CHA PTHR IX. 
THE CLAYS OF OHIO, AND THE INDUSTRIES ESTABLISHED 
UPON THEM. 
By EDWARD ORTON, Jr. 
SECTION I. \ 
THE ORIGIN, COMPOSITION, ANALYSIS AND PROPERTIES OF CLAY. 
The knowledge of the composition and properties of clay now cur- 
rent among the clay-workers in Ohio is almost wholly practical, and 
there may seem to be ground for surprise that such excellent results should 
have been obtained jwith so little aid from science, but it is to be 
remembered that much less has been done for this subject than for 
parallel industries. The scientific research directed to it is much more 
scanty in proportion to the interests involved than in almost any similar 
field. 
The literature of a‘technological subject always represents the pro- 
egress of science in respect to that subject. In this field it is represented 
by only one book that is largely useful in American practice, viz., Pro- 
fessor G. H. Cook’s Report on the Clays of New Jersey (Geological 
Survey of New Jersey,} Annual Report for 1878). This treatise is 
worthy of the valuable deposits that it represents, and for the large use of 
it in this chapter, due acknowledgments are hereby rendered. Much 
excellent reading on the subject is contained in the various scientific 
journals of the day, but this source is inaccessible to many, and but 
little connected information can be obtained from it. 
What work has already been done has proved very valuable, and 
further study, particularly in a virgin field like Ohio, cannot but be 
productive of good. In many respects the field is different from New 
Jersey, as for instance in the geological horizon of our clays, which are 
all coal measure formations, and a careful study of it may be expected to 
throw light on many points of interest. 
