GRIMSLEY: GYPSUM IN KANSAS. 27 
and walls, thoroughly soaked from leaking and unprotected roofs, 
have not been in the least injured; it attains a high polish and is 
now largely used for wainscoting as a substitute for marble; this 
plaster makes walls fire-proof, and they are not affected by change 
of temperature, they do not chip or crack and they become harder 
with age; it is dense and hard and so vermin proof. 
USES. 
The gypsum of Kansas in its ground, uncalcined state, is used 
as land plaster for fertilizer, which is thought to be directly bene- 
ficial in its lime; but its main value is indirect in retaining moisture 
and ammonia which is slowly given up to the growing plants. In 
Many states large portions of the gypsum is thus used, but in this 
State only 560 tons, out of nearly 65,000 tons in 1894, was ground 
into land plaster. In this condition it is also valuable as a disin- 
fectant around houses and stables, through its absorptive properties 
taking up the offensive odors. 
Most of the mineral is calcined, and then in its finer grades it is 
used for dental plaster and as plaster of Paris for casts and moulds 
and white finish for walls. It has been used with marked success 
for fire-proof material. For this last purpose the calcined gypsum 
is mixed with finely ground cinders and poured between the iron 
joists with temporary plates above and below, giving a smooth 
under surface for the finishing coat of the ceiling of the lower sto- 
ries and a smooth upper surface on which the tile floor may be 
laid. This material is claimed to be thirty-five per cent lighter, 
twenty-five per cent greater strength, and sixty per cent cheaper 
than tiling, which has long been used for this purpose. 
The greater portion of the calcined material, however, is manu- 
factured into the form of cement or rock plaster, which is displacing 
in many portions of the country the ordinary lime plasters. 
