Survey of Northeast Greenland. 305 
Ber | | lk | 
Dr oe Pulpit Po Do RP |) opie 
(Km) (Metre) | “BEN (Metre) 
1 Or" ae! 27.8 
2 en ue Be 
о 23 33:3 29 
4 Lan Da m), = 186,2 ai 
5 Ge le cares Nees conti 9 5 
6 a a an ema 5 HD on 
7 3.1 ie 27 LOTO 
8 BENN bone 28 49.3 SØ 
9 5.1 Torre ee 
Pure ØS et 3.8 
11 7.6 ae 60.4 
12 90 nr | 32 а г 
13 ID 3 CR 
14 12.3 RTC RS Tate 
15 14.2 Paso |. 2 77.0 т 
Me ls SB) Aas 
т. 
18 20.4 a a eae 
19 22.7 | 95.7 19 
20 25.2 оо 100.6 
The computation of the distance which is performed with the 
utmost simplicity and very quickly by means of the engineer's scale 
becomes indirect. One begins by computing an approximate value 
où D, 1<e"D; _ —_ and after that one selects au ae table at an 
estimate and rounding off upwards the correction a Ш this 
i 
manner one gets a fictitious altitude H, — H, ple D?, and now 
computes D, — = From the table one takes again at ап estimate 
or Dat i in ae manner one gets a new fictitious altitude H, = 
H,-+ op D and so on. As a rule one has already at the second 
attempt found the true distance, which appears during the computation 
from the fact that the fictitious altitude of the station, after the cor- 
rection for refraction and curyature of the earth, remains unchanged 
in whole metres. 
Example 1, Н = 450m; в — 1°56’. 
tanv — 0.0337. The index of the sliding rule of the engineer’s 
scale is put at 337. The division 450 on the fixed rule then indicates 
D, = 13.34 on the sliding rule. 
The correction corresponding to D,, i.e. = 
(rounded off upwards) at 12m. Thus H, — 462. 
The engineer’s scale is still lying untouched with index at 337. 
20° 
D,? is calculated 
