27 



J/= + 2.22, 



and as this agrccs so very nearly with Dr. Gili>'s resuit, \vc hâve adopted 

 it. The following are the corresponding values from the comparisons of line 

 31 \vith linc 2, and line 55 with line 26: 



iW= + 3.61 Excess of 31 över 2, 

 + 2.78 Excess of 55 över 26. 



But we adopt for thc terminal points of all lincs, not tlieir actual intersections 

 with the other lines, hut with those other lines corrected for sinuosity. Cor- 

 recting the above values for sinuosity, we get: 



fl 



l/= + 2.54 Excess of 31 över 2, 

 + 2.72 Excess of 43 ovcr 14, 

 + 3.25 Excess of 55 över 26. 



Except for accumulated errors of observation, the mean of the first and 

 last values should be cqual to the middle one. This follows from the fact 

 that the sinuosity corrections are supposed to turn the actual réseau lines into 

 ideal straight ones. The mean of the first and third values is: 



M= + 2.d0, 



which is in vcry satisfactory agreement with the middle value. We have 

 adopted as definitive the mean of the two, 



II 



M=+2.8l. 



As an example of the use of équation (13) we take the value already 

 obtained: 



31 - 43^ 

 2å 



|l/(-^^^)= + 0.70 



