88 GEOLOGY OF OHIO. 



status is so inadequately represented by the most recent notice which 

 they have received in the volumes ol the survey, that the present chap- 

 ter has been prepared. 



The industries represented are practically the same as in the report 

 of nine years ago; in the department of pottery manufacture, the china 

 business has been formally introduced, and the whole of the now enor- 

 mous trade in clay paving material has sprung into existence mostly in 

 the last five years. It is a matter of regret that accurate figures show- 

 ing the productions of Ohio as a clay producing state are not accessible. 

 Statistics of this subject are in process of compilation by the Census 

 office at Washington, but no data from the census of 1890 are yet fur- 

 nished the. public. Wherever possible, approximate figures of the pro- 

 duction of 1891 were obtained, but these give us only an idea of our own 

 status and none as to our relative advancements. 



However, there is no doubt of Ohio's supremacy in this line in every 

 department unless, perhaps, the manufacture of fire brick, in which Penn- 

 sylvania has had the lead for many years and whose deposits of clay for 

 this particular purpose are larger and probably better than ours. 



Also it is likely that the production of common building brick is 

 larger in some of the eastern states than in Ohio, on account of the enor- 

 mous consumption of the large eastern cities. But as the production of 

 common bricks is more nearly a commercial question and less a technical 

 problem than any other branch of clay working, it is not material to the 

 points at issue. 



The clay working industries of Ohio may be divided into several 

 well defined groups. The classification is somewhat different from that 

 adopted in the previous report: in this chapter it has been designed to 

 treat under one head all materials manufactured to fill one purpose and 

 the classification is the most easy and most natural one; but in some 

 groups, notably in the manufactures of pipe and hollow goods, it is 

 found that articles which unmistakably belong in this section by the 

 processes of manufacture, find their field of usefulness in another class 

 of work and do not conflict or compare with the regular products of 

 their class. 



In the principal groups however there is no such difficulty of classi- 

 fication. The clay working establishments comprise manufactures in 

 not less than twenty-five distinct lines. These may be divided into the 

 following general groups : 



1st. The manufacture of pottery. 



2d. The manufacture of paving material. 



3rd. The manufacture of pipe and hollow goods. 



4th. The manufacture of refractory material. 



5th. The manufacture of building material. 



It may be said that the last three groups are all substantially brick 

 making industries. This is so in one respect, but the extreme divergence 



