ISO COPPER. 



mercury. 9. For what is it used ? 10. What is said of fulminating 

 powder.'' 11. Of mercury as a solid metal .-' 12. What is the descrip- 

 tion of the quicksilver mines in Peru ? 13. How much must the 

 temperature of mercury be reduced before it will become solid ? (see 

 Appendix.) 14. What is said of freezing mixtures .^ 



LESSON 80. 



Copper and Lead. 



Concen'trated, usually applied to fluids which are rendered stronger 

 by evaporating, by means of heat, a portion of the water they 

 contain. 



Heteroge'neous, dissimilar in nature. Homoge'neous, having the 

 same nature or principles. 



Cu'linary, relating to the. kitchen. 



Copper is a brilliant metal, of a red colour, very hard, 

 sonorous, and elastic ; and the most ductile of all the metals, 

 except gold. Its malleability isalso so great, that it is ham- 

 mered into leaves, and sold in thin paper books in imitation 

 of leaf-gold. It will not burn so easily as iron ; which is 

 evident from its not striking fire by collision. On this and 

 other accounts it has been substituted for iron in the ma- 

 chinery which i^ employed in gun-powder mills. The salts 

 of copper are numerous, and much used in the arts con- 

 nected with chemistry. Concentrated sulphuric acid dis- 

 solves copper by the aid of heat, and thus the sulphate of 

 copper or blue vitriol is formed. Copper exposed to the 

 vapour of vinegar or acetic acid becomes acetate of copper 

 or verdigrifS. All the salts of copper are poisonous, there- 

 fore great care should be taken not to taste wantonly the 

 solutions. The uses of this metal are too various to be enu- 

 merated. Besides its employment to make boilers and other 

 vessels of capacity, and to sheathe the bottoms of ships, it 

 enters as a component part into several of the most 

 valuable alloys. The most important of these alloys is 

 brass, which is formed by the union of copper and zinc, 

 though brass is never made with pure zinc, but generally 

 with calamine, which is a native oxyd, or rather carbonate 

 of zinc. Bronze and gun-metal are formed by the union of 

 aopper and tin in the proportions of a hundred parts of the 

 former to ten or twelve of the latter. Bell-metal is also an 

 alloy of tin with copper, but this usually contains one fourth 



