost again. Experiments 3a and 8a are the only instances
where the copper wire appears to have lost at any time the full amount
of the advantage gained by stretching ; but, even in these instances,
the wire seems to gain advantage in regard to its conductivity as the
stretching goes on.

Thin copper wire being in the process of manufacture, stretched to a
great extent, the advantage gained by further stretching is less marked
than with thicker wire. It is noteworthy that the wire becomes very
brittle before it breaks, and assumes a definite structure like steel
wire.

PROCEEDINGS.

Six hundred and eighty-first Meeting.

i\Iay 25, 1875. — Annual Meeting.

The President in the chair.

The Corresponding Secretary read a letter from Mr. R. C.
Winthrop, accepting his appointment as a delegate to the
International Congress of Geographical Sciences ; and, at
his suggestion, Mr. J. I. Bowditch was appointed a second
delegate to this Congress.

The Treasnrer presented his report, wliich was accepted,
and on his motion it was

Voted, To appropriate for the general expenses of the
Academy, during the coming year, twenty-one hundred dol-
lars ($2100).

The Chairman of the Rumford Committee presented his
report, which was accepted ; and, in accordance with its sug-
gestion, it was

Voted, That an appropriation of fifteen hundred dollars
(81500) be made from the income of the Rumford Fund for
the coming year, to finish the publication of Count Rumford's
works.

Voted, That the Librarian and Treasurer of the Academy
be authorized to sell to each Resident Fellow one, and one
only, complete set of Rumford's Works, including the Life,
for five dollars, and to settle on this basis the account

314 PROCEEDINGS OF THE AMERICAN ACADEMY

of those Fellows who have already purchased the earlier

volumes.

Voted, That ten complete sets of Rumford's Works, includ-
ing the Life, be presented to Professor W. R. Nichols, as an
acknowledgment of his services to the Academy.

Voted, That the sum of two hundred and ninety-one dol-
lars (8291) be appjopriated from the income of the Rumford
Fund to cover the cost of publishing the papers on Light and
Heat in Volume X. of the Academy's Proceedings.

Voted, That the sum of five hundred dollars (8500) be
appropriated from the income of the Rumford Fund, as the
said income will permit, to aid Professor John Trowbridge,
of Cambridge, in conthiuing his researches on the improve-
ment of the Magneto-electric jNIachine and Induction Coil.

Voted, That the Rumford ]\Iedal, for the present year, be
awarded to Dr. John William Draper, of New York, for his
Researches on Radiant Energy.

On the motion of the Corresponding Secretary, it was

Voted, That an appropriation of fifteen hundred dollars
(11500) from the general fund be made to defray the ex-
penses of publication during the year.

Voted, To appoint a committee of five to revise the Statutes
of the Academy. The President appointed ^Messrs. Cooke,
Thomas, Washburn, Deane, and Norton, members of this
committee.

Voted, To adjourn this meeting to the second Tuesday in
June.

The annual election resulted in the choice of the following
officers : —

Charles Francis Adams, President.
Joseph Lovering, Vice-President.
JosiAH P, Cooke, Jr., Corresponding Secretary,
Edward C. Pickering, Ilecording Secretary,
Edmund Quincy, Treasurer and Librarian.

OF ARTS AND SCIENCES. 315

CoU)lciL

John B. IIenck,

WoLCOTT Gibus, \ of Class I

Chaules VV. Eliot, )

Alexandkr Aoassiz, \

John A. Lowkll, ( of Class 11.

Ben J. E. Cottino, )

Geoiige E. Ellis, \

Andrew P. Peabody, > of Class III.

Francis Parkman, )

Rumford Committee.
MouuiLL Wyman. James B. Francis.

AVOLCOTT GiBBS. JOHN M. OrDWAY.

JosiAH p. CooKE, Jr. Stephen P. Ruggles.
Edward C. Pickering.

Committee on Finance.

Charles Francis Adams, ) ^ .

' \ ex officio.
Edmund Quincy, )

Thomas T. Bouve.

The following Committees were aj)poiiited on the nomina-
tion of the President : —

Committee on Publication.

Alexander Agassiz, W. W. Goodwin.

John Trowbridge.

Committee on Library.

Charles Deane. Henry P, Bowditch.

AViLLiAM R. Nichols.

Auditing Committee.
Henry G. Denny. Robert W. Hooper.

316 PROCEEDINGS OF THE AMERICAN ACADEMY

Six hundred and eighty-second Meeting.

June 8, 1875. — Adjourned Annual Meeting.

The President in the chair.

The President announced the death of M. Charles de
Remusat, Foreign Honorary Member.

The Corresponding Secretary read, a letter from M. Bar-
rande, acknowledging his election into the Academy.

Voted, To adjourn the meeting in August to the second
Tuesday in October.

The following papers were presented : —

" On the Hexatomic Compounds of Cobalt." By Dr.
Wolcctt Gibbs.

" On the Supposed. Perchloride of Manganese." By Pro-
fessor J. P. Cooke, Jr.

" On the Use of Field. Instruments in Astronomy." By
Professor T. H. Safford.

" On Photographing Sjiectrum Lines." B}^ Dr. Robert
Amory.

" On a Comparison of Prismatic and Diffraction Spectra."
By Professor E. C. Pickering.

" On a New Method of Calibration." By Professor E. C.
Pickering.

" On a New Instrument for Projecting Lissajou's Curves."
By Professor E. C. Pickering.

On the " Theory of Discount in the Game of Billiards."
By Professor Benjamin Peirce.

Professor William Watson presented a set of models illus-
trating his " Descriptive Geometry."

Six hundred and eiglity-tliird Meeting.

October 12, 1875. — Adjourned Stated Meeting. '

The Vicr-Ppj:sidrnt in the chair.

The Vice-President announced the d"eatli of Professor
Joseph Winlock, and Mr. Chauncey Wright.

OF ARTS AND SCIENCES. 317

The following papers were presented : —

" On a New Pi-operty of Conic Sections." By Professor
Benjamin Peirce.

'' On the Method of Least Squares." By Professor T. II.
Safford.

]Mr. W. A. Rogers described some farther investigations he
had made on the lines of Nol)ert, and presented a paper by
j\l. Ti'ouvelot, " On Veiled Sun-Spots."

The following papers were presented l»y title : —

" On the Flora of Guadalupe Island." By Sereno Watson.

" Remarks on Magnetic Distribution." By Professor H.
A. Rowland.

Six hundred and eighty-fourth Meeting.

November 10, 1875. — Stated Meeting.

The President in the chair.

Mr. W. A. Rogers Avas appointed Secretary /)ro tempore.

Upon the recommendation of the Council, the following
gentlemen were elected members of the Academy : —

Andrew Crombie Ramsay, of London, to be a Foreign
Honorary Member in Class II., Section 1, in place of the
late Sir Charles Lyell.

Alfred M. Mayer, of Hoboken, to be an Associate Fellow
in Class I., Section 3.

Frederick A. Genth, of Philadelphia, to be an Associate
Fellow in Class II., Section 1.

Joseph LeConte, of San Francisco, to be an Associate Fel-
low in Class II., Section 1.

Othniel Charles Marsh, of New Haven, to be an Associate
"Fellow in Class 11. , Section 2.

Daniel C. Oilman, of Baltimore, to be an Associate Fellow
in CljTiss HI., Section 2,

"William Sellers, of Philadelphia, to be an Associate Fellow
in Class I., Section 4.

Albert Nicholas Arnold, of Hamilton, N. Y., to be an Asso-
ciate Fellow in Class III., Section 2.

318 PROCEEDINGS OF THE AMERICAN ACADEMY

Ira Remsen, of Williamstown, to be a Resident Fellow in
Class I., Section 3.

Hiram F. ]\Iills, of Lawrence, to be a Resident Fellow in
Class I., Section 4.

Robert Tiiaxter Edes, of Boston, to be a Resident Fellow
in Class II., Section 4.

Henrj Adams, of Boston, to be a Resident Fellow in Class
III., Section 3.

Professor Cooke announced that the fourth and last vol-
ume of Count Rumford's Works had been issued from the
press.

Mr. R. C. Winthrop made the following Report : —

It has seemed to me proper, Mr. President, that I should make
some brief report of what I did, and of what I left undone, under the
commission with which the Academy honored me, some months ago,
to represent them at the International Congress of Geogi'aphy in
Paris.

Agreeably to a suggestion wliich I ventured to make to the Secre-
tary, on receiving my own appointment, Mr. Ingersoll Bowditch, then
abroad, was afterwards associated with me in the delegation. But I
am sorry to say that neither of us found it practicahle to be in Paris
during the week in whicli the sessions were held. For myself, I
reached there only on the evening of the day on which they were
formally closed. It was ah occasion of public ceremonial, which
I was sincerely sorry to have missed. I regretted much less that I
was unahle to attend the opening ceremonies, as they took place on
Sunday ; and, though I do not care to associate myself with too sancti-
monious a Sabbatarianism, I have always been offended, when abroad,
by the habitual selection of Sunday, particularly in Paris, for spec-
tacles and shows of all sorts. Such a course seems almost like an
insult to Protestantism, and might well be the subject of remonstrance
where the occasion is not of a local character.

I had reported myself, as a delegate from the Academy, previously
to my arrival, and my name had been duly entered on the roll of
the Congress. Nothing remained, however, for the members to do,
except to make a visit to the Sewers of Paris, — a geographical
exploration from which I was willing to excuse myself during the
heats of August, — and to pay their respects to the Prcfet of the Seine,
at a formal reception arranged for that purpose.

O?' ARTS AND SCIENCES. -^19

This latter service I porfonncd, and found a large and l)rilliaiit
assembly at the palace of the Luxembourg, (piite in Imperial style^
notwithstanding the Repnl)li<;ni clcincMt which has recently entered
into the institutions of France. Tiie staircase was lined with (/ens
d' urines in uniform, a mounted police guarded the gateways, and one
of tiie regimental bauds played national airs witliin the palace. Noth-
ing could have been more cordial and gracious than the welcome given
me as a representative of the American Academy by the Prefet, M.
Ferdinand Duval ; and I had an op[)ortunity of meeting not a few of
the literary and scientitic celebrities of France, as well as the dele-
gates from other countries.

The next day I proceeded, with my card of membership, and under
the escort of my accomplished friend, Colonel Perraud, to visit the
Exposition Geogra'phique^ which had been arranged in those parts of
the palace of the Tuileries which had escaped the torches of the Com-
mune. A niai'vellous and most multitudinous exposition it was, and
one which reflected the highest credit on the Geograpliical Society of
France, under whose auspices it was prepared. I could not have
believed it possible that any thing so dry, and so little a\sthetic, as
geography, could furnish the materials for so really interesting and
brilliant a show. It was, indeed, an exhibition of many other things
besides such as might be supposed to belong to geograi)hy proper.
Geology, archaeology, ethnology, antiquities of every sort, historic
and pre-historic, were gathered there, side by side with maps and
memorials of the most recent researches of modern travellers and
geographers.

My eye lighted, for instance, on a photographic facsimile of the
"Mappamondo di Fra, Mauro " of 1459, and on copies or originals of
not a few other maps, on which there was no America. It was a
relief to turn from these and see, as I did, the beautiful chart, pub-
lished by our Coast Survey, of Boston Harbor, hanging at the very
entrance of the little American department.

I remember seeing, too, the War Map used by the heroic Charles
XII. of Sweden, and not far off the manuscript notes and maps of
the not less heroic Livingston and Speke and other recent explorers
of Africa.

A cast of the wonderful Meteorite of Greenland, weighing (the
original) twenty thousand kilos, if I remember right, occu])ied a whole
corner of one apartment. Facsimiles of Domesday liook and of the
black-letter Prayer Book of 1G3G attracted my eye in the English
division.

820 PROCEEDINGS OF THE AMERICAN ACADEMY

This will give a sufficient indication of the somewhat heterogeneous
things which were gathered together from all quarters under the
banners of geography, recalling that comprehensive, all-embracing
description of Cicero : " Omnes etenim artes (ju;ii ad bumanitatem
pertinent, babent quoddam commune vinculum, et quasi cognatione
quadam inter se contincntur."

The archives of all countries, and the museums of all learned
societies, had indeed been made tributary, without reserve, to this
exposition ; and things old and new had been brought forth from pri-
vate cabinets and public collections to enrich and adorn it.

But I must not leave the impression that Geography proper, so to
speak, was without its full representation. Such an array of globes
and maps and photographic illustrations of earth and sea and sky
could never have been congregated anywhere before. The Russian
department was exceedingly rich, and surpassed all others in the
number and perfection of the geographical works with which it was
crowded. The Prussian or German department W'as hardly less
striking ; while the Austrian, Spanish, Portuguese, Italian, Danish,
Norwegian, Dutch, Belgian, and Swiss departments contained many
most interesting and valuable contributions. England was hardly
there in full force, and the American department was small and poorly
supplied.

When I alluded to this, however, as I did with regret, the Prefet
of the Seine, with true French politeness, replied, " Yes, but we know
you are fitly and fully engrossed with your grand Centennial Exposi-
tion at Philadelpliia next year, which is well worthy of all your atten-
tion ; and we sliall all be interested in its success."

I lay upon the table a printed Catalogue of this remarkable Exhi-
bition, with a few other pamphlets relating to it. which may give the
Academy a better idea of its character than I have been able to
convey in these cursory remarks.

Before resuming my seat, however, I may be pardoned for alluding
to the monument of Count Rumfjrd, wiiicli I visited in company with
the American Minister, Mr. Wasiiburne. It received some not very
considerable damage from a shell which struck it, or exjdoded neai" it,
during the siege of Paris. It was understood, before I left Paris, that
this Academy had passed a resolution for its repair, and such a meas-
ure would be a graceful act to be performed by this or some other
American instrumentality. Our Minister was ^nxious to superintend
such a repair, if authority should be given him to do so; and I prom-

OF ARTS AND SCIENCES. 321

isetl- to bring the subject to the renewed consideration of the friends
and guardians of Count Kuniford's memory.

Professor Cooke presented the report of the committee
appointed to revise the Statutes of the Academy, and it was

l\>ted, To hiy this report on the table, and make it the
special subject of an adjourned meeting ; it was also

Voted, That the Corresponding Secretary be requested to
print the report, and distribute it among the Resident Fel-
lows.

Voted, To adjourn this meeting, at its close, to the second
Tuesday in December.

The following papers were presented : —

" On the Flora of Guadalupe Island." By Sereno Wat-
son.

" On the Proper Motion of »/ Dracouis." By W. A.
Rogers.

I

Six hundred and eiglity-flfth Meeting.

December 14, 1875. — Adjourned Stated Meeting.

The President in the chair.

The Corresponding Secretary read letters from Messrs.
Arnold, Genth, Mayer, and Mills, accepting their elec-
tion as Fellows of the Academy ; also, a letter from Mr.
Parkman, declining his election as a member of the Council.

Mr. R. C. Winthrop was elected a member of the Council
in place of Mr. Parkman.

The Corresponding Secretary read a petition from the
Trustees of the Boston Pul)lic Libi-ary to the General Gov-
ernment, asking aid toward the publication of a Topical
Index of the United States Documents ; and it was

Voted, To authorize the President to sign this document
in behalf of the Academ3^

Dr. Gibbs presented a memorial j)etitioning Congress to
remove the dut}- on foreign scientific books not in English,
Latin, or Greek ; and it was

Voted, to authorize the President to sign this memorial.
VOL. XI. (n.s. hi.) 21

822 PROCEEDINGS OF THE AMERICAN ACADEMY

The report of the committee on the Revision of the
Statutes was taken from the table, and its recommendations
discussed. But, in accordance with the provisions of the
statutes, action was deferred until the next stated meeting.

The following papers were then presented : —

" On the Periodic Changes in Right Ascension." B}- Mr.
W. A. Rogers.

" On the Tempel Nebula in the Pleiades." By Mr.
Tronvelot.

" On the Planet Saturn." By Mr. Trouvelot.

" On a New Form of Bunsen Battery." By Dr. Wolcott
Gibbs.

" On the INIilk Supply of Boston." By Mr. S. P. Sharpies.

" On a New Genus of Harpagonella." By Dr. Asa Gray.

Six hundred and eighty-sixth Meeting.

January 11, 1876. — Monthly Meeting.

The President in the chair.

The following papers were presented : —

" Improvements in Inland Navigation Resulting from the
Introduction of a New System of Movable Dams." By Pro-
fessor AVilliam Watson.

" Description of an Apparatus to Measure Directly the
Strain to which the Different Bars of an Iron Lattice Girder
are exposed." By Professor "William Watson.

" On the so-called Etheric Current." By Professor John
Trowbridge.

" On some New Methods of Topographical Surveying."
By Professor E. C. Pickering.

Six hundred and eighty-seventh Meeting.

January 26, 1876. — Stated Meeting.

The President in the chair.

The Corresponding Secretary read letters from IMessrs.

I

OF ARTS AND SCIENCES. 323

LeConte, Remsen, Edes, and Oilman, accepting tlic:r elec-
tion as Fellows of the Acadeni}'.

On the motion of Professor Washburn, it was

Voted, To discharge the committee on Expert Evidence.

Tlie following gentlemen were elected members of the
Academy : —

Charles Edward Hamlin, of Cambridge, to be a Resident
Fellow in Class II., Section 3.

Edwin Lawrence Godkin, of Cambridge, to be a Resident
Fellow in Class III., Section 3.

Thomas Dwight, Jr., of Boston, to be a Resident Fellow
in Class II., Section 3.

Conte Federigo Sclopis di Salerano, of Turin, to be a For-
eign Honorary INIember in Class III., Section 1, in place of
the late Charles de Remusat.

The proposed amendments to the Statutes and Standing
Votes of the Academy, by rule laid over from the last stated
meeting, were acted on seriatim. With some amendments
they were all adopted, and are incorporated in the new draft
of the Statutes and Standing Votes printed at the end of this
volume in connection with the Report of the Council.

Professor Watson presented the following pajjers : —

" A Description of the New Machinery and Processes em-
ployed to Obtain a Supply of Water for the Inland Naviga-
tion of the Champagne District of France."

" Improvements in the Construction of River Locks, and
the Saving made in the Prism of Lift by the Use of Oscil-
lating Liquid Columns."

The following papers were presented by title : —

"• On the Effect of Thin Plates of Iron as Armatures to
Induction Coils." By Professor John Trowbridge.

" On the Action of Methyl Iodide on Plumbic Urate."
By Professor H. B. Hill.

A communication from the Boston Society of Civil Engi-
neers on the introduction of the metric system of Aveights
and measures, was referred to a committee consisting of
Messrs. Pickering and Watson.

324 PROCEEDINGS OF THE AMERICAN ACADEMY

Six hundred and eighty-eighth. Meeting.

February 9, 1876. — Monthly Meeting.

Professor Peirce in the chair.

The Corresponding Secretary announced that the Rumford
Medal would be ready for presentation to Dr. Draper at the
next meeting. He also called attention to the Statutes as
revised, copies of which he presented in print.

The following papers were presented : —

" On the Effect of Thin Plates of Iron as Armatures to
Induction Coils." By Professor John Trowbridge.

" On a New Form of Mirror Galvanometer." By B. O.
Peirce.

" On the Solar Motion and Stellar Distances." By Pro-
fessor T. H. Safford.

" On some New Forms of Iron Viaducts." By Professor
William Watson.

" On two New Machines used in the Construction of Tidal,
Coast, and Harbor Works." By Professor Watson.

" On the Occurrence of Odoriferous Glands in the Walk-
ing-stick." By Professor S. H. Scudder.

" On the Equal Roots of the Principal Equations of the
Circular Perturbations of the Planets as not affecting the Sta-
bility of the System." By Professor Benjamin Peirce.

Six hundred and eighty-ninth 3Ieetlng.

March 8, 1876. — Stated Meeting.

The Academy met at the house of Mr. John A. Lowell.

The President in the chair.

The Corresponding Secretary read letters from Messrs.
Ramsay, Sclopis, Godkin, and Adams, accepting their elec-
tion as members of the Academy.

Voted, To adjourn this meeting at its close to the second
Wednesday of April, and to postpone the stated business of
the meeting until then.

The Chairman of the Rumford Committee then introduced

OF ARTS AND SCIENCES. 325

the special business of tiic evening, and luuuled to tlie Presi-
dent the Rumford jNIechils (in gold and silver), on each
of which had been engraved the following inscri[)tion :
" Awarded by the American Academy of Arts and Sciences
to John W. Draper, for his Researches on Radiant Energy.
May 25th, 1875."

In presenting the medals, the President said : —

Gentlemkn of the Academy, — The foundation of this Society,
you all kuow, dates back but four years less than a century. It fol-
lowed close upon the adoption of the form of government of the State
itself. Further than this privilege of a corporation, I am not aware
that the State has since bestowed any aid to it whatever. During the
long period that has intervened, the individual members have steadily
and honestly contributed their labors and their money to the advance-
ment of science and of the arts, the evidence of which is to be found
as well in the collections of the library as in the long series of their
published transactions. We have not been so lucky as to earn the
favor of the generous and wealthy at all in the proportion given to
some other institutions of the same general character. In point of
fact, we have to ascribe our success more to our own energies than to
the assistance of patrons. This is no bad sign for the future. The
Academy was never in more healthy and vigorous condition than at this
moment. The meetings are constantly attended by numbers who ap-
pear to give or to receive with interest the many valuable contributions
to knowledge which ultimately take their place in the formidable vol-
umes open to the insj^ection of the world.

Yet it is not to be understood from what I have said that the insti-
tution has been altogether without liberal assistance from several
sources. The most remarkable instance of a benefaction was })erha))s
the earliest, that of Benjamin Thompson, better known under the name
of Count Rumford, who, eighty years ago, presented to the Academy
the sum of five thousand dollars, to be devoted to the stimulation of the
study of the various phenomena connected with light and heat, by the
presentation of medals of value as honorary rewards to successful re-
search. It is to the credit of the Academy, in these degenerate days,
to find that its administration of this property has fully justified the
confidence of tJie donor, the original sum having increased more than
fourfold over and above the cost of the medals which have from time
to time been awarded to successful investigation of the great subjects
proposed for study and examination.

32<3 PROCEEDINGS OF THE AMERICAN ACADEMY

It now becomes my agi'eeable duty to announce the fact tliat, after a
careful review of the meritorious services of Pi'ofessor Draper iu this
great field of inquiry, the committee having the subject iu their charge
have, for reasons given by them, recommended through their Chair-
man, that the medals prescribed in the deed of trust should be presented
to him as having fully deserved them. It falls to my lot only to re-
capitulate in brief some of these reasons.

In 1840 Dr. Draper inde[)endently discovered the peculiar pheno-
mena commonly known as Moser's images, which are formed when a
medal or coin is placed upon a polished surface of glass or metal.
These images remain, as it were, latent, until a vapor is allowed to
condense upon the surface, when the image is developed and becomes
visible.

