FERMENTATION. 389 



funnel, E, cools the vapor of the ether, and passes off through 

 the outlet, F. The ether condensing in the inner tube flows 

 into the two-necked receiver, G, and thence into a flask, H. 

 The Liebig condenser is supported by a stand, B ; the outer 

 tube of the condenser is often made of metal. The stopper 

 in the tubulure of the retort, A, may be removed, and more 

 alcohol added as may be needed for the continuance of the 

 formation of the ether to any considerable amount. The 

 chemical process here is this: Sulphuric acid takes away 

 the elements of water from the alcohol and leaves ether, 

 thus: 2(C 2 H 6 O) - H 2 O = (C 2 H 5 ) 2 O. At least this is the 

 simplest explanation which we can give you. Ether is very 

 commonly called sulphuric ether, but the name is improper, 

 as it contains neither sulphuric acid nor sulphur. By man- 

 aging the alcohol and sulphuric acid differently a gas may 

 be produced which is a very different substance from ether. 

 The amount of sulphuric acid used for this purpose is five 

 times that of the alcohol. This gas is olefiant gas, one of 

 the hydrocarbons obtained by distillation of wood and coal. 

 The reaction in this case is a dehydration or abstraction of 

 water from the alcohol : 



Alcohol. Olefiant gas. Water. 



C a H 6 = C 3 II 4 + H 2 O 



550. Chloroform. This valuable substance can be ob- 

 tained in various ways. It is commonly produced by 

 distilling alcohol with water and chloride of lime. Its 

 molecule contains one atom of carbon, one of hydrogen, 

 and three of chlorine, and its composition is therefore ex- 

 pressed thus : CHC1 3 . We have seen in 421 how it may 

 be regarded as a substitution product of marsh gas. It is, 

 like ether, a colorless and very volatile liquid, having a 

 peculiar sweetish smell. Its inhalation produces insensi- 

 bility more readily than ether. 



551. Vinegar. This is a mixture of acetic acid with wa- 



