Survey of Northeast Greenland. 123 
From the observations themselves it appears that the intervals 
between the outer threads are: 
for telescope east 65°.4 
west 655.5 — 
mean 65.45. 
From the table mentioned on р. 106 we get for д = 0 the interval 
between the outer threads 615.22. 
65.45 
61:22? 
With this value as ап argument the values of the single thread 
intervals are interpolated in the above-mentioned table. 
The preliminary weight given in the observation journal should 
only be regarded as an instantaneous, somewhat arbitrary estimate 
of the reliability of the observation. By the weight 1 is indicated a 
normally good observation. 
” ” 
We now arrive at sec[å C] = hence [ö €] = 20°.7. 
The progress of the computation ofthe observation 
is given below, and it will be possible to follow it direct. Only the 
г pp 
[77] 
term used in the computation of the parallax requires 
further explanation. In this term г is radius vector for the latitude с. 
a is the semi-major axis of the elliptical meridian of the earth. 
<’ is the geocentric latitude and 
1 
sins 1". 
For r expressed in metres there is (Bessel’s values of the ele- 
ments of the earth) 
log г = 6.803918 + { 6.861585 + 10 } cos 20 + { 4.2615 + 10} cos4g... 
where { } indicates the logarithms of the co-efficients. 
For a in metres there is log a — 6.804643. 
The difference between the geographical and the geocentric latitude 
is determined by оф’ = { 2.839257 } sin 2 p + { 0.063059 } sin 4¢ 
+ {7.4118 + 10} тб... 
From these formule in the case of Danmarks Havn we arrive 
at the result: 
eg = 5'08”.6; log = — 9.998623 - 10 and 
w is the radius expressed in seconds = 
log, ПОР 17359 10, 
a w 
Furthermore used in the course of the computation: 
Approximate value for the longitude /, = + 1514™50s 
ф = 76°46'16"") 
: 1 division of the level 1p = 4.45. 
1) The final computation of the latitude gave ¢ = 76°46'14”.6 + 0”4. The fact 
that the value of g used at the computation of the longitude is a little too 
great has no bearing on the result. 
