112 University Geological Survey of Kansas. 
ordinary circumstances, why it need be touched by shovel or 
hand until it is packed ready for shipment. 
If the material is the gypsum earth, even the mining opera- 
tions could be conducted profitably by machinery. With the 
many dredging devices now used for lifting sand from the bot- 
tom of rivers, and the various steam shovels employed in the 
large brick factories for lifting the clay from the pits, and 
other similar devices, it would seem that the old-fashioned way 
of handling the gypsum earth by hand, or with team and scra- 
pers, should be replaced by mechanical devices. 
After the material reaches the mill, no matter in what 
form it comes, it can readily be passed through the crushers, 
filled into the calcining kettles, elevated from the hot-pits to the 
bolts, cooled by the process of elevation, carried from the bolts 
to the mixers, and from the mixers to the devices for packing, 
entirely by mechanical operations. So long as steam power re- 
mains cheaper than man power such mechanical devices will be 
desirable. 
The method of cooling and elevating the hot plaster which 
gives the best satisfaction of any thus far employed is that of 
the suction pipe. A sheet-iron pipe ten or twelve inches in di- 
ameter has a strong current of air forced upwards through it 
by afan. The lower end of the pipe should be telescopic in 
character, so that it can be lengthened downwards at will. 
The mouth of the pipe is placed just over the center of the upper 
surface of the hot plaster. The air current forced upwards 
sucks the fine powder up and carries it to any desired hight. 
As the volume of the plaster in the hot-pit decreases the 
pipe is extended downwards so that at all times it is within an 
eighth or a fourth of an inch of the surface of the plaster. 
Such a process saves a large amount of space, where the hot 
material otherwise must be left until it can cool, and saves a 
great amount of time, for the cooling is accomplished during 
the time that the elevation is effected. In mills where the suc- 
tion pipe is not employed it is common to elevate the material 
with a belt-bucket elevator and allow it to fall through several 
feet and again elevate it for the purpose of cooling it, a process 
