22 



SPECIFIC HEAT. 



+ 7 



+ 32 



+ 50 



+ 52 



+ 98 



+ 150 



+ 174 



+ 212 



4-6'62o 



+ 980 



4-1141 



4-1869 



4-2233 

 4-3479 



A mixture of one part of alcohol and three parts 



of water freezes. 

 Strong wine freezes. 

 Ice melts. 



Medium temperature of the surface of the globe. 

 Mean temperature of England. 

 Heat of the human blood. 

 Wood-spirit boils. 

 Alcohol boils. 

 Water boils. 

 Tin melts. 

 Lead melts. 

 Mercury boils. 

 Red heat. Daniell. 

 Heat of a common fire. Do. 

 Brass melts. Do. 

 Silver melts. Do. 

 Iron melts. Do. 



SPECIFIC HEAT. 



Equal bulks of different substances, such as water and 

 mercury, require the addition of different quantities of heat to 

 produce the same change in their temperature. This appears 

 evident from a variety of circumstances. If two similar glass 

 bulbs, like thermometers, one containing mercury and the other 

 water, be immersed at the same time in a hot water-bath, it 

 will be found that the mercury bulb is heated up to the tem- 

 perature of the water-bath in half the time that the water bulb 

 requires ; and if the two bulbs, after having both attained the tem- 

 perature of the water-bath, be removed from it and exposed to 

 the air, the mercury bulb will cool twice as rapidly as the other. 

 These effects must arise from the mercury absorbing only half 

 the quantity of heat which the water does in being heated up to 

 the same degree in the water bath, and from having conse- 

 quently only half the quantity of heat to lose in the subsequent 

 cooling. Again, if we mix equal measures of water at 70 and 

 130, the temperature of the whole will be 100 ; or the hot 

 measure of water, in losing thirty degrees, elevates the tempera- 

 ture of the cold measure by an equal amount. But if we 