At a later period he devised the method of measuring the intensity
of the chemical action of light, afterwards perfected and employed by
Bunsen and Roscoe in their elaborate investigations. This method
consists in exposing to the source of liglit a mixture of equal volumes
of chlorine and hydrogen gases. Combination takes place more or
less rapidly, and the intensity of the chemical action of the light is
measured by the diminution in volume. No other known method
comjiares with this in accuracy, and most valuable results have beea
obtained by its use.

In an elaborate investigation, published in 1847, Dr. Draper estab-
lished experimentally the following important facts : —

1. All solid substances, and probably liquids, become incandescent at
the same temperature.

2. The thermometric point at which substances become red-hot is
about 977 Fahrenheit degrees.

3. The spectrum of an incandescent solid is continuous ; it contains
neither bright nor dark fixed lines.

4. From common temperatures nearly up to 977° Fahrenheit, the
rays emitted by a solid are invisible. At that temperature they are
red, and the heat of the incandescing body being made continuously to
increase, other rays are added, increasing in refrangibility as the tem-
perature rises.

5. While the addition of rays, so much the more refrangible as the
temperature is higher, is taking place, there is an increase iu the inten-
sity of those already existing.

Thirteen years afterward, Kirchhofi" published his celebrated memoir
on the relations between the coefficients of emission and absorption of

OF ARTS AND SCIEN'CES. 327

bodies for liglit aiul ln-at. in wliicli he o.stabli.slied mathematically tho
saiue facts, and announced them as new.

Dr. Draper claims, and we believe with justice, to have been the
first to apply the daguerreotype process to taking portraits.

Dr. Draper applied ruled glasses and specula to produce spectra
for the study of the chemical action of light. The employment of
ruled metallic specula for this [)urpose enabled him to avoid the ab-
sorbent action of glass and other transparent media, as well as to
establish the points of maximum and minimum intensity with reference
to portions of the spectrum defined by their wave lengths. He ob-
tained also the advantage of employing a normal spectrum in place of
one which is abnormally condensed at one end and expanded at the
other.

We owe to him valuable and original researches on the nature
of the rays absorbed in the growth of plants in suidight. These re-
searches prove that the maximum action is produced by the yellow
rays, and they have been fully confirmed by more recent investiga-
tions.

We owe to him, further, an elaborate discussion of the chemical
action of light, supported in a great measure by his own experiments,
and proving conclusively, and, as we believe, for the first time, that
rays of all wave lengths are capable of producing chemical changes,
and that too little account has hitherto been taken of the nature of the
substance in which the decomposition is produced.

Finally, Dr. Draper has recently published researches on the dis-
tribution of heat in the spectrum, which are of the highest interest, and
which have largely contributed to the advancement of our knowledge
of the subject of radiant energy.

And now, in the absence of Dr. Drajier, unable at this inclement
season to execute a fatiguing journey, it gives me pleasure to recognize
you, Mr. Quincy, as his worthy and competent representative.

1 pray you, in receiving these two medals on his behalf, in accord-
ance with the terms of the original trust, to assure him, on the part of
the Academy, of the high satisfaction taken by all its Fellows in doing
honor to those Avho, like him, take a prominent rank in the advance of
science throughout the world.

Mr. Qiiincy, on receiving the medals, said : —

Mr. Puesident, — In the name and on the behalf of Dr. Draper I
have the honor to receive the Rumford Medals in gold and silver,

828 PROCEEDINGS OP THE AMERICAN ACADEMY

■which the Academy has been pleased to award to him, and I will
have them safely conveyed to him to-morrow, together with the assur-
ances of the satisfaction of the Academy in this action which you wish
me to communicate to him. In common with yourself, Sir, and all the
Fellows present, 1 regret that that eminent peison is unable to attend
this meeting and receive the medals himself. And, personally, I re-
gret the absence of Dr. Wolcott Gibbs, who had promised to perform
this grateful service for his friend, and who would have been able to
make a more suitable reply to the able discourse with which you have
accompanied the presentation of the medals, and to have done more
justice to the claims of Dr. Draper to this distinction than I can pre-
tend to do. Dr. Gibbs having also been unavoidably prevented from
being present this evening, I have now the honor to read a communi-
cation from Dr. Draper to the Academy, in acknowledgment of this
testimony to his services to science.

Mr. Qiiincy then read the following letter: —

To the American Academy of Arts and Sciences.

Your favorable appreciation of my Researches on Radiations, ex-
pressed to-day by the award of the Rumford Medal, the highest testi-
monial of approbation that American science has to bestow on those
who have devoted themselves to the enlargement of knowledge, is to
me a most acceptable return for the attention I have given to that
subject through a period of more than forty years, and I deeply regret
that through ill-health 1 am unable to receive it in person.

Sir David Brewster, to whom science is undei' so many obligations
for the discoveries he made, once said to me that the solar spectrum is
a world in itself, and that the study of it will never be com2)leted. His
remark is perfectly just.

But the spectrum is only a single manifestation of that infinite ether
which makes known to us the presence of the universe, and in which
whatever exists — if I may be permitted to say so — lives and moves
and has its being.

What object, then, can be offered to us more worthy of contemplation
than the attributes of this intermedium between ourselves and the outer
world ?

Its existence, the modes of motion through it. its transverse vibra-
tions, their creation of the ideas of light and colors in tiie mind, the
interferences of its waves, polarization, the conception of radiations and
tlieir physical and chemical elTects, — these have occupii'd tlie thoughts

OF ARTS AND SCIENCES. 329

of mei of till' liigliost order. The observiitioiial powers of science have
been <n-eatlv cxti'iuk-d through the coiiseciuent invention of those grand
instrunient*>, the telescope, the microscope, the spectrometer. Throu<fh
these we have obtained more majestic views of the nature of the uni-
verse. Tiirough these we are able to contem[)late the structure and
genesis of other systems of worhls, and are gathering information as
to the chemical constitution and history of the stars.

In this noble advancement of science you, through some of your
members, have taken no inconspicuous part. It adds impressively to
the honor you have this day conferred on me, that your action is the
deliberate determination of competent, severe, impartial ju<lges. I
cannot adequately express my feelings of gratitude in such a presence,
publicly pronouncing its approval on what I have done.
I am, gentlemen, very truly yours,

John W. Draper.

Professor Watson gave an account of an excursion upon
the Marne, with a description of the drum-weirs and river-
gates for inland navigation.

Professor Cooke exhibited the radiometer of Professor
Crookes, and gave the results of some experiments he had
made with it.

Professor William Everett presented a communication on
the sources of the Nile. He first called attention to the fact
that the wonderful extension of our knowledge in the last
few years on this subject had come from explorations directed
from the south, rather than from the direction of Egypt.
In connection with these expeditions, attention had again
been directed to earlier discoveries. The veracity of the
Portuguese explorers had been attested, and the value of
some of the very earliest accounts reasserted. Dr. Living-
stone especially had dwelt with great confidence — probably
too great — on Herodotus's view of the Nile sources. But a
still earlier writer than Herodotus had not received due
attention. In the Prometheus of ^schylus, lines 800-815,
the wanderings of lo are described with some vagueness, it
is true, but in terms which appeared to Professor Everett to
indicate a journey to the extreme east, afterwards tending

330 PROCEEDINGS OF THE AMERICAN ACADEMY

to the south, and approaching Africa from the south-east by
a certain JTorayuo? AWlo-^^^ which he believed to be the
Zambesi. The course is then directed along the shore of
this, as in Livingstone's second expedition ; the central
plateau is then entered, as in his last; and the upper falls of
the Nile are visited, — as by Speke and Baker, — where it
descends Bv/SXlvcou opcov airo, which Professor Everett
thought indicated the vast reaches overgrown by the J3yblus
reed, so prominently noticed by Sir Samuel Baker.

The date of the Prometheus is approximately 472 before
Christ.

Attention was also called to the verifications of the
Homeric geography, given by Mr. Gladstone in 1858, and
since more accurately worked out in Germany.

Six hundred and ninetiefh Meeting^.

April 12, 1876. — Adjourned Stated Meeting.

The Vice-President in the chair.

The Corresponding Secretary read letters from ]Messrs.
Hamlin and Marsh, accepting their election as members of the
Academy ; also, a letter from Mr. E. A. Thompson, of North
Woburn, asking aid in securing the house of Count Rumford
for public purposes. It was

Voted, To present to the North "Woburn Literary Associa-
tion a copy of the " Life and Works of Count Rumford."

The following gentlemen were elected into the Academy : —

John Langdon Sibley, of Cambridge, to be Resident Fel-
low in Class III., Section 2.

Henry A. Rowland, of Baltimore, to be an Associate
Fellow in Class I., Section 3.

Balfour Stewart, of Manchester, to be a Foreign Honorary
Member in Class I., Section 3.

On the recommendation of the Rumford Committee, it
was

Voted, To allow the Associate Fellows to purchase copies

OF ARTS AND SCIENCES. 331

of tlic " Life and Works of Count Rumford" at the same rate
as the Resident Fellows.

The committee appointed to consider the memorial of the
Boston Society of Civil Engineers, regarding the introduc-
tion of the metric system, reported, recommending that the
President be authorized to sign this memorial. After con-
siderable discussion, it was

Vvtcd^ To indelinitely postpone this subject.

The following papers were presented : —

" On George B. Grant's Calculating Machine." By
William A. Rogers.

" On the Methods and Precision of Meridian Observa-
tions." By Truman H. Safford.

" On a New Form of Induction Apparatus." By Henry P.
Bowditch.

" On the Binary System of Arithmetic." By Benjamin
Peirce.

Six hundred and ninety-first Meeting.

May 10, 1870. — Monthly Meeting.

The President in the chair.

The Corresponding Secretary read a letter from Mr. J. L.
Sibley, acknowledging his election into the Academy.

The Corresponding Secretary presented the Annual Report
of the Council, which was accepted, and is hereto appended.

The following papers were presented : —

" Some Formulae relating to the Motions of Planets and
Comets." By T. H. Safford.

" On the Three Brombenzylbromides." By C. L. Jackson.

" On Telegraphing Musical Sounds." By A. G. Bell.

''' On the Perturbations of Uranus by Neptune." By
Benjamin Peirce.

Professor Pickering presented the following papers : —

" On the Intensity of Sound." By W. W. Jacques.

" On the Diffraction of Sound." By W. W. Jacques.

832 PROCEEDINGS OF THE AMERICAN ACADEMY.

Professor Trowbridge presented the following papers by
title : —

" On the Change in Conductivity of CojDper Wires resulting
from Stretching." By G. S. Pine.

" On the Distribution of Magnetism on Armatures." By
Harold Whiting.

Dr. Robert Amory exhibited some photographs which he
had taken of the Solar Spectrum, in which the D line was
for the first time distinct!}'' represented.

REPORT OF THE COUNCIL.

Since the last Report, May 11, 1874, the Academy has lost
by death twelve members, as follows : five Fellows, John
Henry Clifford, Horatio B. Hackett, Joel Parker, Joseph
Winlock, and Chauncey Wright ; three Associate FelloAvs,
Horace Binney, Sir William Logan, and William Sweet-
ser ; four Foreign Honorary Members, Gabriel Andral, Gino
Capponi, Charles de R^musat, and Sir Charles Wheatstone.
During the year, the Council have also, and for the first
time, received notice of the death of Eyries, the Duke di
Serradifalco, and De Macedo, three Foreign Honorary Mem-
bers whose decease took place several years since.

JOHN HENRY CLIFFORD.

The Honorable John Henry Clifford was born at Provi-
dence, Rhode Island, on the IGth of January, 1809, and was graduated
at Brown University in 1827. He studied law in Massachusetts, was
admitted to the Bar of Bristol County in 1830, and was a resident of
2s ew Bedfoi'd until his death. In 1835, he entered the Legislature of
Massachusetts, as a Representative of New Bedford, and was a mem-
ber of the committee for the revision of the Statutes. In 1839, he
was appointed District Attorney for the Southern District of Massa-
chusetts, and served the Commonwealth in that capacity for ten years.
In 1845, he was elected to the Senate of the State; and, in 1849,
he became Attorney-General of the Commonwealth, and was con-
tinued in that office for four years. During this period, he acquired
wide distinction for his management of the prosecution and conviction
of Professor Webster. In 1853, he was elected Governor of Massa-

334 HORATIO BALCH HACKETT.

chusetts, and discharged the duties of that office with great ability.
He declined a re-election, however, and again assumed the office of
Attorney-General, by the appointment of Governor Washburn, and
afterwards by the election, successively, of the Legislature and of the
people. In 18G2, he re-entered the Senate of ]\Iassuchusetts, and was
President of that body. In 1867, he accepted the position of Presi-
dent of the Boston and Providence Railroad Company, and devoted
himself mainly to business pursuits for the remainder of his life.

In 1874, the appointment of United States Minister to Russia was
offered to him by President Grant, and afterwards that to Turkey ;
but he declined them both. He was for many years one of the Over-
seers of Harvard Univei'sity, and President of that Board ; and, as one
of the Trustees of Mr. George Peabody's great Education Fund for
the Southern States, he had become known far beyond the limits of
his own State.

In 1875, he made a visit to Europe for the benefit of his own health
and that of his family ; but soon after his return home he was struck
down by fatal illness, and died on the 2d of January, 187G, in the sixty-
seventh year of his age.

Governor Clifford was a man of marked ability, and in every station
which he held he exhibited peculiar capacity for public usefulness.
Few men of our time have left their names on the records of Mas-
sachusetts more distinctly or more enviably. He was genial, warm-
hearted, public-spirited, patriotic, and greatly endeared to his friends in
all i^arts of the country. His death was the occasion of widespread
sorrow, and his memory will long be cherished as that of a Christian
gentleman, whose chai-acter and whole career had reflected the highest
honor on New Enj^land.

HOKATIO BALCH HACKETT.

Horatio Balch Hackett died very suddenly in Rochester,
N.Y., November 2, 187.). He was born in Salisbury, Mass., in the year
1808. He fitted for Amherst College at Phillips Academy, in An-
dover, where he distinguished hiuiself as a scholar ; and his oration, on
leaving that institution, was of such marked merit, that it led one of
the Trustees to offer to defray the expenses of his college course. He
entered Amherst College in 1820, and was graduated with its higliest
honors in 1830. He completed the regular course of theological studies
in Andover in 1834, after which he went to Germany, and studied for
some time at Ilalle and Berlin. On his return, he spent one year as a

HORATIO BALCII iia<'ki:tt. 335

Tutor in Amlicrst College, and was then chosen Professor of Ancient
Languages in Brown University, in Providence, U I. After four years
(183.3-30), he was invited to fill the chair of Biblical Literature in
the Newton Theological Institution. He occupied this position until
1860 ; and, after spending one year in the service of the American Bible
Union, he a(^ce[)ted the appointment of Professor of Biblical Literature
in the Rochester Theological Seminary, which position he occu[)ied at
the time of his death. He was also for several of the last years of his
life a member of the American Committee for the revision of the
English Scriptures.

Jn 1851-52, Dr. Hackett travelled in Italy, Egypt, Palestine, and
other countries. In 1858-59, he resided several months in Athens,
for the purpose of studying Modern Greek, as auxiliary to the inter-
pretation of the New Testament.

As a scholar, he was both comprehensive and exact. As a teacher,
he combined in rare union the minutest accuracy in details with the
most fervid enthusiasm. His love of truth was intense, his devotion to
sacn-d literature absorbing, his industry unsurpassed, and his mind
remarkably free from theological and other prepossessions. His com-
prehensive and exact classical scholarship was coupled with an unusual
mastery of pure, perspicuous, and picturesque J^nglish, and his modesty
was equal to his learning.

His published works are an edition of Plutarch's " De Sera Numinis
Viudicta," with notes, Andover, 1844, afterwards republished with
additional notes, as the joint work of himself and Professor Tyler, of
Amherst; a Translation of Winer's Chaldee Grammar, with additions,
1845 ; a Hebrew Reader, 1847 ; a Commentary on the Book of Acts,
1851, republished with considerable enlargement in 1858 ; Illustrations
of Scripture, suggested by a Tour through the Floly Land, 1855, which
has passed through several editions, and been reprinted in England and
Scotland, and is his principal work ; Memorials of the War, a volume
comprising brief notices of Christian heroes who fell in the service of
their country during the civil war; the Epistle of Paul to Philemon, a
new Translation with notes for the American Bible Union ; an Ameri-
can Edition of Smith's Dictionary of the Bible, with many additions
and improvements, of which Dr. Ezra Abbot, of Cambridge, was a
joint editor ; and, lastly, many valuable articles contributed from time
to time to the Christian Review, and the Bibliotheca Sacra.

336 JOEL PARKER.

JOEL PARKER.

The limited space within which the Academy is obliged to confine
the notices of its departed members, in the published volumes of its
Proceedings, gives but little opportunity to do justice to the memory
of the Hon. Joel Parker, of Cambridge, whose death occurred
August 17, 1875, at the age of eighty years.

He became a Fellow of the Acadetny February 1, 1853.

He was born in JafFrey, N.H., January 25. 1795, the youngest of
nine children of the Hon. Abel Parker, who was for many years
Judge of Probate for the County of Cheshire. He was prepared
for Dartmouth College at Grotou Academy, and graduated in 1811,
being then less than seventeen years of age. Among his classmates
were Amos Kendall, and Chief Justice Shepley, of Maine. He was
admitted to the Bar of Cheshire County in October, 1817, and en-
tered upon the practice of the law in Keene, which, with the exception
of about a year, was his place of residence till his removal to Cam-
bridge, in 1848. After a career of distinguished success at the Bar,
and a service of two years in the Legislature of that State, he was
appointed a .Judge of the Superior Court of New Hampshire in 1833,
and to the place of its Chief Justice in 1838. He held judicial office
with great acceptance to the Bar and the public till 1848, when,
having been invited to the Royall Professorship in the Harvard Law
School, he resigned his place upon the bench, and entered upon the
duties of his new appointment. He held this office till 1868, when he
resigned it, and from 18G8, to 1874, without changing his residence, he
gave courses of lectures as a Professor of Law to the Senior Class in
Dartmouth College, upon the Constitution of the United States. He
also lectured upon the same subject to the members of the Columbian
Law School in Washington. He was a professor of ^ledical Juris-
prudence in the Medical School of the last-named institution from
1847 to 1857. He had previously lectured on the same subject in
1851 in the Boylston Medical School, and in the Medical College in
New York. His public services, after removing to Cambridge, aside
from his duties as a professor and lecturer, consisted of a member-
ship of the Constitutional Convention of Massachusetts in 1853, and
an active part in the revision of the statutes of that State, to which he
was appointed in 1855. Among the indications of the estimate in
which he was held as a jurist and scholar, may be mentioned the
degree of LL.D., which was conferred upon iiim by his Alma Mater
in 1837, and by Harvard College in 1848. He was also a member
of the Massachusetts Historical Society.

JOEL PARKER. 337

Though a close and earncot student all his life, aud constantly busy
with his peu, unfortunately for tlie permanency of Ids fame as an
author, he left no considerable work upon any one topic, wliich is the
more to l)e rejiretted, when what he did leave shows such unipiestion-
ablc ability to do ample justice to any subject which he might have
undertaken. His leyal opinions, as a judge, extend through thirteen
volumes of the New Hampshire Reports, and will be lasting memorials
of his learning, diligence, judicial acumen, and independent judgment.
Many of them were upon new and important rpiestions, and evince a
remarkable skill at analysis and profound discrimination, which were
marked characteristics of his mind. Among them will be found the
memorable discussion of certain questions growing out of tiie construc-
tion to be given to the word " lien," made use of in the United States
Bankrupt Law of 18-41, upon which Judge Story had given able and
elaborate opinions, which he proposed to enforce in opposition to those
entertained by Chief Justice Parker. It is sufficient for the purposes
of this notice to say that, upon the final determination of these ques-
tions by the Supreme Court of the United States, the positions
assumed by Judge Parker, and which he was equally resolute with
his distinguished antagonist to maintain, were fully sustained. His
publications, aside from his judicial opinions, consisted of lectures,
addresses, literary and historical, and essays and discussions upon
questions of constitutional law, which, if collected, would form a large
volume replete with learning and profound thought, suited as well to
the future as to the then condition of the country which called them
out. No one who should read them would need to be told that he
was not only a bold and independent thinker, but that he never tem-
porized in his course where he thought jjublic duty led the way.

If, now, we pass from a consideration of his public life to the quali-
ties for which he was distinguished within the precincts of his own
home, it may be remarked that his wife, who survives him, was the
daughter of Elijah Parker, Esq., his former professional partner.
They had three children, of whom a son and a daughter now survive
him. With all his habits of close and severe thought and study in the
performance of his official duties, he was eminently domestic in his
tastes and occupations. He loved to make his home pleasant by its
surroundings. He indulged in the culture of flowers, the reading of
his favorite poets, and the free and familiar converse with his family
and friends, characterized, as it often was, by a vein of genial and play-
ful humor which broke down every thing like stiflfness or reserve in
his intercourse in domestic life.

VOL. XI. (n. s. III.) 22

338 JOEL PARKER.

As a judge, he was courteous, patient, and willing to listen atten-
tively, and to weigh candidly whatever was addressed to his judgment,
bringing to his conclusions the processes of close reasoning and careful
analysis, which were among the leading characteristics of liis mind.

As an instructor in law, he was thorough in liis prejjaration, clear
in his statements, without any attempt at rhetoric or fine composition,
leaving upon the minds of his pupils definite and lasting impressions
of the propositions which it was his purpose to enforce. Hundreds,
who are now among the leading minds at the American bar, would
bear willing testimony to his fidelity as a teacher, as well as the cour-
tesy and urbanity which marked his intercourse with those who sought
his instruction or counsel.

In the social intercourse of life, he was dignified without coldness,
often playful, but never frivolous, with easy and agreeable manners,
and a mind well stocked with general information and i-eady resources.
He was not hasty in forming his opinions; but, when formed, he had
no hesitancy in avowing and maintaining ihem. So far as these
related to questions which grew out of the unhappy civil war in which
the country was engaged, it is enough to say that he stood boldly
and manfully for the Constitution in its integrity, by applying to it a
higher test than the expediency of the hour.

With such qualities of mind, and such habits of keen and careful
observation and investigation as he brought to every subject with
which he engaged, he would have been eminent in any of the depart-
ments of science into which the Academy is divided. Horticulture was
with him a study and a delight; but his pursuits were chietiy connected
with literature, and the profession he had chosen.

He was much at home with the early history of New England and
her institutions, and contributed several valuable articles upon subjects
connected with these, which are among his published works.

He was true to the last in his fidelity to his Alma Mater. He was
of her Board of Trustees from 184o to 18G0; and, at his death,
remembered her together with the interests of tiie science to whicli his
life had been devoted, by a liberal benefaction fur founding a law
school in that institution.

Although enough has been shown to claim for Judge Parker an
honorable place among the men who have helped to mark the passing
centur}', it is a fitting tribute for the Academy to pay to tlie memory
of one of her distinguished sous, to place upon her own record some of
the grounds upon which, when living, he commanded the respect and
esteem of his associate Fellows.

JOSEPH WINLOCK.

JOSEPH WINLOCK.

