Upon a REMARKABLE COLD. 



161 



and that upon the fand to -4- 8. I continued to obferve till half 

 an hour after one in the morning ; and the following regifter 

 {hows how the thermometers pointed according to their feveral 

 fituations : 



BY examining the thermometers fo frequently I had occauon 

 to remark, that the balls and ftems of the two which lay upon 

 the fnow and fand were crufted with hoar-froft much foon- 

 er than the other which was to windward in the air. The 

 one upon the fand contracted hoar-froft the fooneft, and, what 

 at the time I thought ftrange, more early than the fourth ther- 

 mometer which I had laid down upon the fnow at the ground. 

 In regard to the thermometer in air, I mould rather think it 

 attracted no hoar-froft whatever, properly fpeaking, and that 

 what was difcernible upon it proceeded from accidental minute 

 floating particles which clung to the glafs, and afterwards en- 

 tangled more of the fame kind : For the ball of this thermo- 

 meter was not, like the one belonging to the fand, crufted over 

 with an uniform dead filver whitenefs, but was befet with a 

 number of fmall tufts or prickles of the hoar-froft, whilft the 

 intervals of glafs between them were entirely clear. 



WITH a view to a repetition of the ftatical experiment, I had 

 carefully afcertained the weight of the fnow-fcale and fand- 



X board 



