t S°8 ] 
‘of the hill to afcertain its dimenfions and figure, from 
whence a calculation may be made, how much the hill 
'Ought to attradl, if its denfity was equal to the mean den- 
fity of the earth ; it is evident, that the proportion of the 
avftual attradtionof the Kill to that computed in this man- 
ner will be the proportion of the denfity of the hill to 
the. mean denfity of the earth. 
Thus there were three principal operations requifite 
to be formed. i. To find by celeftial obfervations the 
apparent difference of latitude between the two flations 
chofen on the North and South fides of the hill. 2. 
To find the diftance between the parallels of latitude. 
34 To determine the figure and dimenfions of the hill. 
I arrived at the hill of 'Schehallien on the laft day of 
June, and found the obfervatory and inftruments there, 
which had been brought down fome time before from 
London to Perth on board a fliip, and thence conveyed 
over land to the hill under the care of Mr. TxEUBen bur- 
row, my late alfiftant at the Royal Obfervatory. The 
obfervatory was fixed half-way up the South fide of 
the hill, as the place where the effect of the hill’s attrac- 
tion would be at the greatefi:, and it was placed in the 
like manner when it was afterwards removed to the 
North fide. A circular wall w'as railed, five feet in dia- 
meter, and covered at top with a moveable conical roof 
for flieltering the aftronomical quadrant ; and a fquare tent 
was put up for receiving the tranfit inftrument, all near ^ 
to the obfervatory. A bothie, or temporary hut, was alfo 
made near it, for my refidenre, while I w^as attending 
7 the 
