C 1 78 ] 
the other nearly SAV. adjacent to where the clock 
flood. The windows being high, and the Sun hav- 
ing no great altitude, during the time the obierva- 
tions were made, the oil was therefore placed at fuch 
a diftance, from the windov/s, that no wind could 
get at it to diflurb it. There was alfo every precau- 
tion ufed to render it as ftill as poflible, by fixing a 
fhed to windward without the windows. 
The method I ufed, in taking all my correfponding 
altitudes, was firft to fcrew the index to a certain 
altitude; then, for the morning obfervations, I firft 
noted, when the upper limb* by reflection, touched 
the lower limb in the oil ; fecondly, when the centers 
coincided, by obferving an equal coincidence in both 
images; and laftly, when the Sun’s lower limb, by 
reflection, touched the upper in the oil. In the af- 
ternoon, I obferved the Sun’s falling, netting each 
contact correfponding to that in the forenoon. I al- 
ways made it a rule to take a large number, that I 
might reject thole, where the oil fullered the lead 
agitation, 
The clock was fixed to an upright fleady poft, in 
a warm room, kept as temperate as poflible, by en- 
creafing or diminifhing a large wood fire oppofite 
the clock. 
Notwithflanding every precaution, the intenfenefs 
of the cold was fo great, that it frequently flopped 
the clock, by which 1 loft many obfervations during 
the months of January and February. 
The following obfervations were made, when it 
was proved to go, at an equal rate, feme days before 
and after. 
1 
f 
The 
