I UC-NRLF
O
B 3 066 711 ■
HOW TO FIND THE TIME AT SEA
IN LESS THAN A MINUTE;
BEING
NEW AND ACCURATE METHODS,
• WITH SPECIALLY ADAPTED
TABLES.
A. G. JOHNSON, R.N.
AUTHOR OF
On finding the Latitude and Longitude in Cloudy Weather/' Ac.
SIXTH EDITION..
Xonfcon :
PUBLISHED BY J. D. POTTER,
Admiralty Agent far Charts,
145, MINORIES, E. 1.
1918.
[all rights reserved.]
THREE SHILLINGS.
HOW TO FIND THE TIME AT SEA
IN LESS THAN A MINUTE ;
BEING
NEW AND ACCURATE METHODS,
WITII SPECIALLY ADAPTED
TABLES.
A, C. JOHNSON, R.N.
AUTHOR OP
On finding tte> Latitude and Longitude in Cloudy Weather," <&c.
SIXTH EDITION
Xon&on :
PUBLISHED BY J. D. POTTER,
Admiralty Agent for Charts,
145, MINOHIES, E. 1.
1 did.
[all rights reserved]
THREE SHILLINGS.
PREFACE TO THE EIFTH EDITION,
The Tables (A) (B) (G) as given in this edition, are intended for
general use and although contracted so that all the logs requisite
for working a "Chronometer" are displayed at one view, the time
may be found by them within a second or two of that obtained by the
ordinary rules. The special Table (D) may be used when the sky is
clear, and the observation can h& taken in the manner indicated ; the
advantage of this being that only a single logarithm has to be looked out
after the observation has been taken, so that finding the time is reduced
to the most simple and expeditious process in the whole range of
nautical astronomy (vide p. 8), whil9 in point of accuracy it is not
inferior to the former method.
The very favourable notice accorded to these little tables by
Lieut. English, B.N. , in bis highly scientific and valuable articles on
Navigation which have from time to time appeared in the "Field"
newspaper, and the marked approval which they have met with from
numerous offioers of our own and foreign services, as well as from the
mercantile marine, have encouraged the author to introduce into this
edition sundry alterations .and improvements which he hopes will still
further add to the usefulness of the book.
Dartmouth, !$07.
385614
CONTENTS,
-^E-
Pags
D ., 0
ith the latitude at Moon... 7
D by Chart 8
teeomdM ... ... 8
-.ions 9
To n^d the Time simultaneously a ... 10
ling the Time byTal E | 11
a Star .. 19
- J. . 12
longitude for error in latitude 12
e 13
. (es 15
>bserred altitude 10
16
20
2G
38
nth,
... 28
INTRODUCTION.
The practice of working out the sights for longitude with the DM. latitude,
and of subsequently correcting the resulting longitude for the error in this
latitude, is, in the present day, generally followed. Now it will make no
difference in the ultimate result if, instead of the D,R. latitude an twinned
latitude approximating to it be used— the object being to reduce the
meridian zenith distance (ichkh is the suv> or difference of the latitiule and
decimation, according as they are of opposite or like names) to an exact number
of degrees, so that it may correspond with the M.Z.D. in Table (D). For
a like reason the altitudo is taken to an exact degree, a matter of perfect
simplicity to a practised observer, and, when taken, no further correction
is necessary. Should, however, the weather be cloudy, and the altitude be
taken in the usual way, we can easily correct the log. from Tablo (D) for
the minutes of altitude, as shown on p. 12.
The observation is supposed to be taken r.nder the usual conditions
as to the bearing hum the meridan, and to an exact degree by allowing
the correction in altitude the opposite way. Thus for 20 ft. and 80°, the
correction in altitude for the sun is + 10' ; and if the index error be -f- 1',
the combined correction is + 11'. If, therefore, the sextant be set at
29° 49', the true altitude of the Sun's .centre- will be 80° at the moment the
lower limb is in contact with the horizon.
For a star the correction in altitude must bo added instead of sub-
tracted, but the index error must be applied as before. Thus, for 20 ft. and
30°, the correction in altitude -is -6', and if the index error be -f 1' the
combined correction will be — 5' ; if, therefore, the index be set at 80° 5',
the true altitude will be 80° when the star is in contact with the horizon.
Tho longitude deduced from the time thus found is to be corrected for the
srror in the assumed latitude in the usual way. {Vide p. 12.)
TO FIND THE TIME. BY TABLE (D).
I. — Assume a latitude that will make the M.Z.'D. an exact number of
degrees.* and let this be called Lat. A.
II. — For this M.Z.D., and the altitude take out the logarithm from
Table (D). This added to the log. secants of the assumed latitude and
declination, -will be tfee log. versine of the hour angle, which will be found
in the part of Table (B) indicated by the approximate time, or hour angle.
If the body be East of Meridian, subtract the H. A. found as above
from 24 hours.
The longitude deduced from this time 13 to be corrected for the error
in the assumed latitude by Table (E).
EXAMPLES.
I.-LafcD.B. 30°25'N. Dec. 19° 45' S. Alt. 28°.
Itfit. A. 30° 16' N. log sec. G3(»
«>ec. 20 45 S, ,, ,. 2fi3
Alt, 28 0ll°3^b-^ ™m
H.A. 2h, 32m. 37s. log vors. 328?
II.— Lat.D.R. 52°20'N. Dec. a0 80' J*. Alt. 10°.
Lat. A. 52° 30' N. log. sec. 2JS6
D*c. 1 30 N. „ „ d
BKZ.D. 61 0)
Aft. 19 0 fl«>g. iob. tD, 4826
H.A. 3h. 59m. 44s.... lo^' vers. oD8'2
The assumed latitude need not differ from the I). JR. latitude 'by more
than 30', and will not, therefore, ati'ect the accuracy of the result.
Ou the next page is shown the practical application of the above in
finding the longitude at noon, and the longitude corresponding to Hit- D.K.
latitude.
* To do this make tbe minutes of latitude equal to the minutes of declination, when
they are of the name name, :md when they are of contrary names subtract the minute* in
the declination ft om 60' to obtain the minutes of. assumed latitude.
HI.— At 8.30 a.m., in lat. D.R. 40° 35' N., G.A.T. by chronotnete*
22h. 20m. 20s., true alt. 0 30°, run to noon N.N.W. 30', lat. by raer. alt
at noon 40° 52' N. Required the true longitude at noon.
I Mi. A. 40" 30' N. 1190 Az. by Tables.*
Dec. 3 SON. 8
;S. 66° E.
M.Z.D. 37 0) Lat. 40° N.
Alt. 30 0|' H.A. 8.30
1
H.A. 3h.-S0m.40i. 5949
S.A.T. 20 29 20
G.A.T. 22 20 20
1 51 0
= 27* 15p W., at 8.30 a.m. (long.
A)
How to find the longitude simultaneously with the latitude
at NOON.
Lat. A. 40° 30' N. Long. A. 27° 45' W.
Run 28 N. Run 13 W.
Approx. lat. 40 58 NT. Appro*, long. 28 0 W.
Lat. mcr. ) 4Q -2 N Cor. -53 x 0 3 g W.
Alt./
Cow. 0 S. True long. 23 34 W.
If it were required to find the longitude corresponding to the D.R.
latitude at 6.30 a.m., we should have :—
Lat. A. 40^ 30* K. Lour. A. 27° 45' W.
h.li. 40 35 K. Cor. 58 x 5 , 3 E.
Corr. 5 N. Approx. long. I 27 42 w
at 8.30 f "' *H w'
The correction for longitude, *56', is taken from Table (E).
To name the correction for the longitude, vide page 12.
The bearing found by Azimuth Table, when exceeding 903, must be
subtracted from ISO'', and reckoned from the opposite point — thus,
N. 120 W. would be S. CO0 W., &c.
Those given In •* Cloudy Weather " may be used ior this purpose.
To find the position AT NOON by the Chart.
Through the point given by the approximate latitude and longitude at
noon, draw the position line, or (in this case) the line at right angles to
S. 60° E. Then where this is cut by the parallel of the true latitude will
be the true place of the ship.
To explain how in actual practice the Time may be found
IN A FEW SECONDS.
As the declination^ and therefore the assumed latitude which depends
on it, are known before the observation is taken, we are already provided
with the M.Z.D., and the two log secants ; a single logarithm only will
then be required to complete the process. Thus, in Ex. I., p. 6, the
declination being 19° 45' S., and. the ship bctwees 80° N. aad 81° K., it is
evident that the assumed latitude must be $0° 15s N., therefore ns have —
Lat, A.
30° 15' N.
636
Dec.
19 45 S.
268
M.Z.D. 50 0 899 N.
Having subsequently observed the altitude to be 28° we have —
N. 8tf9
Log. tab. (D) 2888
h. HJ, 3,
Log. vers. 8287 - 2 82 27
The time is thus found in a fern seconds and with summers t accuracy
for all practical purposes at sea.
Application of the above Principle to Sliding the Position by
TWO OBSERVATIONS.
Let us suppose that the foregoing observation has been taken ; that
the longitude deduced from it i& 20° 45' W«, and that the ship has run
E.S.E. 22' till 4.80 *.m., we have —
Lat. A. 80° 15' N. Long. A. 20* 45' W.
Run 8 S. Bun 28 E.
Lat. B. 80 7 N. Long. K 20 22 W.
The declination being now 19° 47' S<, suppose, and the ship being
between iat. 80° and 31° K., we assume 80° 13' N, for lat, C. Hence
we have
Lat. C. 80^ 18' N. 685
Dec. 19 47 B. 264
M.Z.D. 50 0 899 (N.)
The second altitude is now taken, and is found to be 8°, therefore,
as before : —
N. 899
Log. tab. (D) 7021 h. in. s.
7920 = 4 80 82
Now, supposing that the longitude resulting from this time is
20° 52' W. (or long. C), we have then :—
Lats.
Longs.
Az.
Position Lines.
B 30° 7' N.
B 20° 22 W.
S. 41° W.
N. 49° W.
G 80 18 N.
C 20 52 W.
S. 61 W.
N. 29 W.
Laying down B and C on the chart, and drawing the corresponding
position lines, the point in which they intersect will be the true place of
the ship at the time of the second observation.
The above principle is equally applicable to two stars, taken in the
morning or evening twilight, either simultaneously or in quick succession ;
and, .as it involves only about a quarter of the work of an ordinary
1 Sunnier,' and will give just as good results, it is strongly commended to
the notice of the practiqal navigator.
Obs. —The difference of bearing should not be less than 1£ or 2 points ;
and, as a general rule, should exceed the less bearing. This applies to
all heavenly bodies.
to
To find the Time SIMULTANEOUSLY with the Altitude.
As shown on page 8, we can determine beforehand the M.Z.D. and N. ;
we can therefore take out the H.A. for a few consecutive degrees, which
will include the altitude at the time we wish to take the observation.
Thus, for M.Z.D. 50°, N. 899, and altitudes 29°, 30?, 81°, we have :
899 899 899
1986 1547 1064
2446 1963
(a) 2h. 25m. 18s. (b) 2h. 17m. 53s. (c) 2h. 10m. 14s.
If, therefore, the true altitude is found to be either of the above
s, the corresponding H.A. is known without further calculation.
The altitudes to be selected will, of course, depend on the time at
which it is intended to take the observation. Suppose, for instance,
we fix upon 8 a.m., and that the M.Z.D. is 50°, and N. 899, as before.
Subtracting N. from the log vers. H.A., we look for the remaining log
under the M.Z.D. 50°, hi Table (D), when in a line with it we find the
altitude thus : — .
Log. vers. 4h. = 6990 Tab. (C).
N. = 899
Log. alt, = 6091
Now, in the column M.Z.D. 50°, we find that 6091 comes between
the logs, of 13J and 14°. Hence we may select 18°, 14°, and 15°, fo*
which we take out the time, as above.
So that, if required, while one person is taking the altitude, a second
may be finding the time from the Tables.
If, owing to clouds, the altitude cannot be observed as explained, the
log. from Table (1)) may easily be corrected for the minutes of altitude,
us shown on p. 12.
From the above hour-a)igles and altitudes may he found the Bearings, by
tht Azimuth Tobies, and thence the Variation, tic., */' required.
11
ON FINDING THE TIME BY TABLES (A), (B), (C).
(These Tables are to be used when the observation is taken in the
usual way, and as they are all on the same opening, a great saving of time
and trouble is thereby effected.)
From Table (A) are taken the nat. versines of the Z.D. and M.Z.D.,
and the H.A. corresponding to their difference.
The log. versine of this H.A., Table (C), added to the log, secants of
latitude and declination, Table (B), will be the log. versine of the H.A.,
to be taken from the part of Table (C), indicated by the approximate time..
EXAMPLES.
I.--rAt about 4h. 40m. p.m., in lat. 10° 35' N.,' ©Z.D. was 76° 32', and declination
23' 23' ~S.
Lat. 10° 35r N. 74 sec.
Tab. A.
Dec. 23 2& S.
372 ,,
M.Z. 33 58
ZJ>. 76 32
4h. 24m. 49s.
4 40 46
7756 log vers.
8202
N. Vers. 1706
7672
Diff. 5966f
H.A.
IL—At about 4h. 10m. p.m., in lat. 10° 5' N., ©Z.D. was 63° 35', and declination
23° 19' N.
Lat. 10° 5* N. 67* sec.
Tab. A. Dec. 23 19 N. 370* „
N. Vets. 266* M.Z. 13 14 ^
„ 5551 Z.D. 63 35
Diff. 5285 4h. 7m. 28s. 7230 log. vers.
