234 OUTLINES OF NATURAL PHILOSOPHY. 



to the sum of the two former, or 



32 c + 112 c c x c ' x, and 



c c' 



If c be to c 7 as 10 to 9, which appears, from ex- 

 periment, to be true, as = 288 + 1120 = 1408 ; this, 

 therefore, is the distance of the zero of temperature 

 from the zero of FAHRENHEIT, and its distance be- 

 low the freezing of water, is, therefore, 1440. 



In this investigation, it is supposed, that, however low 

 the ice is cooled, c remains of the same value. 



327. When water is put in a vessel on the fire, 

 it continually receives heat, and its temperature 

 increases, till, at a certain point, the water boils, 

 and rises in the form of vapour, after which the 

 temperature of the water increases no farther, as 

 much heat being carried off every instant by the 

 vapour, as is received from the fire. 



The temperature which water then attains, as was 

 before remarked, is nearly constant, and is the 

 same in all cases, except in as far as it is affec- 

 ted by the pressure of the atmosphere, in the man- 

 ner about to be explained. The vapour thus form- 

 ed, is an invisible elastic fluid, of a temperature not 

 less than 212 degrees. A great quantity of heat 

 passes into the latent state, when vapour or steam 

 is generated. This was also discovered by Dr 

 BLACK. 



328. On 



