94 MURIATIC ACID. 



light, but not to the direct rays of the sun, the gases 

 do not explode, but combine slowly and quietly. 



188. The process by which muriatic acid is procured 

 is very simple: a quantity of oil of vitriol or sulphuric 

 acid is poured on some common salt, acid fumes arise, 

 they are made to pass through cold water, which ab- 

 sorbs them, and in time a very sour corrosive liquid 

 is obtained, which is the muriatic acid, or the spirit 

 of salt of the shops. In order to explain the action 

 which takes place in this process, it is necessary to 

 say a few words respecting the nature of common 

 salt. 



189. Common salt is a compound substance, con- 

 sisting of two elements; the one is chlorine, the cor- 

 rosive yellow-colored gas just described, and the other 

 is a white silvery-looking metal called sodium, a sub- 

 stance having a very strong aflSnity for oxygen, eager- 

 ly combining with it and forming the alkali soda 

 (216). 



190. The substances, then, concerned in the process 

 for making muriatic acid, are common salt, or, to 

 speak scientifically, chloride of sodium, sulphuric acid, 

 and of course a portion of water, as oil of vitriol is a 

 solution of dry sulphuric acid in water. Both the 

 chloride of sodium and the water are decomposed, the 

 oxygen of the water combines with the sodium of the 

 salt, whilst the hydrogen of the water combines with 

 the chlorine of the salt, and thus soda and muriatic 

 acid are formed ; the latter is given off or expelled in 

 the form of gas or vapor, whilst the soda combines 



