168 University Geological Survey of Kansas. 
asserted that in using plaster of Paris it is essential that an old 
dish that has been previously used for mixing should not be 
used. It is evident that this is because some of the crystals of 
hydrated gypsum already formed would start the crystalliza- 
tion in the mass much sooner than it would otherwise begin. 
Uses of Gypsum. 
The uses of gypsum and its products may be divided into two 
classes : 
Uses dependent on the weight, softness, fine texture, color, 
porosity or chemical composition, without burning. 
As alabaster or satin spar, for making ornaments. 
As a fertilizer, under the name of ‘‘land plaster.’’ 
For building purposes. 
To weight fertilizers. 
As an absorbent of organic material in fertilizers. 
As an adulterant of foods and medicinal preparations, under 
the name of ‘‘ terra alba.”’ 
In the manufacture of glass and porcelain. 
Uses dependent on the absorption of water and ‘‘setting’’ of 
the material. Plaster of Paris, or partially dehydrated gypsum, 
is used : : 
As plastering for buildings. 
As filling for fire-proof structures. 
As molds for coins, statuary, pottery. 
For the purpose of deodorizing foul air. 
By surgeons, to hold broken limbs in place. 
By dentists, to get an impression of the mouth. 
For cornices, moldings, etc. 
In alabastine and similar wall washes. 
For making crayons. 
In wines, to retard fermentation and prevent the formation 
of too much free acid. 
In wines, to absorb water and strengthen the product. 
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