40 ANNUAL REPORT 
tic effect is due to the residual chemical energy. Basic salts are produced 
simply by the substitution of oxides in the, place of water taken up. 
hus lead chloride takes up two molecules of water: PbCl,H,(OH). 
while magnesium chloride unites with six molecules of water: MgCl,H,- 
(OH) .. 
The chemical senergy shown by the hydration of these compounds 
may take the form of uniting with as many molecules of another com- 
pound as it has taken up water; or, the water may be replaced by an oxide 
like magnesium oxide, calcium or barium oxide, so that there is produced 
a basic compound like MgCl,3MgO, this being the formula of the 
Sorel cement, named after the inventor, who made the discovery in 1867. 
This extraordinary ability of such compounds to form basic salts 
Kosmann illustrates by the many natural compounds existing which closely 
follow the formula of basic salts. He mentions: ; 
Hydrous Magnesite’ 3MeCO,Me(OH).3H,O 
Malachite CwCOYCu( Old!) « 
Basic zinc carbonate ZnCO,2Zn(OH), 
Clay IN O.2Si1O)2)a © 
Serpentine 3M¢g02S10,2H,O 
Willamite UNS OVLO), 
Magnesite as such is at present not available in large quantities 
in the United States, it being imported chiefly from Greece and Styria. 
Hence its cost would be too great for production on a large scale at this 
time. It owes its importance to its refractoriness, being a valuable basic 
heat-resisting material. Its drawbacks in this connection, however, are 
its great brittleness and its tendency to crumble when exposed to tem- 
perature fluctuations as well as its marked conductivity of heat. 
