[ 334 ] 
and Dr. Reid, at the well window of the room of the 
obfervatory, wherein the aftronomical clock flood ; 
the other two inllruments were placed without, at 
the fbuth and north windows of the fame room, one 
being a refrador of 13 feet, by which Dr. Irvine ob- 
ferved} the other a 12 inch refleblor of Short’s, by 
which my fon obferved. Thefe two obfervers looked 
dlre(flly at the Sun, having their inllruments armed 
with fmoke-glalTes 5 another perfon flood at the 
clock, and counted the feconds by coincident beats 
upon a piece of board, which he held in his hand for 
that purpofe, and who named every fifth fecond, fb 
that all the obfervers could hear him diflindlly. The 
motion of the clock, made by Shelton, was care- 
fully adjufled by many tranfits of the Sun and fixed 
ftars, over the meridian, both before and after the day 
of the tranfit j the clock by which my obfervatjions 
were made was adjufled by Shelton’s, by means of 
fignals made every hour, for fome hours before and 
after the tranfit. It was apprehended, that thefmoke 
of the town might hurt the obfervations j and, to pre- 
vent this as much as polTible, an advertifement was 
put in the news- paper, begging the inhabitants, ’in 
cafes where it would not be very inconvenient, to put 
out their fires from three o’clock that afternoon till 
fun-fettingj the politenefsof the inhabitants of Glaf- 
gow, in complying with this requefl, was far greater 
than could well be expedlcd, infomuch that there 
was not a fpire of fmoke to be perceived in that quar- 
ter from which the obfervations could be incom- 
moded. Having made thefe preparations, we 
thought we had nothing to fear but the clouds j and 
. indeed the weflern part of the heavens was covered 
with 
