SULPHURIC ACID. 21 



mentioned, and forms common salt, a substance having 

 harmless properties in itself, and differing most widely 

 from either of those out of which it is formed. 



Sulphuric acid is the common oil of vitriol, a. It 

 has commonly been called an oil, because of its thick 

 oily appearance, but has few other properties of oils. 

 It is, like them, rather soft and agreeable in its first 

 feeling upon the skin, but this sensation is instantly 

 succeeded by an intense burning pain; for the acid is 

 so powerful in its corrosive effects, as to destroy both 

 skin and flesh wherever it touches. Cloth is at once 

 ruined by it, eaten out in holes. A very small quan- 

 tity taken into the mouth and swallowed is fatal, as 

 all of the internal passages are destroyed or seriously 

 injured by its contact. There have been many cases 

 of death from accidentally swallowing even so small 

 a portion as part of a spoonful. 



b. The name acid would naturally cause us to sup- 

 pose that this liquid would be sour; and a taste of it 

 even when largely diluted with water, shows it to be 

 so in the extreme. When thus diluted, so that the skin 

 may not be at all affected, it is not poisonous, and has 

 a rather agreeable taste. 



b. If paper saturated with blue litmus, a substance to 

 be found in many apothecaries' shops, be dipped into 

 this or other acids, it will become red : if the paper 

 thus turned red be dipped into a solution of potash or 

 soda or ammonia, it will become blue again. This 

 furnishes a test by means of which we can tell whether 

 fluids are acid or alkaline. 



c. Sulphuric acid is occasionally found in springs, 

 uncombined with any thing. There are some in 

 western New York, near Lockport, where the water a3 

 it comes from the spring is sour as vinegar, owing to 

 the presence of free sulphuric acid. 



d. This is a much heavier liquid than water. A 