339

Professor Joseph Wixlock was burn in Slielby County, Ken-
tucky, on February 6, 1826. lie died, suddenly, at Cambridge, Mass.,
in all the strenjjth of his manhood, and at the height of his usefulness,
on June 11, 1S7.'>. The day before that of his death, he was at his
usual work, with no warning of his impending fate except fi'oni a
sense of increasing lassitude which he had felt for several weeks.

His grandfather, a Virginian by birth, was General Josei)h Win-
lock, who joined the American army, at the outbreak of the Revo-
lution, when he was only eighteen years of age. He served at first
as a private, and was afterwards promoted to the rank of ensign,
lieutenant, and captain. He was engaged in the battles of German-
town, Brandywine, Monmouth, &c., and was with Washington at Val-
ley Forge. In 1787, he married Miss Stephenson of Virginia, and
settled in Kentucky, where he was employed in surveying and entering
land. He was sent to the Convention which framed the Constitution
of Kentucky, and, afterwards, for some years to the State Senate.
He commanded the troops of the State which were ordered out to
intercept the expedition of Aaron Burr in 1806. In the War of 1812,
he held the rank of Brigadier-General, and went with three regiments
to Vincennes.

His son. Fielding Winlock, the father of Professor Winlock, was
born in Kentucky on May 4, 1787. He studied law, at first in the
office of Felix Grundy, and, after Mr. Grundy's removal to Nashville,
in the office of Henry Clay. During the preparations for the War of
1812, he was clerk of the committee of the State Senate on military
affiiirs, performing also many of the duties of Adjutant-General. He
left this position to serve in the army as aid to his father, and, in the
campaign which ended with the defeat of Proctor and Tecumseh, on
General Shelby's staff. After the war he held, at different times,
various places of honor and trust, and died at the advanced age of
eighty-five.

Professor Winlock was educated at Shelby College, Kentucky, where
he graduated in 1845. At this early age his tastes and acquirements
were conspicuous ; and he received immediately the appointment of
Professor of Mathematics and Astronomy in that institution. He
devoted his first savings to the purchase of a set of the Astronomische
Nuchrichten ; and, in order to be able to read it, he rose early in the
morning to talk German with a rude laborer upon his father's farm,

340 JOSEPH WIXLOCK.

before the clay's work began. Fortunately for himself and for science,
he attended the fifth meeting of the American Association for the
Advancement of Science, which was held at Cincinnati in the spring
of IHol. It is not among the least of the advantages of this associa-
tion that it brings into notice young men of promise who might other-
wise live and die in obscurity, revealing to themselves as well as to
others, by comparison, their rare intellectual endowments. In this
case, the chief of American mathematicians recognized, in the Ken-
tucky professor, one who had mastered and enjoyed his own highly
condensed treatises, however distasteful they may have been to com-
monplace students and teachers. This happy conjunction of kindred
minds resulted in bringinor Mr. Winlock to CambricJore in 1852. Cam-
bridge was, at that time, the headquarters of the American Ephemeris
and Nautical Almanac ; a great work, ordered by Congress in the Act
of March 3, 1819, and placed under the superintendence of Lieutenant
(now Admiral) C. H. Davis. Mr. Winlock joined the able corps of
computers, on whose ability and fidelity the life of the Almanac
depended, and remained in this service until 1857, when he was ap-
pointed Professor of Mathematics in the United States Naval Obser-
vatory at Washington. He had been in this new position for only a
short time when he was made Superintendent of the Ephemeris and
Almanac, and returned to Cambridge.

He vacated this post in 1859, and removed to Annapolis, where he
had charge of the mathematical department in the United States Naval
Academy. Soon after the removal of the Academy to Newport, in
consequence of the war of secession, he was again made Superintend-
ent of the Ephemeris and Almanac, and lived in Cambridge. During
his long though interrupted connection with this national work, which
has contributed lai-gely to the cultivation as well as to the credit of
mathematics and astronomy in this country, he made many valuable
contribittions to it, among which his carefully prepared Tables of Mer-
cury was the most important.

In 1866, with no effort on his part, he received the ajipointment of
Phillips Professor of Astronomy in Harvard College, and Director of
the Observatory. To his titles was afterwards added that of Professor
of Geodesy in the Lawrence and Mining Schools of the College.
While he was Professor at Shelby College, he had made himself
familiar with tin; construction and manipulation of the etpiatorial tele-
scope. An excellent Merz instrument of this desciiption, having a
focal length of 9.\ feet and an aperture of 7\ inches, was the property
of that institution, and was afterwards borrowdl by Mr. Winlock, and

i

JOSEPH WINLOCK. 341

mounted at Cambridge, tor a time, for his private use. Willi tlii.s
exception, liis scientific labors had been exclusively in the way of the
hi<jher matheinaties, either as teacher or computer. It was not until
he was relieved from the work of routine, and l)eeaine Director of the
Observatory at Harvard College, that lie iiad an opportunity to develop
and manifest his remarkable mechanical ingenuity and genius for
invention. An ample and deserved tribute is paid to the memory and
the services of the two lamented Bonds (the father and the son), when
it is remenibcred that their lives, consecrated to astronomy, founded
the Observatory, and won for it the sympathy and support of the com-
munity. Affection for them, and respect for their disinterested zeal,
inspired the liberal endowments which strengthened its early growth.
Because the men were there, the institution was born and lived. The
buildings and ecjuipments of the Observatory, under its first directors,
put to shame many similar establishments in Europe. The possession
of a magnificent refractor, equatorially mounted, approached by a skil-
fully devised observer's chair, and accommodated under an immense
dome which was moved with marvellous ease, contrasted favorably
with deficiencies in instruments and machinery at older observatories,
and gave to the one at Caml)ridge, at once, a name and a rank among
the best in the woi'ld. With delicacy and disinterestedness of feeling,
eminently characteristic of Mr. Winlock, his first thought, on assuming
the duties of Director, was for the reputation of his predecessors, with
which the reputation of the Observatory was intimately associated.
As rapidly as the resources of the Observatory permitted, he provided
for the reduction and publication of their unfinished work. Thus
the Annals of the Observatory have been enriched by a volume on
Sun-Spots, and others on a catalogue of Zone-Stars. Another is yet
to appear containing a catalogue of Polar and Clock Stars.

But it was impossible for the Observatory to maintain its high
standing and remain stationary, while the old observatories elsewhere
w^ere remodelled, refurnished, and prejjared to start upon a new career ;
and young observatories, richly appointed, were springing up in both
hemispheres. The inventory of instruments, at the disposal of the
Bonds, comprised the large equatorial, a five-foot equatorial, a four-
foot transit-circle, a Bond clock and chronograph, two chronometers,
and a set of Lloyd magnetometers for obtaining the elements of the
earth's magnetism. During the nine years of Mr. Wlnlock's vigorous
administration, the instrumental appliances of the Observatory were
strengthened in all directions. A seven-foot equatorial by Clark,
another Bond chronograph, a Bond standard-clock with break-circuit

342 JOSEPH wrNi,0CK.

attachment for transmitting time-signals, a Frodsham sidereal clock, a
Frodsham hreak-circuit sidereal chronometer (the original device of
Mr. AViiilock), a mean-tirae chronometer, a thermometric chronome-
ter, a photographic telescope of long focus, a Russian transit, made in
the workshop of the Pulkowa Observatory, a Zolluer astrophotometer,
a large RuhmkortF coil, various spectroscopes and self-recording
meteorological instruments, — all this rapid increase of resources,
while it added to the power, greatly multiplied the responsibilities of
the Director. The costly transit-circle, though constructed upon the
best models and by the most excellent artists, had always proved a
failure and a disappointment ; as ]Mr. Bond supposed, from fatal injuries
which it received in its transportation. Though it was useful as a
transit-instrument, implicit reliance could not be jilaced in it as a
circle. The consequence was, that the great equatorial was too fre-
quently called away from its legitimate woi'k to do the duties which
belonged properly to the circle. Mr. Wiulock was not long in in-
spiring the friends of the Observatory with that large measure of con-
fidence in his cai^acities and his sound judgment which prompted them
to contribute over $12,000 for the purchase of a new meridian circle.
In the autumn of 1867, Mr. Wiulock went to Europe, and spent four
months in visiting the principal observatories, and acquainting himself
with the latest improvements in instruments, and especially in circles.
Having studied the advantages and the defects in the highest class of
meridian instruments, he blindly copied no one of them ; but suggested
valuable modifications, with the view of securing greater stability,
increased precision of movement, and the most complete facility of
observation. The improvements which he suggested were warmly
approved and promptly adopted by the artists whom he prefei'red,
Troughtou and Simms of London ; his modifications of the old con-
struction have been fully justified by the results since the new circle
has been put to work, and other astronomers have given the best
indorsement by copying them. The eminent astronomer and mathe-
matician, .7. C Adams, now President of the Royal Astronomical
Society, oidered a circle from the same artists and of the same jiattern
for Cambridge, in England. In November, 1870, when the new
instrument was ready for use, Mr. Wiulock turned it upon the zone of
stars between 50° and 55° of north declination. AVhen the whole
field of observation was divided between the different members of the
Astronumische GeseUschaft, this was the share which fell to the Obser-
vatory of Harvard College. Already 15,000 observations have been
made upon the zone-stars, and in two years more the great work will

JOSEPH WINLOCK. 343

bo oompli'ted. Tii lsi')7, Mv. AViiilock li;iil diroctt'il n series of ol)ser-
vatioiis witli tlir old iiu'ridiiin circle for tlic jtiirpose of ohtaiiiiii^r an
exte'iidt'd list of uccuratidy phu-ed time-stars. Tiie utility of a lar>^er
catalogue of time-stars had beeu evidenci'd in the operations for the
dt'termiiiation of longitude conducted by the Uiiiied States Coast Sur-
vey, of which Mr. ^Vinloek was consulting astronomer. These obser-
vations, wliich assigned exact places to stars only two minutes apart
in right-ascension, but differing widely in declination, wen; finished in
December, 18 G8, and have been reduced and printed. In 1871-72,
the same stars were reobserved with the new circle, and again for the
third and fourth times in 1874 and 187o. An additional set of stars
is required for the instrumental constants, expressing errors in azi-
muth, collimation, level, «&;c. For this purpose 5,000 observations
were made with the new circle in 1873 and 1874, intended to serve as
the basis of an improved catalogue of polar stars, and they are now
ready for publication. Therefore, no time has been wasted in reaping
the full benefits of the new instrument, although the 30,000 observa-
tions already made with it are only the first-fruits of the liappy de-
vices of Mr. Winlock. These materials, to which must be aiUIetl a
catalogue of new double-stars, dissected by the great refractor, and a
most laborious and exhaustive work upon stellar photometry, will
magnify the forthcoming volume of the Annals of the Observatory,
and be a worthy moniunent to the skill and ^perseverance of the Direc-
tor and his gifted and faithful coadjutors.

In 1869, Mr. Winlock was instructed by Professor Benjamin Peirce,
then Superintendent of the United States Coast Survey, to proceed to
Kentucky at the head of a party destined to co-operate with officers of
the survey in observing the total eclipse of the sun, on the 7th of
August. Mr. Winlock gave his attention, particularly, to the physical
aspects of the eclipse, examining the photosphere and the chromo-
sjihere with the spectroscope, and taking eighty photographs of the
eclipse, in all its phases, seven of them during totality. It was his
habit to think out every subject which engaged him for himself; and,
when he acted, he seldom followed in the wake of other men. lie
found good reasons for rejecting tlie method of photographing which
had been tried in Spain on occasion of the total eclipse of 18(50, and
which other American astronomers were preparing to imitate in 18G9.
As he wished, most of all, to secure a good picture of the corona, he
placed the sensitive plates at the focus of the object-glass, thereby
economizing the light, and avoiding the distortion by the eye-piece.
His success was highly satisfactory. In the best of the pictures, he

344 JOSEPH WINLOCK.

immetliately recoguized the fact that the corona was broader in the
direction of the sun's equator than along the axis. He had arranged
for obtaining numerous views of the partial phases of the eclipse, in
the hope of extracting from them valuable information as to the use of
photography in observing the transits of Venus. To this end, he was
afterwards authorized by the Superintendent of the Coast Survey to
engage Messrs. Alvan Clark and Sons to construct a micrometer,
adapted to the nice measurement of distances and positions on the
photographic plates. The Annals of the Observatory will contain a
description and engraving of this micrometer, and an account of the
measures made with it, with various representations of the eclipse
copied from the photographs.

At this time, no one except IMr. AVinlock had succeeded in obtain-
ing a photograph of the corona during any solar eclipse. Although
his photographs were only | of an inch in diameter, tliey seemed to
promise measurements, made under a microscope, which would compare
favorably with the best that could be furnished by meridian instruments.
A larger image would be still better; but this required a telescope
of formidable length, and difficult to manipulate. To surmount this
obstacle, Mr. Winlock conceived the idea of a horizontal telescope, to
be fed by tlie light from a heliostat. He was convinced that a ti'ans-
parent reflector would be better than a silvered mirror, as it would
weaken the light, and su[)ersede the necessity of making the time of
exposure inconveniently short. Moreover, as the instantaneous action
of the light was often sufficient, the heliostat was unnecessary. Soon
after his return from Kentucky he gave an order to the Messrs. Clark
and Sons for a lens of four inches in aperture and forty feet in focal
length, which, after some preliminary trials at their shop, was ready
for use at the Observatory in July, 1870 ; and, since then, has been in
constant employment for procuring photographs of the sun. The lens
is mounted upon one pier, the reflector upon another, and the camera
upon a third jiier. The tube used for excluding the daylight is dis-
connected from the essential jjarts, so as not to disturb their stability.

At the request of the Superintendent of the United States Coast Sur-
vey, Mr. Winlock organized and directed one of the parties sent to the
south of Europe to observe the total eclipse of the sun on December
22, 1870. He selected Jerez de la Frontera, near Cadiz, as a favor-
able station, and was assi?ted by one experienced officer of the survey,
by several eminent astronomers and physicists, and by one of his own
staff at the Observatory. Among the physical and astronomical instru-
ments which he prepared for this expedition was a lens of o'2i^ feet in

JOSEPH WINLOCIv. 345

focal Ifiigth, to be used in the manner just desciibed for instantano-
eiis photographs. At this time, Mr. Winlock's method was widely
known and higlily appreciated, and every party which went into the
field to observe this eclipse had decided to dispense with an eye-piece,
and j)h()tograph in thi' focus of the object-glass. Unfortunately all the
parties, European and American, failed, by reason of bad weather, in
obtaining a picture of tlie corona, except the party in Spain ; and
there, also, the sky was not favorable for the best results. All the
observers who went to India to photograph the total eclipse of 1871
preferred the same method, and were successful. Lord Lindsay
a[)plied it at the Mauritius in connection with the horizontal telescope.
A telescope of long focus is not a new thing; a telescope placed upon
the ground is not a new thing ; there is no novelty about the heliostat;
more than one person may have discovered the advantage in photo-
graphing which belongs to telescopes of great focal length. Neverthe-
less, the adaptation to photographic purposes of a telescope of long
focus, fixed horizontally, and used without an eye-piece or a heliostat,
is original, and whatever merit there is in it belongs to Mr. Winlock.

In a former generation, *an eclipse of the sun excited the interest of
astronomers, as furnishing the means of verifying or correcting the
dynamical theory, or giving ditFerences of geographical longitude. It
is the consolation of science, that as fast as old fields are exhausted
new ones call loudly for cultivation. As soon as one question is set-
tled and curiosity flags, another problem springs into life and a fresh
interest is born. The old ambition to fit out a comet with its orbit
has yielded to the passion for knowing more about its physical changes
and constitution. Now that the law of gravitation asserts an un-
challenged supremacy in tiie solar system, the complex structure of
the sun and the origin of the solar radiations claim a share of the
astronomer's attention. In this way physical astronomy has acquired
a new meaning ; and a physical as distinguished from an astronomical
observatory, either under the same or an independent superintendence,
is one of the necessities of to-day's astronomy. It has been largely in
the interest of physical astronomy, in this new sense, that observers
luive traversed continents, crossed oceans, and taken up their quarters
in desolate islands, wherever a total eclipse of the sun or tiie transit
of Venus has invited them. Where special physical observatories
have not been started, the old observatories must assume their work,
but not to the prejudice of the preferred duties of an astronomical
observatory. Mr. Winlock gave a liberal portion of his time to celes-
tial spectroscopy, and stocked the Observatory with the requisite

346 JOSEPH WINXOCK.

instruments, and of the best class. These little instruments cliA'ided
with the larger ones the benefits of his inventive spirit. In his two
eclipse expeditions, he provided abundantly for the spectroscopic exam-
ination of the sun's surroundings, catching the sun itself in the reversal
of the lines, and witnessing other interesting transformations. The
secret of his success lies in the direction of his rule of having a definite
idea of what he wished to do, and the best way of doing it, before
going into the field. He went to Spain with the purpose of studying
especially that fainter portion of the sun's corona which is outside the
limits of the best photography. His experience in the Kentucky
expedition had taught him that much valuable lime is lost in the brief
duration of totality, when the position of the dark or briglit lines is
registered by means of a scale which must be read and recorded at
the time. To meet this difficulty, he invented the simple expedient
of graving corresjjonding lines upon a silver plate, previously graduated
by a few standard spectral lines. The differences could be leisurely
measured at some future time. This improvement was promptly
adopted by the English astronomers, and applied by them to the
eclipse of 1870. Mr. Winlock was of opihion that his contrivance
would be useful in observing the spectra of comets and nebuliB, and
wherever the lines were faint. It might also be convenient for finding
declination with meridian instruments. Another device was the use
of a mirror to reflect the slit, and enable the observer to place it
upon any |)art of the sun's image without the help of an assistant.

In January, 1854:, the Hon. R. C. Winthrop, Chairman of the Com-
mittee of the Board of Overseers of Harvard College, appointed to
visit the Observatory, reported that the Observatory time was sent to
Boston for the i-egulation of marine chronometers, for the arrange-
ment of railroads, and for the general convenience of the people
through a large part of New England. He adds : " The impor-
tance of such a system to the business operations of the community can
hardly be over-estimated." At this time the signals were sent to
Boston by way of Watertown, Brighton, and Roxbury, a circuitous
line of twelve miles in length, and the wires were often broken. In
185G, a loop connected the Observatory with the Fitchburg line, and
was owned by it until 1862. This has, of course, been available for
the occasional transmission of time ; but it was designed for the deter-
mination of differences of geographical longitude, in connection with
the United States Coast Survey; a service which began under t])e
administration of the first Director, and has been continually expand-
ing, until it has taken into its embrace the Pacific coast and the

JOSEPH wmLOCK. 347

western shore of Europe. In 1800, the necessities of tlie Coast
Siirvev (h-iuaiidiMl that the h)op should be reueweil l)et\v«'('u tli(!
Observatory and the main lines of the country ; and this was done at
tlie expense of the survey. From its foundation, the Observatory, in
one way or another, had furnished exact time to the community
gratuitously ; for which, elsewhere, observatories receive a liberal com-
pensation. In 1872, JMr. Winlock introduced improvements which
have made this service more widely and constantly useful, and at the
same time remunerative. A contract was made for a special wire
between Cambridge and Boston, which shoukl not be diverted to any
other business. An attachment to the mean-time clock of the Obser-
vatory interi-upts the voltaic current once in each two seconds, omitting
the last break of every minute, aud the last thirteen breaks of every
five minutes, so that there can be no mistake as to the identity of any
second or minute. Branch wires unite the City Hall of Boston, the
telegraph offices aud railroad depots, and the principal clock and
watch factories and warehouses with the first wire. In some places,
an electro-magnetic clock is used, controlled by the Observatory
clock ; but a cheap vibrating armature is all which is necessary, and
is generally employed. The superiority of the new system is here :
clocks, watches, and chronometers can be compared with the best
standard time, not merely once a day, but at any moment ; and the
public have appreciated and rewarded it. In one sense, it may be
always said that time is money. In this instance, the Observatory
time has opened so good a market that it has yielded a yearly income
of $2,000.

In 1872, Mr. Winlock began to prepare a series of astronomical
engravings, which should represent, with sufficient accuracy, the most
interesting objects in the heavens, as they appear in the powerful
instruments of the Observatory. This work was intended for the
benefit, not of astronomers, to w^hom the *' Annals " are accessible, and
precise measurements are indispensable, but of a larger class of readers,
who, without pursuing asti'onomy as a specialty, are interested in
following its progress and achievements. Thirty-five large plates,
beautifully executed from the most carefully prepared drawings and
photographs, were completed at the time of Mr. Winlock's death, and
wait only for a i'ew pages of letter-press to be ready for publication.
They will gratify the scientific public with admirable representations
of the planets, Mars, Jupiter, and the ring-encompassed Saturn ; of the
sun's spots, protuberances, and corona ; of the moon's craters and
geography ; of seven of the most famous clusters and nebula) ; of

348 JOSEPH TTIKLOCK.

Donati's comet of 1858, and Coggia's comet of 1874, in some of their
wonderful transformations.

In August, 1874, Mr. Wiulock was appointed by Secretary Bristow
chairman of the commission established by Act of Congress for making
inquiries into the causes of steam-boiler explosions. He entered into
this investigation with remarkable energy; carefully analyzed the
various theories which had been suggested to explain this class of
accidents ; and ended with devising a number of ingenious experi-
ments calculated either to confirm or refute them in detail. The
arrangements were nearly completed for making these experiments
at Sandy Hook and at Pittsburgh, when death put an end to his
labors.

In the early part of his active career, Mr. Winlock was known and
trusted as an accomplished teacher and an excellent mathematician ;
well versed in theoretical astronomy, and capable of applying it in
laborious and responsible calculations. These qualifications pointed
him out as a proper person to be made director of an observatory.
With his new opportunity, he developed other talents, which, if not
indispensable, were none the less valuable in his changed condition.
It might have been expected that his clear mathematical mind would
easily comprehend the ph3^sics and the geometry' of the instruments
whose usefulness he was to guide, and seize upon any defects which
might exist in their construction. In devising remedies for these
defects, as simple as they were sufficient, he displayed an originality in
his mechanical ideas, and a spirit of invention, which left nothing
wanting to fill out the measure of a consummate director. Without
any passion for innovation, or any conceit of his own methods, he was
not afraid to leave an easy and well-worn path, or disturb the most
time-hallowed routine, if he could give good reasons for the change.
The life of an assistant at an observatory, obliged to work while other
men sleep, exposed to the caprices of the clouds, made nervous by the
irregularity of his hours, the nice handling of his instruments, and the
delicacy of the work expeoi^ed of him ; disappointed at the critical
moment in realizing the fruits of anxious days of preparation, — such a
life is dependent, in no small degree, not only for its happiness, but its
endurance even, upon innumerable and indescribable little facilities for
observation, which individually are not worth the mention, but which
in the aggregate tell distinctly upon the success and the comfort of the
profession. In his many innovations, of which every room and each
instrument in the Observatcny is a witness, ]\h'. Winlock was not
misled by any theoretical abstractions, but moved always within the
limits of practical good sense.

