Upon a REMARKABLE COLD. 151 



DECEMBER 28. 1783. 



ACCORDINGLY, this night, betwixt ten and eleven o'clock, 

 one of the thermometers was expofed to the free air in the Ob- 

 fervatory-park, four feet from the ground, and at a confidera- 

 ble diftance to windward of the hoxife. To an arm which 

 projected from a flender frame of wood, the thermometer was 

 fo applied, as to prefent itfelf floping, not far from a horizon- 

 tal pofition, for the greater convenience of quickly reading off 

 the .degrees. Near by the frame, another thermometer was 

 laid down upon the furface of the fnow, which covered the 

 ground to a confiderable depth. At this time, the heavens 

 were very clear all around, and the motion of die air from the 

 eaft, fo foft as only to bend a little the flame of the candle, when 

 fteadily held out. 



AT eleven o'clock, the thermometer in air pointed to + 5, 

 and the one upon the fnow to 7, the difference being 

 twelve degrees. Half an hour after, they pointed to + 4 and 

 7 ; and every thing wore the appearance of a fine fettled 

 frofty night. 



I NOW returned to the Obfervatory to attend to fome aflro- 

 nomical bufinefs. After lighting up the tranfit-room, I fet the 

 meridian telefcope to the altitude of a flar, which preceded the 

 planet in right afcenfion, and which was very fbon to pafs the 

 mid wire at a certain fecond by the clock. When the time 

 drew near, I looked for it in the field of view without finding 

 it. Having glanced at the index to be certain that the inftru- 

 ment was rightly direcled, I looked for the flar again, but 

 could perceive nothing. Stepping now forward, and turning 

 my back towards the candles, the better to behold the heavens 

 through the tranfverfe flit in the roof, I immediately difcover- 

 ed, that the flar-light there was wholly gone. This was quite 

 unexpected, as about five or fix minutes before, the heavens-, 



when 



