CLAY WORKING INDUSTRIES. 101 



to estimate closely. The duration of a grind depends on the size of a charge, 

 and the hardness of the clay. It is not less than one and one-half hours on 

 the average, or 7 charges per day at 1,200 pounds per charge — 8,400 pounds 

 = t.20 tons per day per mill. It would occupy t.ie time of one man to tend 

 this mill, and this clay would cost 30 cents. By using more mills the labor 

 cost could be reduced somewhat. There is not much odds in the labor cost 

 of clay by the two processes. 



The selection of the clays for the stoneware industry has been dis- 

 cussed and their preparation for use in the potter's hands. In both of 

 these subjects, there is much room for chemical and technical investiga- 

 tion and discussion. In the actual fashioning of the wares from the pro- 

 posed clays, there are but few points of a scientific nature involved. The 

 problems are mainly mechanical and industrial ones. However, as the 

 processes employed in all branches of pottery, from the highest to the 

 lowest, are substantially the same, a brief description of the various steps 

 will be given in this conection. 



Pottery is manufactured by three different plans; 1st, by turning; 2d, 

 by jollying in molds; 3rd, by casting. Turning clay by hand was the 

 original method, the two latter processes are out-growths from it. Stone- 

 ware ten years ago was nearly all turned; now there is probably fifty per 

 cent, of it jollied ; all of the lighest pieces of simple shape, are produced 

 in this way. 



The steps to the production of turned ware from prepared clay are 

 wedging, turning and drying. 



In wedging the clay, a lump is cut off of a proper size and weight 

 to make the desired object. This is cut in two by a wire and united again 

 by a violent blow, kneaded, cut and reunited again, and so on for a few 

 moments. This treatment is supposed to work out air blebs and make 

 the clay solid and dense. The turning or spinning is done on a rapidly 

 revolving horizontal disc. The clay is slapped down against this so as to 

 adhere and revolve with the disc. On wetting it and covering it with fine 

 pulp of clay, and pressing it with the fingers it can be made to take any 

 shape when in revolution. There is great art and skill in doing fine turn- 

 ing. The men take great pride in the possession of this skill and fre- 

 quently vie with each other in trials of it. 



The turner works by a standard known as the " day's work". A day's 

 work is a definite number of gallons of each kind and size of ware; it is a 

 very complicated standard and one which ought to be abandoned, as a 

 turner now makes frequently seven or eight days' work in a day. The 

 standard varies greatly in different districts; fifty-six gallons of one of 

 the standard sizes is a day's work in one place, while eighty maybe the 

 number in another, and also in making twenty gallon crocks only three or 

 four would be a days work, which does not compare in labor and time 

 with making sixty or eighty one-gallon pieces, or thirty or forty two- 

 gallon pieces. 



