128 



ClIEMISTKY. 



Fig. 49. 



tation will even blister. When given as a medicine it re- 

 quires to be considerably diluted. If an overdose be taken 

 by accident, the best antidote is one which is always at 

 hand viz., vinegar, which forms with the ammonia a salt 

 that is harmless. The water of ammonia with sweet-oil 

 forms a soapy liniment the volatile liniment so much used 

 as an external application. The disposition of this solution 

 to form soapy compounds with fatty substances makes it 

 very effectual in removing grease spots from woolen clothes. 



Both the gas ammonia and the solution react strongly 

 alkaline, turning reddened litmus paper blue. 



164. Cyanogen, CN". Carbon and nitrogen unite to form 

 a colorless gas of a penetrating odor much like that of hy- 

 drocyanic acid, its compound with hydrogen. It forms cy- 

 anides with the metals, as chlorine, iodine, etc., form chlo- 

 rides, iodides, etc. Because of this and its formation of an 

 acid with hydrogen it is classed with these elements. Yet 

 it is not an element, but a compound, the constituents of 

 which are carbon and nitrogen. A body which is compound, 

 and yet acts in some respects like an element, is called a rad- 