JOSEPH WINLOCK. 349

In his adiniiii.-tmtivc cainicity, whicli was tested in the Xantical
Ahnanac, at the Observatory, and on two eclipse expeditions, Mr Win-
lock evinced a disinterestedness, a strengtli, and a trancpiillity of mind,
which connnanded the respect and won the all'ection of his associates.
His leadersliip was nowhere asserted, but everywhere acknowledi^^cd.
A man of few words, but of much thought ; of no pretensions, but of
great performance, — he did his own part patiently and well, and by
his example inspired others to do theirs. The magnitude and the
variety of work embraced in his programme, none of which suffered
by default, certify to the prudence and the vigor with which his
forces w^ere selected and mai-shalled.

In his private life, Mr. Winlock was exceptionally quiet and retir-
ing. But little inclined to general society, he was full of hospitality.
His happiness was not complete without a few very intimate friends ;
and he had no enemies. He was remarkably silent before strangers ;
but no one talked more or better in the circles which he loved. Indis-
posed as he was to take up his pen, when he wrote his words were as
trans])arent as his thoughts. Modest and without self-assertion, he
had as much as any other man the courage of his own opinions. Slow
to put himself forward, he was genial and accessible ; giving his time
and his instruction freely to all who asked ; never hoarding up a dis-
covery for his own exclusive benefit, but sharing with all his last
thought and his newest invention. He was keenly alive to the ridicu-
lous ; but there was no ill-nature in his criticisms. Pretence and
charlatanism in science amused him ; but they did not destroy his
equanimity. AVithout any selfish aims, he took no security for his
own discoveries and inventions ; so that others, less scrupulous than he
was, too often entered into his labors. His friends sometimes wished
that his ambition had been more aggressive ; but perhaps he was
wiser, in the simplicity of his character and the purity of his motives,
than the men of this generation. The discoveries and inventions
which he did not claim for himself will be vindicated for him.

In an age of bribery and corruption, every example of honor and
fidelity in the execution of a public trust is to be cherished. In an
age, when superficiality is preferred to depth, when the asjiirants for
scientific distinction sometimes forget to be just, and even the stars of
heaven are obscured by the dust of earth, every life consecrated to
honest study, not deflected from its high jiath by the love of popular
applause, silent in its own strength, as the planets whose courses it
follows, is a blessing and a legacy to mankind. In an age, when
priority of discovery often counts for more than the advancement of

350 CHAUNCEY WEIGHT.

human knowledge, and the vahie of inventions is read only on the
patent-rolls, the seeds which are scattered broadcast by the roadside
and not selfishly garnered in some private granary, though the sower
may have no sense of his own merits, will make the harvest of future
science. The deep impression which a quiet, unobtrusive, self-poised
career, like that of Mr, Winlock, makes upon the community, can
never be known until it is finished. And then we see the beautiful
spectacle of all — friends and strangers, those who knew him best,
and those who seemed to know him but little — spontaneously offering
the tributes of gratitude and affection which they would have refused
to the noisy claimant. This is the best hope and the highest reward
of science.

CHAUNCEY WRIGHT.

Chauncey Wright, who died suddenly at Cambridge on the
12th of September, 1875, was born at Northampton, September 20,
1830, and was graduated at Harvard College in 1852. He was an
accomplished and able mathematician, and was a member of the
Academy in the mathematical section ; but it was in the direction of
philosophy that his original, profound, and accurate thought had its
most congenial exercise, and found frequent public expression through
various journals and reviews. After the publication of Darwin's
Origin of Species, his attention was chiefly devoted to the discussion
which then received so powerful an impulse ; and he is, probably,
most widely known as a participant in that discussion. Oue of his
articles, which appeared in tlie " North American Review," was con-
sidered so important a contribution to the literature of this school, tliat
it was ref)ublished in pamphlet form in England, — a compliment the
more noteworthy, because it was paid to one who was not a professed
naturalist. Mr. Wright took much interest in this Academy, and was
for several years its Secretary. He exerted an important and peculiar
influence in scientific and literary circles, and one which, there is every
reason to believe, would have become wide and commanding, if his
life had been spared. We cannot hesitate to say that liis loss is one
of the most serious that the Academy and tlie wliole educated eom-
iinuiity liave this year to deplore ; and we are ghid to li'aiii that his
friends are preparing a republication of his writings, now scatteied
through the volumes of periodicals, and will join to it an account of
his life and mental characteristics.

HORACE BINNEY. 351

HORACE BINNEY.

Horace Binney was born in Pliiladditliia, on the Itli of January, "
17S0, and diinl in tliat city on the Tilh of August, 187"), liavini; more
than half coniplott'd his ninety-sixtli year. Thoujih Pliilaih'l|ihia saw
his birth and deatli, and witnessed liis honored pnbUe and piivate life
for tlu-ee ([uarters of a century, Massachusetts furnished the sound
stock from which his paternal ancestry sprung. The first liinney of
his race emigrated to New England in 1()8<). He came from Hull, in
England, and was one of the founders of the worthy little town of the
same name on our coast, looking towards Nantasket Roads, distin-
guished for many years as the seat of the smallest constituency entitled
to representation in the country, vying in that particular with Old
Sarum itself, until the ruthless hand of reform swept away its Lillipu-
tian franchise. The sea offered an obvious career to the inhabitants
of the miniature township ; and, accordingly, early in the last century
we find the grandfather of Mr. Binney sailing out of Boston, as
master of a vessel, and afterwards established there in trade. His son,
Barnabas Binney, made a step forward in life, being one of the first
thirty graduates of Brown University, taking his degree in 1774. He
received whatever medical education the country then afforded at
Philadel|»hia, and, on the breaking out of the war, he took service
as a surgeon in the ^Massachusetts line, from which he was afterwards
transferred to that of Pennsylvania. Dr. Binney settled in Phila-
delphia, and married Mary Woodrow, of a good Scotch-Ti-ish family,
in 1777. He is described as having been a man of unusual intellectual
power, uncommonly well-read, of great strength of principle and
force of character. His wife strongly resembled her husband in all
the material qualities of his mind and character, and was in every
respect a helpmeet for him.

Whatever qualities of mind and tendencies of disposition Mr.
Binney may have derived from his father, they came to him by
inheritance only, as Dr. Binney died in 1787, when his son was but
seven years old. His mother, however, was equal to the charge of his
education, the beginnings of which were had at schools in Philadelphia
and its neighborhood. In the year 1791, when her son was eleven years
of age, Mrs. Binney entered into a second marriage with Dr. Marshall
Spring, of Watertown, in this State, a connection which was in every
way favorable to the happiness and improvement of the young boy.
His mother survived her second marriage only two years, dying in

352 HORACE BIXXEY.

1793, just after his admission to college. Left thus on the very thresh-
old of life, at thirteen, without father or mother to advise and direct
him, he gave the best possible proof of his reverence for their memory,
by his devotion to the opportunities of improvement which lay before
him. In 1797, he took his degree at the head of his class, though
but seventeen years old. Among his classmates were that eminent
scholar, the Rev. Dr. William Jenks ; Dr. John Collins Warren ;
Judge Daniel Appleton White ; Professor Asahel Stearns, the imme-
diate predecessor of Judge Story in the Law School of the University,
all of them Fellows of the Academy ; and Chief Justice William
Merchant Ilichardson, of New Hampshire. IMr. Biiiney bore this
testimony, long afterwards, to the advantages he had derived from
his academic education : "■ The unfading art which I acquired at col-
lege was that of stud}^ ; and, if the acquisitions I then made are faded
or fallen from the surface, the art or faculty of study ha-? never left
me." A just recognition of the truth that the function of a Univer-
sity is to train, even more than to store, the young mind.

When young Biuney first began to consider what should be the
serious business of his life, it is not surprising that he should have
first inclined towards the profession of medicine. His liither and his
step-father having been both of them in that line of life, his thoughts
naturally turned themselves in that direction. Dr. Spring, however,
discouraged this inclination ; and he applied for admission to the
counting-house of an eminent firm of merchants in Philadelphia, with
the idea of devoting himself to trade. Fortunately for his future,
there was no room for him there ; and, as a last resort, he turned to the
law, and entered the office of Jared Ingersoll, an eminent lawyer of
that day. Having once made his choice of the law as the business of
his life, he applied the whole force of his mind, with all the power
of application his previous discipline had given it. to mastering the
science and learning the methods of its reduction to the business of
life. His devotion to that jealous mistress was absolute ; and lie
allowed himself to be diverted from it by none of the seductions of
pl(!asure or of society. In 1800, when but a little past his twentieth
year, he was admitte<l to the bar, and entered upon that probationary
novitiate through which all young lawyers hnve to pass. The
enforced leisure of waiting, however, was sedulously improved by
continued study and regular attendance upon the courts, to fit him
for the success which awaited him.

That success was not very long delayed. We have no room within
the limits permitted us here to go into the particulars of his beginnings

HOKACE BINNEY'. SAS

and his progress. His gains could not have been insignificant ihiring
the first ten years of his professional life, since at the end of thera,
when he was but thirty years old, he was able to build the large and
elegant house in Fourth Street, in which he lived for the remaining
sixty-five years of his life. Indeed, he had but small reason to com-
plain of neglected merit, when, at seven or eight and twenty, he was
dividing the best business Of Philadelphia with men nnich his seniors,
and who enjoyed a national reputation for eminence in the law. At
thirty-five, according to the authentic testimony of Mr. Justice Strong,
of the Supreme Court of the United States, given in the Eulogium
on the Life and Character of Mr. Binney, delivered last .January, —
at thirty-five he was " in the possession of all that the profession of
the law could give to its professor, whether of reputation or emolu-
ment." And, during those years of active practice, he piepared six
volumes of Reports, condensing the decisions of the Supreme Court
of Pennsylvania, from 1799 to 1814, of which Judge Strong says:
'' When they came from his hands, they left nothing to be desired.
They must always be regarded as the work of au accomplished
lawyer." He was a model lawyer in the earnest attention he gave
to the business intrusted to him, and in his devotion to the interests
of his clients. He was not to be turned aside from his practice at the
bar by any of the usual allurements of ambition, not even of promo-
tion to the highest distinctions of the law. While yet in the prime of
his life, he twice declined offers of a place on the Supreme Bench
of his own State, and at least once of one on that of the Supreme
Court of the United States.

Mr. Binney refused to be tempted to leave his profession by the
fascinations of political life. A single term in the State Legislature
in his youth, and one in Congress towards the close of his active pro-
fessional career, were all the deviations he made from his chosen
path through life into that enchanted ground. And his consent-
ing to serve his city in the twenty-third Congress was induced by
the pressure of a great question, the right decision of which should
have depended on the judicial voice of law, and not on the passionate
outcries of partisan politics. It was at the time of the war declared
by President Jackson against the Bank of the United States, which
he waged as against a tribe of savages which he was bound to extir-
pate per fas aid nefus. Or, to use his own figure of speech, as against
"a monster," of which it was reserved for him, as the appointed
champion, to rid the land with whatever weapon came uppermost.
Mr. Binney maintained the re^Jutation he had gained at the bar in the
VOL. XI. (n. s. III.) 23

354 HOEACE BESraTEY.

new fit-Id of parliamentary debate ; but he only appeared in it on
great occasions, to the height of which he always rose. The removal
of the deposits of the Treasury from the United States Bank by
General Jackson, in open defiance of law, and the threatening state
of our relations with France, caused by the passionate violence of
language of that headstrong magistrate, were the chief subjects which
called forth Mr. Binney's eloquent resistance. At the adjournment
of that Congress he retired from the j^olitical arena, determined never
to enter it again.

From Washington he returned to the practice of his profession, in
which he continued actively engaged for about ten years longer.
Then he withdrew from the conflicts of the bar; but for several years
longer acted as Chamber Counsel, and gave opinions in cases of legal
difficulty, which were not unseldom accepted as final judgments by
the parties in interest. His last appearance at the bar was when
the attempt was made in 1844 to invalidate the will of Stephen Girard,
as an attack upon Christianity. Mr. Binney was matched against Mr.
Webster, who brought all the power of his thunderous eloquence to
defend the Christian religion against this assault of the French infidel
banker. Mr. Binney confined himself to a lucid exposition of the law
of charitable bequests and its application to this case. The Supreme
Court of the United States unanimously went with the lawyer and not
with the orator, and maintained the validity of the will. It was a fitting
occasion for the last words in court of a great lawyer. But, though Mr.
Binney kept himself thus free from entanglement with politics, and
gave himself with this entire dedication to the law, it was not because
he did not take a deep interest in political questions. He always gave
the weight of his private and personal influence on the side he deemed
the right one. His academic and professional education falling in the
midst of tlie excitements of the French Revolution, and at the time of
the birth of the political parties which sprung from that tremendous
event, Mr. Binney began life as a Jeffersonian Democrat. His guardian,
Dr. David Jackson, in whose family he lived, was one of the strong-
est opponents of the administration of Washington ; and every
domestic influence must have been on that side. But when he
began to examine opinions and practices for himself, as his mind
developed itself, he joined the Federal party from convictiou of the
truth of its principles and the purity of its purposes ; and he remained
faithful to it through evil report and good report, as long as it had
a name to live. When the war of the Rebellion broke out, Mr.
Binney, though more than eighty years of age, stood by the Union

HORACE BTNNEY. 355

with the enerfry ami dovotion of the yomijLjost patriot. He sustiiiiicd
the action of PresitU'iit Liiicohi in its most stringent niunil'estations,
though not without quahtications and remonstrance, after the worst of
the danger was over, against the possible abuses of extraordinary
powers. When Mr. Lincohi suspended the privik'ge of the writ of
/labeas corpus, by proelaination, without the consent of Congress, —
action which e.xcited general doubt and widespread opposition, — Mr.
Binney came to the rescue, and sustained the action of the President
in three pamphh^ts. of which Judge iStrong says that " they will never
cease to be regarded as models of acute reasoning apiilied to Consti-
tutional law."

From the accounts given of it by those accustomed to hear him in
court, Mr. Biuney's forensic delivery was of the highest, because of
the most fitting, description. Without aiming at flights of oratory, his
speech was always exactly adapted to the needs of the trial. Though
forcible and energetic, vehement even on occasion, his style was
generally the calm, unimpassioned expression of the logic of the facts
and the pure reason of the law of the case. Fluent without haste,
deliberate \vithout hesitation, exact in apprehension, and accurate in
expression, never missing or mistaking a word, his sentences fell on
the ear of judge or jury with beautiful completeness, and kept the
attention awake by the grace of their style as well as by the distinct-
ness of their meaning. His published writings, though too few, are
marked by the same clearness, force, and elegance of style that
distinguished his speech. His discourses on the Lives and Characters
of Chief Justice Tilghman, of Pennsylvania, and of Chief Justice
Marshall, of the United States, are models of that most ditlicult
branch of oratory which deals with the characteristics of the dead.
The delicacy of touch, the accuracy of discrimination, the nicety of
analysis, the distinctness of characterization, with which he places the
eminent qualities of those great magistrates before the mind of the
reader, the whole warm with personal affection and radiant with
generous admiration, show to what distinction he might have risen in
literature, had he given himself to its pursuit.

In 1850, at the age of seventy, Mr. Binney retired absolutely to
private life, and addressed himself to the vocation — so difficult to
the most of men, so beautiful when it is well discharged — of growing
old gracefully. How perfectly and how beautifully he did this, all
can say who have ever had the happiness of seeing the handsome old
man, his white locks crowned with the black velvet skull-cap he
usually wore, in his delightful home, and of enjoying the pleasure of

356 HORACE BINNEY.

his affluent talk, set off and enhanced by the charm of his majestic
presence. The society of Mr. Binney had none of the drawbacks,
from some of which extreme old age is rarely exempt. Besides
having the perfect possession of his memory, and the same command
of language as in his prime of life, he was in the full enjoyment of all
the special senses. Though the weight of more than ninety years had
abated his natural force, yet was his eye not dim, and it was a faithful
and untiring servant to the end. And what is even more rare in the
very old, his hearing was as perfect at ninety as at nineteen. There
was, therefore, in his case, hone of the painful consciousness of effort
on the part of speaker and of hearer, which generally lessens the
pleasure of conversing even with the most interesting and intelligent
of old men. Indeed, one forgot, in talking with him, that he was an
old fiian, as there was nothing in the manner or the matter of his
conversation to remind one of it. Like most good talkers, he was a
delightful letter-writer ; a good letter being, indeed, only good talk
flowing from the pen instead of the tongue. His interest in all the
events of the day, in literature, and in the law, remained warm to the
last. And his love for his Alma Mater, whose eldest son by several
years he lived to be, did not wax cold with age. When the great
Boston fire had seriously impaired the property of the University, at
the first appeal of President Eliot, he instantly sent a thousand dollars
for the relief of the nursing mother of his mind.

The life of ]Mr. Binney was certainly one of a felicity rarely
equalled. Though his many days were not unclouded by great
sorrows, his strength was made equal to the darkest of them by
occupation, by reason, and by religion. It was a life singularly
rounded and complete. Twenty-five years given to preparation for
his life's work ; fifty years of active devotion to it ; a crowning quarter
of a century of honorable and honored repose, — make up a sum of
happiness such as has fallen to the lot of few mortals to enjoy. He
passed his active years in doing well what he liked best to do. His
declining years had every blessing that filial affection, devoted friend-
ship, and general reverence could bring to smooth and adorn them.
Witliont having aspired to or won high oifice, he enjoyed a great
reputation coextensive with the country. And lie died in the fulness
of near a century of years, universally honored and revered as the
patriarch of the American bar, and the foremost citizen, not of his
State only, but of the nation.

sill WILLIAM EDMOND LOGAN. 357

SIR WILLIAM EDMOND LOGAN.

Siu "Wii.LiA^i En^ioxn Lo(jan, Knii^lit, was born in ^Montreal,
Canada, in 171)<S. and died at Castle Mali^wyn, LIcclnyd, in Soiilli
"Wales, June 22, 187;"). Like so many others who ha\e attainc(l dis-
tinction in liritish North America, Logan was descended from a loy-
alist stock, one of those families who, adhering to the British crown,
left the revolted colonies a liundred years since. His grandfather
then removed from the neighborhood of Schenectady, N.Y., to Mon-
treal, carr3ing with liim two sons, one of whom was the father of our
late associate. They were of Scottish origin ; and when the father and
uncle of Mr. Logan had gained wealth in commercial pursuits, and
transferred their business as merchants and bankers to Gi'eat Britain,
the former purchased a small estate near Stirling in Scotland, a cir-
cumstance which has led one of his English biographers into the error
of speaking of Mr. Logan as a Scotchman. His education, begun in
Montreal, was continued at the High School and the University of
Edinburgh ; but we find him already at the age of twenty in the count-
ing-house of his uncle in London, where he remained for ten years,
devoting much of his leisure to the study of natural history, as well as
to music and painting, in both of which he was a successful amateur.
In 182t), his uncle having acquired an interest in a copf)er-smelting
establishment, with some coal lands at Swansea, in South Wales,
Logan removed there to assume their direction, where he remained for
nine years, becoming a successful copper-smelter and coal-miner. The
study of the coal-field of the neighborhood here engaged his attention,
and he made of it a very careful and minute map, which was presented
by him to the British Association in 1837. When, later, the geologi-
cal survey of Great Britain under De la Beche was extended to this
region, the work of Logan was placed at the disposal of the govern-
ment, and, its exactness having been verified, was adopted and pub-
lished by the survey. In the course of these labors, he made careful
studies as to the relations of the stigmariie constantly found in the
clays which immediately underlie the coal-beds, and in 184U brought
this matter before the Geological Society of London, announcing the
conclusion that the stigmariae belonged to the plants which had fur-
nished at least a large part of the coal. It was afterwards shown that
other observers had already indicated a similar relation, and that
Mammatt, from his studies of the coal-field of Ashby-de-la-Zouche,
had in 1836 maintained that the coal was the product of a vegetation
in situ, rooted in the under-clay. To Logan is, however, due the

358 Sm WILLIA]\I EDMOXD LOGAX.

credit of careful and original observations on the subject, which he sub-
sequently extended to the coal-fields of Nova Scotia and Pennsj-lvauia,
which were visited by him in 1841. In 1842, he was offered the
direction of a geological survey of Canada, which he accepted, begin-
ning his work in the spring of 1843, with the aid of Mr. Alexander
INIurray, now director of the geological survey of Newfoundland. It
was nut till four years later that he was joined by Dr. T. Sterry
Hunt. The labors of Logan for 1843 and 1844 were directed to the
coal basin of Nova Scotia and New Brunswick and to the paleozoic
formations of the adjacent peninsula of Gaspe, and included his study
of the now fiimous section of the Joggins at the head of the Bay of
Fundy, where over 14,000 feet of coal measures, hicluding seventy-six
coal seams, are displayed in unbroken sequence. In 1845, his atten-
tion was turned to the more ancient rocks which appear on the
Ottawa River and its tributaries; and in 1846 he made with Mr.
Murray a preliminary survey of the geology of the north shore of
Lake Superior.

It is with the ancient crystalline rocks that his name will be chiefly
associated, and especially with the formations since called Laurentiau
and Huronian ; and it may be well in this connection to state briefly
the results of their examination by the Canadian survey, wliich now
belong to the history of geological science. The gneissic character of
the crystalline rocks which were known to underlie the paleozoic for-
mations in northern New York and Canada had long been recognized;
but the prevalent view with regard to such gneissic rocks, both there
and elsewhere, was that expressed by Emmons, who had carefully
studied them in the first-named region, that they were igneous or
fire-formed rocks, the laminated structure of which is not due to
the intervention of water. He maintained that they were in no sense
of sedimentary origin, and included no sedimentary layers, a view to
which some recent writers still incline. In the first year of the
Canadian survey, however, Mr. Murray (in his report published in
1844), having studied these rocks to the north of Lake Ontario, de-
clared that these granites and gneisses (the extension of those of the
Adirondacks) "present evidences of stratification," and were therefore
to be regarded not as primary, but rather as " met^unorphic " rocks ; a
term which had been proposed l)y Lyell to designate crystalline sedi-
mentary strata. In the subsequent i-eport of Logan, who examined
the same rocks on the Ottawa in 1845, and puldished his report in
1847, they were again described as " metamdrphic rocks, .... ap-
])ariiitly of sedimentary origin, chiefly syeuitic gneiss with crystalline

I

SIR WILLI A>[ i:i»M(»ND LOGAN". 359

linu'stones," which were said to be disliiictly iiiterlietldtMl. Kesiing
upon tliese on Lake Tomiscaining, Loi^au described in the same
report a newer series, cliieHy of eldorifie shites holdinjf pebbk^s of the
underlying gneiss; and in his report of his examination of Lake Supe-
rior in 1(S45 (also published in 1847), these two seiies were distinctly
indicated as a lower formation of granitic gneiss, often syenitic, and an
ui)per one of micaceous, chloritic. and talcose slates, freijnently with
epidote, associated with hornblendic rocks and greenstones, (piartzites,
and conglomerates including pebbles of the older rocks ; this up[)er
series being probably several thonsand feet in thickness.

