PHYSICAL AND LITERARY. 147 



moved very nimbly to and fro in the air ; or 

 if, while the ball v^as wet with fpirit of 

 wine, it was blown upon by a pair of bellows; 

 or indeed if the air about the ball was other- 

 wife any how put in motion. If any of thefe' 

 means for putting the air in motion are em- 

 ployed, the repeated moiftenings of the ball 

 of the thermometer may be performed by 

 dipping it into the fpirit of wine. But, 

 when a certain degree of cold has been 

 produced by a firft dipping, that is apt to be 

 diminished by dipping again into the- warmer 

 fpirit ; and therefore the thermometer ought 

 either to be dipped into the fpirit and taken 

 out again very quickly, or, what is ftill better, 

 the ball of the thermometer ought to be moifl- 

 ened by a feather that has been dipped into 

 the fpirit of wine. By taking thefe methods, 

 I have by fpirit of wine made- the mercury 

 iji the thermometer fink fpm 44 degrees to 

 below the freezing point j and, by employing 

 fome other fluids' to, be mentioned by and 

 by, I have produced a finking of the thermo- 

 meter much more confiderable. ,, 



In making experiments of thi§ .icind, it 

 is to be obferved, that the cold produced is 

 of very fl^ort duration. On this account it 



is 



