HYDROGR. SECTION — APPENDIX B { 40 ) 
The Danish Committee can only execute this program with this understan- 
ding, that the lines from Faeroe to Iceland are given up. 
~ Appendix B 
On the determination of temperatures 
by measuring the resistances in telegraph cables 
by 
MARTIN KNUDSEN 
On the recommendation of Professor O. Kriimmen an attempt has been made 
to determine the mean temperatures of certain telegraph cables by measuring the 
resistances. The measurements have been made by the Great Northern Telegraph 
Cable Company and placed at the disposal of the Danish Hydrographical Labora- 
tory. As examples the results of the measurements on the cables Newbigsin-— 
Marstrand, Newbiggin—Sündervig and Oye—Fanû have been worked out at the 
Bureau. 
The average temperatures of the cables 
The temperatures have been calculated from the formula: 
M, = M, 
” M, x 0,0040 
where M, means the resistance the cable would have if the resistance at 0° re- 
mained throughout the same as at the time of the last of all the measurements; 
and M,, which is determined by adjustment of observed values of M, and corre- 
sponding values of temperature, is thus the resistance of the cable at 0° at the 
time of the last measurement. 
t 
Newbiggin—Marstrand 
y — M 31923 
ri 12.5 
M, was measured both at Newbiggin and at Marstrand so that the average 
error could be determined. The average error of the mean amounts to 4°3, which 
gives the temperature a possible error of 0°35, As the mean deviation between 
observed and calculated temperatures is 0°35, M, may be considered as sufficiently 
well determined. 