H.A. 4 21 48 7667 „
When the sun is west of mer. the H.A. is apparent time. When
east, subtract the H.A. from 24 hours.
When the sum of the logs, exceeds four figures, reject the fifth figure
on the left.
The parts marked with an asterisk may be written down before the
observation is taken, thus enabling the remaining part of the calculation to
be quickly gone through.
In usiog Table (C) it may sometimes be required to subtract an
apparently greater logarithm from one apparently less, in which case the
latter must be increased by 10,000, which is done by prefixing 1.
Thus : 0026-9970 = 10028-9970=0056.
t Here diff. 5966 gives 4h. 24m. 49a. by Table (A). And 4h. 24m. 49s. give
log. vers. 7756 by Table (C). In Ex. II. 5285 gives 4h. 7m. 28s. by Table (A), and
4h. 7m. 28s. give log. vers. 7230 by Table (C).
12
TO FIND THE TIME BY A STAR.
Find the hour-angle as in either of the preceding examples ; then to
the star's H.A. add its R.A., and from the sum (increased, if necessary, by
24h.) subtract the R.A. of the mean Sun. The remainder will be mean
time at ship. The longitude is then found in the usual way.
N.B. — If the star is East of meridian, subtract the H.A. found as
above from 24 hours.
The star's bearing, when required, may be taken from Burdwood's
Tables, or from ''The Bearings of the Principal Bright Stars," by the
Authoi, published by J. D. Potter, London, price 3a.
To take out the Log. from Table (3D) when there are minutes
in the Altitude.
Take the difference of the logs, for the two degrees of altitude between
which the given altitude lies, multiply it by the minutes expressed as
the decimal of a degree*, and subtract.
Thus for M.Z.D. 10° and Alt. 20° 24'
We have for Alt. 20° 6081
Diff. 112 x -4;-- 45
Log. required 8036
Again, for M.Z.D. 4°, and Alt. 25° 20'
We have 7S96
Diff. 120 x '88- 40
Log. required 7C56
As the logs, decrease, they are conveniently arranged for subtracting.
To correct the longitude for an error in the latitude.
Table (E) gives the correction for 1' error in the latitude — this,
multiplied by the latitude correction, will be the correction required.
To name the Correction.
Under the sun's bearing, at the time of observation, write the opposite
bearing, and connect the letters diagonally,
Thus for Bearing N.W.
X
We Jiavo S.E.
* The multiplier nifty be taken from Table (D), p 25.
18
Which shows that a North correction of latitude gives an East correction
of longitude, and vice versa.
Ex. lat 80° N. 0 Bearing N. 80° E., corr. of lat. 20' S.
Lat. 80° i ntnn N'?'
Az.800^0'-20 s/
• . • The correction = '-20 x 20 or 4' E.
The name of the correction may also be found by reversing the first
letter of the bearing, thus for N.E. we Lave S.E., showing that a corr. S.
gives E. and rice verm.
EXAMPLES FOR PRACTICE.
Finding the Hour- Angle
by Table
D
.
(1.) Lat. assumed, 50' 30' X.
Dec. V SO' X.
Alt. 2C
II.A. afibut 3^ his.
l±J „ 10 45 S.
„ 10 15 X.
,, 15
4 „
(2) ,. 7 13 X.
„ 2 15 X.
,. ">o
2J .,
(4.) ., 30 40 X.
„ \ 20 S.
11
,.■ H ..
(5.) ,, 29 10 X.
., t2 10 X
ANSWEBS.
„ 33
4 .,
(1.) 3h. 30m. lGs. (2.) 3h.
59m. 12a. <3.)
2h. 31m. 3s
(4.) 2h. 19m. Is,
(5.) 3h. 55m. 37a.
Finding the Hour- Angle by Tables (A), (B), (C).
(1). True Lat. 50'' 21' N. Dec. 123 10' N. Alt. 40° 30' H.A. about 2J hrs.
(2). ., 40 30 S. „ 10 51 X. „ 35 17 „ „ 1J ..
(3). „ 20 10 X. ., 10 20 X. ■ „ 50 15 „ „ 2| „
(4). ., 2 5 8. „ 1 3 S. „ 60 10 2 „
ANSWEBS.
(1.) 2h. 34m. 33s. (2.) lh. 21 m. 303. (3.) 2h. 40m. 13s. (4.) lh. 59m. J7s.
14
The M Z.D. and N., having been previously determined ; to find
the Hour-Angle.
(1.) M.Z.D. 50' X. 295 Alt. 209 H.A. about. 3 hoars.
(2.) ,. 48 X. 1216 „ 17 „ „ 4£ „
(». „ 45 X. 312<$ „ 15 „ ,, 6§ „
. AXSWERS.
(1.) 8h. 9m: 12s. (2.) 4h. 20m. 54s. (3.) 5h. 41m. 52s.
Correcting Log. Table D, for Minutes.
(1.) M.Z.D. 10' Alt. 40* 20'
42.) „ 20 „ 13 20
(8.J „ 30 „ 20 4h
AXHWBRS.
(1.) 32*4. (2.) 5889. (».) "iW.i.
Correcting the Longitude, for an Error in Latitude.
11.) La*. 50" X. Bearing S. 00' E. Coir, for hat. 2W X.
(2.) „ 40 S. „ S. 70 W. „ 10 »S.
(3.) „ 20 X. „ X. 75 h. „ 15 N.
AXSWEHS-CORUECTIOXS.
(J.) 18' E. (2.) 5'E. (3.) 4'W.
EXPLANATION OF THE TABLES.
Wlten a logarithm has to be taken out in two parts, place the forefinger of i^e
left-hand on one part and the pen on the other, when the tipo parts ore
easily added together at night*
• Tho parts for the minutes seldom exceed two figure*, and frequently only a single
figure fc reruired to be added.
15
Tab. (A). To take out Nat. Vers. 31° 53' : We have 30° at the Bide, and
1° 45' at the top, or 31° 45' = 1496, and the parts for 8' (to make up 58')
are 12 — which, being added, we have 1508 ; the Nat. Vers, required.
To take out Nat. Vers. 59° 25|' : We have 55° at the side, and 4° 15' at the
top, or 59° 15' = 4887, and the parts 10J' (to make tip 25V)
are 26 — which, being added, we have 4913.
This Table is arranged in two parts. The second being supposed to be a
continuation of the first from left to right,* so that any veraine not
appearing in the first part will be found in the second, and vice versa.
To take out the time. for Nat. Vers. 4188 : The Nat. Vers, next less is 4157,
which gives 3h. 37m., and the cliff. , 31, gives 54 seconds: hence the
time is 8h. 37m. 54s.
Conversely : The Nat. Vers, of 3h. 37m. 54s. is 4188, for 3h. 37m.
gives 4157, and 54s. give 31— which, being added, we have 4118
as above,
fables (B) and (C) are used in the same manner.
The use of Table (D) when there are minutes in the altitude is
explained on p. 12.
To convert Arc into Time by Table (A.).
Ex. Convert 76° 40' into time: We have 76° 30' = 5h. 6m., and K>* = 40s.
■.• 76°40' = 5h. 6m. 40s.
Conversely: 5h. 6m. 40° = 76° 40', for 5h. 6m. = 76° 30*, and 40s. =10'
♦.- 5h. 6m. 40s. = 76° 4tf.
For an Arc greater than 90° subtract 90° ; convert the remaining degrees
into time and add 6h., and for time exceeding 6h., subtract 6 hrs., convert
the remaining time into Arc and add 90°.
To find the Natural Versine of an Arc greater than 90° . Subtract the Nat.
Vers, of its supplement from 19999.
Thus for 120° 80' (whose supplement is 58° 80') we have Nat.
Vers. 59° 80' = 4925.
• . • 19999 -4925 = 15074 = Nat. Vers. 120° 80*
Conversely: Nat. Vers. 15074 = 120° 80'.
For 19999 -15074 ^492$ = 59° 30'.
And 180°- 59° 80' =120° 30'.
* In the. same way as Table B,
To convert a Nat. Vers, into a Lor/. Vers. :
E . — Convert Xat. Vera. 7IG8 into a Log. Versirus.
By Table (Aj, Nat. Vers. 7168= 4h. 54m. 12s.=Log. Vers. 8564, Table (C).*
III. To find the Hour- Angle of a Star, referred to the Meridian
below the Pole.
To obtain the M.Z.D. in this case add together latitude and declina-
tion and subtract the sum from 180°, then proceed as before.
EXAMPLE.
Lat. 50° 20' N. Dec. 48° 80' N. Z D. 79° 40' •
M.Z.D. 81° 10' 8465 Lat. 50° 20f 1950
*Z.D. 79 40 8207 Dec. 48 80 1787
Nat. Vers. 258 = Log. Vers. 4114
H.A. Ih. 20m. 28s. 7851
If the M.Z.D. exceeds 90°, find its Nat. Vers, as above.
As in this particular case the M.Z.D. will always be greater than the Z.D.,
it is written down first.
TABLES FOR CORRECTING THE OBSERVED ALTITUDE.
( .) CORR
FOR SUN'S OBS.
ALT.
+
CORK.
FOR STAR'S OBS
. ALT. -
HEIGHT IN
FEET.
HEIGHT
IN
FEET.
ALT.
5
S
10
15
20
25
30
35
40
45
50
55
60
*tr.
5
iC
15
20
25
SO
35
40
45
50
58
60
6
s
4
4
3
3
2
2
,
,
I
o
0
6
IO
n
12
«3
'3
14
'4
'5
'5
15
IS
rti
7
7
6
S
4
4
3
3
3
2
2
1
i
■i
9
IO
II
!2
12
'3
■3
»4
14
14
IS
'5
8
7
6
6
5
5
4
4
3
3
3
3
2
8
9
IO
IO
II
II
12
12
«3
*3
13
14
14
10
0
8
7
6
6
5
s
S
4
4
4
4
10
7
8
9
IO
IO
11
II
ii
12
12
12
«3
18
>o
<>
9
S
8
7
7
0
6
6
s
S
15
6
7
7
8
8
0
9
IO
IO
IO
1 1
ti
20
11
IO
IO
9
9
8
8
7
7
7
6
6
20
s
5
6
7
7
8
8
9
9
9
IO
IO
25
12
I,
IO
IO
9
9
8
8
7
7
7
6
25
4
fi
6
6
7
7
8
8
9
9
9
IO
30
12
I I
1 1
IO
IO
9
9
8
8
8
7
1
30
4
1
1
6
6
7
7
8
8
9
9
y
85
•3
12
ii
IO
IO
o
9
9
8
8
7
7
sa
3
4
S
6
6
7
7
8
8
8
9
9
40
n
12
ii
II
IO
IO
9
8
8
8
7
7
40
3
4
5
5
6
6
7
7
8
8
8
9
48
n
12
ii
II
IO
IO
IO
9
0
9
S
8
45
3
4
s
s
6
6
7
7
7
8
8
8
50
»3
12
ii
I!
IO
IO
IO
9
9
9
9
8
60
3
4
5
5
6
6
7
7
8
8
8
60
11
12
12
II
IO
IO
IO
q
9
9
S
8
60
3
4
4
S
S
6
6
7
7
7
8
8
70
n
fl
12
11
II
IO
IO
9
9
9
s
8
70
2
3
4
s
5
6
6
6
7
7
8
8
80
»4
>3
12
I]
II
IO
IO
IO
9
9
8
8
80
2
3
4
4
5
5
6
6
7
7
7
8
When there are tewer than four figures ^n the Nat. Vers, make them up to four by
adding ciphers : thus, in following example, Nat. vers. 258 becomes 2580 « 2b. 48m. 20s.
Tab. (A), = Log. Vers. 4111 Tab. (0/.
TABLES
IS
TABLES
FOR FINDING
Table (A) NAT.-VERSINES of M.Z.D. and Z.D.
Time
0 0
20
40
1 0
20
40
2 0
20
40
3 0
20
40
4 0
20
40
5 0
20
40
Time.
Arc
1
15
0 0 0150301)45 1 6
0) 0
42| 46
160 167
m m
3 4
m m
6 7
115 130!! 4.5
, 352 364
603 618
0371 956
1340)1302
18081834
2340i2368__.
2929129602991 U
3572 3606 3639 3673
4264 4300
•50005038
5774 5813
65806621
9931012
14061428
974
1384 __
1859 1884J1910
2396|2424!2453
30223053
1372
5076 5114
5853 5893
6662 <
7496
741217454
8264
9128J91729215
7538
8393
Arc
0 10
30
50
1 10
30
50
2 10
30
50
3 10
I?
4 10
30
50
5 10
30
50
2 30
10
237
463
761
1130
m
245)3 0
12j 14
91! 97
247; 256
476i 489
778J 795
1 5011171
1566 1590; 1618
206GJ2093|2l20
•2627J265'7 a'iOC
3244l3276i3309
3912i3947j3982
4627j4664|470lJ4
5383io42l|546P
fal
•.'93t703=»i7076
3341'3374
4017 [4052
73814775
5499i5S38
31621416254 6294^335
■"* 7118:7160
7836:787817921
8695I8738J8781 1882518868)
85 |9564j9607l9651
0
50 55| 59
175 184| 192
376; 387i 399
649j 664 680
|1031
1451
1936
2482
3707
4408
5152
5933
14741496,*,,.
