kckkl.J LITERATURE. 17 
in the preliminary chapters, to describe the chemical and physical 
properties which a Portland-cement material must have, and also to 
show that the value of cement material depends almost entirely upon 
location with respect to fuel supply, transportation routes, and markets. 
Second, cement manufacturers or those wishing- to engage in the cement 
industry often inquire concerning the localities in some given State or 
group of States where cement materials will probably be found and 
desire information in advance of actual testing concerning the physical 
and chemical character of the materials. The latter portion of this 
report, dealing with the cement resources of the separate States, is 
Resigned to furnish information of this type. 
The scope of the report is fairly well de lined by the preceding state- 
ments. It is intended to be primarily a discussion of cement mate- 
rials, not a manual of cement manufacture or a guide to cement testing 
or utilization. A brief sketch of the processes of Portland-cement 
manufacture is presented on pages 21-59, in order to make the subject 
clear to the great number of people who are interested, in one way or 
another, in the condition and growth of this important industry. 
In Parts III and IV of the bulletin, on pages 333 to 372, will be found 
a comparatively brief discussion of the raw materials and manufacture 
of two classes of cements allied to Portland cement, i. e., natural 
cements and puzzolan (slag) cement-. 
It is with pleasure that the writer acknowledges his indebtedness to 
the managers and chemists of the various Portland, natural, and slag 
cement plants throughout the United States. Most of these plants, 
with their quarries or mines, have been personally examined by the 
writer, and in every case all possible facilities have been afforded for 
making the examination as thorough as was necessary. A considerable 
part of the information obtained in this manner can, of course, for 
obvious business reasons, be only stated in a general way; but in most 
sases permission to publish the data obtained has been freely given. 
LITERATURE ON CEMENTS. 
Frequent references have been given, in the text or in footnotes, to 
'eports or papers which give more detailed information in regard to 
r arious phases of the subject. It is a matter of regret that no single 
)ook has been published which adequately summarizes the conditions 
)f the modern cement industry in America. This is doubtless due in 
>art to the fact that all our technical industries are in present daj 7 s 
ubject to such rapid advance that data must be sought in the engineer- 
ng and other technical journals, and not in books. In part, however, 
he lack of a cement manual is due to the fact that the leaders in the 
progress of the American cement industry have been cement manu- 
Bull. 243—05 2 
