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HALL 78. 
SALTS OF THE ALKALIES AND ALKALINE EARTHS. 
These include besides salt and similar compounds such min- 
erals as asbestos and mica. Here belong also the borates, phos- 
pnates, etc., which occur in nature chiefly in combination with 
lime or soda. Besides the alkali and alkali earth compounds, 
sulphur and abrasives may be found in this hall as well as 
various useful minerals of special or limited use. 
CASE 1. — An unusually large and complete display of the 
"‘Stassfurt Salts.” These salts are rich in potash and magnesia, 
and furnish nearly the whole of the world’s supply of potash. 
CASE 2. — Applications of potash salts. A collection of the 
compounds of potash used in the arts. 
CASE 3. — Soda salts. 
The most important mineral in this class is salt, many vari 
eties of which are shown. Cryolite and its uses. The process of 
making soda and alymina from cryolite is fully illustrated. 
CASE 4. — Lime and Magnesia salts. These include gypsum, 
dolomite and magnesite. Applications of gypsum are included 
here. Barium and Strontium salts, including chiefly barite and 
celestite, compounds of strontia and baryta, alkaline earths allied 
to lime. 
CASE 5. — Gypsum. This is a hydrated sulphate of lime 
from which plaster-of-paris and the fertilizer land-plaster are 
made. 
CASE 6. — Borates. The minerals from which borax is ob- 
tained and their products. 
CASES 7 AND 8. — Phosphates. 
Minerals and rock phosphates from well-known localities in 
England, Spain, Canada, Carolina, Tennessee, and Florida. 
Guano from Venezuela and Santiago de Cuba. 
PLATFORM 14. — A large specimen of apatite from Canada. 
This should be studied in conjunction with the phosphate col- 
lections of cases 7 and 8. 
CASE 9. — Sulphur. Besides native sulphur from many lo- 
calities, examples are given of the more important metallic com- 
pounds from which sulphur is obtained in commercial quantities. 
The various forms in which sulphur comes to the market are 
illustrated. 
