[ 5o6 ] 
been away, we fliould be able to decide upon the efFe(5t of 
attradlion. This will be found, by repeating the obferva- 
tions of the liars at the Eafl or Welt end of the hill, 
where the attradlion of the hill, a6ling in the direction of 
the prime vertical, hath noeffedl on the plumb-line in the 
diredlion of the meridian, nor confequently on the appa- 
rent zenith dillances of the liars ; the differences of the 
zenith dillances of the liars taken on the North or South 
hde of the hill, and thofe obferved at the Eall or Well 
end of it, after allowing for the difference of latitude an- 
fwering to the dillance of the parallels of latitude palling 
through the two llations, will Hiew the quantity of the 
attradlion at the North or South llation. But the experi- 
ment may be made to more advantage on a hill like 
-Schehallion, which is lleep both on the North and South 
lides, by making the two obfervations of the liars on 
both Tides ; for the plumb-line being attracted contrary 
ways at the two llations, the apparent zenith dillances 
of liars will be affedled contrary ways; thofe which 
were increafed at the one llation being diminiihed at the 
other, and confequently their difference will be affedled by 
the fum of the two contrary attradlions of the hill. On 
the South hde of the hill, the plumb-line being carried 
Northward at its lower extremity, will occahon the ap- 
parent zenith, wTich is in the direction of the plumb-line 
continued backwards, to be carried Southward, and con- 
fequently to approach the equator; and therefore, the 
latitude of the place will appear too fmall by the quan- 
tity of the attra(5lion ; the dillance of the equator from 
the 
