TURNING AND MOULDING. 



called slip, the surfaces to be united. This slip acts as a cement, 

 becoming almost immediately hard enough to retain the handle in 

 its place. 



A number of handles ready moulded or cast are lying on the 

 slab beside G, ready to be attached to similar articles. Various 

 plaster moulds appear on the floor near the table. 



The convex surface of the article to be moulded is produced in 

 like manner, by pressing a concave mould upon it. Some of these 

 concave moulds appear on the floor. 



The process of moulding by casting has been explained in the 

 case of statuary porcelain. 



4. The operations of the thrower and moulder are sometimes 

 abridged by combining them. The apparatus represented in 

 tig. 36 supplies an example of this. 



It consists of a porte-calibre, K, and a copper bar, BE', which 

 plays on a hinge or pivot, at one extremity, and is supported on a 

 frame, HH', of wood solidly attached to the table of the wheel. It 

 is raised and lowered by turning it on the hinge, t, and when 

 lowered is supported on the upright H 7 at t'. The porte-calibre 

 slides on this, its motion being regulated by a groove. To this is 

 attached by screws the " calibre," or profile, c, which is formed to 

 correspond with the shape and mouldings of the article to be 

 produced. 



The mould which gives the form to one side of the article, 

 (suppose for example the concave or upper surface of a plate,) being 

 attached to the disc of the potter's wheel, a cake of dough of the 

 proper magnitude and thickness is laid over it, and pressed upon 

 it by a wet sponge, so as to cause it to apply itself closely at every 

 part to the surface of the mould. When this is accomplished the 

 calibre or profile is lowered gradually upon it, and the wheel 

 being put in revolution, the convex side or bottom of the plate 

 receives its form in the same manner as an object placed in the 

 chuck of a turner's lathe is shaped by a cutting tool guided by 

 a slide-rest. 



183 



