182 IRON. 



LESSON 81. 



Iron and Tin. 



Chalyb'eate, a term descriptive of those mineral waters which 



are impregnated with iron. 

 Pyri'tes, a name given to certain ores, as of iron, copper, tin, &c. 



which contain u large quantity of sulphur, and liave a metallic 



lustre. 



. If utility were made the standard of estimation, iron 

 would hold the first place in the class of metals, and would 

 be counted more valuable than gold, as it appears indispen- 

 sably necessary to the carrying on of every manufacture. 

 It appears to be one of the principal means of civilizing 

 mankind. There has never been an instance of a nation, 

 acquainted with the art of manufacturing iron, which did 

 not in time attain to a degree of civilization infinitely be- 

 yond the inhabitants of those countries where this metal was 

 wanting, or its use unknown. It is plentifully and univer- 

 sally diffused throughout nature, pervading almost every 

 thing, and is the chief cause of colour in earths and stones. 

 It may be detected in plants and in animal fluids. There 

 is a great variety of iron ores, which have different nameS 

 given them by the workmen, and are of very different quali- 

 ties. They are chiefly composed of the oxyds of iron and 

 clay. This metal is susceptible of two degrees of oxydize- 

 ment : — the scales, which are detached from forged iron by 

 a high degree of heat, are in the state of black oxyd, and the 

 common rust of iron is the red oxyd. If a bar of iron be 

 heated red-hot, and a stick of sulphur applied to it, a fluid 

 substance will drop from its end, which is found to be a com- 

 pound of sulphur and iron, and in chemistry is called sul- 

 phuret of iron. Iron-filings mixed with sulphur, and made 

 into a paste with water, in a certain time become very hot, 

 and even produce flame. This mixture is sometimes buried 

 under the f.^round to produce an artificial volcano. In this 

 experiment the water is decomposed, the oxygen unites with 

 the iron to form an oxyd of iron, and with the sulphur to 

 form sulphuric acid, while the hydrogen combines with ano- 

 ther portion of the sulphur, and produces sulphuretted hy- 

 drogen gas, which occasions the flame. Green vitriol or 

 copperas, which is of so much use in dyeing, in colouring 