1961198712014
:510 253912569
3085 31163148J3180
3741 3775 3809 3843
4444 4481I4517J4554
5190
usro 5228 5267 5305J5344
5973 6013 6053 609316133
6827 68688910 6951
67446786
7581
843C
7623
8479
^259 93029340
7606 7708 775017793
S522|8565j8608|8651
9390943^9477 9520
315J330 345
I ■ "
161 19 21
103 110 116
266| 276]' 287
503[ 517i 531
812! 829] 847
U91|1212U233
1637il66ljl685
2147|2174;2201
2686 27l6j2746|27!
4087
4812
5577
F5376
7202
9695,9738,9762
64j 69
201 1 210
4121 424
696! 712
105111070
m m
8 9
20
215
6
75
219
437
728
1090
1520
PARTS.
s s s s
1 4 8 1216202428 32364044 48 52 56
80
228
450
745
1110
1543
2040
2598
3212
3878
4590
I 8
4 0j4 15:4 30 4 45
24 27! 3l! 341
123| 1301 137j 144
297! 308j 319: 330
545j 559) 574' 588
865| 882 900: 919
1254|1275[l296jl8l8
1710!l734ll759ll784
2229 2256I22S4J2312
6|2807|2837 2867f2898
3407 34393472135063539
4122'4157!4193 4229
4850|4rt87|4925'4962
561g'5656|5695:5734
j6457|6498.6539
7244|7286|7328[7370
6876 6416
7964.8006 8049 8092 818981788221
8911|8955]8998j9042l908e
9826|9669l9913!995G
Tabic (B) LOG-SECANTS of LAT. and PEC.
De*
0'
6
10
15
25
30
35
40
0 0,6 15)030 045J1 0115
18 20
17,
68| 70j 73
16li 156' 101
2-io 277! 284
427j 436 445
625! 636' 647
866 880! 893
1157117811190
45 1505 1524J1543
50 1919!l942ll966
55 12414.2441 2469 }2496
81 8
171] 17
166
291! 298; 306
454 468 473
65$' 6691 681
907) 020! 934
1206 122211239
1563! ! 562 It
1968,3011 2035j2068|
[2524j255a 2581
1301452 6,215
1 2' 3'
30! 32 36
J 88j 92j 96j 106
188 188 194! 200
313' 3211 828! 336
482] 492! TSOij 511
692i 7G4J at* 728
948; 962} 9771 991
1255:1272112891306
02 1622il642|l662jl683
2082j2107|2131
2610 26392668
iia
1
1 1
2 1
3 1
8 1
5 2
6 2
6 2
s s
1 4
il2
3 4 5
1
2 2
2 3
3 4
4 5
1 2
6 8
11
12 14
6 8 10|12 18 15
9
9110
6 8 1013
7 9 11
7 10 12 15
8 10 13 15 18 20 23 26 28 31
8 11 13
19 21
8 11 14117 19 22
8 11 14
9 11 14
9 12 1
4 5
6 7 8
2 21
4
11 11
13 14 15
8 9 10112 13 14 15 17 18
1214
15 17
16 18
17 19122
16
24 27
25 23
20
20 2
23 05
28 31
26 29 3
17 20 23 26 29 3
121620 2428 3238 4044
6 7 8
91011
1 l
3 3
5 6
7 8
9 11 11
910
15 17
15 17 19
17 19
123
19 21 2
20 2:
24 26
23 25
•::>o
33 36
35 37
36 39
H 37 40
37 40
35 38 41
9 1011
12 13 14
l 1
4 4
7 7
18 20 21
21 22 24
25 27
27 29
29 32
as si 34
4852 56
12 13 14
PARTS.
12
1 1
* I
1 1 1
2 1 2
2 12
3 1
4 13
5 2 3
5 2 4
3 4 5
1 2 a
21 8
4
8 3
3 4
4
1 5 7
5 6 8
6 6 911
6 7 8
1 1
2] 2
3
4i 4
4 6
8 8
9 1011
ft 4 6 7 8 9110 11 12
9 11
11 13
13 1
10 11
4 4
fi 5
6 7
13
13 1511 £
16 17
19 2123
12 13 14
2 2
2
8 4
5 5
6 7
8 9
10 11
12 13
14 16
17 18
31 2
25 2
19
THE TIME AT SEA.
20
Ta
zU:
>). MERIDIAN ZENITH-DiSTANCE.
ALT.
0° 1°
2° |
3° ! 4°
5°
6°
r \ 8° | 9°
10°
11° Alt.
0
8
7
8
3604 EM503
9601
9597 9592 j 9586
9578
9568
9557
9545
9531 | 9516
5°
32 1520
9518
9514 i 9509 9502
9494
9484
9473
9460
9446 j 9430
G
943t 9485
9433
9429 9424
9417
9403
9399
9SS7
9374
9360 9344
7
934;.
U8
9346
9343 9337
9330
9321
9311
9300
9287
9272 9255
8
926"
£60
9258
9?.54 9249
9242
9233
9223
9211
9197 .
9182 9166
9
10
li
12
13
14
9172
^171
9168
9164
9159
9152
9143
9132
9120
9106
9091 i 9074
10
908'
9079
9077
3D73
90G7
9060
9051
9040
9028
9014
8998
89B1
11
39GS
-987
8984
8980
8974
8967
8958
8947
8934
8920
8904
68S6
12
889S
8892
B890
8836
8880
8872
8862
8851
8838
8824
8807
87S9
1.3
8797 j
B796
8794
8789
8783
8775
8786
8754
8741
8726
8709
8691
14
15
16
17
18
19
869U 1
8598
869G
8891
8685
8677
8667
8655
8842
8626
8809
8590
15
860>J> J
8599
8596
8591
8585
8577
8567
8555
8541
8525
8507 1
8488
16
8498 j
8 497
8494
8490
S483
8475
8464
8452
8438
8422
8404
8384
17
8395 1
8S94
8391
8386
8379
8371
8380
8348
8333
8317
8298
8278
18
8283
8288
8285
8280
8274
8265
8254
8241
8226
8209
8190
8169
19
20
21
22
23
24
8182
8181
8178
8173
8166
8157
8146
8133
8117
8100
8081 |
8059
20
8073
8072
8069
8064
8056
8047
8038
8022
8006
7989 7969 1
7947
21
7961
7960
7957
7952
7945
7935
7923
7909
7393
7875
7855
7832
22
7848
7847
7844
7838
7981
7821
7809
7795
7778
7759
7738
7715
23
7732
7731
7728
7722
7715
7705
7692
7678
7661
7641
7820
7596
24
25
26
27
23
29
7615
7612
7610
7604.
759(5
7586
7573
7558
7541
7521
7499 |
7474
25
7495
7493
7490
7484
7476
7465
7452
7437
7419
7398
7375
7350
26
7372
7371
7367
7381
7»53
7342
7328
7312
7294
7273
7249
7223
27
7247
7246
7242
7236
7227
7216
7202
7186
7167
7145
7121
7094
28
7120
7118
7115
7108
7099
7087
707?
7056
7037
7015
6990
6982
29
30
31
32
33
34
6990
5998
6984
6978
6968
6956
6942
6924
6904
6881
6856
6827
30
6857
6856
6852
5845
6835
6823
6808
6790
6769
6745
6719
6689
31
6722
6720
6716
6709
6699
6686
667?
6852
6631
6607
6579
6549
32
6584
6582
6578
6570
6560
6547
6531
6512
6490
6464
6436
6405
33
6443
6441
6436
6429
6418
6405
6388
6368
6345
6319
6290
6258
34
35
36
37
38
39
6298
6297
6292
6284
6274
6259
6242
6222
6198
6171
6141
6107
35
6151
6150
6145
6137
8126
6111
6093
6072
6047
6020
5988
5953
IS
6001
5999
5994
5986
5974
5959
5941
5919
5893
5864
5832
5796
37
5847
5845
5840
5832
5820
5804
S785
5762
5736
5706
5672
5634
38
5690
5688
5683
5674
5661
5645
5625
5602
5574
5543
5508
5469
39
40
41
42
43
44
5529
5527
5522
5513
5500
5483
5462
5438
5409
5377
5341
5300
40
5365
5363
5357
5348
5334
5317
5295
5270
5240
5207
5169
5126
41
5197
! 5195
5189
5179
5164
5146
5124
5098 | 5067
5032
4992
4948
42
5024
5022
5018
5006
4991
4972
4949
4921 4889
4853
4812
4766
43
4848
4846
4839
4828
4813
4793
4769
4741 j 4707
4669
4626
4578
44
45
46
47
48
49
4667
4665
4658
4647
4631
4610
4585
4555
4520
4481
4436
4386
45
4482
4479
4472
4461
4444
4423
4396
4365
4329
4287
4240
4138
46
4292
4289
4282
4270
4252
4230
4202
4170
4132
4088
4039
3984
47
4097
4094
4087
4074
4056
4032
4003
3969
3929
S883
3832
S775
48
3897
3894
3886
3872
3853
3829
3799
3763
3721
3673
3619
3559
49
50
51
52
53
54
3691
3688
3680
3666
3646
3620
3588
3551
3507
3457
3400
3336
50
3480
3477
3468
3453
3433
3405
3372
3332
3286
3233
3174
3107
51
8263
3260
3251
3235
3213
3184
3149
3108
3059
3003
2940
2869
52
3040
3036
3027
3010
2987
2957
2920
2876
2825
2766
2699
2C24
53
2810
2806
2796
2779
2754
2723
2683
2637
2583
2520
2450
2371
54
55
56
57
58
59
2573
2570
2559
2540
2514
2481
2440
2390
2333
2267
2192
2108
55
2329
2325
2313
2294
2267
2231
2188
2135
2074
2004
1925
1835
56
2077
2073
2061
2040
2011
1973
1927
1872
1807
1732
1648
1552
57
1817
1813
1800
1778
1747
1707
1658
1599
1530
1460
J860
1257
58
1548
1544
1530
1506
1474
1431
1378
1316
1242
1157
1060
0950
59
60
61
62
6<
1270
1265
1250
1226
1191
1145
1089
1022
0943
0851
0747
9630
60
0982
0977
0961
0935
0897
0848
0788
0716
0631
0583
0421
0294
61
0684
0678
0661
0633
0592
0540
0476
0398
0307
0201
0080
9942
62
0374
0368
0350
0319
0276
0220
0150
0066
9968
9853
9722
9572
63
64
0052
0046
0026
9993
9940
9886
9810
9720
9613
9489
9846
9182 01
2J
Table (D) MERIDIAN ZENITH-DISTANCE.
Alt
12° | 13c
14°
15°
16°
1?o
18°
19°
20°
21°
22°
23°
JAxt.
5C
9499
9480
9460
9439
9416
9391
9365
9337
9307
9276
9243
9208
5°
6
9413
9394
9374
9352
9328
9303
9276
9248
9218
9186
9152
9117
Q
7
9326
9307
9286
9264
9240 [ 9214
9187
9157
9127
9094
9060
9024
7
8
9237
9218
9197
9174
9149 ! 9123
9095
9065
9034
9000
8965
8928
8
9
9
9147
9127
9106
9082
9057 9030
9002
89Z1
8939
8905
8869
8831
10
9055
9035 9013
8989
8963 i 8936
8906
8875
3843
8808 | 8771
8732
10
11
11
896-2
8941 j 8918
8894 8867 : 8839
8810
8778
8744
8709 8671
3631
12
8866
8845
8822
8797 8770 | 8741
8711
8678
8644
8607 : 8569
8528
12
13
8769
8747
8724
8698
8671 ' 8641
8610
8577
8541
3504 ; 8465
.8423
13
14
14
8670
8648<
8624
8597
8569 8539
S507
8473
8437
8399 , 8359
8316
15
35C9
8546
8522
8495
8466 j 84S5
8403
8368
8S31
8291 i 8250
8207
15
16
8467
8443
8418
8390
8361 ; 8329
8296
8260 8222
8182 8139
8095
18
17
8362
8338
8312
8284 8254 | 822.1.
8187
8150
8111
8070 8028
7981
3?
18
8255
8230
8204
8175 3144 8111
8076
8038
75*98
7956 1 7911
7864
18
19
19
8146
8121
8094
8064 I 8032 j 7999
7962
7924 7883
7839 : 7793
7745
20
8085
8010
7981
7951 ! 7919 ! 7884
784'1
7807- 7765
7720 ] 7673
7623
20
2]
21
7922
! 7896
7867
7836 7802 ! 7787
7728
1 7687 ! 7644
7598 I 7550
7498
22
7807
7780
7750
7718
7684 7647
7608
1 7566 ! 7521,
7474 I 7424
7371
2?
23
7689
7661
7631
7598
7563 ! 7525
7484
! 7441 j 7395
7347 7295
7241
23
24
24
7569
7541,
7509
7476
7439
7400
7359
7314 j 7267
7217 j 7164
7108
25
7447
7417
7385
7350
7313
7273
7230
7184 i 7185
7084 ! 7029
«971
25
26
2?
28
29
26
7322
7292
7259
7223
7184
7143
•7099
7051 ! 7001
6948 6891
6832
27
7195
7163 7129
7092
7052 i 7010
6964
6915
8864
6399 ! 6750
668S-
;>.