Li their report for 1851 on the geology of Lake Superior, Messrs.
Foster and Whitney also described these crystalline rocks, including
the two divisions, as the Azoic system, which they recognized as of
sedimentary origin. The fiirther studies of the Canadian survey
established the importance of the two divisions, and the necessity of
separate designations for them; and in Logan's report for 1853 (pub-
lished in 1854) the name of the Laurentian series was given to the
lower formation, which forms the chief part of the elevated region to
the north-west of the St. Lawrence to which the title of the Laurentide
Mountains had been previously assigned. The name of Laurentian has
since been adopted for the similar rocks of Continental Europe and
of the British Isles. In 1855, the designation of Huronian was given
by the Canadian survey to the upper division, including the series
characterized by greenstones and talcose and chloritic schists which is
largely developed on the sliores of Lakes Huron and Superior (where
it had been carefully studied and mapped by Mr. Alexander Mui-ray),
and constitutes tlie Huron Mountains to the south of the latter lake.

The subsequent labors of Logan on the Ottawa established clearly
the regularly stratified character of the Laurentian series, of which he
measured about 20,000 feet, consisting of four gneiss formations sepa-
rated by three limestones, each of the latter having a thickness of
from 1,000 to 1,500 feet, and associated with quartzites ; the whole con-
stituting a series comparable in value to the entire lower Paleozoic.
These strata, greatly affected by undulations and penetrated by eruptive
rocks, were by Logan traced with infinite labor over an area of 2,000
square miles ; and a geological map of this region, published by him in
the Atlas to the Geology of Canada in 1863. is the first attempt to un-
ravel the stratigraphy of this most ancient and disturbed series of rocks.

At the summit of this series. was found a mass of about 10,000 feet
of stratified crystalline rocks, which, unlike those below, consisted
chiefly of labradorite and hypersthene rocks, with some little included

360 Sm WILLIA3I EDMOXD LOGAX.

gneiss and quartzite and a band of crystalline limestone. This series
Logan subsequently showed to be unconformable to the older gneisses,
and gave it the name of Upper Laurentian, subsequently exchanged
fur that of Labradovian or Norian.

Indirect evidence that these lowest rocks were not really Azoic was
soon pointed out, and in 1858 obscure forms resembling those of
Stromatopora were detected in the Laurentian limestones, and were
exhibited by Logan to the American Association for the Advancement
of Science, in 1859, as probably organic; but it was not till 18C4 that
Daw'son announced that these and other similar forms were the remains
of a gigantic rhizopod, to which he gave the name of Eozoon Cana-
dense. The history of this curious form is well known, and its organic
nature, though at one time much contested, is now disputed by few.

To Logan we owe a large part in the investigations of the Canadian
Survey which have established the following great facts in the geology
of the Azoic or, as they may henceforth be called, the Eozoic rocks : —

I. The relations of the Laurentian as a great stratified series of
crystalline rocks of aqueous origin, occupying a position at the base of
the known geological column and containing evidences of organic life.

II. The fact of the unconformable superposition to the Laurentian
of tlie Upper Laurentian or Norian series.

II L The firt^t recognition that unconformably overlying the Lauren-
tian was still another series of crystalline stratified rocks, the Iluro-
nian. (The relative ages of the Norian and Huronian still remain
undetermined, for the reason that they have never yet certainly been
found in juxtaposition.)

IV. The fact that the Laurentian, Norian, and Huronian, are all of
them unconformably overlaid by the lower members of the New York
Paleozoic series.

His labors on the Laurentian rocks w-ere continued at intervals up
to 18G7, and were performed with an amount of fatigue and sacrifice
of personal comfort which can only be understood by those who have
had to traverse these rugged forest regions. He often wandered for
days through a wilderness, with a prismatic conijiass in hand, counting
his paces, and gathering rock-specimens as he went. His notes, made
in pencil, were always written out each night in ink, and the journey-
ings of the day protracted, often by the light of the camp-fire.

In the iutervals of these investigations, Logan was devoting his
attention to another region of crystalline rocks, the extension of the
Green Mountains of Vermont through eastern Canada to a point a
little south-east of Quebec, the study of which he began in 1847.

SIR WILLIAM EDMOND LOGAN. 3G1

The j)revious attemi)ts to estiihlisli a })anilluli.sui between the geoh>gi-
cal succession in eastern New York and western New England had
led most American geologists to supposi^ that the crystalline schists of
the latter region were the stratigraphical ecjiiivalents of the lower
members of the New York Paleozoic series in an altered coiiditi(jn ;
thongh there were not wanting those who, with Ennnons, regarded
these crystalline strata as a part of the primary or so-called Azoic series.
Logan, who began, as was his custom, to work out the stratigraphy of
these rocks in minute detail, accejtted the views of the majority on
this disputed question, and endeavored to establish a parallelism be-
tween the subdivisions of these crystalline strata of the Green Moun-
tains and their prolongation into Canada, and the uncrystalline fossili-
ferous sti-ata which are found everywhere along their north-western
base from the valley of Lake Champlain. These, the so-called Upper
Taconic of Emmons, he at first looked upon as newer than the Tren-
ton limestone, but, yielding to the evidence of organic remains, assigned
them at length to their true position immediately below the horizon of
this limestone, and named them the Quebec group. That these un-
crystalline strata were really newer rocks than the adjacent crystal-
lines (of which they include fragments), Logan was unwilling to admit,
and spent many years in an unsuccessful attempt to establish a corre-
spondence between the two series. That these latter rocks, called by
him the *' altered Quebec group," belong to the same Huroniau series
which he was the first to distinguish farther to the westward as of pre-
jjaleozoic age, will now be questioned by none who have compared the
two regions.

The record of Logan's later life is little else than that of his patient
and unwearying devotion to the work of the geological survey of Canada,
of which he remained the director for twenty-five years. In 1863, he
prepared and published, with the aid of Professor James Hall, a
geological map of northeastern America, including the region north to
James's Bay, south to Virginia, and west to Nebraska. This map, on
a scale of twenty-five miles to the inch, remains the most complete
attempt to delineate the geology of the region. Ilis other published
works are confined to the reports of the geological survey, and a few
papers to scientific societies on kindred subjects. He- had little aptitude
for literary labor, and found the work of composition difficult. He
rendered good sei'vice to science and to his native country at the inter-
national exhibitions of 1851 and 1855, being a juror at the first, and a
commissioner at the second. On the latter occasion he was knighted
by the Queen, and by the Emperor Napoleon made a chevalier ot the

362 WILLIA3I SWEETSEE,.

Legion of Honor, in which order he was subsequently raised to the
rank of officer. He was a Fellow of the Royal Society of London, of
the Imperial Leojjoldo-Carolinian Academy of Germany, and of many
other scientific societies. In the year 1857, he was president of the
American Association for the Advancement of Science.

In 1869, his advancing years and failing health, together with the
necessity of devoting more time to his large estate, led him to resign
his position as director of the geological survey, though he still con-
tinued to spend a portion of his summer in geological exploration,
much of which was in the western parts of Vermont and Massachu-
setts. The incompleted results of these last few years, however,
remain unpublished. He left his home in Montreal in August, 1874,
to spend the autumn and winter in Great Britain, intending to re-
turn to his geological labors in the spring ; but, his bodily ailments
increasing, he died and was buried at the home of his sister in AVales.

Sir AVilliam Logan was unmarried, and, though genial and kindly in
his social relations, led a solitary and very retired life. His work in
science was neither that of a paleontologist, a lithologist, or a miner-
alogist ; in all of which departments he was, throughout his career,
ably seconded by the labors of James Hall, Sterry Hunt, Dawson, and
Bilhngs. His great merit was the jiossession of a rare skill in strati-
graphy, and an amount of patience, industry, and devotion to his work,
which lias rarely been equalled, and has enabled him to connect his
name imperisliably with the geology of the older rocks.

WILLIAM SWEETSEE.

William Sweetser, son of William and Elizabeth (Bennison)
Sweetser, was born in Boston, September 8, 1797. He was fitted for
college under the tuition of Rev. Mr. Frothingham, then of Saugus,
afterward of Belfast, Me. He entered Harvard College in 1811,
was graduated in 1815, and received his medical degree in 1818. He
then settled at Sherburne, Mass., where he came at once into an
extensive country practice, and won the entire confidence and high
regard of the community.

He received the Boylston prize in 1820, for a dissertation on
" Cynanche Trachealis, or Croup;" and again, in 1823, for one on
"The Functions of the Extreme Capillary Vessels in Health and
Disease." He subsequently, in 1829, received a premium offered by
the Massachusetts Medical Society, for the best dissertation on " In-
temperance."

GABRIEL ANDRAL. 303

In 1S2 I, he returned to liis native city, and remained there till his
removal to New York, about tliirty years ago.

His serviees as a teac^lier were so early and so fully retjuiri'd, that,
on leaving Sherburne, he virtually relin(iuished the regular praelieo
of his profession. On the strength of his reputation in the Medical
School, as a student of rare merit and promise, he was, in 181'J, chosen
l*rofessor of the Theory and Practice of Medicine, in the Uiuversity
of \'ermont. In 1845, he was elected to a similar Professorsliip in
Bowdoin College. He subsequently held professorships in Geneva
College, and in the Medical School at Castleton, Vt., and for two
years was a lecturer at Jefferson Medical College in Philadelphia.
During the prime of life, he arranged his courses of lectures at these
different institutions, so as to hold several professorships at the same
time ; but with increasing years he resigned them successively, and
closed his public career by a last course of lectures at Bowdoin Col-
lege in 18G1.

The remainder of his life was passed in retirement with a devotion
to his private studies and to general literature, which yielded only
and late to growing bodily infirmity. He died on the 14th of October,
1875.

Dr. Sweetser's professional and scientific reputation was high, and
it was thoroughly genuine. He had no extraneous attractions of per-
son, address, or elocution ; and his modesty never suffered him to push
his own claims, or to seek recognition for his own merits. Whatever
fame he had was won by native ability, deep thought, hard study, and
faithful service. In private life, he was a man of amiable disposition,
pure and high principle, and blameless character, most respected and
loved by those who knew him best.

His published works, besides the dissertations already referred to,
and numerous addresses, and other occasional pamphlets, are as fol-
lows : —

Treatise on Consumption, 1833 ; Treatise on Digestion and its
Disorders, 1837 ; Mental Hygiene, 1843 ; Human Life, 18G7.

GABRIEL ANDRAL.

Gabriel Axdral, the son of a prominent physician, was born in
Paris, November G, 1797, and died in that city, February 13, 187G,
in the seventy-ninth year of his age.

Audral studied medic-ine at the college of Louis le Grand, and took
his medical degree in 1821. He gained a sub-professorship, by com-

364 GABRIEL AXDEAL.

petition, in 1823. He was chosen Professor of Hygiene in 1828,
and the same year was appointed one of the physicians of the Hos-
pital La Pitie. He was promoted to the chair of Internal Pathol-
ogy in 1836, and to that of General Pathology and Therapeutics, the
highest in rank, in 1839. He was elected to the Academy of Medicine
in 1823, and to the Academy of Sciences in 1843.

Thus, early taking prominent positions, he rose progressively to the
highest eminence as practitioner, author, and teachei", and became a
ruling influence in the exciting movements and bustling progress of
medical science in his day.

As a practitioner he was abundantly successful, numbering among
his clients the highest and noblest in the land. He was courteous in
manner, and considerate in manipulation. His prudence in experi-
mentation, and his little reliance upon drugs as remedies, less supersti-
tious certainly than that of some of his associates, led occasionally to
the ungracious remark that he was more interested in pathological
verifications than in therapeutic success. Nevertheless, he was noted
for great accuracy in diagnosis, and for eminently judicious treatment
of the sick.

The most considerable of his publications, the first volume of which
was published in 1823, only two years after his graduation, was his
Clinique Medicale, which reached its third edition in five volumes in
1834. This work of years, still much consulted, is distinguished for
good faith in researches, ardent regard for truth, opposition to hypo-
thesis, and a philosophic spirit. In 1829, he began his Precis d'Ana-
tomie Pathologique, which, in its three parts, ultimately formed two
volumes. This was an attempt to trace out more thoroughly the laws
connecting morbid appearances found after death with the symptoms
manifested by disease during life. With more comprehensive views
than his contemporaries, then leaning too much to solidisin, he showed
this to be one, but only one, of the important methods for establishing
in full the science of the sick man. In the same spirit, in connection
with Gavarret and Delaford, he instituted observations on the blood,
in health and disease, and published the results in 1843, in a treatise
entitled Essai d Hematoloijie Palliulocjiqiie.

As a teacher he was unrivalled. By his originality, good judgment,
Bound learning, and brilliant s|ieech, he compelled the interested atten-
tion of the most indifferent student, as that of the ablest scientists who
crowded his amphitheatre. Honest and earnest, he gained the con-
fidence of all by the remarkably clear statements of what he himself
implicitly believed. Some idea, however inadequate, of the substance

I

MARCHESE GINO CAPPOXI. SG')

and spirit of these leetures, may l»e ohtaiucd from ;i very faithful aiul
appreciative report of a portion of them published by Latoiir in threo
vohnnes in 1836, under the title of Cunrs de Putholoffie Interne.

At the height of his fame, Andral was without question the grandest
professor in the Faculty at Paris, then the most renowned in the
workl.

Andral married the daughter of the celebrated Royer-Collard, by
whom he had one son, Charles Guillaume Paul Andral, born June 13,
1828, now Vice-President of the Council of State, and an eminent
member of the French bar. In ISGG, his wife becoming ill of a pain-
ful and incurable disease, Andral gave up his extensive practice, his
professorship, and high scientitic positions, and retired while in the
full possession of his physical and mental powers to Chateauvieux, her
family country-seat, there to devote himself entirely to her necessities
and comfort, — a self-sacrifice worthy and characteristic of his affec-
tionate nature, and well-known goodness of heart.

A few months after the death of his wife, Andral came up to Paris,
temporarily, to revisit the scenes of his former labors and triumphs.
In the chilly court of the Institute, he was seized with bronchitis, which
in a few days terminated his life. Thus he died, as he had always
wished, in his native city.

His obsequies were attended by distinguished statesmen, deputations
from the Institute, the Medical Faculty, and the Academies, a military
body-guard from the Legion of Honor (in which he was a Commander),
and a host of eminent associates and friends, who, to the number of
more than a thousand, in spite of a furious storm, overcrowded the
church of St. Pierre-de-Chaillot, in their earnest desire to pay him the
last tributes of affection and respect.

THE MAECHESE GINO CAPPONI.

On the 5th of February, of the present year, Florence put on
mourning for her illustrious son, Gino Cap])oni. Clothed in the simple
dress of a " Brother of Mercy," his body lay for several hours of that
day exposed to public view in a hall on the ground floor of the palace
of his family, and was thence followed to its last resting-place by min-
isters, magistrates, senators, deputies, and persons specially deputed
to represent the most eminent literary and artistic bodies of the
States. The telegraph brought messages of condolence to the Syndic

366 MABCHESE GINO CAPPONI.

of Florence from his brother syndics of other Italian cities, and the
King at Rome wrote to the Marchese Farinola : —

" I feel the most lively grief at the very bitter loss which Italy has
suffered this day in the death of Gino Capponi. I share fully in the
mourning of his family and of the country.

" Victor Emmanuel."

The honors then paid by men of all ranks and parties to '* I'ottimo
nostro Gino Capponi," as the Florentines loved to call hiui, were his
due. Last scion of an illustrious house, he was himself illustrious for
his virtues and his unselfish patriotism. Like his ancestors, many of
whom had taken part in public affairs, he always stood on the side of
liberty and progress, feeling that nobility of race is only respectable
and respected in its possessor, when he recognizes that it obliges him
to make use of the prerogatives which belong to it for the common
advancement of all good and noble ol)jects. Eminent as a wise and
far-sighted patriot, who knew how to act and speak at the right mo-
ment, as well as to stand firm and be silent when deeds and words
would have retarded rather than advanced the cause which he had at
heart, being in short a wide-minded conservative and a genuine Re-
publican, but in no sense a radical or an agitator, Gino Capponi passed
hopefully through the dark days which were Italy's portion from 1815
to 1848, kept a firm hand on the helm during the crisis which fol-
lowed, and lived to see the increasing brightness of the new day which
has now fully dawned upon his beloved country. But not only was
he a true patriot, and as such beloved by all who had the good of Italy
at heart, he was also the friend and protector of such eminently patri-
otic writers as Nicolini, Giusti, Gioberti, Balbo, and Leopardi, whose
pens were as sharp swords ever directed against the breasts of those
who sought to make the world believe that Italy was a land of the
dead ; a land having a glorious Past, whose echoes they would fain have
silenced, but which now contained nought but "spectres and mum-
mies." Li " La Terra dei Morti," a poem which Giuseppe Giusti, the
Tuscan satirist, dedicated to his friend Gino Capponi, he thus bitterly
designates his fellow-countrymen, crushed under Austrian rule, and
with words which sting cries out to them : " "What do a dead people
care for history? to you skeletons, what importeth to talk of liberty
and glory?" That the heart of Gino Capponi fully sympatliized in
the poet's emotion is proved by the dedication of this burning page to
him ; and that the poet counted on his affection is shown in a poem,

MARCHESE GINO CAIM'OXT. 807

written years afterwards, wlieii the dark cloud liad passed awav and
bettor days had eonie to Italy. '' Since the (hivs of I'ctrarcii," lie,
writes in the letter pretixed to it, " tlie poetic law has been recognized
that the public is the proper conddaiit of the rhymer's affections. No
one who knows that you are the only one to whom 1 have recourse in
all which [)asses between myself and me (• tru me e me '), will wonder at
this public confession which I send you ; and to those who do not know
it, I have wished to say in verse what bonds unite us." Tlu^se bonds,
be it said, were never severed until the 31st of IMarch, 1H50, when
Giusti, who had for months been the guest of his illustrious friend, ex-
pired at the Palazzo Capponi, and was thence carried to his grave in
the church of San Miniato. Himself an author of no mean repute, the
sympathies of men of letters centred round Gino Capponi. They had
none of that jealousy of him, which too often divides the craft, but for
half a century were in the habit of looking up to him as "a perma-
nent minister of literature." In him they found a wise adviser and an
influential friend, sympathetic, kind, hospitable, and generous. A short
abstract of the chief events of his life founded on Count Passerini's
biographical notice in Litta's Famiglie Celebri, as published in " La
Nazione," will ^uifice to show how nobly he filled the triple role of
patriot, patron, and friend.

Son of the Marchese Pier Roberto and the Marchesa Maria INIad-
daleua Frescobaldi, Gino Alessandro Giuseppe Gasparo Capponi was
born at Florence, on the 14th of September, 1792. At the age of
seven, when the Grand Duke Ferdinand HI. was driven out of Tus-
cany by the invading French, he left his native city with his parents ;
and during four years of exile, as also after his returA home, pursued his
studies under the best masters until 1813, when he was sent to France
as one of a deputation charged to offer aid and assistance from the City
of Florence to the Emperor Napoleon, whose power and prestige had
received a rude shock in the Russian cam|)aign and by the disastrous
battle of Leipsic. In recognition of his services on this important
mission, he was appointed Chamberlain to the Grand Duke, an otfice
which did not prevent him from visiting France, Germany, and Eng-
land, for the purpose of completing his education, and of gaining that
valuable experience of men and things, which he was to turn to good
account in after life. On his return to Italy, he immediately assumed
the position to which his birth, his talents, and his virtues entitled
him. Every good enterprise found in him a ready helper ; and through
the interest which he took in the opening of schools, savings banks,
and infant asylums, he did much to advance the cause of morality and

368 IMAKCHESE GIXO CAPPOXI.

civilization among his countrymen. Regarding the press as a most
vahiable agency to this end, his pen was never idle. He was one of
the founders of the " Antologia," a paper which he enriched with
many valuable articles ; as also of the " Archivio Storico Italiano," a
periodical filled with Italian chronicles and documents of tlie greatest
historical interest. Ilif^tory had great attractions for him, and his
private library contained many valuable manuscripts and rare books,
of which he himself compiled and published a catalogue. The volume
of historical documents, which he published in 1838, and " Le Istorie
di Giovanni Cavalcanti," which followed it two years later, together
with many numerous and important newspaper articles, gave him a
litei'ary reputation which was acknowledged, not only by the four
learned societies of Florence, the Crusca, the Georgofili, the Ateneo,
and the Colombaria, but also by the most celebrated Transalpine
Academies, all of which desired to enroll him among their members.
To one not cognizant of the condition of Italy, during the years wliich
began at Campo Formio and ended at Novara, it is difficult to realize
the tact, prudence, and discretion required of a man who, like the
Marchese Gino Capponi, had the best interests of Italy at heart, and
desired to serve them. To be a liberal, and the friend of liberals, was
to be an object of suspicion ; and although the position of Tuscany was
then far better than that of Lombardy, the Roman States, or the
Kingdom of Naples, it was a task of no small difficulty to aid in steer-
ing the ship of reform through the nundierless shoals and quii-ksands
which beset her path, without running her aground and aggravating
the dangers of her position. The great object in view was to form
a national resolve that liberty should be achieved, and to strengthen
the national character, so that, when that result was brought about,
it should not degenerate into license. Like Napoleon III., who was
always on the eve of " crowning the edifice," to use his favorite ex-
pression, the Grand Duke was wont to dangle projects of reform
before the eyes of his subjects. His government professed to be lib-
eral, and proposed to institute advanced reforms in the State ; but it
wished to take its own time, and did not care to have the task taken
out of its hand by spirits impatient of a long delayed result. Thus it
happened that, when Gino Capponi and his friends asked to be allowed
to print a journal which was intended to direct public opinion in the
right direction, permission was refused by the Minister, on the ground
that the government desired to be itself the initiator of even greater
reforms than those which they projected. The pressure of outside
events at last became so great, that, late in the year 1847, Capponi

I

MARCHESE C.INO CAPrONI. 369

was imitotl by tlio (Jniiid Duke to I'oiin one of a coinniith'f* <liaii:;( d
to propose a form of reprcsi'iitative jfovornmciit suitid to the iifcils of
Tusrauy. This Coniinisfsioii iiislitiMrd a Council of Statu, in wiiicli
C'appoiii. wlio was eU'ctcd Senator, was called upon to take a seat; and
wlun, after the events of 184<S, a new ministry was to l)(3 (•onstituteil,
he was charged to form it, and to become its President. Dui-ing the
short time that he retained this olHce, he gave proof of his great ability
and judgment. The acts of his government were directed towards the
founding of liberal institutions, the furthering of the war of independ-
ence, and the confederation of the Italian princes, that they mi'dit
represent Italian nationality as a principle and an accomplished fact.
Events impossible to control, jealousies not to be appeased, and the
increased strength of those who would not be content with such a
measure of law-abiding liberty as the Capponi ministry favored,
brought about its downfall after a few months ; but, if it did not reap
the laurels of success, it carried with it in defeat the respect of honest
men, who recognized that it had striven to conciliate liberty and order,
and to keep down those disorderly elements which now got the upper
hand and threatened to shipwreck both. In the provisional govern-
ment, which was constituted in P^ebruary, 1848, after the flight of the
Grand Duke, Capponi took no part, feeling that the wisest course was
to bide his time. This came m 1849, when constitutional government
was restored by the people and the Priors of the Commune, who, on
assuming the reins of government, called Capponi, with other distin-
guished citizens, to assist them in their difHcult task. One month
later the Commission resigned its powers into the hands of the Count
Luigi Serristori, who had been nominated by the Grand Duke as his
commissioner with full powers, and Capponi then retired into private
life. He continued however, to use his influence with the govern-
ment to satisfy the legitimate demands of the people ; and, had his
advice been listened to, the resolution of April, 1850, which put an
end to the rule of the Austro-Lorraiue dynasty in Tuscany for ever,
might have been averted or delayed. Although Capponi was one of
those who had noui'ished the vain belief that the government of the
Grand Duke could be brought into harmony with the aspirations of
the country, and therefore may be classed with those who are popu-
larly known as " Codini," he frankly accepted the situation ; and, being
above all things anxious to bring about that state of affairs most favor-
able to the unity of Italy, he took his seat in the Tuscan Assembly,
and with his colleagues voted the perpetual exclusion of the Austro-
Lorraine family from power, and that union of Tuscany to the Sub-
voL. XI. (x. s. III.) 24

870 CHAKLES-FEAirgOIS-MAIlIE, COMTE DE EEMUSAT.

alpine kingdom, which was soon after consummated by the never-to-
be-forgotten entrance of King Victor Emmanuel into Florence. He
could not see, as others did, those streets strewn with flowers, those
houses draped with banners and tapestries, that King of a United
Italy, who, riding on a white charger, came with an endless crowd of
willing subjects, to add one more jewel to his crown ; for since 18-44 he
had been blind. But his ears were open to the sounds of rejoicing,
and no heart of all those which swelled with emotion on that day to
think that Italy was no longer " a geographical expression," but a
country one and indivisible, beat more loyally than his, or responded
more warmly to the calls of that memorable occasion. "With it his
connection with political events ceased. During the remainder of his
life, he occupied himself with literary labors, and by the publication of
his " History of the Florentine Republic," a year before his death,
brought them to a noble termination. For many years, as he says in
his preface to this work, it had from time to time engaged his atten-
tion, but owing to frequent interruptions it was not completed until
its author had attained the age of eighty. With what conscientious-
ness he labored to make it a faithful record of events, and why he did
so, he himself tells us in this same preface, in these simple words :
" Once that I had undertaken it, it seemed to me to be the duty of an
lionest man to labor at it with the utmost diligence, and to give it my
best thoughts, because a history carelessly written is often a false his-
tory, or, in other words, a lie. Wherefore, for all the shortcomings of
this book, I have no other excuse to offer to the reader but this very
plausible one, that I was unable to make it better than it is."

