PROPERTIES. 359 



Before decomposition. After decomposition. 



Chloride of f Chlorine Chlorine. 



sodium I Sodium 



Sulphuric acid- Sulphuric acid. . "~ ^^^ Sulphate of soda 

 Peroxide of / Oxygen - " 



manganese I Protox. manga .*^^ 

 Sulphuric acid. . Sulphuric acid. .- Illr^^Sulp. of manga. 



Or in symbols ; 



NaCl and 2SO 3 and MnO 2 = NaO, SO 3 and MnO,SO 3 and Cl. 



Properties. Chlorine is a dense gas of a pale yellow colour, 

 having a peculiar suffocating odour, absolutely intolerable even 

 when largely diluted with air, and occasioning great irritation 

 in the trachea, with coughing, and oppression of the chest. 

 Some relief from these effects is experienced from the inhalation 

 of the vapour of ether or alcohol. The density of chlorine gas 

 is, by experiment 2470, by theory 2440. Under a pressure of 

 about 4 atmospheres, chlorine condenses into a limpid liquid of 

 a bright yellow colour, of a sp. gr. about 1 .33, and which has 

 not been frozen. Water at 60 dissolves twice its volume of 

 this gas, and acquires the yellowish colour, odour and other 

 properties of chlorine. To form chlorine water, a stout bottle 

 filled with the gas at the tepid water trough, may be closed with 

 a good cork and removed to a bason of cold water ; on loosening 

 the cork with the head of the bottle under water, a little water 

 will enter it, from the contraction of the gas by cooling ; and 

 this water may be agitated in contact with the gas, by a lateral 

 movement of the bottle, without removing it from the water ; 

 on loosening the cork again more water will be found to enter 

 the bottle, and by repeating the agitation and admission of 

 water, the whole gas (if pure) is absorbed, and the bottle is in 

 the end filled with water, which of course contains an equal 

 volume of chlorine gas. With water near its freezing point, 

 chlorine combines and forms a crystalline hydrate, which Fara- 

 day found to contain 10 atoms of water. Hence, chlorine gas 

 cannot be collected at all over water, below 40. Exposed to 

 light, chlorine water soon loses its properties, water being de- 

 composed and hydrochloric acid formed, with the evolution of 

 oxygen gas. But it may be preserved for along time in a stone- 

 ware bottle. When diluted so far that the water does not con- 



