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IOWA ACADEMY OP SCIENCES. 
CEMENT MATERIALS IN IOWA. 
BY E. H. LONSDALE. 
[Abstract.] 
Some time after the discovery of massive deposits of the 
Cretaceous chalk in the northwestern portion of the state the 
question arose as to the adaptability thereof-- whether this cal- 
careous material might be considered of any practical value 
and if so what means should be taken to reduce it preparatory 
to its application. Certain initiatory steps were undertaken 
towards determining these points but as yet but little has been 
done. Chemical analyses have been made of the rock and test 
shafts put down in order to ascertain the thickness of the beds, 
but further development has never been attempted. 
Vicat and Pasley were among the investigators who sought 
to determine some means through which the manufacture of 
artificial cement might be made possible and they soon proved 
that a mixture of chalk with clay or river mud produced the 
desired results. Since that time the growth of the industry has 
been rapid in this as well as foreign countries. 
The well known Portland cement now so extensively pro- 
duced and generally utilized is made by the calcination of a 
mixture of chalk with argillaceous material. It sets more 
readily and its adhesive powers are claimed to be stronger than 
in the case of the natural cement. The relative amounts of the 
two components vary at different plants. In the United States 
and in Prance and England what is known as the wet process 
is used, while in Germany the dry method is adhered to. The 
affinity which caustic lime has for silica and alumnia and the 
affinity of the combination for water gives rise to the hardening 
of the materials. The degree to which the calcining should be 
carried on depends upon the percentage of the alkaline silicates 
in the calcareous body, and since these are shown by analyses 
to be practically absent from the Iowa chalk, a high calcination 
