Page:Popular Science Monthly Volume 40.djvu/179

Rh the others in succession. A recent invention has simplified this process very materially. This device is a clay press consisting of a series of sacks in which the slip is placed. The moisture is forced through the bags by strong pressure, and the clay is ready for use Mr. A. J. Boyce, of East Liverpool, Ohio, has recently perfected an improved hydrostatic press, which is being introduced into many of the more progressive factories throughout the country. The illustration will convey a clear idea of the clay



press used in reducing the slip to a workable mass. In each chamber is placed a sack made of ten-ounce Woodberry duck, which, if of the proper quality, will last some time. The moisture is pressed through the fabric, and the clay, on removal, is ready for manipulation.

"Jiggers" and "jollies" now greatly facilitate the manufacture of circular and swelled vessels, such as jars, jugs, crocks, cuspidors, and umbrella jars. A "jigger" is a machine which carries a revolving mold, in which the clay is shaped by a former, which is brought down into the mold and held in place by means of a lever We give here an illustration of one of the jiggers made by Mr. Peter Wilkes, of Trenton, N. J. A is the jiggerhead or receptacle in which the mold is placed, which is screwed fast to the revolving spindle. B is a stationary iron column on which the frame or sleeve C slides up or down. D is an iron fork