[ S20 ] 
Ing of the wooden hand on which it was fupported, might 
affedt the accuracy of the obfervations ; or there might be 
variable and difcordant refradtions, even near the zenith, 
on the fide of fo fteep a hill, more than are found in 
lower fituations. Add to this, that when I began my ob- 
fervations on the South fide of the hill, having a profpedt 
of bad weather before me, and not knowing how few ob- 
fervations I might be able to get on either fide of the 
hill, I thought it prudent to endeavour to obfcrve mod: 
of the flars in the Britifli catalogue, which came within 
the reach of the inftrument, that I might be lure of being 
provided with obfervations of fome at leafl of the fame 
flars, which I might afterwards obferv^e when I fliould 
be removed to the North fide of the hill; where, after 
an interval of perhaps fome months, many flars, that 
before paffed the meridian in the night, would pafs it in 
the day, and confequently be either invifible through 
the telefcope of the fedlor, or more precarious of being 
feen. 
Although ameridian line hadbeen found by the tran fit 
inflrument at the South obfervatory, whereby the re- 
lative fituation of the two flations of the obfervatory, as 
well as of the other points of the hill, with refpedl to the 
meridian, might be determined; yet I judged it would be 
more fatisfadtory to confirm this by another meridian 
line drawn at the Northern obfervatory. This I found, 
as I had done the former, by fetting the tranfit inflru- 
ment to agree with the pole-flar at the computed time of 
its paffing the meridian, and confirmed it by comparing 
I the 
