Rev. 0. Fisher on Variations of Gravity and their 

 " III. Inland Stations 1000 to 2000 feet high. 



Station. 



Height. 



Apparent varia- 

 tion in vibration- 

 numbers. 



Namthabad . . . 



Kodangal 



Damargida . . . 

 Somtana 



1173 

 1914 

 1946 

 1714 

 1120 

 1693 

 1763 

 1641 



-5-54 

 -4-59 

 -6-56 

 -4-31 

 -4-03 

 -4-38 

 -361 

 -5-60 



Badgaon 



Ahmadpur . . . 



Kalianpur 



Pahargarh 



Mean ... 



1620 



-4-83 



" IV. Inland Stations over 2000 feet high. 



Station. 



Height. 



Apparent varia- 

 tion in vibration- 

 numbers. 



Bangalore 



Dehra 



3064 



2242 



6920 



15408 



- 5-68 

 -11-36 



- 8-22 

 -24-09 



Mussoorie 



More 





The method followed by Col. Herschel in estimating local 

 attraction was to employ the formula for the attraction of a 

 circular spherical cap, being "the part of a spherical shell 

 bounded by a right cone, whose vertex is the centre of the 

 sphere. Two such cones on a common axis intercept between 

 them a zone, which is clearly the difference between two caps 

 having a common axis. - "* The proper altitude of sections, every 

 one of a set of such zones, taken around the station as their 

 centre, each of appropriate width for its distance, was estimated, 

 and also for the last zone the distance at which attraction would 

 cease to be appreciable. The density of the masses was taken 

 at 2*75, being half the mean density of the Earth. It is 

 obvious that such an estimate would stop at the sea-level, and 

 take no account of variations of density below it ; nor yet does 

 it seem that the rise of the sea-level, which under the supposed 

 conditions would be considerable, was allowed for. The for- 

 mulae used are essentially the same as those given by Pratt 



* Op, ciu p. [151], 