7064
7032 ! 6997
6959
6918 ; 6874
6827
8777
6723
6666 j 6606
6542
29
6931
6898 j 6862
6823
6780 I 6735
6686
66£4
8579
6520 6458
0S92
30
6796
6761 6724
6683
6640 6593
6542
6489
6432
6371 6806
8238
30
31
32
33
34
31
6657
6621 6583
6541
6495 6447
6395
6340
8280
6217 j 6150
'j080
32
6515
6478 1 6438
8395
6348
6298
6244
6187
6125
6060 5991
5917
33
6370
6332 j 6291
6246
6197
6145
6090
6030
5967
5899 5827
5750
34
-6222
6182 6139
|
6093
6043
5989
5931
5870
5804
5783 j 5658
5579
35
6070
6029 5985
5937
5885
5829
5769
6705
5686
1
5563 5485
5402
35
38
37
38
39
3$
5915
5872 I 5826
5777
5723 ! 5665
5602
5536
5464
5388
5S07
5221
37
5756
5712 5664
5612 5556 ! 5496
5431
5362
5288
5208
5124
50S4
38
5593
5547 f 5498
5444 [ 5386 j 5323
5256
5183
5106
5023
4S35
4841
39
5426
5379 5327
5271 i 5211 5145
]
5075
5000
4919
4882
4740
4642
40
5255
5206 ; 5152
5094 5031 4963
4889
48H
4726
4636 4539
4436
40
41
42
43
44
41
5080 J 5029 4973
4912 I 4846 ; 4775
4698
4616
4528
4433 : 4832
4223
42
4900 ' 4846 ! 47R8
4725 | 4656
4581
4501
4415
4323
4223 ! 4117
4( ■:'.
43
47 5 ' 4659 4598
4532 I 4460
4382
4298
4208
4111
4007 ; 8895
3775
44
4525 j 4467 | 4403
4334 4259
4177
4089
3994
3892
8783 3665
8538
45
4380
4269 4203
4130
4051
3965
3873
3773
3666
3559 3426
5292
45
48
47
48
49
46
4130
4066 ! 3996
3920
.3837
3747
3650
3545
3431
8309 j 3177
3036
47
3 923
3856 : 3783
3703
3615
3521
3418
3307
3188
3058 2919
27 '
18
3710 3640 3563
3479
3387
3287
3179
3062
2935
2797 | 2649
248S
49
8492 3418 3336
3247 ! 3150 j 3045
2930
2806
2671
2525 2367
2i96
50
3265 |
3187 ' 3102
3008 ■ 2905 2793
2672
2fi0
2397
2241 2072 1
1888
50
51
52
53
54
si
3032
2950 2859
2760 ! 2651 i 2532
2403
2263
2110
1943 1762
-: 5« t
52
2791
2703 ' 2607
2502 ,2387 j 2261
2123 i
1973
1809
1631 1436 1222
2541 j
2448 i 2347
2235 j
2112 ' 1978
1830 j
1670 j
1494
1301 1091 1 0859
54
2282 '
2184 | 2076
i
1956
1825 1682
1524
1351 !
1162
0954 , 0725 j 0472
55
2014 ; 3909 1794
1666 ;
1526
1372
1203
1016 0811
0585 ! 0336 i
00 i8
I
58
59
56
1735 :
1624 1500
1364 !
1213
1047
0864
066?
0440
0198 ! 9919 i
9813
57
1445 (
1326 1193
1047 i
0885
0705
0507
02sri
0044
9773 j 9470
9129
58
1143
1015 0872
0714 |
0539
0345
0129
9889
9621
9321 j 8984
8601
59
0827
0689 0536
0365
0174
9962
9726
9462
9166
8832 8153
8017
60
0497
0348 ! 0182
9996
9788
9556
9296
9003
8673
8297
7865
7362
60
61
62
63
64
61
0151
9989 i 9808
9605
9377
9121
8886
8503
8134
7706
7207
6617
62
9786
9611 9413 9190
8938
8654
8332
7964
7539
7044
6458
5747
63 y«ra
64 3996
9210 8992 j 8467 j
8467
8149
7785
7365
6874
6291
fi .--■'
8784 8543 | 8269 1 7957
7598
7182
6695
6117
5414 1
Table (D). MERIDIAN ZENITH-DISTANCE.
AlTw
24°
25°
26°
9094
27°
28°
29°
30°
31°
32°
33°
34°
35°
Alt.
5°
9172
9134
9052
9008
8962
8915
8865
8813
8759
i 8703
8645
5
6
9080
9041
9000
8957
8912
8865
8817
8766
8713
8658
8600
8541
6
7
8986
8946
8904
8860
8814
8767
8717
8665
8610
8554
i 8495
8434
7
8
8889
8840
8806
8761
8714
8666
8614
8561
8506
8448
8388
8325
8
9
8792
8750
8706
8660
8612
8562
8310
8456
8399
8339
8278
8213
9
10
8692
8649
8604
8557
8508
8457
8403
8348
8289
8228
| 8165
8099
10
11
8590
8546
8500
8452
8402
8349
8294
8237
8177
8115
j 8050
7982
11
12
8486
8441
8394
8344
8293
8239
8183
8124
8063
7999
! 7932
7862
12
13
8380
8334
8286
8235
8182
8127
8069
8009
7946
7880
i 7811
7739
13
14
8271
8224
8175
8123
8069
8012
7953
7890
7826
7758
7687
7613
14
15
8161
8112
8062
8008
7953
7894
7833
7770
7703
7633
j 7560
7485
15
16
8048
7998
7946
7891
7834
7774
7711
7646
7577
7505
1 7430
7352
16
17
7932
7881
7828
7772
7713
7651
7586
7519
7448
7374
| 7297
7216
17
18
7814
7762
7707
7649
7589
7525
7459
7389
7316
7240
• 7160
7077
18
19
7694
7640
7583
7524
7461
7396
7328
7256
7181
7102
7020
6934
19
20
7570
7515
7457
7396
7331
7264
7193
7119
7042
6961
6875
6786
20
21
7444
7387
7327
7264
7198
7129
7056
6979
6899
6815
6727
6635
21
22
7315
7257
7195
7130
7062
6990
6915
6836
6753
6666
6575
6479
22
23
7183
7123
7059
6992
6922
6847
6770
6688
6602
6512
64 IS
6319
23
24
7048
6986
6920
6851
6778
6701
6621
6536
6447
6354
6256
6153
24
25
6910
6846
6778
6706 6631
6551
6468
6380
6288
6191
6090
5983
25
26
6768
6702
6632
6558
6479
6397
6311
6220
6124
6024 J
5918
5807
26
27
6623
6554
6482
6405
6324
6239
6149
6055
5956
5851
5741
5625
27
28
6475
6403
6328
6248
6365
6076
59S3
5885
5782
5673
5558
5437
28
29
6322
6248
6170
6087
6000
5909
5812
5710
5602
5488
5368
5242
29
30
6165
6089
6007
5922
5831
5736
5635
5529
5416
5298
5172
5040
30
31
6004
5925
5841
5752
5657
5558
5453
5342
5225
5101
4969
4830
31
32
5839
5756
5669
5576
5478
5374
5265
5149
5026
4896
4758
4612
32
33
5669
5583
5492
5395
5293
5185
5070
4949
4820
4684
4539
4386
33
34
5494
5405
5310
5209
5102
4989
4869
4742
4607
4463
4311
4149
34
35
5314
5221
5122
5016
4905
4786
4660
4527
4385
4234
4073
3902
35
36
5129
5031
4928
4817
4701 4576
4444
4304
4154
3995
3825
3648
36
37
4938
4836
4727
4612
4489
4359
4219
4071
3913
3745
3564
3371
37
38
4740
4634
4520
4399
4270
4132
3986
3829
3662
3483
3292
3085
33
39
4537
4425
4305
4178
4042
3897
3742
3576
3399
3209
3004
2784
39
40
4326
4208
4082
3948
3805
3652
3488
3312
3123
2920
2701
2464
40
41
410.8
3984
3851
3710
3558
3396
3222
3034
2833
2615
2380
2124
41
42
3881
3751
3611
3461
3300
3128
2942
2742
2527
2293
2039
1761
42
43
3646
3508
3361
3202
3031
2847
2649
2435
2202
19.30
1674
1372
43
44
3402
3256
3099
2930
2748
2552
2339
2109
1858
1584
1283
0952
44
45
3148
2993
2826
2646
2453
2240
2012
1763
1490
1191
0861
0494
45
46
2«83
2718
2539
2347
2138 1911
1664
1393
1096
0767
0402
9992
46
47
2605
2429
2239
2032
1807 ! 1561
1293
0997
0671
0307
9898
9435
47
48
2315
2126
1921
1699
1455 1 1188
0895
0570
0208
9801
9340
8809
48
49
2009
1807
1586
1345
1080 J 0789
0465
0105
9701
9241
8712
8092
49
50
1688
1469
1230
0968
0678 i 0357
9999
9596
9138
S611
7993
7252
50
51
J 348
1111
0851
0564
0245
9889
9488
9032
8507
7891
51
52
0988
0730
0445
0128
9774
9376
8922
8398
7784
7047
52
53
0604
0321
0007
9655
9259
8807
8286
7674
6938
6024
if
54
0192
9881
9c 32
9138
8688
8169
7559
6826
'5914
4721
55
9749
9403
9011
8565
8048
7440
6709
5800
4608
2905
55
56
9269
8880
8130
7922
7317
6588
56
57
8743
8302
7790
7188
6462
5557
57
58
8162
7654
7054
6331
5428
58
59
7611
6914
6194
5294
59
60
6769
6051
5155
■
60
61
5902
1
61
23
Table (D). MERIDIAN ZENITH-DISTANCE.
Alt
36°
37°
38°
39°
40°
41°
42°
43°
44°
45°
46°
47°
Alt.
5C
8585
8522
8456
8388
8318
8245
8169
8090
8008
7924
7835
7744
5°
6
8479
8414
8347
8278
8205
8130
8052
7972
7887
7800
7709
7615
6
7
8371
8304
8236
8164
8090
8013
7933
7850
7.63
7673
7580
7483
7
8
8260
8192
8121
8048
7972
7893
7810
7725
7636
7543
744T
7347
8
9
8146
8077
8004
7929
7851
7769
7684
7596
7504
7409
7310
7206
9
10
8030
7959
7884
7807
7726
7642
7555
7464
7369
7271
7168
7062
10
11
7911
7838
7761
7681
7599
7512
7422
7328
7231
7129
7023
6912
11
12
7789
7714
7635
7553
7467
7378
7285
7189
7088
6983
6873
6759
12
13
7665
7587
7508
7421
7333
7241
7145
7045
6941
6832
6718
6600
13
14
7537
7456
7373
7285
7194
7099
7000
6897
6789
6676
6558
6435
14
15
7405
7322
7236
7146
7052
6954
6851
6744
6632
6516
6393
6265
15
16
7270
7185
7096
7003
6906
6804
6698
6587
6471
6350
6222
6089
16
17
7132
7044
6952
6855
6755
6650
6540
6425
6304
6178
6045
5907
17
18
6990
6899
6803
6704
6599
6490
6376
6257
6131
6000
5862
5717
18
19
684.4
6749
6651
6547
6439
6326
6207
6083
5952
5815
5671
5520
19
20
6693
6596
6493
6386
6274
6156
6033
5903
5767
5624
5473
5315
20
21
6538
6437
6331
6220
6103
5981
5852
5717
5575
5425
5267
5100
21
22
6379
6274
6164
6048
5927
5799
5665
5524
5375
5218
5052
4877
22
23
6215
6106
5991
5870
5744
S611
5470
5323
5167
5002
4828
4643
23
24
0045
5932
5812
5687
5555
5415
5269
5114
4950
4777
4593
4397
24
25
5870
5752
5628
5497
5358
5213
5059
4896
4723
4541
4346
4139
25
26
88
5690
5566
5436
5299
5154
5002
4840"
4668
4487
4'293
4087
8867
27
5502
3374
5238
5094
4942
4782
4611
4430
4238
4033
3814
3580
27
28
5309
5174
5032
4881
4721
4552
4372
4181
3977
3759
3525
8274
23
29
5108
4967 4817
4659
4491
4312
4122
3919
3702
3469
3219
2949
29
!?'
4900l
4751 j 4594
4427
4249
4060
3859
3648
3411
3162
2893
2601
30
4683
4527 4361
4185
3997
8796
3581
3351
3103
2835
2544
2226
31
32
4458
4293
4118
3931
3731
3518
3288
3041
2774
2484
2168
1821
32
32
4222
4018
3863
3664
3452
3224
2978
2712
2423
2108
1761
1379
33
34
3976
3792 3595
8384'
3157
2912
2.47
2359
2045
1700
1318
0892
34
35
3719
3523 i 3313
3087
2844
2580
2 293
1»81
1636
1256
0831
0351
35
36
3448
3240
3015
2773
2611
2225
1913
1571
1191
0767
0289
9741
36
37
3164
2941
2700
2439
2154
1844
1502
1124
0701
0224
9677
9041
37
3S
2864
2624
2364
2081
1772
1432
1055
0633
0157
9612
8976
8217
38
39
2545
2287 2006
1698
1359
0983
0562
0087
9543
8909
8152
30
40
2207
1927
1620
1283 1 0908
0489
0016
9473
8840
8083
!
40
41
1646
1540
1204
0*JI ! 0413
9941
9399
8768
8013
41
42
1458
1123
0751
0335 1 9864
9324
8693
7940
42
43
1039
0668
0254
9784.' 9245
8616
7864
43
44
0593
0169
9701
9164 8536
7785
I
44
45
0032
9616
9080
8453
7704
j |
45
40
0527
8993
8368
7620
1
i
46
47
S9C2
«279
7533
I
47
49
81S7
7442
6520
!
