MEASURES, WEIGHTS, &c. USED IN THIS WORK. 



Temperature is measured by degrees of Fahrenheit's scale, of which the freezing point is 

 32, and the boiling point 212. 



Heat is commonly measured by the number of degrees it would increase the temperature of 

 a given quantity of water at 60, with the barometer at 30 inches. 1 



Mechanical power is measured by the elementary horse power, as settled by Watt. A 

 horse power is = 33,000 ffis. raised one foot high per minute, or = 550 Ibs. raised one 

 foot high per second ; and a day's work of a horse is this power acting 8 hours. 



This horse power is, in French measures, 4661 kilogrammes raised one metre high per 

 minute. 



The pound is the avoirdupois pound, = 7000 troy grains, = '4535 French kilogrammes. 

 The foot is = -3048 French metre. 



( 30 inches 1 , 

 An atmosphere is = | .^ 62 metre j of mercury. 



= 14*70 Tbs. per square inch. 

 = 11 '55 circular 



1 It is more properly measured by the volume of water at 60, which it would raise exactly one degree ; this measurement 

 being strictly proportional to the absolute quantity of heat. ED. 



