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 lbs. raised one foot high per minute, or = 550 lbs. 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. 
. . r 30 inches 1 £ 
An atmosphere is = | .y 62 metre j of mercury. 
= 14*70 lbs. 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.