48
48 7349 j
S428
1
49
50 6332 j
1 1
50 j
24
Table (D). MERIDIAN
ZENITH-DISTANCE.
Alt.
48°
49° | 50°
51°
52°
53°
54*
55°
56°
57°
58°
59°
Alt.
5°
7649
7550.
7448
7341
7231
7115
6995
6870
6740
6604
6462
6313
5°
1
7517 i 7416
7310
7200 | 7085
6966
6842
6712
6577
6436
6288
6133
6
3
7382 | 7277
7168
7054 | 6935
6812
6883
6J49
6408
6281
6107
5946
7
8
7242 ! 7134
7021
6903 6781
6652
6519 1 6379
6233
080
5919
5750
8
S
7099 j 6986
6870
674S | 6620
6487
6348 j 6203
6050
5891
5723
5546
8
10
6950
6834
6712
658,7 j 6454
6316
6171
G020
5861
5694
5518
5332
10
11
6797
6677
6420 6282
6138
5983
5829
5688
5488
5303
5109
11
12
6689
6514
6384
6247 ! 6104
5954
5796
5631
5457
5273
5079
4878
12
ia
■
6476
6346
8210
6068 j 5919
5762
5424
5341
5047
4843
4625
13
6306
<"
60S0
58S2 ! 5726
j
5562
5389
5207
5014
»
4777
4810
4594
4364
14
15 j 6131
18 i 5949
5991
5843
568S | 5525
5353
5171
49«0
4561
4331
4086
15
5803
5648
5486 5315
5135
4944 4741
4526
4298
4053
3791
16
17 j 5761
18 ' 5564
5607
5446
5276
5096
4900
4704 4490
4262
4019
3758
3477
17
5404
5235
5056
4866
4666
4452
4225
3988
3722
3442
3139
lb
i9
5360
5192
5014
4825
4625
4413
4187
3945
8685
3406
3104
2775
19
1?
5147
4970
4782
4583
4372
4146
3905
3647
3067
2739
2381
20
4924
4738
4540
4329
4104
3864
3606
3829
3028
2701
2344
1950
21
52
4681
4494
4284
4060
3821
3564
3287
2988
2662
2305
1912
1475
22
23
4447
4238
4015
3776
3520
3245
2946
2621
2265
1873
1436
0945
23
24
4190
3968
3730
3475
3200
2'. >2
2578 2223
1831
1396
0905
0346
24
25
8918
3428
3163
2857
2533
2179
1789
1354
0864
0306
9658
25
28
3682 , -/S
3105
2809
2487
2) i
1744
1310
0821
0264
9616
8846
26
27
3827
065
2760
2439
2086
16i*7
1264
0777
0220
9574
8804
27
28
S003
2388
2037
1649
1217
'
0175
9529
8760
28
29
2666
1986
1599
1168
0682
0127
9482
8715
29
30
2282
193S
1547
1117
0632
0078
9434 ! 167
30
33
1878
1493
1064
i;580
0027
9384
8618
31
3!
1487
1008
0526
9974
9332
81 ?
32
SS
0951
0470
9278
8514
33
34
M12
9862
9222
34
35
9803
9164
8402
35
38 : 9108
6343
36
37 ' 8283
J
«
37
25
Table (D). MERIDIAN ZENITH-DISTANCE.
kvp.
60°
61
62°
63
64-
65°
66°
67°
63°
69°
70° 1 71°
SlLT.
5°
6
6158
599i>
5324
5645
5456
5256
5046
4823
4586
4333
4063 3773
5°
5971
5801
5622
5434
5235
5025
4803
4587
4315
4046
3756 3445
6
7
5776
5598
5411
5213
5004
4782
4546
4295 4027
8738
3427
3090
7
8
5573
,5386
5189
4981
4760
4525
4274
4006
3719
8408
3072
2704
•8
9
5360
5164
4956
4736
4502
4252
3985
3698
3388
3052
2685
2282
9
10
11
5137
-±930
4710
4477
5228
3961
3675
3366
3031
2*65
2263
1816
10
4904
4683
4451
4203
3937
3651
3343
3009
2643
2242
1796
1296
11
12
4655
4423
4176
3911
3626
3318
2985
2C20
2219
1774
1275
0706
12
13
4394
4147
3883
3599
3292
2959
2596
2195
1751
1252
0685
0027
13
14
4118
3854
3571
S265
2933
2570
2170
1,20
1228
0661
0004 9224
1
14
15
8823
3,541
3236
2904
2542
&L43
1700
1203
0637
9980
9201
15
16
3509
3206 2874
2513
2115 1673
1176
0631
9955
9177
16
1?
3173
f- 13
2482
2085
1648
1148
0583
9928
9151
17
18
2810 i J450
2054
1813
1118
0554
9900
9123
j
18
13
2416 '2020
1581
1086
0523
9870
9094
19
20
1986
1547
1054
0191
9839
9063
20
21
1512
1019 j 0457
9806
9031
1
22
0983
0422 1 9771
8397
23
0385
9735 1 8882
23
24
9697
8925
1
24
25
8886
25
Table (D). M
ERIDIAN
ZENITH-DISTANCE.
AiT.
72p
73°
74°
7-
76°
77°
78°
78° 1 803
0156 9370
81c
82°
1 83°
5°
5
3461
3122
2753
2347
1897 1392
0819
6
3107
2738
2333
1883
1S80
0807
0144
9i»59
6
7
2722
2317
1869
1266
0794
0182
9347
•
7
8
2300 1853
1550
0779
0118
9334
i
8
9
1835 I 1383
0763
0102
9319
9
10
1315 ! 0745
0086
9303
i
10
11
0727 | 0067
9285
i
11
12
0048 9267
12
13
9246
1
13
14
!
14
Table (D). MULTIPLIERS FOR MINUTES OF ALTITUDE.
MlN
0'
r
2'
3'
4' 5'
6'
7'
8'
9'
10'
0
•00
•02
•
03 '
•05
•07 • -08
10
•12
13
♦16
•17
10
17
•18
20
•22
•23 1 -25
•27
•28
•30
.•82
•33
20
•33
•35
•37
•38
•40 1 '42
•43
•45
•47
•48
•50
30
•50
•52
•53
•55
•57 ' -58
•60
•62
•63
•65
•67
40
•67
•68
•70
•72
•74 -75
•77
•78
•80
•82
•83
50
•83
•85
•87
•88
•90 -92
•93.
•95
•97
•98
J 00
ti
c
Ch
10
12
14
Table (E). LATITUDE.
6
4
8
lb
12 14
16
18
20
22
24
a
28
0
30
32
5-67
4-71
401
r
5-70
472
402
5-73
4-75
4-04
5-76
4-78
4-06
5-79
4-81
409
5-85
4-85
412
5-91
4-89
4-16
5-97
4-95
4-20
6J)3
501
4-26
6-12
508
4-32
6-21
5-16
4-38
6-30
5-28
446
6-42
5-34
4-54
6-55
5-43
4-63
6-69
5-55
4-73
16
18
20
3-49
3-08
2-75
3-50
3-09
2-76
3-52
311
2-78
3-54
313
2-79
3-56
315
2-81
3-59
3-18
2-83
3-62
3 20
2-86
3-66
3-24
2-89
3-70
3-28
2-92
3-76
3-32
2-96
3-82
3-37
301
3-88
3-43
3-06
3-94
3-49
312
4-02
3-55
3-17
4-11
3-63
3-24
22
24
26
2-47
2-25
205
2-47
2-26
2-05
2-48
2*27
207
2-50
2-28
208
2-52
2-30
210
2 54
2-32
211
2-57
2-34
2-13
2/60
2-37
2-15
2-63
2-39
2-18
2-66
2-43
2-21
2-70
2-46
2-24
2-75
2-50
228
2-80
2-55
2-32
2-86
2-59
2-37
2-92
265
2-42
28
30
32
1-88
1-73
160
1-88
1-73
1-60
1-90
1-75
1-62
1-91
1-76
1-63
1-92
1-77
1-64
1-94
1-78
1-65
1-96
1-80
1-66
1-98
1-82
1-68
200
1-84
1-70
203
1-87
1-73
2-06
1-89
1-75
2-09
1-92
1-78
2-18
1-96
1-81
2-17
2 00
1-83
2-22
2-04
1-89
S4
36
38
1-48
1-38
1-28
1-48
1-38
1-28
1-49
1-39
1-28
1-50
1-40
1-29
1-51
1-41
1-30
153
1-42
1-31
154
144
1-32
1-56
1-46
1-34
1-57
1-47
185
1-60
149
1-37
1-62
1-51
1-39
1-65
1-63
1-41
1-68
1-55
1-44
171
1-59
1-48
1-75
1-62
1-51
40
42
44
119
111
104;
1-19
111
104
1-20
1-12
1-04
1-21
113
105
1-22
1*14
10G
1-23
114
107
124
115
108
1-25
1-17
1-09
1-27
1-18
1-10
1-28
1-20
1-12
1-30
1-22
113
1-32
1-24
1-15
1-35
1-26
M7
1-38
1-28
1-20
141
1-31
1-22
46
4.8
50
0-97
0-90
0-84
0-97
0-90
0'84
0-98
0-91
0-85
0-98
0-91
0 85
0-99
0-92
086
100
0 93
0-87
1-01
0-94
0-87
1-02
0-95
0'88
1-03
0-96
0-89
1-04
0-97
0-91
106
0-99
0-92
1-07
1-00
0 93
109
1-02
0-95
111
104
0 97
1-14
1-06
0-99
52
54
56
0-78
0 73
0-67
0-78
073
0-67
0-79
0-73
0-68
0 79
0-74
068
0-80
0-74
0-69
0 80
075
0-69
0 81 1 0-82
0 75 I 0-76
0-70 | 0-71
0-83
0-77
0.71
0-84
0 78
0-72
0-85
0-79
0-73
0-87
0 81
0-75
088
0-82
0-77
090
0 84
0-78
0-92
0-86
0-79
58
80
62
063
0-68
053
063
0-58
053
063
0-59
0-54
0-03
059
0-54
0-64
0-59
0-54
064
0-60
055
0-65
0-60
055
0-66
0-61
0-56
0-66
0-62
056
0-67
0-62
057
0-68
0-63
0-68
0-89
065
0-59
0-71
0-66
0-60
0 72
067
0-61
0-74
0-68
0-63
64
68
88
0-49
0-45
040
0-49
0-45
0 40
0-60
0-43
0-40
0-50
0-45
0-41
0-50
0-46
0-41
0-51
0-46
041
0-51
046
042
0-52
0-47
042
0-52
0-47
0-43
0-53
0-48
0-43
0-54
0-49
0-44
0-55
0-50
0-45
0-56
0-50
0 45
0-56
0-51
0-47
0'57
0-52
0-47
70
72
74
038
0-33
0-29
0-36
0-33
0-29
0-88
0-33
0-29
0-37
0-33
0-29
0-37
034
0-30
0-37
0-34
0-30
0-37
0-84
0 30
088
0-34
0-31
0 38
0-35
031
0-39
035
0-31
039
0-36
0-32
.0-40
036
032
0-41
0-37
0*33
0-42
0-37
0-33
0-43
0-38
0-84
76
78
80
025
0 21
018
0-25
0-21
018
0-25
0-91
018
0-25
0-21
018
0-25
0-21
0-18
0-26
0-2-2
018
0-27
0 22
018
0-27
0-22
018
0-27
0 22
0-19
0-27
0-23
019
0-27
0 23
019
0-28
0-23
0-20
0-28
0-23
0 20
029
024
020
0-29
0-25
0-21
82
84
86
014
010
007
0-14
0-10
007
014
010
007
014
0 10
007
0-14
0-10
0-07
014
010
0-07
0-14
Oil
0 07
015
0-11
007
0-15
Oil
008
0-15
0-11
0-08
015
Oil
008
015
Oil
0-08
015
0-11
008
016
0*12
G'08
017
012
0'08
88
89
90
003
0-01
000
003
001
0 00
003
001
000
0-04
0-02
000
004
0 02
0 00
004
0-02
000
0 04
002
000
0-04
002
000
004
002
000
0-04
0-02
0-00
004
004
0'02
000
004
002
000
0-04
002
000
004
002
000
002
000
27
Table (E). LATITUDE.
K'*j
c
1
o
10
12
14
2 *i*
0
0
0
0 1 0
0
0
c
0
(,.| .
o
n
34
36
38
40 1 42 . 44
46
48
50
52
54 58
58
60
3li
6-84
5-67
4-84
7-01
5-81
4-95
7-20
5-97
5-09
7-40
6-14
5-23
7-63
6-33
5-40
1
7-88
6-54
5-58
816
6-77
6-77
8-48
7-03
5-99
8-82
732
6-24
921
7K54
6-51
9 65
800
682
1014
8-41
717
1070
8-88
7-57
11-33
9-41
8-02
5-76
4-70
413
16
18
20
4-21
371
8-31
4-31
3-80
3-39
4-43
3-90
3-49
4-55-
4-02
359
4-69
4-14
3-70
4-85
4-28
3-82
502
4-43
3-95
5-21
4-60
411
5-42
4-79
4-27
5-66
500
4-46
593
5-24
4-67
6-24
5-50
4-91
6-58
581
6-19
6-97
615
5--49
3 63
3-24
2-92
22
24
26
2-98
271
2-47
3-06
2-77
253
3-14
2-85
2-60
3-23
2-93
268
3-33
?-02
in
3-44
3-12
2-85
3-56
3-23
2-95
3-70
3-36
3-06
3-85
3-49
3-19
4-02
3-65
3-33
421
382
349
4-43
402
3-66
4-67
4-24
"3-87
4-95
4-49
410
2-67
2-46
2-28.