CHARLES-FRANg^OIS-MAEIE, COMTE DE E^MUSAT.

Charles-Fran(;ois-Marie, Comte de Kemusat, died on the 6th
of June, 1875. lie was born on the 14th of INIarch, 1797, and had thus
noai'ly readied his seventy-eighth year. He was the son of Count de
licmusat, a chaml>erlain of the first Napoleon, who married a niece
of the Count de Vergeniies, an intimate friend of the Empress Jose-
phine. Some of his early years were thus passed at St. Cloud, where
his father was Prcfet of the Palace. He was educated at the Lycee
Napoleon, and was there distinguished for his scholarship. He began
early to write in the journals and periodicals, and always on the
liberal side. In 1830, he took bold ground, with 31. 'J'liiers, against
the ordinances of M. Poliguac, which cost Charles X. his throne.

I

CHAIILES-FRAN9OIS-MAIUI:, COMTE DE r6mUSAT. 371

lie luul just before luiinied, for his second wife (llie lirst having
survived her marriage only two years), Mile, de Lasteyrie, the
graiid(hiui,diter of the cele])rated Manpiis (hi Lafayette. He was an
aide-de-eani[) of l-,afayette at this period, when the marquis was com-
mander-in-chief of the National Guard. He soon entered the Ciiara-
ber of Deputies, was in the conlidential cabinet service of M. Casimir
Perier, and afterwards Minister of the Interior. As writer, deputy,
and minister, he uuiforiuly espoused and advocated liberal opinions
and measures. He protested against the coup d'etat of Napoleon III.
in 1801, and was imprisoned and afterwards exiled.

He had been made a member of the Academy of Moral and Politi-
cal Sciences in 1842, and one of the forty members of the French
Academy in 1846. His exemption from political service during the
Second Empire gave him the desired opportunity to pursue his philo-
sophical and literary studies. Pie had published two volumes of Philo-
sophical Essays, in 1842; two volumes on Abelard, in 184"); and,
in the same year, an elaborate Report to the Academy on German
Philosophy. In 1854, he published a work on the spiritual power
of the eleventh century, under the title of " Saint Anselm of Canter-
bury ; " in 1856, he published "Studies and Portraits of England in
the Eighteenth Century," a work which he enlarged to two volumes
in 1865 ; in 1858, he published his " Life, Time, and Philosophy of
Bacon ; " and, in 1864, a volume on Religious Philosophy.

A volume entitled " Chanuing, sa Vie et ses Qi^uvres," of which
a second edition was printed in 1861, has been sometimes included in
the works of Remusat; but he wrote only the prefaces to the succes-
sive editions, while the volume itself was written by an accomplished
English lady, Mrs. Robert Hollond.

In 1871, after the downfall of the empire and the conclusion of the
war with Germany, M. de Remusat was made Minister of Foreign
Affairs, and was prominently associated with M. Thiers in achieving
the territorial liberation of France from German occupation. When
M. Thiers resigned the Presidency of the French Republic in 187.'3,
M. de Remusat also retired from ministerial service. He remained,
however, a member of the Chamber of Deputies to the end of his life.

A few months only before his death, he laid before the French
Academy his " History of Philosophy in England from Bacon to
Locke," in two volumes.

He was buried in the old Ciraitiere de Picpus in Paris, where the
tomb of Lafayette is well known to American travellers. F^ulogies
were jDronounced at his grave by representatives of the French Acad-

372 Sm CHAPtLES WHEATSTOlSrE.

emy and of tlie Chamber of Deputies; and an elaborate INIemolr of
his life and Avritings was communicated to tlie Revue des Deux
Mondes (November, 1875) by his life-long friend, M. Duvergier de
Hauranue, iu which ample justice was done to him as an eminent
writer, a religious pliilosopher, and a constant and able supporter of
liberal principles.

The United States Minister to France (Mr. Washburne), in a pub-
lished despatch to the State Department at Washington (18 June,
1875), after alluding to the friendship which M. de Remusat had
always manifested for our country and its institutions, speaks of him
as follows: "To quick intelligence and rare culture he united the
simplest manners and most unaffected modesty. His genial disposi-
tion, the graces of his spirit, and the charm of his conversation, left
upon all the impression of his purity and worth as a citizen, his
accomplishments as a statesman, and his fidelity, honesty, and patriot-
ism as a public servant. The love of France was the hope and
inspiration of his life. . . . Though always holding liberal opinions, his
inclinations were monarchical ; but, yielding to the logic of events and
the demands of circumstances, it was his judgment that the Republic
was the oidy form of Government that could give peace and safety to
France."

He was elected a member of this Academy on the 12th of Novem-
ber, 1873.

SIR CHARLES WHEATSTONE.

Charles Wiieatstone was born at Gloucester, in the year 1802.
His early education appears to have been very limited ; but he dis-
played, as a boy, a strong taste for mechanics, and especially for the
construction or modification of musical instruments. He began his
scientific career with the study of acoustics, and made numerous original
experiments and researches, his first paper appearing in the " Annals
of Philosophy," in 1823. For some years he was a dealer in musical
instruments ; but he soon began to direct his attention to other sub-
jects, and in 1834: published the results of a series of experiments on
the velocity of electricity, made with apjtaratus constructed for him by
the late Mr. Joseph Saxton, of Washington. The progress of science
has shown that Wheatstone's experiments led him to conclusions wliich
were in some respects untenable; but his paper was received with
acclamation, and certainly gave a decided im2)ulse to the science of

SIK CHARLES WHEATSTONE. 373

electricity. The application of the irvolviug mirror to the nieasiire-
inent of very small intervals of time was the germ of the later deter-
mination of th(^ velocity of li^ht l)y Kizeaii and Foucanlt. In 1837,
"VVheatstone associated himself with Cooke in a new attempt to solve
the often mooted problem of an electric telegraph. The history of
"NVheatstone's share in the invention has often been written. He was
not the tirst inventor of an electric telegraph, lie was not even the
first who atteni[)ted to carry into execution a clearly delined scien-
tific conception. But he brought to the practical solution of tiie
problem great mechanical resources, with extraordinary energy and
perseverance, and in the end he triumphed in England exactly as
Morse triumphed iu this country, — triumphed by the tenacity of his
intellectual grasp of the subject, by unflagging perseverance and
unwavering faith. In estimating Wheatstone's merit in connection
with the develoi^meut of the electric telegraph, the eminent services
rendered by his partner, Cooke, must not be forgotten. The two
together did for England what Morse alone did for this country; but
the special methods of Cooke and Wheatstone are already neai-ly for-
gotten, while those of Morse are in almost universal use. The list of
AVheatstoue's papers iu the catalogue of the Royal Society includes
only thirty titles. Iu 1838, he published his first paper on binocular
vision, and during the same year he gave to the world the eai'liest
form of tlie stereoscope. lie seems to have considered the subject
from a purely scieutific point of view, and the form which lie gave to
the instrument was not adapted to popular use. The invention of the
lenticular stereosco^De by Sir David Brewster was the next step; but
the full beauty and usefulness of the invention did not appear until
after the discovery of the art of photography. With the somewhat
bitter controversy which followed Brewster's improvemeut, we have
nothing to do. To Wheatstone belongs the creation, not merely of a
scientific instrument which almost takes rank with the microscope and
telescope, not merely of a -toy which has found its way to the house-
holds of all civilized races of men, and which is an unfailing source of
cultivated and refined pleasure, but of a whole branch of physiological
optics, the science of binocular vision, applicable to color as well as to
form, and full of fruits of usefulness and beauty. In 1843, Wheatstone
rendered another great service to science by the publication of a memoir
on new instruments and processes for the determination of the con-
stants of a voltaic circuit. In this paper he made known to Eng-
land, and we believe we may also say to America, the theory of the
galvanic circuit first proposed by Ohm. He gave to the ai)plicatious

374 SIR CHARLES WHKATSTONE.

of the theory a simple and clear mathematical form, devised a new
and advantageous terminology, and introduced most ingenious special
forms of apparatus, in particular that now universally known as
Wheatstone's bridge. His prismatic analysis of the light of the elec-
tric spark taken between electrodes of mercury belongs with the early
history of the spectroscope, and deserves to be cited in connection
with that instrument. Wheatstone's eminent services to science re-
ceived the fullest recognition during his lifetime, in both wealth and
honor. It is, perhaps, too soon to measure his intellectual stature
with perfect fairness, and materials for the story of his life are still
wanting; l)ut his name will always be associated with two of the most
beautiful and useful of human inventions. On the 19th of October
last, he closed a life which may well be called memorable.

Since the last Annual Meeting, the Academy has received
an accession of nineteen new members : eight Fellows, —
Henry Adams, Thomas D wight, R. T. Edes, E. L. God-
kin, Charles E. Hamlin, Hiram F. Mills, Ira Remsen, John
L. Sibley; eight Associate Fellows, — A. N. Arnold, Joseph
Le Conte, F. A. Genth, D. C. Gilman, O. C. Marsh, Alfred
M. Mayer, H. A. Rowdand, W. Sellers ; and three Foreign
Honorary Members, — Balfour Stewart, A. C. Ramsay, Count
Sclopis di Salerano. On the other hand, by removal from
the State, or by resignation, the following ten Fellows have
abandoned their membership : S. P. Andrews, A. N. Arnold,
J. B. Greenough, R. S. Greenough, Thomas Hill, Nathaniel
Holmes, Edw^ard Pearce, W. H. Pettee, G. M. Searle, W. H.
Swift.

The list of the Academy corrected to May 10, 1876, is
hereto added. It includes 191 Fellows, 9-1 Associate Fel-
lows, and 66 Foreign Honorary ]\Iembers.

LIST

OF THE FELLOWS AND FOREIGN HONORARY MEMBERS.

May 10, 1876.

FELLOWS. — 101.

(Number liniitud to two hundrod.)

Class L — Mathematical and Physical Sciences. — 01.

Section I. — 8.

Mathematics.

Ezekiel B. Elliott,
William Ferrel,
Benjamin A. Gould,
Gustavus Hay,
Benjamin Peirce,
James M. Peirce,
John D. Runkle,
Edwin P. Seaver,

Washington.

Washington.

Cordoba.

Boston.

Cambridge.

Cambridge.

Boston.

Cambridge.

Section II. — 7.
Practical Astronomy and Geodesy.
J. Ingersoll Bowditch, Boston.
Alvan Clark, Cambridgeport.

Henry iMitchell,
Robert Treat Paine,
William A. Rogers,
George M. Searle,
Henry L. Whiting,

Roxbiiry.
Boston.
Cambridge.
New York.
Boston.

Section III. — 27.
Physics and Chemistry.
John Bacon, Boston.

John H. Blake, Boston.

Thos. Edwards Clark, Williamstown.
W. J. Clark, Amherst.

Josiah P. Cooke, Jr., Cambridge.
James M. Crafts, Boston.

William P. Dexter, Roxbury.
Charles W. Eliot, Cambridge.
Moses G. Farmer, Newport.
Wolcott Gibbs, Boston.

Augustus A. Hayes, Brookline.
Henry B. Ilill, Cambridge.

Ebeu N. Ilorsford, Cambridge.

T. Sterry Hunt, Boston.

Chark'S L. Jackson, Cambridge.
Joseph Lovering, Cambridge.

John M. Merrick, Boston.
William R. Nichols, Boston.
John M. Ordway, Boston.
Edward C. Pickering, Boston.
Ira Remsen, Williamstown.

Edward S. Ritchie, Boston.
S. P. Sharpies, Cambridge.

Frank H. Storer, Jamaica Plain.
John Trowbridge, Cambridge.
Cyrus M. Warren, Brookline.
Charles H. Wing, Boston.

Section IV. — 19.

Technology and Enyineerinr/.

H. L. Abbot,
G. R. Baldwin,
John M. Batchelder,
C. O. Boutelle,
Edward C. Cabot,
Henry L. Eustis,
James B. Francis,
John B. Henck,
John C. Lee,
William R. Lee,
Hiram F. Mills,
Alfred P. Rockwell,
John Rodgers,
Stephen P. Ruggles,
Charles S. Storrow,
John H. Temple,
William R. Ware,
William Watson,
Morrill Wyman,

New York.

Quebec.

Cambridge.

Washington.

Boston.

Cambridge.

Lowell.

Boston.

Salem.

Roxbury.

Lawrence.

Boston.

^Vashington.

Boston.

Boston.

W. Roxbury.

Boston.

Boston.

Cambridge.

FELLOWS.

Class II. — Natural and Physiological Sciences. — G6.

Section I. — 11.

Geology, Mineralogy, and Physics of
the Globe.

Thomas T. Bouve,
Williaiu T. Brigham,
Algernon Coolidge,
John L. Hayes,
Charles T. Jackson,
Jules Marcou.
Raphael Punipelly,
AVilliaui B. Rogers,
Nathaniel S. Shaler,
Charles U. Shepard,
Josiah D. Whitney,

Boston.

Boston.

Boston.

Cambridge.

Boston.

Cambridge.

Boston.

Boston.

Cambridge.

Amherst.

Cambridge.

Section II. — 10.

Botany.

Jacob Bigelow,
George B. Emerson,
William G. Farlow,
George L. Goodale,
Asa Gray,
II. H. Hunnewell,
John A. Lowell,
Chas. J. Sprague,
Edward Tuckerman,
Serene Watson,

Boston.

Boston.

Boston.

Cambridge.

Cambridge.

Wellesley.

Boston.

Boston.

Amherst.

Cambridge.

Section III. — 2G.

Zoology and Physiology.

Alex. E. R. Agassiz, Cambridge.

J. A. Allen, Cambridge.

Robert Amory, Brookline.

Nath. E. Atwood, Provincetown.

James M. Barnard, Boston.

Henry P. Bowditch, Boston.

Thomas M. Brewer, Boston.

Sanmel Cabot, Boston.

John Dean, Waltham.

Silas Darkee, Boston.

Herrmann A. Hagen, Cambridge.

C. E. Hamlin, Cambridge.
Alpheus Hyatt, Cambridge.
Wm. James, Cambridge.
Samuel Kneeland, Boston.
Theodore Lyman, Boston.
John McCrady, Cambridge-
Edward S. jNIorse, Salem.
Alpheus S. Packard, Jr., Salem.
Charles Pickering, Boston.

L. Francis Pourtales, Cambridge.
Frederic W. Putnam, Salem.
Samuel H. Scudder, Cambridge.

D. Humphreys Storcr, Boston.
Henry Wheatland, Salem.
James C. White, Boston.

Section IV.
Medicine and
Samuel L. Abbot,
Henry J. Bigelow,
Henry I. Bowditch,
Edward H. Clarke,
Benjamin E. Cotting
Thomas Dwight,
Robert T. Edes,
Calvin Ellis,
Richard M. Hodges,
Oliver W. Holmes,
R. W. Hooper,
John B. S. Jackson,
Edward Jarvis,
Edward Reynolds,
Horatio R. Storer,
John E. Tyler,
J. Baxter Upham.
Charles E. Ware,
Henry W. ^yilliams,

. — 19.
Surgery.

Boston.
Boston.
Boston.
Boston.
, Roxbury.
Boston.
Roxbury.
Boston.
Boston.
Boston.
Boston.
Boston.
Dorchester.
Boston.
Boston.
Boston.
Bo.ston.
Boston.
Boston.

FELLOWS.

377

Class III. — Moral and Political Sciences. — 01.

Section I. — 19.

Philosophy and Jurisprudence.

George Heini.«, Boston.

George T Bigelow, Boston.
Francis Bowon, Cambridge,

llichanl 11. Dana, Jr., Boston.
C. C. Everett, Cambridge.

Horace Gray, Boston.

Kich. St. John Green, Cambridge.
Frederic H. Hedge, Cambridge.
L. P. Ilickok, Nortlianipton.

Ebenezcr R. Hoar, Concord.
Mark Hopkins, Williamstown.

C. C. Langdell, Cambridge.

Henry W. Paine, Cambridge.

Theophilus Parsons, Cambridge.
Charles S. Peirce, Washington.
"William A. Stearns, Amherst.
Benjamin F. Thomas, Boston.
Emory Washburn, Cambridge.
Francis Wharton, Cambridge.

Section H. — 11.

Philology and Archceology.

Ezra Abbot,
William P. Atkinson,
H. G. Denny,
Epes S. Diswell,
William Everett,
William W. Goodwin,
Ephraim W. Guruey,
Chandler Robbins,
John L. Sibley,
E. A. Sophocles,
Edward J. Young,

Cambridge.

Boston.

Boston.

Cambridge.

Cambridge.

Cambridge.

Cambridge.

Boston.

Cambridge.

Cambridge.

Cambridge.

Sectio.v hi. — IS.

Political Econninij ami llislory.

Clias. F. Adams, Jr., (iniiicy.
Henry Adams, Boston.

Erastus B. Bigelow, Boston.
Caleb Cashing, Newburyport.

Charles Deane, Cambridge.

Charles F. Dunbar, Cambridge.
Samuel Eliot, Boston.

George E. Ellis, Boston.

E. L. Godkin, Caml)ridge.

William Gray, Boston.

Edward Everett Hale, Boston.
J. L. Motley, Boston.

Francis Parkman, Brookline.
A. P. Peabody, Cambridge.

Edmund Quincy, Dedliam.

Nathaniel Thayer, Boston.
Henry W. Torrey, Cambri<lge.
Robert C. Wiuthrop, Boston.

Section IV. — 1(3.

Literature and the Fine Arts.

Charles F. Adams, Boston.
William T. Andrews, Boston.
George S. Boutwell, Groton.
J. Elliot Cabot, Brookline.

Francis J. Child, Cambridge.

Ralph W^aldo Emerson, Concord.
John C. Gray, Cambridge.

George S Hillard, Boston.
Henry W. Longfellow, Cambridge.
James Russell Lowell, Cambridge.
Charles Eliot Norton, Cambridge.
John K. Paine, Cambridge.

Thomas W. Parsons, Boston.
Charles C. Perkins, Boston.
John G. Whittier, Amesbury.
Edward Wigglesworth, Boston.

378

ASSOCIATE FELLOWS.

ASSOCIATE FELLOT\^S. -94.

(Number limited to one hundred.)

Class I. — Mathematical and Physical Sciences. — 36.

Section I. — 7.
Mathematics.
Charles Avery, Clinton, N.Y.
Alexis Caswell, Providence, R.I.
Charles Davies, New York.
Simon Newcomb, Washington, D. C.
II. A. Newton, New Haven, Conn.
James E. Oliver, Ithaca, N.Y.
Truman H. Safford, Chicago, HI.

Section II. — 12.

Practical Astronomy and Geodesy.

S. Alexander, Princeton, N.J.

W.H.C. Bartlett, West Point, N.Y.

J. H. C. Coffin, ' Washington, D.C.

Chas. H. Davis,
Wm. H. Emory,
J. E. Hilgard,
George W. Hill,
Elias Looniis,

Washington, D. C.
Washi ngton , D . C.
Washington. D.C.
Nyack, N.Y.
New Haven, Conn.

Maria Mitchell, Poughkeepsie, N.Y.
C. H. F. Peters, CUnton, N.Y.
Charles Wilkes, Waslungton,D. C.
Chas. A. Yomig, Hanover, N.H.

Section IH. — 12.

Physics and Chemistry.

F. A. P. Barnard, New York.
John W. Draper, New York.
Joseph Henry, Washington, D.C.
S. W. Johnson, New Haven, Conn.
John Le Conte, San Francisco, Cal.
A. M. Mayer, Hoboken, N. J.
W. A. Norton, New Haven, Conn.
Ogden N. Rood, New York.
H. A. Rowland, Baltimore.
L.M. Rutherfurd, New York.
Benj. Silliman, New Haven, Conn.
J. L. Smith, LouisviUe, Ky.

Section IV. — 5.

Technology and Engineering.

R. Delafield, Washington, D.C.
A. A. Humphreys, Washington, D.C.
Wm. Sellers, Philadelphia.

George Talcott, Albany, N.Y.
W.P.Trowbridge, NewHaveu, Conn.

Class II. — Natural and Physiological Sciences. — 30.

Section I. — 14.

Geology^ Mineralogy , and Physics of
the Globe.

George J. Brush, New Haven, Conn.

James D. Dana, New Haven, Conn.

J. W. Dawson, Montreal, Canada.

Edward Desoi', Neufchatel, Switz.

