[ 53 ° 1 
It muft be owned, that this point will be fettled with 
rather more certainty when all the obfervations made 
with the fedtor, which exceed 300, fliall have been com- 
puted ; but, as from the agreement of thefe refults toge- 
ther, as well as from the fmall differences that are ufually 
found in obfervations made within a few days of one 
another, one may prefume, that therefult from the whole 
will not differ materially from that deduced above from 
40 obfervations, I thought 1 had better take this oppor- 
tunity of gratifying the impatience of the Society in pre- 
fenting them with thefe my firft computations before 
their fummer recefs, than delay giving them any account 
at all of this experiment, till I had leifure to complete the 
whole of my calculations. 
I am now to fliew, what the diftance is between the 
parallels of latitude palling through the two Ifations of 
the obfervatory in feet, according to the trinogometrical 
menfuration; and thence, what the difference of latitude 
ought to have been^ if the hill had been away, or had 
exerted no fenfible attradlion. This depends on the enu 
meration of feveral particulars. 
The length of the bafe meafured in the meadow 
ofRannoch was 5897,119 feet, according to the ftate 
of the brafs flandard when the thermometer was at 
40°; but, to reduce it to anfwer to the ftate of the brafs 
flandard in the heat of 62°, we mull fubtradl 16,721 
feet; we fhould alfo fubtradl farther 0,327, for the di- 
minution which the brafs flandard has fuffered by wear, 
and there remains 5880,07 1 feet for the true length of 
the 