23
30
32
2-27
209
1-93
2-32
214
198
2-39
220
2 03
2-45
2-26
2-09
2-53
2-33
215
2-61
2-41
2-22
2-71
2-49
280
2-81
2-60
2-39
2-92
2-69
2-49
305
2-81
2-60
3 20
2-95
2-72
3-36
3-10
2-86
3-55
3-27
3-02
3. 70
3-46
320
213
2 00
1-89
34
36
38
1-79
166
1-54
1-83
1-70
1-58
1-88
1-74
1-62
1-93
1-80
1-67
1-99
1-85
1-72
2-06
1-91
1-78
213
1-98
1-84
2-22
206
1-91
2-31
214
1-99
2-41
224
2-08
2-52
2-34
218
2-65
2-46
2-29
2-80
2-60
2-41
2-96
2-75
2-56
1-79
1-70
1-62
40
42
44
1-44
1-34
1-25
1-47
1-37
1-28
1-51
1-41
1-31
1-55
1-45
1-35
1-60
1-49
1-39
1-66
1-54
1-44
1-72
1-60
1-49
1-78
1-66
1-55
1-85
1-73
1-61
1-94
1-80
1-68
2-03
1-89
1-76
213
1-99
1-85
2-25
2-09
1-95
2-38.
2-22.
207
1-56
1-49
1-44
46
48
50
1-16
109
101
1-19
111
104
123
1-14
106
1-26
1-17
109
1-30
1-21
1-13
1-84
1-25
1-16
1-39
1«30
1-21
1-44
1-35
1-25
1-50
1-40
1-31
1-56
1-46
1-36
1-64
1-53
1-43
1-73
1-61
1-50
1-8-2
1-70
1-58
1.93
1-80
1-68
1-89
1-35
131
52
54
56
0-94
0-88
0-81
0-96
0-90
0-83
0-99
092
085
101
0-95
0-88
1-05
0-98
0-91
1-09
1-01
0-94
1-12
1-04
0-97
1-17
109
101
1-22
1-13
1-05
1-27
1*18
1-10
133
1-23
115
1-4Q
1-30
1«21
1-47
1-37
1-27
1-56
1:45
1-35
1-27
3-24
121
58
60
62
0.75
0-70
0-64
0-77
0-71
0-6G
0-79
0-73
0-67
0 81 ! 0 84
0-75 078
069 0-72
0-87
0-80
0 74
090
0-88
0-76
0-93
0-86
0-79
0-97
0-90
0-83
1-01
094
0-86
108
0-98
090
112
1-03
095
1-18
1-09
1-00
1-25
1-15
1-06
1-18
115
1-13
64
68
63
0 59
0 54
0-49
0 60
0 55
0 50
062
056
051
0 64 ' 0-66
058 ; 0-60
0 53 ! 0-54
0-68
0-62
0-56
0-70
0-64
0-58
0-73
0-66
0-60
0>76
0-69
0-63
0-79
0-72
0-65
083
0-76
0-69
0-87
073
0-72
0-92
0 84
0-76
0-97
0-89
0-81
111
109
1-08
70
72
74
044
0-39
0-oi
0-45
0-40
03b
046
0-41
0-36
0-47
0-42
0 37
0-49
0-44
038
0-51
0-45
040
0-52
047
0 41
0-54
0-49
043
0-57
051
0'44
0-59
053
0-46
0-62
0 55
0-49
0 65
0-53
0 52
0-68
0-61
0-54
073
065
057
1-06
1-05
104
76
78
80
0-30
0-25
0 21
0 31
0 26
022
031
0-27
0 22
0-32
0-28|
0-23
0-33
0-29
024
0-34
029
0-24
086
0-30
025
037
0 32
0-26
039
0 33
027
0*0
0 34
0 29
0 42
03f-
0 30
0 45
0 33
0-31
047
0-40
0 33
050
0 42
0-35
1-03
102
102
82
84
86
0 17
On
008
017
0 18
008
018
013
009
0 18 i 0 19
0 14 ! 0 14
0 09 : 009
019
0 14
0 10
0-20
015
010
0-21
016
0-10
022
0-16
Oil
0 23
017
Oil
0 24
0 18
0 12
0-25
0 19
0 12
0-20
0 20
013
0-23
0 21
014
1-01
1-01
VOO
88
89
90
001
0 02
0 09
0 04
002
0 00
001
0 02
o a«:
0 04 ' 0 05
0 02 1 0 02
0 00' 0 00
005
0.02
000
005
0 02
000
0 05
003
0 00
0 05
003
0-00
0 06
003
000
0-06
ooe
0 00
0 06
004
000
0-07
oos
000
0 07
0 0-5
ooo
100
100
100
1
1
1
1
1
MOTES.
I. — If it be de.sired to take more than one altitude iu the maimer
directed on page 5, set the sextant first at 30° -11', and secondly at
BO" +11', when the Mean of the two will be SO0, as requi.ed. This-
applies to a.m. sights : For p.m. we must begin with ihe greatest altitude
and proceed in like manner.
To take four altitudes, set the sextant at 30° - 22', 30° - 11',
30° + 11' and 30° + 22', for A.M. sights; and in the. reverse order for
P.M. observations
II-— Application of Tables A, B, G, to finding the^ Altitude
Azimuth,
(a) Lai. and Dec. of same name : Take difference of lat. and alt.
(b) Lat. and Dec. of contrary names : Take sum of lat and alt.
For North declination, take N.P.D. and reckon Azimuth from North.
For South declination, take S.P.D. and reckon Azimuth from South, and
proceed as in finding the time.
Example I., a.m. Example II., p.m.
L it. 23° 45' N., Alt. 21° 42', Dec. 20° 49' N.
Lat. 23° 45' N. 384 Lat. 25° 31 N. 446
Tab. A. Alt. 21 42
6 Diff.
6446 N.P.D.
>49'N.
384
319
Lat. 25°
Tab. A.
31
'N.Dec. 14° 47' S, Alt.] 5C
Lat. 25° 31 N.
Alt. 15 46
2486
7449
4963
Sum 41 17
S.P.D. 75 13
8090
3h. 59m. 2s.
8793
*4h. 18m 30s.
6440 4h. 36m. 36s.
*5h. 3m. 48s. 8793 *4h. 18m HOs. 7570
.-. Az. = N. 75* 57' E. .-. Az. = S. 64' fty W.
When the Azimuth exceeds the limit of Table (B), which it can only
do when latitude and declination are of the same name, substract the sum
of lat. and alt. from 180^, and proceed as before, marking the Azimuth
with the contrary name to the declination.
III. — To find the time of sunset and sunrise by the same Tables ;
proceed as in the following Examples :
74
372
9187
Tab. A.
Lat.
Dec.
1706
10000
M.Z.
Z.D.
8294
5h.
Sunset
Sunrise
5
6
10° 35' N.
23 23 S.
33 58
90 0
20m
. 41s.
41
18
24 p.m.
36 A.M.
9633
IV.— To find the Azimuth at rising or setting, make the Altitude 0°,
and proceed as in Examples I and II. above,
» Thus 5h. 3m. 48s. = 303m. 48s., wnich divided by 4 75? 57' ;
and 4h. 18m. 30s. = 258m. 30s., which divided by 4 - 64* 37^'-
LIST OF NAUTICAL WORKS
PUBLISHED BY
J. D. POTTER.
145, MINORIES,
LONDOK E. 1
LIST OF NAUTICAL WORKS
Published by J. D. Potter.
ALTITUDE TABLES.
s. a.
Computed for Intervals of Four Minutes between the Parallels of Latitude
31' and 60° and Parallels of Declination 0° and 24°, designed for the Determination
of the Poiition Line at all Hour Angles without Logarithmic Computation, by
Frederick Ball, M.A. (late Scholar of Exeter College, Oxford), Chaplain and Naval
Instructor in Eis Majesty's Fleet ... ... ... ... ... ... ... ... 18 0
Ditto, ditto, between the Parallels of Latitude 0" and 30" and Parallels of Declination
0° and 24° 18 0
Ditto, ditto, between the Parallels of Latitude 24° and 60° and Parallels of Declination
24° and 60° 18 0
These Tables are so arranged for working by the Neiv Navigation that only one correction
has to be applied to the altitude taken direct from the book. The entire lo garithmic
work is replaced by a single subtraction and the application of the correct ion. In
conjunction with the Nautical Almanac all the usual problems of Navigation are solved.
The Tables have been adopted for use in the Japanese Navy.
Altitude and Azimuth Tables, for Facilitating the Determination of Lines of
Position and Geographical Position at Sea. The simplest and readiest in solution.
Plane and Spherical Traverse Tables for solving all problems of navigation. By
Lieut. Radler de Aquino (Brazilian Navy). All sights for position are worked out
by the same method ivithout logarithms, with haidly any calculation. All the other
problems in navigation are easily and rapidly solved by inspection without in-
terpolation. This work has received the favourable endorsement of the United
States Ej drographic Office. 2nd Stereotyped Edition... .. . ... ... 12 O
Ni»W Log and Versine Altitude Tables (Reprinted from the 2nd Edition of
above Book), by Lieut. Radler de Aquino (Brazilian Navy). The simplest and readiest
way of finding the Altitude by means of logarit)i?ns ... ... ... ... ... 2 6
DOUBLE ALTITUDES.
Method for finding the Latitude by the Simultaneous Altitudes
Of Two Stars, by Capt. Burdaood, R.N. (reprinted 180C) 1 0
COOKERY.
Ship's Cook and Steward's Guide, containing Hints for Management, and Two
Hundred and Fifty Recipes, by Jawe* B. Wilton ... ... 1
List of Eautical Works published by J. D. POTTER.
AZIMUTHS.
Sun's True Bearing or Azimuth Tables, by John
Burdwood, (Staff Commander, R.N., of the Hydrographic Department,
Admiralty.) The Revised Edition of the above, with Extensions
in Latitude, Declination and Hour- Angle, has been prepared,
with the permission of H.M. Stationery Office, bv Percy L. H.
Davis, FM.A.S., Chief Assistant (retired) in H.M. Nautical
Almanac Office ... ... ... ... ... ... ... 8 6
This book contains a complete set of " Horizon Tables " for the reduction of observations.
Davis's Sun's True Bearing, or Azimuth Tables (30° N. to 30° S.), by
J. E. and Percy L. H. Davis. The only means of ensuring a correct course at sea is
by the use of calculated or tabular azimuths, and the latter render the operation
speedy and accurate. These tables, an addendum to those of Capt. Burdwood, R.N.,
which preceded them, have been in very general use since their publication.
The instructions in several European languages have proved of great service to
foreign seamen 11 6
(Supplied to H.M. Fleet by Admiralty order.)
Davis's Supplementary Azimuth Tables (now published separately). The
Time Azimuth Tables in general use do not often give azimuths near the
meridian, which are in frequent demand for ex-meridian observations, but they
will be found in this book, in addition to complete tables extending to latitude 64° 8 0
(Supplied to H.M. Fleet by Admiralty order
Davis's Star Azimuth Tables, computed for all latitudes between 60° North
and 60° South, by P. L. H. Davis. This book has followed on the very general
adoption of stellar observations as a means of navigation, and supplies the seaman
with the same details regarding stars, as he can get from "Burdwood and Davis"
when the sun is concerned. Some ingenious altitude marks are used for the
first time in these tables which materially aid in the identification of any hastily
observed star, as to which doubt may exist 11 6
(Supplied to H.M. Fleet by Admiralty order.)
High Latitude Tables, between 61° and 78°. By Percy L. H. Davis 7 0
This work, which was originally prepared for and used by the Antarctic
Expedition of 1901, has now been adopted for use in H.M. Xavy and will certainly
be a necessity in all ships trading to northern ports.
(Supplied to H.M. Fleet by Admiralty order.)
Short, Accurate, and Comprehensive Altitude-Azimuth Tables to
show the true bearing of the Sun, Moon, Planets, &c, for latitude 0° to 75c north
or syuth; altitudes 0° to 75°; and declination 30° north to 30° south ; also the
Approximate Ship Time, by A. C. Johnson, B.N. (Published by request) 3 6
(Supplied to H.M. Fleet by Admiralty order.)
Captain Weir's Azimuth Diagram 1 6
(Supplied to H.M. Fleet by Admiralty order.)
Time Azimuth Diagram, by Hugh Godfray, M.A 3 u
4
List of Nautical Works published by J. D. POTTER.
CHARTS. s. d.
Charts: their use and meaning, with thirteen figures and eight charts,
by Dr. G. Herbert Fowler ... 4 o
This, which is believed to be the first book on charts yet published, brings
together information which hitherto h.;s been obtainable only from verbal
teaching. It deals with Mercator and Gnomonic navigational charts, and with
Meteorological and other scientific charts, frcrn a practical point of view in simple
language.
CHRONOMETERS.
Davis's "Chronometer" Tables; or, hour angles for selected altitudes between
latitudes 0° and 50°, with variations for 1' in all elements, by P. L. H. Davis.
