IOWA ACADEMY OP SCIENCE 
115 
letters dated back to 1870 and 1880 from city engineers of leading cities in the 
United States. The gist of all these letters being that Portland cement readily 
decomposes in the presence of the acids of sewers; that the substance is porous 
or becomes so to the extent that it allows water to pass through it in a very 
short time. The findings of the chemists indicate that disintegration would 
take place; the letters from the city engineers show that disintegration does 
take place. 
Now we find that by this that Portland Cement is attackable by acid solu- 
tion and alkali solutions and our work, the work of my brother and myself, 
shows a marked power of distilled water to dissociate the elements of cement. 
These reveal great instability of the calcium compounds as found in Portland 
Cement. And the instability of calcium in the natural combination of our na- 
tive minerals merely presists in the artificial compound called Portland Cement. 
Apparently water is the great vehicle in the presence of which chemical re- 
actions with calcium of Portland Cement take place. 
We hope that with these few suggestions we point the way toward investi- 
gations of great scientific interest. The nature of calcium upon which the na- 
ture of Portland Cement rests is a subject of so great industrial importance that 
it is worthy the combined efforts of the geologists, mineralogist and the chemist 
in the study to establish definitely and dependably the nature of calcium. 
Just a word concerning the magniture of the interests involved and of the 
reasons why an investigation of this subject should be made. Several hundred 
of millions of dollars will be invested in farm land drainage and in city 
sewerage systems in the next fifty years in Iowa, Minnesota and the Dakotas. 
The chief among the materials used for these purposes stands burned clay 
products. The field is so great that other materials, chief among them Portland 
Cement, are entering into the construction of some of these drainage systems. 
The failure of a material to be permanent when put in place would work in- 
calculable loss to the land' owners and tax payers, many of whom might not 
survive the financial hardships which it would work to them. In sewerage 
systems for the sewerage to penetrate the walls of the sewer and contaminate 
the surrounding soil would be fatal to the health of those in the locality. 
We do not wish to theorize and speculate beyond reasonable limits. But 
it does seem to us that it is possible for laymen like ourselves who meet with 
the actual problems to suggest lines of research which will guide the student 
helpfully and will appeal to you who have both the opportunity and facilities 
for the needed research. 
