ACIDS. 5 



in the root of the me.dicinal squills, common rhubarb, pars- 

 ley, fennel, &c., &c. 



Prussic Acid exists, as is well known, in the kernel of the 

 bitter almond, in laurel leaves, peach leaves and blossoms, 

 &c., &c. 



Gallic Acid is formed in the common nutgall, which is an 

 excrescence formed by the puncture of an insect upon an 

 Asiatic species of oak ; also in the bark of many trees, viz. 

 the oak, chestnut, beech, mountain-ash, sumach, birch, plum, 

 and many others. 



Besides these vegetable acids, there are other acids ex- 

 tracted from the mineral kingdom, which are much used in 

 the arts. Among these is Sulphuric Acid, which is manufac- 

 tured by burning sulphur, which, combined with soda, forms 

 the well-known substance, Glauber salts. Sulphuric acid is 

 much used in the bleaching and dyeing processes. 



Carbonic Acid is obtained from various substances, and is 

 now produced in a solid form. It exists in common air in 

 minute quantities ; in larger proportions it is poisonous. 



Acids and oxygen combine with copper, and in this man- 

 ner poisonous matter is generated. Culinary vessels, if 

 made of this material, should be lined with tin. Copper- 

 bottomed ships are avoided by marine animals on account 

 of the poisonous properties contained in the metal. Bell- 

 metal is copper united with tin, and, for the reason above 

 assigned, is objectionable for culinary purposes, and, if used, 

 must be kept religiously cleaned. 



Leaden vessels for milk have been known to produce in- 

 jurious effects. The air combining with the cream, the latter 

 furthers the oxidation of the lead, and carbonic acid being 

 attracted, a carbonate of lead (white lead) is created, which 

 throws a poisonous property into the milk. In the old 

 country, where extensive dairies have been kept, painter's 

 colic has been communicated to dairy-maids through the 

 1* 



