706 PHILOSOPHICAL TRANSACTIONS. [aNNO IJSO. 



Exper. 1. At half past one o'clock, when 



the thermometer pointed to - 11% the snow At Night. 'y^'^f "• °" Therm, in 

 r " tne snow. the air, 



contiguous to the ball was blown on for 1 8< 12" 0° 



minutes bv a pair of hand-bellows, held with 9 14- — y 



•^ r » jQ — 14.... 4 



the pipe nearly horizontal, and half a foot n 17!. !.. 6 



above the surface of the snow. The bellows "t — is — 6 



, , , , . , , - Friday morn. 



had been lymg out on the snow to cool from j. 20 8 



the time Mr. W. first came over; and, in 1 — 23 — 7 



order to promote their cooling, they were now 2^ ...... .. 22 . ! ! 1 — 9 



and then wrought in the open air. Care was 2| — 21 — 8 



also taken to stand to leeward of the ther- 31, . .' ! Z^ 10 



mometer, and to extend the bellows as far as 4 — 12 



possible from the body in the time of blowing. ^^ — 12 



He was surprized to find however, notwith- 5^ — 12 



standing all the precautions, that the ther- g^"_' _„„ ~ I* 



mometer at the end of the experiment had got 7 — 22 — J3 



7A — 22 — 13 



8 — 19 — 10 



up no less than 10°, for it now pointed only to "^^ ^^ '^ 



— 12°. In this experiment the nozzle of the 



bellows was held about 6 inches from the thermometer, but the blast, though 



moderate, frequently drifted away the snow from the ball. 



Exper. 2. At half past 1 o'clock, a bread-basket was filled with snow, taken 

 up near the ground at ■\- 14°. The contents being relatively so warm, the 



basket was placed to leeward of the common At 3" — 10° 



station, and the thermometer laid on the sur- ^^ H i6jl 



face of this snow. At the several hours in the 4| = . — is 



morning, the thermometer on the basket ^, — \\ 



pointed as annexed: viz. 6"' — 18 



Exp. 3. At 4 in the morning, when the thermometer in the basket had got down 



to — 16°, a piece of thin fir plank about a foot square was laid on the snow, on 



which was placed a small plate of tin which accidentally lay at hand. On this was 



laid one of the thermometers which had been . . 



At 5 — 10 



hanging in the air. At the several tunes it b\ — 16 



pointed as annexed. ^ '^ 



During the whole time not a cloud was perceivable, but there was a faint haze 



in the air when viewed towards the horizon. There was little or no tremor in 



the atmosphere, which made the stars shine with a full and steady light like that 



of the planets. Many of the town's people, who had thermometers hung out 



at their windows in diflferent parts of the town, found them pointed several 



degrees below O at 9 o'clock in the morning. On the afternoon of this day, 



