relation to the Constitution of the Earth' 's Crust. 19 



To illustrate how much increasing the distance of the station 

 from the edge of the plateau diminishes the attraction, it may 

 be mentioned that the former of the above integrals gives, for 

 a = 80, 



The logarithmic term = —11*274, 

 The two circular terms = +24*651 ; 

 whereas for a=6 = 400 they are 



The logarithmic term = —2*888, 

 The two circular terms = +5*807. 



In like manner the latter integral gives, for a = 80, 



The logarithmic term = +0*0519, 

 The circular term = —0*1061 ; 



whereas for a = & = 400 these are respectively 

 + 0-00798 and -0*0185. 



As another instance of the effect of form and extension, it 

 will be found that a circular plateau of the above height and 

 of 80 miles radius (and therefore of infinitely smaller area 

 than the parallelepiped) will, with its root, produce an attrac- 

 tion corresponding to about 11 swings per diem. 



Archdeacon Pratt, in " a postscript on Himalayan attrac- 

 tion," in the Phil. Trans. 1859, p. 774, gives the rough dia- 

 gram of the plateau here reproduced, referring to a work on 

 the physical geography of the Himalayas by Major R. Strachey, 

 adding : — " On a careful consideration of all the data, Captain 

 H. Strachey estimates the mean elevation of the tableland 

 between the Himalayan and Turkish watersheds, and to the 

 west of the ridge between the sources of the Indus and 

 Brahmaputra, to be 15,000 feet (p. 56) "*. This is the 

 height of the station More. 



As far as I can judge by comparing the map in the 

 ' Account ' &c, the only one in which the locality is marked, 

 with the relief-map by Major Gr. Strahan, and with Pratt's 

 diagram, it appears that More is distant about 80 miles from 

 the nearly straight south-western escarpment of the range 

 facing the plains, and 400 miles from the escarpment facing 

 the north-west. If we imagine a series of cap-sectors drawn 

 about the station, it will appear that the hypothesis of the 

 parallelepiped makes the sectors on the north side too short 

 near the cross section, and on the south side too long, while 

 parallel to the range they are necessarily too long. This 

 would make the attraction at the station too small. On the 

 other hand, the actual plateau rises from the plains which are 

 * Loc. tit. p. 776. 

 C2 



