FICTILE MANUFACTURES. 



doughy mass, which is cut into pieces, and heaped 

 together in a damp cellar, where they lie for the 

 space of about six months. The clay here be- 

 comes black, exhales a fetid odour, and undergoes 

 a slight degree of fermentation, during which 

 carbonic acid gas and sulphuretted hydrogen are 

 disengaged. This improves both the colour and 

 texture of the clay, and tends to bring it to a 

 homogeneous mass. The longer the clay-paste 

 is kept, the finer it becomes in the grain ; and 

 vessels made from it, when old, are not so apt to 

 crack as those formed from newer paste. 



The process of firing, as generally carried out, 

 is a very wasteful one as regards the expenditure 

 of fuel, and is attended with inconveniences. In 

 view of these, more perfect processes have been 

 introduced to get rid of the superfluous water : 

 amongst others, we may notice the screw-press, 

 and filtration by means of a vacuum ; more 

 recently still, a hydraulic press has been intro- 

 duced, which is rapidly superseding other appli- 

 ances. 



To assist in forming the clay into a fine mass, 

 the operation of sloping or wedging is performed 

 at intervals during the period the clay is lying to 

 ferment. This consists of slicing the clay with a 

 spade, and dashing the slices together so as to 

 expel the air which lodges in the mass. This 

 process in large establishments is aided, or per- 

 formed, by passing the clay through a mill. The 

 last process previous to the throwing is the 

 ' slapping,' which is performed by cutting masses 

 into portions by means of a wire, provided with 

 handles at its extremities, and dashing the pieces 

 together again, care being taken to make them 

 join parallel to each other; if this is' not attended 

 to, the grain being disturbed, the pieces are likely 

 to crack during the process of baking. 



The clay, being thus completely kneaded, is put 

 upon the potter's wheel (fig. 5), where it is formed 



Fig. 5- 



into articles of various shapes. This lathe con- 

 sists of an upright iron shaft, the lower point of 

 which turns in a socket, and the upper is fixed in 

 a broad wooden disk. Near the top, the shaft 

 passes through a socket attached to the frame- 

 work of the lathe. In the centre is a pulley, with 

 grooves of different circumferences, by which the 

 speed of the shaft can be increased or lessened as 

 circumstances require. This shaft is driven by 

 a fly-wheel, from which an endless belt passes to 

 the pulley. The clay is weighed out and handed 

 to the workman at the lathe, called the thrower, 

 who dashes the mass upon the revolving wooden 

 disk. He then dips his hands frequently into a 



dish of water placed beside the lathe, and pressing 

 the clay with both hands, it gradually assumes an 

 irregular conical form. By pressing one hand 

 upon the top of this cone, it is again flattened 

 down to a cake, by which operation all air-bubbles 

 are extricated. He next lessens the speed of the 

 shaft by shifting the belt from a small to a larger 

 groove in the pulley, and with his hand forms the 

 clay into the shape of the vessel required. This 

 operation is called throwing; and when per- 

 formed, the vessel is cut off from the disk by a 

 wire attached at each end to a piece of wood. 

 The vessel is then allowed to dry gradually, until 

 it arrives at a certain point called the green state ; 

 after which it is put upon a turning-lathe, similar 

 to that used by the worker in wood. Here it is 

 turned to its proper shape by a sharp tool, which 

 also smooths it, and after this, it is burnished with 

 a steel surface. 



In the green state, also, are attached handles 

 and other appendages to vessels, this being the 

 point at which the clay possesses its greatest 

 tenacity. Handles of tea-pots, &c. are formed by 

 squeezing the dough through different-shaped 

 orifices, which, as it issues, is cut into proper 

 lengths, and bent into the desired forms. These 

 being formed, are attached to the vessels by a 

 paste called slip, and the seams are smoothed off 

 with a wet sponge. The ware is next placed in 

 an apartment heated to about 90 F. and fitted 

 all round with shelving. When completely dry, 

 they are rubbed over, and are then ready for the 

 baking-kiln. 



The articles made in the manner above de- 

 scribed are all of a round form ; but there are 

 many which are of a different shape, and require 

 a different process in the manufacture. Oval- 

 shaped vessels are formed by what is called press- 

 work, which is done in moulds made of plaster of 

 Paris. One half of the pattern is made in the 

 one side of the mould, and the other half in the 

 other side. The parts are formed to fit each other 

 exactly, and are joined in the same manner as 

 the handles are to vessels. Imitations of flowers 

 and foliage, and all delicate pieces of ornamental 

 ware, are cast in moulds of plaster of Paris. The 

 clay is poured into the mould in a thin state, and 

 is there left for a certain time. 



The plaster absorbs the water of that portion 

 which lies nearest to it, and solidifies the mixture 

 of clay and flint ; the central fluid portion is then 

 poured out, and the film or coating of clay left to 

 dry. Another portion of fluid clay and flint is 

 then poured in, which is passed through the same 

 process as before. The mould is placed in a stove, 

 and after being dried, is touched up and rendered 

 perfect in outline by a modeller. 



Plates, saucers, wash-bowls, &c. are made by 

 the process called ' flat-ware pressing.' A mould, 

 bb (fig. 6), is made, which gives 

 the outline of the internal shape 

 of the article ; and a profile- 

 plate, cc, that of the outside. 

 The latter is mounted upon a 

 frame or carrier, by which the 

 depth can be adjusted so as to 

 give any desired thickness to 



Fig. 6. 



the material. The mould, bb, is placed upon a 

 whirling-table, aa, and the clay is pressed down 

 upon its surface, and moulded by the hands till 

 it assumes the proper shape. Where an exact 



