224 I. P. KocH. 
The table which is filled in, according as the computation pro- 
gresses, serves to control the computation. If we further desire to 
control the measurements, we must include a fourth point in the 
survey (see the example below). 
The station pointing demands, as shown by the above, that from 
P at least three triangulation points are visible; in case one wants 
to secure a control of the survey, four are required. If still more 
are visible, one should select the most 
adaptable ones. In this respect we have 
to take into consideration: 
1) The sum of the angles a+ В-Ру-д 
must not be too near 180° 9: P must not 
be near the circle through the three 
given points. 
2) The three base points must not 
Fig. 31. lie too close together and not at too great 
a distance from P. 
The station pointing of the Observatory (Fig. 31) was carried 
out with the permanent instrument. The magnitude of the angles 
measured appears from the computation table. 
PIO er 82r254197 logtanu........ 0.19332 Ее 57°21’03” 
Br We 242 59 52 — tan (45° - и) 9.34034n 45° = u . +12 2103 
a+fß-+r--6... 325 2511 — tan !ls(p+g) 9.49814 Ve(p+q М 1724 
1]. (a + В + 7 + д) 162 4236 — tan !!s(p-+-g) 8.83348n  "I2 (p — q) + 3 5356 
1/9 (p + (Qo cocaces 17 17 24 pi 13°23'28") 
de 21°11’20”[ 
log sin log side 
Cd VIS eee 31937753” 9.11971 3.42299 
PRL. ле Е 13 23 28 9.36473 3.06801 
WO AT ee 134 5839 9.84966 3.55294 3.70328 
Ре 50 47 27 9.88921 3.39917 
DIRES NT eee 21 11 20 9.55804  3.06800 
IDR ee RUE A 108 01 13 997816 3.48812  3.50996 
ist control of computation: 7 + 0 = 82°25'20". 
2nd control of computation: log tanu = log sin 4 + 105 sin p = 0.193831. 
: : Г 3.06801 
> . = 
ord control of computation; log т = А 3.06800" 
1) The previously mentioned condemned measurings gave p—13°23'42”, q—21°11"27", 
у = 5004722”, 6 = 31°38'05". It must here be borne in mind that these 
values are possibly erroneous in consequence of an eccentric signal. 