Means of working a Sun "Chronometer " arithmetically have been for many years
a desideratum, and have been published, in 1793, by Lalande ; in 1827, by Lynn ;
and by Hommey, in 1863 ; but Mr. Davis, by the omission of useless or undesirable
altitudes, and the inclusion of Variations in l'of Altitude, Latitude ami Declination,
has made a table of great practical utility. The book, 'as a substitute for or
a check on logarithmic calculation, is almost a necessity, and is especially useful
in latitudes less than 45°. A comparison has been made in actual work of the
tabular results with those obtained in the ordinary way, showing practically
identical results ... ... 11 6
Notes on the Management of Chronometers and the Measurement of
Meridian Distances, by Rear- Admiral Charles Shadxvell, F.R.8. (1861) 4 6
EQUAL ALTITUDES.
Tables for Facilitating the Method of Equal Altitudes, by F. A. L. Kitchin,
B.A., Naval Instructor, R.N. ... ... ... ... ... ... ... ... ... 1 0
COMPASS.
Rev. William Hall's Visible Astronomical Compass, for Lat. 50.
Channel and adjacent zone. Important for sea and air navigation, size, Gin.
diameter ... 1 0
An Explanation of the Adjustment of Ships' Compasses, illustrated with
numerous diagrams, by Captain the Honou vynd, R.N. ... 2 0
Handbook to Beall's Compass Deviascope, by Captain George Beall,
contains, in addition to a complete explanation of this well-known instrument,
much information necessary to compass correction ... ... ... ... ... 1 6
Elementary Manual for the Deviations of the Compass in Iron
Ships, intended for the use of Seamen of the Royal Navy and Mercantile Marine,
and Navigation Schools, by E. W. Creak, C.B., F.R.S., retired Captain, R.N. 10 0
Practical Information on the Deviation of the Compass, for the use of ^1
Masters and Mates of Iron Ships, by J. T. Towson, F.R.G.S |
AND '
Supplement to the above ; being the Questions on the Deviation of the Compass f
issued by the Board of Trade for the Examination for Masters' and Extra Masters' |
Certificates, and Answers to the Questions, by Capt. William Mayes, R.N. J
The Roxburgh Compass Error Card. For quickly and accurately correcting
True and Compass Courses and Bearines by a New Method ; extremely simple and
easy to work. Size 10 X 11 inches, printed in black and red; varnished. By
C.B.Wylie 3 0
The Pocket Compass Corrector. Makes an error in applying variation
and deviation almost impossible ... ... ... ... .. ... ... ... 2 0
The Binnacle Compass, Corrected by itself, or the Deviation found with one
Compass by both methods, and the Corrections applied, by Capt. A. B. Becker, Ji.N. 1 0
The Storm Compass, or Seaman's Hurricane Companion, containing a familiar
explanation of the Hurricane Theory, by Capt. A. B. Becker, R.N., illustrated with
Diagrams and Accounts of Hurricanes ... ... ... ... ... ... ... 1 6
Plain Deviation Curve Diagram, by Captain J. C. Robinson u 6
5
List of Nautical Works published by J. D. POTTER.
GREAT CIRCLE SAILING. a. d.
A Chart Of South Latitudes, beyond 20 degrees, to facilitate the practice of Great
Circle Sailing ; with an accompanying diagram for the determination of the
courses and distances, by Hugh Oodfray, M. A. ... 3 0
EX-MERIDIANS.
Davis's Ex-Meridian Tables and Supplementary Azimuths, by P. L. H.
Davis. This important woi-k contains Calculated Keducticms to the Meridian
for hour angles less than 7om and altitudes lower than 84°, Declinations and
Latitudes 3-±° and 64° N. and S. The use of the book is quite easy to anyone
familiar with the Azimuth Tables. The Supplementary Azimuths, which accompany
it, give bearings too near the meridian for inclusion in ,; Burdwood and Davis," which
are now in great request for position lines and ex-meridian work ... ... ... 11 6
Tables for the Reduction of Ex-Meridian Altitudes, by J. T. Towson,F.R.G.S. 1 0
Ex-Meridian Diagram, by F. A. L. Kitchin, B.A., Naval Instructor, R.N 1 0
EOUR ANGLES.
Tables of Calculated Hour-Angles and Altitude Azimuth Tables,
30°N.to30°S. Ex-'vSerid'an Tables and Calculated Reductions and
Azimuths of Bright Stars, 60° N. to 60' S., by H. S. Bl.iclbume 7 6
The Calculated Reductions and A zimuths of 27 of the brightest stars up to about one hour from Meridian abov*
the Pole, and from two (-o thre > i the Pole for eircumpolar stars, make accural*
position finding- from two stars at fcwilig it si apler th*n by any pre . Lously published tables.
The " Excelsior" Azimuth and Position Finding Tables (being
the Second Edition of the above book, 1916) H. S. Blackbunw 10 6
HYDROGRAPHICAL ENGINEERING.
An Essay on Hydrographical Engineering, as applicable to Floating Sea
Barriers, Harbours, Batteries, Coast Defences, and Naval Fortifications, by Capt.
Adderly Sleigh, K.T.S., F.R.S.L. (with Illustrations), (1859) 10 0
INTERPOLATION.
Notes on Interpolation, Mathematical and Practical, by Rear-Admi ral C. Shadivell
F.R.S 2 0
LATITUDE AND LONGITUDE.
On Finding the Latitude and Longitude in Cloudy Weather and at
Other Times, by A. G. Johnson, R.N. Enlarged to 56 pages, with Appendix
and Part II % 0
Short Tables and Rules for finding Latitude and Longitude, by Single
and Double Altitudes, Pole Star, Lunars, &c, by A. C. Johnson, R.N. ... ... ... 3 0
Scales of Latitude from 5° to 60° proportional to a scale of Longi-
tude, Where ^ in. = one mile, arranged to facilitate the finding of position
from two Sumner lines, by R. E. Pealce, A.M.I.C.E. per set 5 0
Charts to accompany above each 2 6
Tables showing the Length in Feet of a Degree, Minute, ana
Second of Latitude and Longitude, with the corresponding number of
Statute Miles in each Degree of Latitude ; and the number of Minutes of Latitude or
Nautical Miles contained in a Degree of Longitude, under each Parallel of Latitude,
by R. C. Carrington, F.R.G.S. (1868) 1 0
LAW.
Handbook on the Law and Practice relating to Apprentices to the
Mercantile Marine Service, by F. W. Gardner (of the Middle Temple) ... 1 6
LIGHTS.
Light Range Table (height of light, 10 to 1000 feet ; and height of eye, 10 to 12C
feet), compiled and arranged by /. S. Commaiuder, Master Mariner ... ... ... 0 6
Lights in Lyrics, or a Glauce at the Channel Lights as Piloting Marks, on a run from
Scilly to the Nore, accompanied by a Parting Precept on Compass Deviation,
addressed to ail younger Mariners. With a view of the Casquets, Notes and Charts.
(1859) 1 0
6
List of Nautical Works published by J. D. POTTER.
LUNARS. «. d.
Notes on the Reduction of Lunar Observations, Mathematical and
Practical, by Rear-Admiral C. Shadwell, F.R 8. (1881) 4 6
See also Latitude and Longitude.
LOGARITHMS.
Davis's Requisite Tables (Logarithmic), by P. L. H. Davis. Tables of
Logarithms to five places of decitn-tls only, for practical sea work. The typography
and arrangement of the book will render it suitable for habitual use, and it coutams
a table of Logarithmic and Natural Haversines specially designed for modern
navigation ... ... ... ... ... ... ... ... ... ... ... 7 6
Davis's Five-Figure Logs and Anti-Logs, by P. L. H. Davis. Specially pre-
pared for use in Actuarial and General Calculations. These tables are very iegible
and do not fatigue the eye in use ... ... ... ... ... ... ... 5 0
Ditto ditto witb Index Tabs 6 0
MAST-HEAD ANGLES.
Tables Of Mast-Head Angles, for five feet intervals, from 30 to 280 feet, and varying
distances from a cable's length to four miles, with their application to Nautical
Surveying; also the determination of distance by sound, with an example 2 0
MEASURES.
Foreign Measures and their English Values, compiled from Official Sources,
by R. C. Carrington, F.R.G.S. (1864) 7 6
MERCANTILE MARINE.
A Voice from the Quarter-Deck on the State of our Mercantile
Marine, by Joseph Mayne (Master Mariner) (1876) 1 0
An Address delivered to the Boys of the Training Ships " Chichester "
and " Arethusa," by G. M. Coxhead (1885) 0 4
METEOROLOGY.
Solectrics ; a theory explaining the causes of Tempests, Seismic and Volcanic
Disturbances, and how to calculate their time and place. Illustrated by over
150 diagrams, by Alfred J. Cooper, Navigator. (Second Edition) ... ..." ... 6 0
The Causes of Weather and Earthquakes (with four Diagrams), bv
Alfred J. Cooper (1902) ,.", 2 0
Light as a Motive Power, a Series of Meteorological Essays (1875), by Lieut
R. H. Armit, R.N. ... _ 15 0
See also Winds.
REVERSIBLE TRANSIT INSTRUMENT.
Notes on the use of the Portable Reversible Transit, and the
Method of Calculation of the Observations, with diagrams and
photographs, by Capt. C. E. Monro, R.N. 3 q
ROYAL NAVY.
Chart of the Navy of Great Britain, from the Earliest Period of
History, compiled from Historical publications, old records, Parliamentary returns,
and other authorities, by Frederick Perigal (of the Admiralty), 1860 ' 3 6
RULES OP THE ROAD.
The Rules of the Road at Sea, comprising the Regulations for preventing
collisions at Sea, 1897, and Rules in force in Harbours, Rivers, and Inland Waters ;
with explanatory notes and observations, by H. Stuart Moore, of the Inner Temple
aiid the Admiralty Court, Barrister-at-Law. (Third Edition) 7 Q
Diagrams, with Explanations, illustrating the Rule of the Road for
Sailing Ships, by Capt. H. S. Blackburne 2 0
3.H (How's Her Head) Indicator and Rule of the Road at Sea,
by George Spillane ... .16
7
List of Nautical Works published by J. D. POTTER.
NAVIGATION AND NAUTICAL ASTRONOMY. s. d.
The "Conway" Manual of Navigation. In this book of 80 pages nothing is
taken for granted. All formulas are proved and the dependence of Navigation and
Nautical Astronomy upon the solution of Plane and Spherical Triangles is clearly
brought out. Particular emphasis has been laid upon method. By J. Morgan,
M.A. (Senior Master) and T. P.Marchant, A. L. Wood (Navigation Masters), H.M.S.
" Conway " School Ship 5 0
Nautical Astronomy, by W. P. Symonds (Ex.-Cummissioner of Surveys). The best
methods of calculating Hour-Anarle, and finding Longitude and Latitude. The shortest
Ex-Meridian method with New Table. Sidereal and Mean Time made clear. Tlie New
Navigation explained and the Modern methods of working Double Altitudes, and
drawing Position lines. The Equation of Equal Altitudes made easy, and used for
finding Longitude from Ex-Meridians, and for determining error in Latitude due to
Ship moving N. or S. Lunars simplified. Chapters on finding Distances, the Tides,
&c, with many diagrams ... ... ... ... ... ... ... ... ... 6 0
Nautical Astronomy Made Easy, by A. C. Johnson, B.N. All the Rules being
worked by a Small Table on One Page, designed to economise Time and Labour ... 3 0
An Introduction to the Practice of Navigation and Nautical
Astronomy, by R. E. Hooppell, M.A., F.R.A.S. 3 6
The Practice of Navigation and Nautical Astronomy, comphte with tables,
by Lieut. Raper, R.N. ... ... ... ... (See also the "New " Navigation) 18 0
Nautical Tables, by Lieut. Raper, R.N. ( do., do. ) 14 0
Inman's Nautical Tables. A New Edition of tin's standard work, revised and
brought thoroughly up to the present date, by the Rev. William Hall, R.N., and
containing all the aids to rapid fixing of position which are essential in modern
Navigation ... ,., .,. ... ... ... ... ... ... ... ... 18 0
Lectures on Elementary Navigation, by Rev. J. B. Harbord, M.A. (Retired
Naval Instructor, R.N. ; late Inspector of Naval Schools, Admiralty ; Examiner
in Navigation and Nautical Astronomy for the Department of Science and Art ;
Author of " Glossary of Navigation ") ... ... ... ... ... ... ... 7 6
Navigation Simplified, by a System of Teacliir g based on First Principles, for
Officers (from 2nd Mate to Extra Master) in the Mercantile Marine and Yachtsmen.
Illustrated by numerous diagramt, by Captain P. Thompson, F.R.A.S., Younger
Brother of the Trinity House, Senior Examiner of Masters and Mates, and Secretary
to the Local Marine Board of London ... .. ... ... ... ... ... 12 0
Examination Diagrams Simplified, for Navigation Students; illustrated by
sixteen diagrams (including 5£ inch Boxwood Scale), bv Captain P. Thompson,
F.R.A.S " 2 6
Navigation, intended for Self-Instruction up to the Second Mate's Examination, by
William Roy ... . 0 6
Practical Coastal Navigation, with numerous charts and diagrams, by Count
de Miremont ... ... ... ... ... ... ... ... ... ... ... 4 0
Tables of Allowance for Current when affecting Compass Course
and Ship's Speed, by Capt. O. E. Hoar, War Department Fleet. A small aud
convenient Table to give by inspection the correction to a Compass Course made
necessary by a Current in any direction, and the resulting distance made good. A
desirable book for all Coastwise Navigation 2 0
"THE 'NEW NAVIGATION."
