176 CHEMISTRY. 



sulphuric acid are added in successive portions. At 

 the ordinary rate of working, four days are required 

 to make good marketable bleaching powder. 



Nitrogen or Azote. 



A body which unites with oxygen in five propor- 

 tions, and in which every additional proportion is a 

 multiple of the first. Thus: 



Nitn. Oxn. 



1 + 1 . or . 14+ 8 Nitrous oxide. 

 1 + 2 . or . 14 + 16 Nitric oxide. 

 1 + 3 . or . 14 + 24 Sub-nitrous acid. 

 1 + 4 . or . 14 + 32 Nitrous acid. 

 1+5 . or . 14 + 40 Nitric acid. 



Muriatic Acid. 



This is a compound of chlorine and hydrogen, 

 and is obtained by distilling common salt with sul- 

 phuric acid. It is the spirit of salt of commerce. 

 Recent discoveries tend to prove that the alkaline 

 muriates are chlorides, and not muriates. 



When it is mixed with nitric acid, the compound 

 acquires the power of readily dissolving gold, which 

 neither of the acids possess separately. 



Carbonic Acid. 



A gazeous compound of carbon and oxygen ; the 

 fixed air of Dr. Black, and mephitic air of older 

 chemists. It is produced by the combustion of the 

 diamond (which is pure charcoal) or pure charcoal. 

 It is thus named because it is identical with the re- 

 sult of the combustion of charcoal in oxygen. Car- 

 bonic acid is not above -g-^th to ^^th of the atmos- 

 pheric air. 



Living bodies produce an excess of carbon, and 

 the presence of the oxygen gas of the atmosphere is 



