142 SALTS. ^ 



i 



to effloresce. Salts have not only the: property of dissolving' 

 in water, but by exposure to great heat they will melt, andl 

 they require different degrees of heat to put them in a statej 

 of fusion, as well as different quantities of water for the;fi^ 

 solution. y 



Many of the salts are found native, and the carbonate^^ 

 sulphates, and muriates are the most frequent. Chalk,' 

 limestone, and marble, are all included in the term carboH 

 nate of lime. Few salts are more copiously disseminated^ 

 than the sulphate of lime, particularly in the vicinity of Pai^ 

 lis, and hence its name Plaster of Paris. Of the native miik 

 riates, muriate of lime occurs with rock-salt, and muriate of] 

 Imagnesia is found in abundance in sea-water ; and muriatol 

 of soda not only exists in immense quantities in the ocean,^ 

 but vast mountains in different parts of the world are en^ 

 tirely formed of this salt. Nitrate of potash, known by thw 

 more familiar name of nitre or salt-petre, is collected in vsm, 

 rious parts of the globe. Phosphate of lime, which is thi^ 

 basis of all animal bones, exists native in Hungary, ani 

 composes several entire mountains in Spain. Mountains ofj 

 salt were probably formed in very remote ages, and bjl 

 processes of which we can form no idea. It may be sup^ 

 posed, however, that these changes have been slow and^ 

 gradual, for several of the native salts exhibit marks of regii-{ 

 larity and beauty in their crystallization, which cannot b^ 

 imitated by art. 



Q„UESTioNS. — 1. To what substances is the name acid given 

 To what do most acids owe their origin ? 3. How do they form salts i 

 4. What is said of the division of acids ? 5. How is sulphuric aci 

 procured ? 6. Muriatic acid ? 7. What is carbonic acid ? 8. Ho^ 

 may you obtain carbonic acid gas ? 9. What are some of the propei 

 ties of this gas ? 10. Why do fatal accidents often happen from t! ' 

 burning of charcoal ? 11. How may it be destroyed at the bo|tom < 

 wells .-* 12. What is said of the number and uses of the acids ? 11 

 How are the different salts known from each other ? 14. How niaj 

 salts be separated from their water of solution .'' 15. To what change! 

 are crystallized salts liable on exposure to atmospheric air ? 16. Wha 

 native salts are mentioned ? 17. What is said of salt mountains .' 