J. C Fremont, New York.

F. A. Genth, Philadelphia.
Arnold Guyot, Princeton, N.J.
James Hall, Albany, N.Y.

F. S. Holmes, Charleston, S.C.
Joseph LeConte, San Francisco.
J. Peter Lesley, Pliiladeli)hia.
Fred. B. Meek, Wa.shington.D.C.
Wm. T. Roepper, Bethlehem, Pa.
Geo. C. Swallow, Columbia, Mo.

ASSOCIATE- FELLOWS.

379

Skctiox II. — t.
liotanij.

A. W. Chapman, Apalacliicola, Fla.
G. Engi'linauii, St. Louis, Mo.
Leo Lesc^uoioiix, Coluinbu.s, Ohio.
S. T. Ohioy, rrovidence, K.L

Section IIL — 9.
Zoology and Physiology.
S. F. Baird, Washington, D.C.

C. E. Brown-Sequard, New York.
J. C. Dalton, Xew York.

J. P. Kirtland, Cleveland, Ohio.
J. L. LcConte, PliilatU'lphia.
Joseph Leidy, Philadelphia.
O. C. Marsh, New Haven, Conn.
S.Weir Mitchell, Philadelphia.
St. John Kavoiiel, Charleston, S.C.

Section IV. — 3.

Medicine and Surgery.

W. A. Hammond, New York.
Isaac Hays, Philadeljihia.

George B. Wood, Philadelphia.

Class III. — 3Ioral and Political Sciences. — 28.

Sfxtion I. — 6.
Philosophy and Jurisprudence.
D. R. Goodwin, Philadelphia.

R. G. Hazard,
James McCosh,
Noah Porter,
Isaac Ray,

Peacedale, R.I.

Princeton.

New Haven , Conn.

Philadelphia.

Jeremiah Smith, Dover, N.H.

Section II. — 11.
Philology and Archa:ology.

A. N. Arnold,

D. C. Oilman,
S. S. Haldeman,
A. C. Kendrick,
Geo. P. Marsh,
L. H. Morgan,
A. S. Packard,

E. E. Salisbury,

Hamilton, N.Y.
Baltimore.
Columbia, Pa.
Rochester, N.Y.
Rome.

Rochester, N.Y.
Brunswick, Me.
New Haven, Conn.

A. D. White, Ithaca, N.Y.

W. D. Whitney, New Haven, Conn.

T. D. Woolsey, New Haven, Conn.

Section HI. — 7.

Political Economy and History.

S. G. Arnold, Newport, R.I.

Geo. Bancroft, Washington.

S. G. Brown, Clinton, N.Y.

Henry C. Carey, Philadelphia.

Henry C. Lea, Philadelphia.

Barnas Scars, Scranton, Va.

J. H. Trumbull, Hartford.

Section IV. — 4.

Literature and the Fine Arts.

James B. Angell, Ann Arbor, Mich.
Wm. C. Bryant, New York.
F. E. Church, New York.
Wm. W. Story, Rome.

380

rOKEIGN HONOR AKY MEMBERS.

FOREIGN HONORARY MEMBERS. — 66.

(Appointed as vacancies occur.)

Class I. — Mathematical and Physical Sciences. — 25.

Section I.

— 8.

Section III

— 11.

Mathematics.

Physics and

Chemistry.

John C. Adams,

Cambridge.

Bunsen,

Heidelberg.

Sir George B. Airy,

Greenwich.

Chevreul,

Paris.

Brioschi,

Milan.

Dumas,

Paris.

Arthur Cayley,

London.

Ilclmholtz,

Berlin.

Chasles,

Paris.

Kirchhoff,

Berlin.

Le Verrier,

Paris.

J. C. Maxwell,

Cambridge.

Liouville,

Paris.

J. C. Poggendorff,

Berlin.

J. J. Sylvester,

Woolwich.

Regnault,
Balfour Stewart,

Palis.
Manchester

Section II

— 4.

G. G. Stokes,
Wdhler,

Cambridge.
Gottingeu.

Practical Astronomy and Geodesy.
Dollen, Pulkowa.

H. A. E. A. Faye,

Peters,

Otto Struve,

Paris.

Altona.

Pulkowa.

Section IV. — 2.
Technology and Engineering.
ClaiLsius, Bonn.

Sir VVm. Tliomson, Glasgow.

Class IL — Natural and Physiological Sciences. — 25.

Section I. — 8.

Geology, Mineralogy, and Physics of
the Globe.

Barrande,

Charles Darwin,

Dove,

James Prescott Joule ,

W. H. Miller,

Rammelsberg,

A. C. Ramsay,

Sir Edward Sabine,

Prague.

London.

Berlin.

Manchester.

Cambridge.

Berlin.

London.

London.

Section II. — 7.

Botany.

George Bcntham, London.

Alexander Brauu, Berlin.

Decaisne, Paris.

Alphonsc dc Candolle, (ieneva.

Elias Fries, Upsal.

ITofraeister, Tiibingen.

Joseph Dalton Hooker, London.

FOREIGN HONORARY MEMBERS.

381

Section III.— 8.

Zooltxjij and Phi/siulorji/.

Von Baer, St. Petersburg.

T. L. W. BischoiT,
^lilnc-Edwards,
Ehrenborg,
Albrecht Ktilliker,
Richard Owen,

Munich.

Paris.

Berlin.

Wiirzljurg.

London.

C. Th. Von .Slubold, Miinii;h.
Valentin, Berne.

Section IV. — 2.
Medicine and Surcjery.

Rokitansky,
Vu-chow,

Vienna.
Berlin.

Class III. — Moral and Political Sciences. — 1 G.

Section I. — 4.

Philosophy and Jurisprudence.

T. C. Bluntschli, Heidelberg.

Sumner Maine, London.

James ^lartineau, London.

Sclopis di Salerauo, Turin.

Section IT. — 6.
Philology and Archceology.

Pascual de Gayangos, Madrid.
Benjamin Jowett, Oxford.
Christian Lassen, Bonn.

Lepsius, Berlin.

]\Ias ^liiller,
F. llitschl.

Oxford.
Bonn.

Section III. — 5.
Political Economy and History.
"W. Ewart Gladstone, London.

Charles Merivale,

Oxford.

Mommsen,

Berlin.

Vou Ranke,

Berlin.

Thiers,

Paris.

Section IV. — L
Literature and the Fine Ai'ts.
Gerome, Paris.

STATUTES

STANDING VOTES

AMERICAN ACADEMY OF ARTS AND SCIENCES.

(Adopted May 30, 1854: amended September 8, 1857, Novemher 12, 1862,
May 24, 1804, November 9, 1870, February 11, 1873, and January 26,
1876.)

CHAPTER I.

or FELLOWS AND FOREIGN HONORARY MEMBERS

1. The Academy consists of Fellows and Foreign Honorary
3Iemhers. They are arranged in three classes, according to
the Arts and Sciences in which they are severally proficient,
viz. : Class I. The Mathematical and Physical Sciences ;
Class II. The Natural and Physiological Sciences; Class III.
The Moral and Political Sciences. Each Class is divided
into four Sections, viz.: Class I. Section 1. Mathematics;
Section 2. Practical Astronomy and Geodesy ; Section 3.
Physics and Chemistry ; Section 4. Technology and Engi-
neering. Class II. Section 1. Geology, Mineralogy, and
Physics of the Globe ; Section 2. Botany ; Section 3. Zoology
and Phj^siology; Section 4. Medicine and Surgery. Chiss III.
Section 1. Philosophy and Jurisprudence ; Section 2. Philol-
ogy and Archaeology ; Section 3. Political Economy and
History ; Section 4. Literature and the Fine Arts.

384 STATUTES OF THE

2. Fellows resident in the State of Massachusetts can alone
vote at the meetings of the Academy.* They shall each pay
to the Treasurer the sum of ten dollars on admission, and an
annual assessment of ten dollars, with such additional sum,
not exceeding five dollars, as the Academy shall, by a stand-
ing vote, from time to time determine.

3. Fellows residing out of the State of Massachusetts shall
be known and distinguished as Associate Fellows. Tliey
shall not be liable to the payment of any fees or annual dues,
but, on removing within the State, shall be admitted to the
privileges,! ^^^^l be subject to the obligations, of Resident
Fellows. The number of Associate Fellows shall not exceed
one hundred, of wdiom there shall not be more than forty in
either of the three classes of the Academy.

4. The number of Foreign Honorary jMembers shall not
exceed seventy-five ; and the}" shall be chosen from among
persons most eminent in foreign countries for their discoveries
and attainments in either of the three departments of knowl-
edge above enumerated. And there shall not be more than
thirty Foreign JMembers in either of these departments.

. CHAPTER n.

OF OFFICERS.

1. There shall be a President, a Vice-President, a Corre-
sponding Secretary, a Recording Secretar}^, a Treasurer, and
a Librarian, which officers shall be annually elected, by writ-
ten votes, at the Annual Meeting, on the day next preceding
the last Wednesday in May.

2. At the same time and in the same manner, nine Coun-
cillors shall be elected, three from each Class of the Academy,
but the same Fellows shall not be eligible for more than three

* Tlie number of Resident Fellows is limited by the Cliarter to 200.
t Associate Fellows may attend but cannot vote at meetings of the Academy.
See Chapter I. 2.

AlSrERICAN ACADEMY OF ARTS AND SCIENCES. 385

successive years. These nine Councillors, with the Prositlent,
Vice-President, the Treasurer, and the two Secretaries, shall
constitute tlie Council. It shall be the duty of this Council
to exercise a discreet supervision over all nominations and
elections. With the consent of the Fellow interested, they
shall have power to make transfers between the several sec-
tions of the same Class, reporting their action to the Acad-
emy.

3. If any office shall become vacant during the year, the
vacancy shall be filled by a new election, and at the next
stated meeting.

CHAPTER III.

OF THE PRESIDENT.

1. It shall be the duty of the President, and, in his absence,
of the Vice-President or next officer in order, as above enu-
merated, to preside at the meetings of the Academy ; to sum-
mon extraordinary meetings, upon any urgent occasion ; and
to execute or see to the execution of the Statutes of the
Academy.

2. The President, or, in his absence, the next officer as
above enumerated, is empowered to draw upon the Treasurer
for such sums of money as the Academy shall direct. Bills
presented on account of the Library, or the publications of
the Academy, must be previously approved by the respective
committees on these departments.

3. The President, or, in his absence, the next officer as
above enumerated, shall nominate members to serve on the
different committees of the Academy which are not chosen
by ballot.

4. Any deed or writing, to which the common seal is to be
affixed, shall be signed and sealed by the President, when
thereto authorized by the Academy.

VOL. XI. (n. S. III.) ^

386 STATUTES OF THE

CHAPTER IV.

OF STANDING COMMITTEES.

1. At the Annual Meeting there shall be chosen the fol-
lowing Standing Committees, to serve for the year ensuing,
viz. : —

2. The Committee of Finance, to consist of the President,
Treasurer, and one Fellow chosen by ballot, who shall have
charge of the investment and management of the funds and
trusts of the Academy. The general appropriations for the
expenditures of the Academy shall be moved by this Com-
mittee at the Annual Meeting, and all special appropriations
from the general and publication funds shall be referred to or
proposed by this Committee.

3. The Rumford Committee, of seven Fellows, to be chosen
by ballot, who shall consider and report on all applications
and claims for the Rumford Premium, also on all appropria-
tions from the income of the Rumford Fund, and generall}^
see to the due and proper execution of this trust.

4. The Committee of Publication, of three Fellows, to
whom all Memoirs submitted to the Academy shall be re-
ferred, and to whom the printing of Memoirs accepted for
publication shall be intrusted.

5. The Committee on the Library, of three Fellows, who
shall examine the Library, and make an annual report on its
condition and management.

6. An Auditing Committee, of two Fellows, for auditing
the accounts of the Treasurer.

CHAPTER V.

OF THE SECRETARIES.

1. The Corresponding Secretary shall" condiict the corre-
spondence of the Academy, recording or making an entry of

AMERICAN ACADEMY OF ARTS AND SCIENCES. 887

all letters written in its name, and presorvincf on file all let-
ters which are received; and at each meeting he shall present
the letters which have been addressed to the Acadeinv since
the last meeting. With the advitie and consent of tiie Presi-
dent, he may effect exchanj^es with other scientific associa-
tions, and also distribute copies of the pnl)lications of the
yXcadeni}' among the Associate Fellows and Foreign llonorai'v
]\Iembers, as shall be deemed expedient ; making a report of
his proceedings at the Annual Meeting. Under the direction
of the Council for Nomination, he shall keep a list of the
Fellows, Associate Fellows, and Foreign Honorary Members,
arranged in their Classes and in Sections in respect to the
special sciences in which they are severally proficient ; and
he shall act as secretary to the Council.

2. The Recording Secretary shall have charge of tlie Char-
ter and Statute-book, journals, and all literary papers belong-
ing to the Academy. He shall record the proceedings of the
Academy at its meetings ; and, after each meeting is duly
opened, he shall read the record of the preceding meeting.
He shall notify the meetings of the Academy, and apprise
committees of their appointment. He shall post up in the
Hall a list of the persons nominated for election into the
Academy; and, when any individual is chosen, he shall in-
sert in the record the names of the Fellows by whom he was
nominated.

3. The two Secretaries, with the Chairman of the Com-
mittee of Publication, shall have authority to publish such of
the proceedings of the Academy as may seem to them calcu-
lated to promote the interests of science.

CHAPTER VI.

OF THE TREASUBER.

1. The Treasurer shall give such security for the trust
reposed in him as the Academy shall require.

2. He shall receive officially all moneys due or payable,

388 STATUTES OF THE

and all bequests or donations made to the Academy, and by
order of the President or presiding officer shall pay such sums
as the Academy may direct. He shall keep an account of
all receipts and expenditures; shall submit his accounts to
the Auditing Committee ; and shall report the same at the
expiration of his term of office.

3. The Treasurer shall keep a separate account of the
income and appropriation of the Rumford Fund, and report
the same annually.

4. All moneys which there shall not be present occasion to
expend shall be invested by the Treasurer, under the direc-
tion of the Finance Committee, on such securities as the
Academy shall direct.

CHAPTER VH.

OF THE LIBRARIAN AND LIBRARY.

1. It shall be the duty of the Librarian to take charge of
the books, to keep a correct catalogue of the same, and to
provide for the delivery of books from the Library. He shall
also have the custody of the })ublications of the Academy.

2. The Librarian, in conjunction with the Committee on
the Library, shall have authority to expend, as the}"" may deem
expedient, such sums as may be appropriated, either from the
Rumford or the General Fund of the Academy, for the pur-
cliase of books and for defra3ung other necessary expenses
connected with the Library. They shall have authority to
propose rules and regulations concerning the circulation, re-
turn, and safe-keeping of books; and to appoint such agents
for these purposes as they may think necessary.

3. To all books in the Library procured from the income of
the Rumford Fund, the Librarian shall cause a stamp or label
to be affixed, expressing the fact that they were so procured.

4. Every person who takes a book from the Library shall
give a receipt for the same to the Librarian or his assistant.

5. Every book shall be returned in good order, regard

AMERICAN ACADEMY OF AllTS AND SCIENCES. 381)

being had to the necessary wear of the book wilh gixxl usage.
And if any book shall be lost or injured, the person to whom
it stiinds charged shall replace it by a new volume or set, if
it belong to a set, or pay the current price of the volume or
set to the Librarian ; and thereupon the remainder of the set,
if the volume belonged to a set, shall be delivered to the
person so paying for the same.

6. All books shall be returned to the Library for examina-
tion, at least one week before the Annual Meeting.

CHAPTER VIIL

OF meetin;^s.

1. There shall be annually four stated meetings of the
Academy; namely, on the day next preceding the last
Wednesday in May (the Annual Meeting), on the second
Wednesday in October, on the second Wednesday in Janu-
ary, and on the second Wednesday in March; to be held
in the Hall of the Academy, in Boston. At these meetings
only, or at meetings adjourned from these and regularly noti-
fied, shall appropriations of money be made, or alterations of
the statutes or standing votes of the Academy be effected.

2. Fifteen Fellows shall constitute a quorum for the trans-
action of business at a stated meeting. Seven Fellows shall
be sufficient to constitute a meeting for scientific communica-
tions and discussions.

3. The Recording Secretary shall notify the meetings of
tlie Academy to each Fellow residing in Boston and the
vicinity ; and he may cause the meetings to be advertised,
whenever he deems such further notice to be needful.

390 STATUTES OF THE

CHAPTER IX.

OF THE ELECTION OF FELLOWS AND HONORARY MEMBERS.

1. Elections shall be made by ballot, and only at stated
meetings.

2. Candidates for election as Resident Fellows must be pro-
posed by two or more Resident Fellows in a recommendation
signed by them specifying the section to which the nomina-
tion is made, which recommendation shall be transmitted to
the Corresponding Secretary, and by him referred to the
Council for nomination. No person recommended shall be
reported by the Council as a candidate for election, unless he
shall have received a written approval, signed at a meet-
ing of the Council by at least eight of its members. All
nominations thus approved shall be read to the Academy
at a stated meeting, and shall then stand on the nomination
list during the interval between two stated meetings, and
until the balloting. No person shall be elected a Resident
Fellow, unless he shall have been resident in this Com-
monwealth one year next preceding his election ; and any
Resident Fellow, who shall remove his domicile from the
Commonwealth, shall be deemed to have abandoned his Fel-
lowship. If any person elected a Resident Fellow shall
neglect for one year to pay his admission fee, his election
shall be void ; and, if any Resident Fellow shall neglect to
pay his annual assessments for two years, provided that his
attention shall have been called to this article, he shall be
deemed to have abandoned his Fellowship ; but it shall be
in the power of the Treasurer, with the consent of the Coun-
cil, to dispense {sub silentio') with the payment both of the
admission fee and of the assessments, whenever in any special
instance he shall think it advisable so to do.

3. The nomination of Associate Fellows shall take place in
the manner prescribed in reference to Resident Fellows ; and
after such nomination shall have been publicly read at a
stated meeting previous to that when the balloting takes

AMERICAN ACADEMY' OF ARTS AND SCIENCES. 391

])l;ice, it shall Ix.' ri'fcrred to a Comu-il fur Nomiiiiition ; and
a wiitten approval, autliorizud and signed at a nici'tiiig of
said Council by at least seven of its nienibers, shall he recpii-
site to entitle the candidate to he halloted for. The Council
may in like manner originate nominations of Associate Fel-
lows ; which must be read at a stated meetinjj^ previous to
the election, and be exposed on the nomination list during the
interval.

4. Foreign Honorary IMemhers shall be chosen only after a
nomination made at a meeting of the Council, signed at the
time by at least seven of its members, and read at a stated
meeting previous to that on which the balloting takes place.

5. Three-fourths of the ballots cast must be affirmative,
and the number of affirmative ballots must amount to eleven,
to effect an election of Fellows or Foreign Honorary Mem-
bers.

6. Each section of the Academy is empowered to present
lists of persons deemed best qualified to fill vacancies occur-
ring in the number of Foreign Honorary Members or Associ-
ate Fellows allotted to it; and such lists, after being read at
a stated meeting, shall be referred to the Council for Nomi-
nation.

7. If, in the opinion of a majority of the entire Council, any
Fellow — Resident or Associate — shall have rendered him-
self unworthy of a place in the Academy, the Council shall
recommend to the Academy the termination of his Fellow-
ship ; and, provided that a majority of two-thirds of the Fel-
lows at a stated meeting, consisting of not less than fifty
Fellows, voting by ballot yea or nay, shall adopt this recom-
mendation, his name shall be stricken off the roll of Fellows.

CHAPTER X.

OF AMENDMENTS OP THE STATUTES.

1. All proposed alterations of the Statutes, or additions to
them, shall be referred to a committee, and, on their report at
a subsequent meeting, shall require for enactment a majority

392 STATUTES OF THE

of two-thirds of the members present, and at least eighteen
affirmative A-^otes.

2. Standing Votes may be passed, amended, or rescinded,
at any stated meeting, by a majority of two-thirds of the
members present. They may be suspended by a unanimous
vote.

CHAPTER XI.

OF LITERARY PERFORMANCES.

1. The Academy will not express its judgment on literary
or scientific memoirs or performances submitted to it, or
included in its publications.

RUMFORD PREMIUM.

In conformity with the terms of the gift of Benjamin Count
Rumford, granting a certain fund to the American Academy of
Arts and Sciences, and with a decree of the Supreme Judicial
Court for carrying into effect the general charitable intent and
purpose of Count Rumford, as expressed in his letter of gift,
the Academy is empowered to make from the income of said
fund, as it now exists, at any annual meeting, an award of a
gold and silver medal, being together of the intrinsic value of
three hundred dollars, as a premium, to the author of any
important discovery or useful improvement in light or in
heat, which shall have been made and published by printing,
or in any way made known to the public, in any part of the
continent of America, or any of the American islands ; pref-
erence being always given to such discoveries as shall, in the
opinion of the Academy, tend most to promote the good of
mankind ; and to add to such medals, as a further premium
for such discovery and improvement, if the Academy see fit
so to do, a sum of money not exceeding three hundred
dollars.

AMERICAN ACADEMY OF ARTS AND SCIENCES. 393

STANDING VOTES.

1. Communications of which notice has been given to the
Secretary shall take precedence of those not bo notified.

2. Resident Fellows who have paid all fees and dues charfre-
able to them are entitled to receive one copy of each volume
or article printed by the Academy, on application to the
Librarian personally or by written order, within two years
from the date of publication. And the curi-cnt issues of the
Proceedings shall be supplied, when read}' for publication,
free of charge to all the Fellows and Members of the Acad-
emy who desire to receive them.

3. The Committee of Publication shall fix from time to
time the price at which the publications of the Academy may
be sold. But members may be supplied at half this price with
volumes which they are not entitled to receive free, and which
are needed to complete their sets.

4. One hundred extra copies of each paper accepted for
the Memoirs of the Academy shall be separately printed, of
which fifty shall be placed at the disposal of the author, free
of charge.

5. Resident Fellows may borrow and have out from the
Library six volumes at any one time, and may retain the same
for three months, and no longer.

6. Upon special application, and for adequate reasons as-
signed, the Librarian may permit a larger number of volumes,
not exceeding twelve, to be drawn from the Library, for a
limited period.

7. Works published in numbers, when unbound, shall not
be taken from the Hall of the Academy, except by special
leave of the Librarian.

8. Books, publications, or apparatus shall be procured from
the income of the Ruraford Fund only on the certificate of
the Rumford Committee, that they, in their opinion, will best
facilitate and encourage the making of discoveries and im-
provements which may merit the Rumford Premium.

394 AMERICAN ACADEMY OF ARTS AND SCIENCES.

9. The annual meeting shall be holden at half-past three
o'clock, P.M. The other stated meetmgs, at half-past seven

o'clock, P.M.

10. A meeting for receiving and discussing scientific com-
munications shall be held on the second Wednesday of each
month, not appointed for stated meetings, excepting July,
August, and September.

INDEX TO YOL. III.

A.

