REVIEWS. 93 



" Potash and soda both occur native." Not only is this untrue, but the 

 nature of these substances forbids the possibility of its being true. 



" Common salt," we are told, " is formed by the combination of soda 

 with hydrochloric acid, or muriatic acid, as it is sometimes called." This 

 is also untrue ; common salt is composed of the metal sodium and the 

 metalloid chlorine. 



" Alabaster and plaster of Paris are made of gypsum." Plaster of Paris 

 is an article of manufacture, alabaster is not. 



"Fluor-spar the beautiful mineral called blue-John in Derbyshire 

 is fluorate of lime." Such a substance as is here described is unknown to 

 chemists ; the mineral spoken of is fluoride of calcium. 



Alum is spoken of as a substance " of which there are many varieties, 

 all combinations of alumina and sulphuric acid, together with other 

 matters. Common alum is a sulphate of alumina." A rare substance, 

 called " feather alum," is a sulphate of alumina. Common alum is a 

 sulphate of potash plus a ter-sulphate of alumina. 



Silicates of magnesia are represented as "all easily melted by the heat 

 of the flame of a blow-pipe." The exact reverse is the case ; they are, 

 in general, most refractory substances, and can never be fused, except in 

 cases where they include abundance of lime or iron. 



" They (the metals) are commonly combined either with oxygen or 

 with some of the various acids such as the sulphuric, the carbonic, or 

 the nitric." No mention whatever is made of sulphur and arsenic, the 

 great companions of the metals ; and, as for the acids, we need not refer 

 the reader to works on metallurgy or mineralogy to prove the well-known 

 fact, that the metals are only sometimes combined with carbonic, but 

 rarely with sulphuric, and never with nitric acid. 



Meteoric stones are said to contain, as well as iron, " almost invariably 

 a small proportion of the rarer metal (nickel) combined with sulphuric 

 acid." This is not only untrue, but impossible. 



" Copper is not unfrequently met with native, but not often in any con- 

 siderable quantities." There is a specimen from Cornwall, in the hall of 

 the Museum, in Jermyn-street, with which our author should be familiar, 

 which weighs some tons ; and at Lake Superior native copper exists in 

 great abundance, and is worked with profit. 



We have done with our unpleasant labours, and greatly regret, for the 

 sake of Mr. Hughes's series, that in its first volume an article should have 

 occurred which is so bad as to be past mending in a second edition. We 

 can see no remedy but in its removal ; it is a case for the surgeons ; 

 no cure but complete excision. With pleasure we turn to an article, 



