146 Archdeacon Pratt on the Anglo-Gallic, Russian, 



virtually abandoned (see Monthly Notices of the Royal Astrono- 

 mical Society, vol. xx. p. 265), is thus proved to be unnecessary 

 and without any foundation. 



In a future communication I will consider the effect of the 

 revision of my method of treating this subject upon the esti- 

 mated amount of local attraction in India, and upon my specu- 

 lations regarding* the constitution of the earth's crust. 



2. I will now give the calculations above referred to for 

 finding the Mean Figure. The data given in the following 

 Table are gathered from the British Ordnance Survey Volume, 

 pp. 766-768, and the Monthly Notices of the Royal Astronomical 

 Society, vol. xix. p. 35, and the values of n are calculated from 

 the formula n= 13*75 sin 21. The meaning of brackets en- 

 closing an algebraical symbol, thus (^), has been already exr 

 plained to be, that the sum of all quantities like that within the 

 brackets is to be taken for all the stations of the arc under con- 

 sideration. The meaning of brackets when a logarithm is en- 

 closed within them is this, that the number is to be taken of 

 which the number within the brackets is the logarithm ; thus 

 58-6109= (1-7679784). 



Arcs. 



(mx). 



(m/3). 



(-)- 



(*«• 



(/3 2 ). 





n. 



Anglo-Gallic. 



Russian 



Indian 



+ 118-9207 

 +386-3623 

 - 12-7516 



- 45-3653 

 -126-4488 



- 10-4936 



+ 1550671 

 +335-5318 

 + 46-5750 



- 35-5339 

 -1121421 



+ 36-6984 



+ 11-1906 

 +39-9745 

 +29-3612 





13-5500 



13-7491 



81031 





i 



(m)(j3) 



i 



i 



i 



i 



(A. 



i 



i 



Anglo -Gallic. 



Russian 



Indian 



- 60-3098 

 -291-4511 

 + 0-3492 



+ 24-3352 

 + 85-4950 

 + 0-5757 



- 27-7474 

 -228-4246 



- 0-3135 



+ 11-1962 

 + 67-0066 

 - 0-5168 



- 4-5177 

 -19-6559 



- 0-8521 



+0-9034 

 +4-1918 

 -0-1979 



- 03645 



- 1-2296 



- 0-3264 



The sums of the above quantities. 



Anglo-Gallic. 



Russian 



Indian 



+ 58-6109 

 + 94-9112 

 - 12-4024 



- 210301 



- 40-9538 



- 9-9179 



+ 127-3197 

 + 1071072 

 + 46-2615 



- 24-3377 



- 45-1355 

 + 36-1816 



+ 6-6729 U-0-9034 

 +20-3186+4-1918 

 + 28-5091-0-1979 



+ 13-1855 1 

 + 12-5195 ! 

 + 7-7767 j 



I. The Anglo -Gallic Arc. 



The equations of my last paper for finding the values of U t and 

 Vj become, when the numbers are substituted from the Table, 



58-6109 + 127-3197Uj -24-3377 V, + 0-9034(0 =0, 

 -21-0301- 24-337711!+ 6-6729^ + 13*1855(0=0, 



