Chemical Science. 175 



known to exist, and has given the composition of many of them 

 obtained by direct analysis. 



The substance known in this country by the name of bleach- 

 ing-powder, is a subchloride of lime ; it consists of 



Hydrate of lime, 1 atom - 67.914 



Chlorine - 1 atom - 32.086 



when put into water, half the lime is liberated, and a solution of 

 neutral chloride of" lime is obtained, which consists of 



Hydrate of lime, 1 atom - 51.416 



Chlorine - 2 atoms - 48.584 



This solution is not altered by long boiling, for it still destroys 

 the colour of indigo, and that even after evaporation, provided it 

 has not been perfectly dried. Acids liberate chlorine, even the 

 carbonic acid of the air can effect this decomposition. 



The chloride of hydrated baryta is not a sub, but a neutral 

 chloride, being formed of 



2 atoms of chlorine - 29.28 



1 atom of hydrate baryta - 70.72 



Its properties are the same as those of the neutral chloride of 

 lime. 



Hydrate of zinc dissolves readily in chlorine, and the solu- 

 tion, when boiled for a quarter of an hour, strongly discolours 

 indigo ; evaporated to dryness, it leaves oxide of zinc, and 

 disengages a little chlorine. On being analyzed, it was found 

 to contain 



oxide of zinc, - - 53.2 



chlorine, 1 atom - - 46.8 



The chlorides of magnesia and of the oxide of copper re- 

 semble that of the oxide of zinc. 



Hydrated per-oxide of iron, dried between paper, when 

 placed in chlorine gas, immediately liquefied, and gave a deep 

 rod solution tliat discoloured indigo. When boiled, the chlo- 

 rine was disengaged, and oxide of iron deposited. 

 ^ Oxides of alumium, bismuth, antimony, tin, tellurium, were 

 not dissolved by chlorine; per-oxide of barium was reduced to 

 protoxide, and then a chloride of that oxide formed. The pro- 

 toxide of lead, nickel, cobalt, and manganese were peroxidized. 



Hence chlorine appears capable of combining with most of 

 the metallic oxides, which are not reducible by heat; of those 

 with which it will not combine, some do not act at all on it, 

 except at high temperatures ; others peroxidize, and thus lose 

 their tendency to combine with it, just as they lose in part their 

 affinity for acids. Desiccation converts the chlorides of oxides, 

 either into metallic chlorides, or chlorates; all of them, except 

 tlies lb-chloride of lime, are, in their composition, analogous to 



