IN CHEMISTRY. 51 



8. What alkali abounds in sea-weed? 

 Soda. 



g. What alkali abounds in land-plants ? 



Potash. The former salt is a constituent of sea-water, and the 

 latter of rocks which decompose to form the soil. 



10. How is lime-water made from oyster-shells ? 



The oyster-shells, in burning, lose their CO 2 . This leaves the 

 lime uncombined ; hence it readily dissolves in water. 



1 1. What other tests of lead than HS ? 



KI gives a yellow precipitate, NH 4 S a black, and SO 3 a white 

 one. 



12. Will not lime lose its beneficial effect upon soil after a 

 time ? 



Lime acts in various ways to improve the fertility of a soil. 

 It corrects its acidity, aids in the decomposition of the rocky con- 

 stituents, hastens the decay of the humus, and also makes the 

 soil more porous. It does not, however, benefit the growing 

 plant directly, but works up other materials in the soil. It 

 therefore loses its effect after a time. The Belgian farmers have 



a proverb : 



" Much lime and no manure 

 Make farm and farmer poorer." 



13. What is the derivation of the term zinc ? 



The name is probably derived from the Germnn zinken, signi- 

 fying " nails," and is applied to this metal on account of its fre- 

 quently forming pointed particles somewhat resembling nails, 

 when melted and suddenly poured into water. (Griffiths.) 



14. What is the action of permanganate of potash (chameleon 

 mineral) as a disinfectant? 



It gives up its O to oxydize the organic impurities of the water 

 in which they collect. 



15. Do all fish die when taken out of the water? 



No. Some fish have an apparatus for moistening their gills. 

 They can therefore crawl about in the grass, and even migrate 

 from one stream to another. 



