IE.] 
AZIMUTH. 
27 
'he formula for reduction of azimuth observations at any hour 
a sin / 
is tan A = 
I — b cos / 
t where a=sec </> eot tf, 6= tan <f> cot S. 
log sec <f>, 47 57 57=0.17421 
log cot 6, 88 45 1:6= 8.33439 
log a =8.50860 
in. s. 
Vatch correction =—0 34 
longitude correction = — 44 06 
log tan ^=0. 04505 
log cot £= 8.33439 
log b =8.37944 
Total correction =—44 40 
Watch time of observation . 
Reduction to local meridian 
Local mean time 
Correction to sidereal 
a of sun 
Sidereal interval 
a of Polaris 
£... - 
t in arc 
Log cos t 
Log/) --. 
Log b cos t 
b cos t.- 
1 — 6 cos t 
Log sin t 
Log a -. 
Log a sin t 
Log (1 — 6 cos t) 
Log tan A 
Azimuth of star. 
Anglo to mark 
Level correction 
Azimuth of mark 
8--H& Mon-S^c. 
tion of first 
observation 
/< . /// . s. 
10 27 52 
—44 40 
9 43 12 
+ 1 36 
7 03 11 
16 47 .V.i 
-1 21 51 
15 26 08 
o I II 
231 32 00 
9. 79383 
8.37944 
8. 17327 
.01490 
1.01490 
9.89375 
8. 50860 
8. 40235 
0.00642 
ond obser- 
vation. 
10 33 48 
—44 40 
9 49 08 
+1 37 
7 03 11 
16 53 56 
-1 21 51 
15 32 05 
o ' // 
233 01 15 
9. 77925 
K.:57!U4 
8. 15869 
.mill 
1.01441 
9.90246 
s .-.list ii) 
8. I! l"ii 
0.00621 
Mils.", 
L81 .T. 32 
L81 
27 18 
181 29 41 
-34 24 46 
:;i 
26 30 
-34 28 50 
+9 
+2 
—4 
1 47 (Mi .V, 
117 
(hi 50 
117 00 47 
Computa- 
tion of third 
observation. 
10 42 02 
—44 40 
9 57 22 
+ 1 38 
7 03 11 
17 02. 11 
-1 21 51 
15 40 20 
o ' // 
235 05 00 
9. 75769 
8.37944 
8. 13713 
.01371 
1.01371 
9.91381 
8. 42241 
0.00591 
8. 41650 
Computa- 
tion of 
fourth ob- 
servation. 
//. in. S. 
10 46 08 
—44 40 
10 01 28 
+ 1 39 
7 03 11 
i; ii.; L8 
-1 21 51 
15 44 27 
o ' // 
236 06 45 
9.74630 
8.37944 
s. L2574 
.01336 
L. 01336 
9. 91915 
8.50860 
8 12775 
1 1. (Hi;,;;, 
5.42200 
181 30 !'•' 
:;, 30 01 
147 00 44 
The mean of twenty observations reduced in a similar manner = 
7° 00' 51". 15. 
Check azimuths along the random Line were measured with Young 
msit No. 6838. The insi nimciii was usually sel over one stadia 
ition and a mark placed on another station. Six measurements 
iree direct and three reversed) of angle between Polaris and mark 
re then made. These observations were reduced at once by the 