Appendix to Raoer's Practice of Navigation. Being an explanation of the
New Astronomical Navigation by the method of Calculated Zenith Distances,
with Soecial Tables for Simplifying and Shortening the work, by William Hall.
R.N., F.R.A.S., Chaplain and Naval Instructor (Chief Naval Instructor, Royal
Australian Navy) 1 0
See also Altitude Tables.
List of Nautical Works published by J. D. POTTER.
SAILING DIRECTIONS.
d.
Canadian North Atlantic Steamship Routes between the British
Isles and Canada. Distance, Latitude, Longitude, Variation, and true Course,
by R. A. Woodward, Lieut B.N.R 5 0
Correct Magnetic Courses and Distances, from and to Various
Ports round the British Isles, by Arthur Underhill, LL.D., Commodore
of the Royal Cruising Club, assisted by several Members of the Club. Second
Edition ... ... 2 0
Concise Navigating Directions for the River Thames, including all the
Pools, Readies, and Channels, from London Bridge to the South Foreland and
Oifordness, and for the English Channel to Beachy Head; also for the Port of
Dunkt-rque and the approaches to the Scheldt, by Stephen Penny, Trinity Pilot,
Gravesend (illustrated by nineteen Charts) 7 6
East Coast Rivers. Charts and Sailing Directions for the Rivers Roach, Crouch,
Blackwater, Cc lne, Stour, Orwell, Deben, Ore and Aide; together with General
Charts Irom the Thames to Southwold, by Lieut. S. V. S. C. Messum, R.N 5 0
The Pilot's Guide for the English Channel (with which is now incorporated
"The Pilot's Handbook for the English Channel" by Staff Commander J. W. Kintr,
R.N.), comprising the South Coast of England, and general directinns for the
Navigation of the Channel ; with numerous Charts and Plans of Harbours, edited
by H. D. Jenkins, F.R.G.S 10 0
A Chart of the Dutch Waterways, by J. & A. B. Powell 4 o
From Calcutta to Bombay Coasting, being the Second Edition of the Hand-
book to the Ports on the Coast of India between Calcutta and Bombay, including
Ceylon and the Maldive and Laceadive Islands, with 11 Charts and 12 Photographs,
by Lieut. H. S. Brown, R.N.R., Port Officer, Marine Department, Madras Presidency. 1 0 0
The Occurrence and Paths of Storms, and the Method of
Avoiding Damage from Them, by " Kail Siad." An Essay on "The
occurrence and paths of those storms known as ' Cyclones,' as they are encountered
in Eastern Seas between Aden and Singapore, including the neighbourhood of
Mauritius and that part of the Indian Ocean between Mauritius and India. Also
the method of avoiding damage I rum them" ... ... ... ... ... ... 1 0
Winds and Currents of the Mediterranean, by Capt. A. B.Becker, R.N., with
remarks on its Navigation at different Seasons of the Year, compiled from various
authorities, chiefly Spanish (1864) 3 o
Navigation of the Atlantic Ocean, by Capt. A. B. Becher, R.N., with an account
of the Winds, Weather and Currents found therein throughout the year (with
Charts) (1892) - ... ...50
Navigation of the Indian Ocean, China and Australian Seas, by Capt.
A. B. Becher, R.N., with an account of the Winds, Weather, and Currents found
therein throughout the year (with Charts) (1864) 5 0
Chart Of the Sulina Branch Of the Danube (European Commission of the
Danube), surveyed by Robert Hansford, Surveyor of the Commission, under the
direction of C. A. Hartley, Engineer in Chief (showing 45 nautical miles of the
River from Sulina), size 10 ft. x 2 ft 3 in. (1860) 20 0
Notes On Cherbourg (Geographical and Historical description of, Ac), and Chart
(1858), by Commander Bedford Pirn, R.N., F.R.G.S 1 0
SALVAGE.
How Ships are Lost, and How to Save Life and Property at Sea
(Illustrated), by W. P. B. Manser (1877), 1 0
9
List of Nautical Works published by J. D. POTTER.
SEAMANSHIP. s. d.
Under Square Sail, by Capt. Withers (1898) 2 0
Under the Red Ensign; or, "Going to Sea," by Thomas Gray (1892) ... 1 6
SEXTANTS.
Stars and Sextants. Star Distance Tables for facilitating the use of Lord
Ellenborough's method of Correetinsr the Centring and Total Errors of Sextants at
Sea, by John Abner Sprigge, Wm. Iraser Doak, M.A., F.B.A.S., T. Charlton Hudson,
B.A., F.B.A.S., of H.M. Nautical Almanac Office, Admiralty, and Arthur S. Cox,
B.Sc., A.R.C.S 2 6
Captains' and Officers' Bridge or Poop Companion. Tables for finding
the distance of an object at sea by inspection (without the use of pencil or
paper), afc the same time giving the distance the ship will go wide of the object
before getting to it, and the course to steer to obtain a required distance.
The anove gives, with the aid of a compass only, the distance of a moving ship
from any fixed object. By A. Hiitteroth
Course and Position by Sextant Observations of two known
Objects, by Lt.-Col. English, late B.E 0 6
SHIPPING.
Historical Notes on Shipping, by p. L. Isaac, M.I.N.A. (1879) l 0
SPEEDS.
Speed and Consumption of Steam-Ships and Stability, with Algebraic
Formula for Economical Speed, and Rules for calculating the alterations in Draught
and Trim corresponding to Changes in Displacement, and for using the Hydrometer
to estimate those due to Differences in the Specific Gravity of the Water ; for use in
the Royal Navy and Mercantile Marine ; to which has been added a Chapter on
Stability, with Practical Rules; Second Edition, Revised and Enlarged, by J. F.
Buthven, Master Mariner, late Lieut. B.N.B., Assoc. Inst. N. A., Younger Brother of tlie
Trinity House, F.B.G.S -1 0
Speed Tables, for finding the distance run in a given time at a given speed, between
the limits of 10 to 18 knots, by J. D. Macpherson (Pacific Steam Navigation Co.) ... 1 0
STABILITY.
A New Theory of the Stability Of Ships, second edition, revised and enlarged
(with 28 diagrams), by Alf. J. Cooper (1899) 2 0
See also Speed and Consumption of Steamships.
STARS.
Steering by the Stars, for Night Flying, Night Marching and Night
Boat-Work, between Lat. 40° N. and 60° N., with Sketch Maps and Directions
for finding the selected Stars. By James Dundas White, LL.D., M.F. ... ..10
Position-Line Star Tables. A new and simple method of fixing ship's position
by observations of stars near Meridian and Prime Vertical without logarithmic
calculation, by H. B. Goodwin, B.N. [These Tables have been adopted officially in
the United States Navy.] 5 C
The Bearings of the Principal Bright Stars of greater declination than 23 u
north or 23° south ; also those of the Moon and Planets when similarly situated,
by A. C. Johnson, B.N. (Published by request) 3 0
Pole-Star Latitude : a Method of Finding the Latitude from an Altitude of the Pole
Star, by Damton Hutton (Master Mariner), B.A., M.Inst.C.E 1 0
Tables for Facilitating the Determination of the Latitude and Time
at Sea by Observations of the Stars, by Rear-Admiral C. Bhadwell, F.B.S. 2 6
A Handbook for Star Double Altitudes, by A. C. Johnson, B.N., with directions
for selecting the Stars ... ... ... ... ... ... ... ... ... 2 6
See also Sextants.
List of Nautical Works published by J. D. POTTER.
SIGNALS.
s. d.
Signal Cards— British System, with PlateB, containing Instructions for Sema-
phoring by Day, and with the MorBe Code by Day or Night, together with the
principal " Urgent " Light or Sound Signals, in accordance with the New Code.
Also, Sheet of New Code Flags (34 Flags, coloured). Compiled by J. Whitly Dixon
(Retired Captain, Royal Navy). (Size, 24^ x 19£) 1 6
Ditto ditto mounted on thick card 2 0
SUKVEYING.
Practical Nautical Surveying and the Handicraft of Navigation, bv
Com. T. A. Hull, R.N. 3 0
Practical Observations on Surveying (on determining the Position of a Vessel
when Sounding), by Commander P. F. Shortland, R.N. 1 0
TIDES.
"'How far is that Light?" Tables to allow for current in finding the distance
by doubling the angle on the bow, by Fredk. Ball, M.A. ... ... ... ... 1 0
Capt. D. Fulton's Tidal Diagram, an easy and ready method of computing the
correction to be applied to the soundings, mounted on stiff cardboard with Rule and
Case complete ... ... ... ... ... ... ... ... ... ... ... 4 0
Moxly's Theory Of the Tides, with numerous diagrams, Second Edition, Revised
and Enlarged, by Capt. J. F. Ruthven, F.R.G.S 5 0
Tide Charts of the English and Bristol Channels and entrance of
the Thames, compiled from the Admiralty Tide Tables, by Algernon Heber Percy,
late Lieut. Royal Navy ... ... ... ... ... ... ... ... ... 5 0
The Direction and Rate of the Tidal Streams at every Hour, for 48
Localities between the Nore and Scilly Isles, compiled from Admiralty
Sources only, by F. Hoivard Collins ... ... ... ... ... ... ... ... 2 0
The General Direction of the Tidal Streams in the North Sea for
every Hour " before " and " after," and at High Water, Dover,
compiled by Com. G. K. Gandy, R.N.R., from Official Publications (on one sheet,
size 23 by 17 inches) 1 0
The Universal Tidal Ready Reckoner, calculated by Capt. W. E.Hutchinson, l 6
The North Sea. Its Physical Characteristics, Tides, Currents and Fisheries, by
W. H. Wheeler, M.Inst.C.E. 2 6
TIME.
How to Find the Time at Sea in less than a Minute, being a New and
Accurate Method, with specially adapted Tables, by A. C. Johnson, R.N. ... ... '.\ 0
Time, Tide, and Distances. A handy book of reference for the Shipowner,
Underwriter, or Traveller. Contains the World's Time compared with Greenwich ;
the Tides round the British Coasts and those from Bergen via the Eastern Route
to Japan with that at London Bridge ; approximate Distances from Home Ports to
Home and Foreign Ports (over 13,000 references) ; and a Speed and Distance
Table for Rates of Speed from 8 to 21 knots for distances up to 14,000 nautical
miles, by J. McKirdy, R.N.R 15 0
Time-Altitudes for Expediting the Calculation of Apparent-Time,
&C, by A. C. Johnson, R.N. ... ... ... ... ... ... ... ... ... 4 U
Th© Blue Coat Boys' Clock. A dial showing the simultaneous time of day at all
parts of the earth's surface, size 20 x 17 inches 5 0
List of Nautical Works published by J. D. POTTER.
WINDS.
b. d.
The True Direction and Velocity of Wind, obsprved from Ships while Sailing,
by James N. Miller (Member of the Liverpool Polytechnic Society), with Table for
Indicating the True Direction of the Winds at Sea (1870) 0 6
The Wind in its Circuits: with the explanation of the Origin and Cause of
Circular Storms and Equinoctial Gales ; illustrated with numerous Diagrams and a
Chart of the Prevailing Winds of the World for Spring and Summer, by Lieut. R. H.
Armit, R.N. (1870) 7 6
USEFUL PUBLICATIONS FOR YACHTSMEN.
Amateur Sailing. Reminisoences by C. F. Abdy Williams 4 0
Navigation Simplified, by a System of Teaching based on First Principles, for
Officers (from 2nd Mate to Extra Master) in the Mercantile Marine and Yachtsmen.
Illustrated by numerous diagrams, by Captain P. Thompson, F.R.A.S 12 0
Practical Coastal Navigation, with charts and diagrams by Count de Miremont 4 0
Concise Navigating Directions for the River Thames, including all the
Pools, Reaches, and Channels, from London Bridge to the South Foreland and
Orfordness, and for the English Channel to Beachy Head; also for the Port of
Dunkerque, and the approaches to the Scheldt, by Stephen Penny, Trinity Pilot,
Oravesend (illustrated by nineteen charts) 7 6
East Coast Rivers. Charts and Sailing Directions for the Rivers Roach, Crouch,
Blackwater, Colne, Stour, Orwell, Deben, Ore and Aide ; together with General
Charts from the Thames to Southwold, by Lieut. 8. V. S. C. Messum, R.N. 5 0
The Pilot's Guide for the English Channel (with which is now incorporated
"The Pilot's Handbook for the English Channel"), comprising the South Coast of
England and general direction for the Navigation of the Channel ; with numerous
Charts and Plans of Harbours, edited by H. D. Jenkins, F.R.O.8. ... ... ... 10 0
A Chart of the Dutch Waterways, by J dk A. B. Powell 4 o
Correct Magnetic Courses and Distances, from and to Various
Ports round the British Isles, by Arthur Underhill, LL.D., Commodore of
the Royal Cruis-ng Club, assisted by several Members of the Club. 2nd edition ... 2 0
3 H (How's Her Head) Indicator and Rule of the Road at Sea,
by George Spillane 1 6
The Roxburgh Compass Error Card. For quickly and accurately correcting
True and Compass Courses and Bearings by a New Method; extremely simple and
easy to work. Size 10x11 inches; varnished. By C. R. Wylie 3 0
ADMIRALTY CHARTS.
Official Catalogue of Admiralty Charts, Plans, and Sailing
Directions. A Vol. of 330 pages and 24 Index Charts Ko charge.
On the Correction and Use of Charts, Light Lists, and Sailing
Directions. 40 pp., bound red cloth ... , » Ko charge.
12
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