Abutilon Xewberryi, 125.
Adolphia Californica, 126.

iufesta, 120.
Alchemilla occidentalis, 11-4.
Alsia Californica, 121.
Auiblyopappus pusillus, 110.
Aiusiiickia veruicosa, 118.
Anagallis arvensis, 117.
Anemone alpina, 121.

occidentalis, 121.
Anc^eliea tonientosa, 141.
Antirrhinum Nuttallianmn, 117.

speciosum, 117.
Aplopappus Palmeri, 74.
Appropriations, 313.
Arabis Breweri, 123.

Drunmiondii, 122.

Lyallii, 122.

repanda, 122.
Aralia Californica, 144.
Ai'chemora, 14.5.

Fendleri, 14.5.
Arctostaphylos Andersonii, 83.
Arenaria brevifolia, 72.
Armatm-es, Distribution of Mag-
netism on, 2!)3.
Artemisia Californica, 110.

Palmeri, 79.
Asagraja spinosa, 132.
Aspidium munitum, 120.
Aster Coloradoensis, 76.
Astronomical Instruments, Port-
able, and their Use, 157.
Astronomical Observations, Sources

of terror in, 195.
Atriplex Endole])is, 102.

Palmeri, 119, 140.

Suckleyana, 103.
Avena fatua, 120.

B.

Ba>ria Palmeri, 110.
Bahia lanata, 110.
Barbala atrovirens, 121.

rigida, 121.

ruralis, 121.

vinealis, 121.
Bigelovia Engelmanni, 75.

Greenei, 75.

spathulata, 74.
Biographical Notices : —

Gabriel Audral, 3()3.

Horace Binncy, 351.

]\Iarchese (iino Capponi, 365.

John Henry Clifford, 333.

Horatio Balcli Ilackett, 334.

Sir William Edmond Logan,
357.

Joel Parker, 836.

Charles- Francois-Marie,

Comte de Kejnusat, 370.

William Sweetser, 302.

Sir Charles Wlieatstone, 372.

Joseph Winlock, 339.

Chauncey Wright, 350.
Botanical Contributions, 71, 105.
Brahea armata, 140.

edulis, 120, 140.

filauientosa, 147.
Brassica nigra, 113.
Brickellia microphylla, 74.
Bromus sterilis, 120.

c.

Calamintha Palmeri, 100, 117.
Calandrinia Brewori, 124.

JSIenziesii, 113, 124.
Calystegia subacaulis, 90.

villosa, 90.

I

396

INDEX.

Campanula biflora, 82.

Coloradoeiisis, 82.

flagellaris, 83.

intermedia, 83.

leptocarpa, 82.

Ludoviciana, 83.

Montevidensis, 83.
Campylocera leptocarpa, 82.
Cardamine Gambelii, 147.
Cassia armata, 136.
Castilleia foliolosa, 117.
CeanotliLis crassifolius, 114.

cuneatus, 114.
Ceratocarpus, 103.
Ceratodon purpureus, 121.
Cercidium floridiim, 135.

Texanum, 136.
Cham?esaraclia, 90.

Coronopus, 90.

nana, 90.

sordida, 90.
Chapmannia, 103.
Chenopodiuni album, 119.
Cicuta Bolanderi, 139.
Claytonia perfoliata, 113.
Cleomella oocarpa, 72.

plocasperma, 72.
Clouds, Height and Velocity of, 263.
Cobalt, Hexatomic Compounds of,

1.
Cobaltamines, Formation and Prep-
aration of, 37.

Theoretical Views, 44.
Collinsia, 91.

barbata, 92.

bartsiajfolia, 92.

bicolor, 92.

corymbosa, 92.

grandiflora, 93, 94.

Greenei, 92.

heterophylla, 92.

hirsuta, 92.

minima, 93.

parviflora, 93.

septemnervia, 92.

solitaria, 93.

siiarsiflora, 93.

tenella, 93.

tinctoria, 92.

Torreyi, 93.

verna, 93.

violacea, 93.
Collomia gilioides, 118.
Committees, 314, 315, 323.
Communications from Messrs.
A. Agassiz, 231.

R. Amory, 70, 279, 310, 332.

Communications from Messrs.
A. G. Bell, 331.
H. P. Bowditch. 281, 331.
C. H. Davis, 185.
J. P. Cooke, Jr., 316, 329.
W. Everett, 329.
W. Gibbs, 1, 316, 322.

A. Gray. 71, 322.
H. B. Hill, 323.

C. L. .Jackson, 331.

W. W. Jacques, 265, 269, 331.

B. Peirce, 316, 317. 324, 331.
B. O. Peirce, Jr., 218, 324.

E. C. Pickering, 256, 263, 273,
316, 322.

G. S. Pine, 303, 332.

W. A. Rogers, 237, 317, 321,
322, 331.

H. A. Rowland, 191, 317.

T. H. Safford, 52, 157, 193,
210, 316, 317, 324, 331.

S. H. Scudder, 324.

S. P. Sharpies, 149, 322.

L. Trouvelot, 62, 174, 317, 322.

J. Trowbridge, 202, 322, 323,
324.

S. Watson, 105, 317, 321.

W. AVatson, 316, 322, 323,
324, 329.

H. Whiting, 293, 332.

W. P. Wilson, 228, 283.
Condensers and Geissler's Tubes,

228.
Conioselinum Fischeri, 140.
Convolvulus Californicus, 90.

luteolus, 90.

occidentalis, 89, 118.

villosus, 90.
Cornus Torreyi, 145.
Cucurbita Californica, 138.

palmata, 137.
Cupressus macrocarpa. 119.
Cuscuta Californica, 90.

salina, 90.

subinclusa, 90.
Cymopterus glcbosus, 141.

montanus, 141.
Cypripedium occidentale, 147.

parviflorum, 147.

passerinum, 147.

D.

Dalea, 132. *

Californica, 132.
Daucus pusillus, 115.

INDEX.

397

Diamoqiha pusilla, 71.
Dii'oria Braiidt'jfei, 7ti.
Diffraction of Souml, "JGO.
Diplacus oliitiiiosus, 1)7.

loiiniriorus, !)7.
Diplostfpliiuin oanuin, 75, 115.
DistaiKH's, Mt'asun'iiient of, 'J57.
lK)(l.>ca(lii"on M.'adia, 117.
Draper, ,Iolm W., Award of Iliiiu-

ford Medal to, ;ni, ;L'.5.

Dysmioodoii I'aliforuicum, 83.
ovatum, 83.
perfoliatum, 83.

E.

Ecliidiocarya, 89.

Arizoiiica, 89.
Echini, Viviparous, from Kerguelen

Island, 2:31.
Echinocystis fabacea, 138.

muricata, 139.
Electrical Resistance in Wires,
C'iiange of, bv Stretching,
303.
Electro-Magnets, on Thin Plates of
Iron used as Armatures, 202.
Ellisia chrysanthemifolia, 118.
Emmenanthe peuduliflora, 118.

pusilla, 87.
Encelia viscida, 78.
Epilobium miuvituni, 115.
Eriogonum chrysocephalum, 101.

Kingii, 101.
Eritrichium angustifoliuni, 118.

muriculatum, 118.
Erodium cicutarium, 108, 113.

moschatum, 109, 111.
Eschscholtzia Californica, 112, 122.

minutiflora, 122.
Etheric Force, on the so-called,

206.
Eunanus bicolor, 90.

Bigelovii, 9G.

Coulteri, 95.

Douglasii, 95.

Fremonti, 96, 97.

Tolmiaei, 96.
Eurotia, 103. ,
Eurj-j^itera lucida, 142.
Expert Evidence, Committee on,
323.

F.

Fellows, Associate, List of, 378.

Fellows deceasi'd: —

.John Henry ("lifford. 333.
Horatio M.'llackett, 333.
Joel I'arker, 333.
•Joseph Winloek, 310.
I'iiauncey Wright, 310.
Fellows elected: —

Henry Adams, 318, 321.
Albert Nicholius .\rMold, 317,

321.
Thomas Dwight, Jr., 323.
Robert Thaxter Edes, 318,

323.
Frederick A. Ceiith, 317, 321.
Daniel C. Gilman, 317, 323.
Edwin Lawrence (Jodkin, 323,

32L
Charles Edward Ilandiii, 323,

330.
Joseph LeConte, 317, 323.
Othniel Charles Marsh, 317,

330.
Alfred M. IMayer, 317, 321.
Hiram F. :Miris. 318, 321.
Ira Remsen, 318, 323.
llenrv A. Rowlan.l, 330.
William Sellers, 317.
John Langdon Sibley, 330,
331.
Fellows, List of, 375.
Ferula Newberryi, 1-15.
Festuca microstachys, 120.
Filago Arizonica, 115.
Flora of Guadalupe Lsland, 105,

112.
Foreign Honorary Members de-
ceased : —
Gabriel Audral, 333.
Gino Capponi, 333.
De Macedo, 333.
Eyries, 333.

Charles de Remusat, 316.
Duke di Serradii'alco, 333.
Sir Charles Wheatstone, 333.
Foreign Honorary Members elect-
ed:—
Andrew Crombie Ramsay, 317,

324.
Conte Federigo Sclopis di Sa-

lerano, 323, 324.
Balfour Stewart, 330.
Foreign Honorary Members, List

of, 380.
Fossombronia Californica, 121.

longiseta, 121.
Fossomiironia Palmeri, 121.
Frankenia Falmeri, 124.

398

INDEX.

Franseria bipinnatifida, 115.

ilicifolia, 77.

G.

Galium angiilosum, 7i, 115.

Aparine, 115.
Galvanometer, Mirror, New Form

of, 208.
Geissler's Tubes, Condensers and,

228.
Gentiana calycosa, 81.

Newberryi, 81.

setijjera, 81.
Geographical Congress, Interna-
tional, 313, 318.
Gilia Brandegei, 85.

Haydeni, 85.

Larseni, 81.

multicaulis, 118.

pusilla, 118.
Githopsis specularioides, 116.
Glossopetalon Nevadense, 73.

spinescens, 73.
Gnaphalium Sprengelii, 116.
Grayia, 103.

Brandegei, 101.
Grimmia pulvinata, 121.

trichophylla, 121 .
Guadalupe Island, Flora of, 105,

112.
Gymnogramine triangularis, 120.

Halenia Rothrockii, 84.
Harpagonella, 88.

Palmeri, 88, 118.
Hedeoma hyssopifolia, 96.
Height of Clouds, 263.
Heights, Determination of, 258.
Ilelianthus gracilentus, 77.
Ilemizonia floribunda, 79.

frutescens, 79, 115.
Ilerpestis pilosa, 99.
Ilesperetea, 83.

Palmeri, 83, 118.
Ilesperocnide tenella, 119.
Ilexatomic Compounds of Cobalt, 1.
Ilorkelia purpurascens, 118.

tridentata, 118.
Ilosackia :irgo])hylla, 114.

grandiilora, HI.
Ilydrograpliic Sketch of Lake Titi-

caca, 283.
Hypnum myosuroides, 121.

I.

Inductive Apparatus, New Fonn

of, 281.
Ipomfea sagittajfolia, 90.
Iva Hayesiana. 78.

J.

Juncus bufonius, 120.
Juniperus Californica, 119.

K.

Kerguelen Island, on Yiviparous
Echini from, 221.

L.

Laclmostoma hastulatum, 87.
Lake Titicaca, Ilydi'ographic

Sketch of, 283.
Lathyrus, Revision of, 133.

Engelmanni, 133.

Lanszwertii, 134.

linearis, 134.

littoralis, 134.

maritimus, 133.

Nevadensis, 133, 134.

ochroleuctis, 133.

paluster, 134.

polymorpluis, 134, 135.

polyjiliYUiis, 133, 134.

pusillus, 133.

sul}>hureus, 133.

Torreyi, 134.

venosus, 133, 134, 135.

vestitus, 134.
Latitudes, on Determination of,

160.
Latitude Observations, on Reduc-
tion of, 167.
Lavatera occidentalis, 113, 125.
Least Squares, on the ^Method of,

193.
Lei^idium lasiocarpum, 113.

IMenziesii, 113.
Leptosyne gigautea. 115.
Ligusticum apiifoliiim, 140.

tilicinuui, 1 lO.

soopulonim. 1 10.
Linaria Canadensis, 117.
Loeselia, 86.

INDEX.

399

Loeselia offusa, 8G.

ti'iuiit'dlia, 86.
Lupimis tJiavi, 126.

niveus, lli, 1l*6.

onustiis, 127.
Luteocobalt, '27.

List of Salts of, 36.

Ammouio-c'obalt-iiitrite, 3t.

Cliloro-platiuo-oliromate, 26.

Diohromatc, 30.

llypt'rhroinides, 37.

IIvpL-riodidi's, 37.

]\lVtamoric Salts, 31.

Oxalo-auro-ehloride, 28.

rvrophos])hate, 2!).

Sidphatc of Thalliuia and, 30.
Lyrocarpa raliuei-i, 123.
Lyciiim Californicum, 117.

M.

IMadntheca navicularis, 121.
Magnetic Distribution, Notes on,

191.
Magnetism, Distribution of, on Ar-
matures, 293.
Malacotlirix Clevelandii, 116.
Malva borcalis, 113.
iMalvastrum Coulteri, 125.
Marah muricatus, 138.
Matricaria discoidea, 116.
Megarrhiza, Revision of, 138.

Californica, 138.

Guadalupensis, 115, 138.

Marah, 138.

muricata, 139.

Oregona, 138.
Melica imperfecta, 120.
Members, Foreign Honorary. See
Foreign Ilonorary Members.
Mentzelia albicaulis, 137.

dispersa, 115, 137.

micrantha, 137.
Metric System, Action upon, 323,

331.
Microcala quadrangular is, 84.
^licrometer-Level, 260.
Micropus Californicus, 115.
]Microseris linearifolia, 116.
Milk, on Specimens of, 149.
Mimulus, Revision of, 91.

alatus, 98.

alsinoides, 98.

bicolor, 99.

Bigelovii, 96.

Mimulus Holaudi'ri, 97.

bri'vipi's, 97.

canliualis, 98.

cuiireus, 98.

dentatus, 98.

Douglasii, 95.

ijuriliundus, !)9.

Frcmonti, 96.

glutiuosus, 97.

iuconspicuus, 99.

Jamcsii, 98.

laciniatus, 98.

latifolius, 95, 117.

leptali'us, 96.

Lcwisii, 98.

lut.'us, 98.

microiiliyllus, 98.

montioides, 99.

moschatus, 99.

nanus, 96.

Tarryi, 97.

pilosus, 99.

Prattenii, 99.

primuloides, 99.

I'ulsiferiB, 98.

ringens, 98.

ruliellus, 99.

tenellus, 98.

Tilingii, 98.

Torreyi, 97.

tricolor, 95.
Mirabilis Californica, 118.
Mirror Galvanometer, New Form

of, 208.
Monardella, Revision of, 100.

Breweri, 102.

candicans, 102.

Douglasii, 102.

lanceolata, 102.

leucocepliala, 102.

linoides, 102.

macrantlia, 100.

nana, 10 1.

odoratissima, 101.

undulata, 102.

villosa, 101.
^Mountain Surveying, 256.
Muhlenbergia debilis, 120.

N.

Neillia Torreyi, 136.
Nemopliila aurita, 118.
Nicotiana Bigelovii, 117.
Nobert's Test Plates, Explanation

of Method of Ruling, 237.
Notholajna Newberryi, 121.

400

INDEX.

O.

Obione Suckleyana, 103.
ffiuanthe Californica, 139.

sarmentosa, 140.
CEuothera Guadalupensis, 115, 137.
Officers elected, 314, 321.
Oligomeris subulata, 109, 113.
Orthotrichuiu Lyellii, 121.

P.

Palmer, Edward, Collection of

Plants, 112.
Palmerella, 80.

debilis, 80.
Parietaria debilis, 119.
Parkinsonia, 135.

florida, 135.

microphylla, 136.

Texana, 13(J.

Torreyana, 135.
Pectocarya penicillata, 118.
Pellsea ornithopus, 120.
Pentstemon barbatus, 94.

Clevelandi, 94.
Perityle Emoryi, 116.

incana, 78, 116.
Petalostemon tennifolius, 73.
Peucedanum, Revision of, 141.

abrotanifolium, 142.

ambiguuni, 142.

bicolor, 144.

carnifolium, 143.

dasycarpum, 145.

Euryjitera, 142.

farinosum, 142.

foenicnlaceuin, 143.

graveolens, 142.

Hallii, 141, 143.

Ijevio^atum, 142.

latifolium, 142.

leiocarpuni, 141.

leptocarpnin, 112.

niacrocai'puni, 143, 144.

mari^inatnni, 143.

niillel'oliuni, 143.

Nevadense, 143.

Newberry i, 145.

nudicaule, 143, 144.

Nuttallii, 142.

Parryi, 143, 144.

parvifoliuin, 142.

simplex, 142.

tenuissimuni, 142.

tomentosum, 145.

Peucedanum triternatum, 142.

utricLilatum. 143.

villosum, 144.
Phacelia phyllomanica, 87, 118.
Phoradendron Bolleanum, 119.
Photographs of the Solar Spectrum,

70, 279.
Pinus insignis, 119.
Plantago Patagonica, 116.
Pogogyne tenuiflora, lOO, 117.
Polygala acanthoclada, 73.
Polypodium Californicmn, 120.

Scouleri, 120.
Potentilla Wheeleri, 148.
Procyon, Companions of, 185.
Proper Motion of the Stars, 52, 210.
Pterostegia drymarioides, 119.
Purpureocobalt, List of Salts of, 11.

Ammonio-cobalt-nitrite, 7.

Chloro-fluosilicate, 9.

Chloro-nitrate, 3.

Cobalto-nitrite, 8.

Neutral Sulphate, 5.

Nitrates, 1.

Oxalo-chloride, 4.

Pyrophosphate, 6.

Tungstate, 4.
Pyrrliopappus Rothrockii, 80.

Quercus chrysolepis, 119.

R.

Ranunculus hebecarpus, 112.
Reports, 313, 318, 321, 322, 331.
Rliamnus crocea, 114.
Rluis laurina, 114.
Ribes sanguineum, 114.
Roseocobalt, List of Salts of, 24.

Acid Oxalo-sulphate, 21.

Acid Sulphate, 14.

Basic Oxalo-sul]iIiate, 21

Chloro-aurate, 19.

Cliloro-hydrargyrate, 20.

Chl()r])latinate, 16.

lodo-sulphate, 13.

Sulpliat.'s, 12.

Sulphato-cliloro-aurate, 19.

Sulphato-chlorplatinate, 18.

Yellow Sulphate, 14.
Ruling Test Plates, Explanation
of Nobert's Method, 237.

1NM)KX.

101

Ruinfonl Coiumittoo, Apprupria-
tions, ;U;3, 3U.
JMedul, Award of, 314, 325.
^loimiiuMit at Paris, 3'JO.
Rumlord's Works, 313, 314, 318,
330.

S.

Sanicula Menziesii, 115.

Nevadensis, 139.
Saracha aciitifolia, 90.
Saturn, on Some Physical Observa-
tions of, 174.
Scutellaria nana, 100.
Seduni pusillum, 71.

varie^atuin, 137.
Selinum Pacificum, 140.
Senecio Palineri, 80, 110.
Silene antirrhina, 113.

Gallica, 113.
Sisymbrium canescens, 113.

deflexum, 113.

reflexum, 113.
Smelowskia Fremontii, 123.
Solan um Californicum, 91.

nigrum, 117.

umbelliferum, 91.

Xanti, 90, 117.
Solar IMotion in Space and the
Stellar Distances, 52, 210.

Spectrmn, Photographs of, 70,
279.

Spots,' Veiled, 62.
Sonchus oleraceus, 116.
Sophora Arizonica, 135.

speciosa, 135.
Sound, Diffraction of, 269.

Proof of Law of Inverse

Squares, 265.

Sparks, Induction, from breaking

the Circuit between the Poles

of a Magnet, 218.

Spectra, Comparison of Prismatic

and Diffraction, 273.
Spectrum, Solar, Photographs of,

70, 279.
Specularia, Revision of, 81.

biflora, 82, 116.

leptocarpa, 82.

Lindheimeri, 82.

Linsecomia, 82.

ovata, 83.

perfoliata, 83.
Sphseralcea incana, 125.

sulphurea, 113, 125.

VOL. XI. (n. s. iu.)

SjiiniM Calit'ornica, 1 IS.

nionogyna, 136.

opulil'tilia, 136.
Statutes and Standing Vntes, 382.

AmeiidMicnls to, 321, 322, 323.
Stellar Distances. 52, 210.
Stellaria niteus, 113.
Stenochloe Calit'ornica, 120.
Suckleya, 103.

I>i'ti()hiris, 103.
Surveying, Mountain, 256.

T.

Test Plates, Nobert's Method of

Ruling, 237.
Theniiopsis Californica, 126.

fabacea, 126.

macrophylla, 126.

montana, 126.
Thysanocarpus erectus, 113, 124.
Tiedemannia teretifolia, 145.
Tilla>a cymosa, 71.

minima, 115.
Tonella, 92.

collinsioides, 93.

floribunda, 93.
Tribulus Californicus, 125.
Trifolium, Revision of, 127.

aciculare, 130.

altissimum, 128.

amabile, 129.

amphianthum, 129.

amplectens, 114, 131.

Andersonii, 127.

Andinum, 130.

barbigerum , 131.

Beckwit-hii, 128.

Bejariense, 130.

bifidum, 129.

Bolanderi, 128.

Brandegei, 128, 130.

Breweri, 129, 131.

Carolinianum, 129.

ciluitum, 129.

ciliolatuni, 129.

cyathiferum, 131.

dasjqihyllum, 130.

denudatum, 129.

depauperatum, 131.

dichotomum, 129.

diversifolium, 131.

eriocephalum, 128.

fiml)riatum, 130.

fucatum, 131.

26

402

INDEX.

Trifolium Gambelii, 131.
gracilentum, 129.
gymnocarpon, 129.
Haydeni, 128.
heterodon, 130.
involucratura, 130.
Kingii, 128.
Lemmoni, 127.
longipes, 128.
Macraji, 129.
macrocalj^s, 130.
megacephalum, 127.
melananthum, 130.
microcephalum, 114, 131.
microdoii, 131.
monanthura, 131.
nanum, 128.
obtusiflorum, 130.
oliganthum, 131.
Palmeri, 114, 129, 132.
Parryi, 130.
pauciflorum, 130.
platycephalum, 127.
plumosuni, 128.
polyjihyllum, 130.
reflexum, 127.
spinulosum, 130.

Trifolium stenophylhim, 131.

stoloniferum, 127.

subcaulescens, 129.

tridentatum, 130.

variegatuni, 130, 131.

Wormskioldii, 130.
Triodalliis rupestris, 83.

V.

Vauquelinia corymbosa, 148.

Torreyi, 147.
Velocity of Clouds, Determination

of, 263.
Yicia Americana, 134.

exigua, 114.
Viviparous Echini from Kerguelen
Island, 231.

W.

Weissia viridula, 121.
Wires, Change of Electrical Resist-
ance in, by Stretching, 303.
AVyethia coriacea, 77.

Cambridge: Press of John WilHon & Son.

MHI. WMOI I.IHKAKY

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