all 
A SS A EO STEREO TET LE LEBEL ID A ETE ED GLE II ETRE Re 
IV. Of the Sotips of Greatest ATTRACTION, or those 
which, among all the Souips that have certain Properties, 
Attract with the greatest Force in a given Direction. By 
Joun Prayrair, F.R.S. Lond. and Edin. and Professor of 
Natural Philosophy in the University of Edinburgh. 
[Read 5th January 1807.] ° 
a hae inveftigations which I have at prefent the honour of 
fubmitting to the Royal Society, were fuggefted by the 
experiments which have been made of late years concerning 
the gravitation of terreftrial bodies, firft, by Dr Masxutyne, 
on the Attraction of Mountains, and afterwards by Mr Caven- 
DIsH, on the Attraction ef Leaden Balls. 
In reflecting on thefe experiments, a queftion naturally 
enough occurred, what figure ought a given mafs of matter to 
have, in order that it may attrac a particle in a given direc- 
tion, with the greateft force poffible? This feemed an inquiry 
not of mere curiofity, but one that might be of ufe in the fur. 
ther profecution of fuch experiments as are now referred to. 
On confidering the queftion more nearly, I foon found, though - 
it belongs to a clafs of problems of confiderable difficulty, 
which the CatcuLus VariaTIonvm is ufually employed to re- 
folve, that it neverthelefs admits of an eafy folution, and one 
leading to refults of remarkable fimplicity, fuch as may intereft 
Vou. VI.—P. II. Aa Mathematicians 
