4o Chemical and Physical Notes 



When the mass is all liquid the temperature of the liquid 

 will rise rapidly until it finally assumes that of the room. 



We see, then, that at temperatures below IS'8 C. chloride 

 of ammonium and ice are indifferent to each other; above 

 this temperature they melt each other, and at temperatures 

 between o C. and I5'8 C. chloride of ammonium is a 

 deliquescent salt. 



It might be thought that, as the cryohydric temperature 

 of chloride of sodium is 2i - 85 C. and that of chloride of 

 ammonium is - I5'8 C., the cryohydric temperature of a 

 mixture of them in equal proportions would be somewhere 

 near the middle, or about i8'8 C. But this is not so. The 

 cryohydric temperature of a mixture of the two salts lies 

 below that of either of the salts ; and the same is the case 

 even with the mixtures of the chlorides of sodium and of 

 potassium, the cryohydric temperatures of which are so far 

 apart. 



The following observations (Table II) were made in 



TABLE II. Buchanans Results. 



the Engadine on September 20, 1897, when a heavy snow- 

 fall occurred. The temperatures were all observed with the 

 same thermometer and no correction has been applied. The 

 temperature marked - o'3 C. in melting snow, which makes 



