POTTERY 



together. The slip is pumped into 

 them ; when full the pressure is 

 continued, and the water exudes 

 through the linen, leaving the clay 

 within. Each chamber is then 

 opened, and the contents, now 

 solid, rolled up and removed. 



The clay then goes through a 

 process of kneading in the pug- 

 mill, a cylindrical chamber with a 

 rc\( living shaft down the centre 

 having knife-like arms attached, 

 and the clay comes out in a square- 

 sectioned shape, which is cut off 

 in pieces of suitable size for the 

 different potters to c.irry away. 



The Potter's Wheel 



The potter's wheel, n small hori- 

 zontal revolving table, has scarcely 

 altered during 4,000 years, only the 

 method of supplying power having 

 undergone modifications. The 

 name thrower, applied to the 

 potter who makes upon the wheel, 

 doubtless comes from the action of 

 the workman as he throws the ball 

 of clay on to the centre of the 

 wheel. As he presses the clay with 

 his hands, it rises in a spiral column 

 between his fingers, to be depressed 

 and again allowed to rise, when it 

 is once more brought down and 

 centred or trued. Then, pressing 

 the thumbs into it, he rapidly forms 

 a cylinder. With one hand inside 

 and the other outside, he feels the 

 thickness as he draws up and out 

 the revolving mass, which soon 

 becomes, under his will, a bowl, 

 jug, or vase. 



Some rough earthenware is 

 finished when it leaves the wheel, 

 but more generally turning upon 

 the lathe is the process used to 

 complete the shape, in the same 

 manner as woo i, metal, or ivory is 

 turned. This is done when the clay 

 has been dried to a green hardness 

 not unlike the consistency of cheese. 



Pressing is making hollow ware, 

 i.e. such articles as soup tureens 

 and oval shapes, with the aid of a 

 pi ister-of -Paris mould. The maker 

 flattens out a thick slab of clay 

 and presses it against the plaster 

 mould, working, of course, from 

 the inside, putting the parts to- 

 gether and making good the joints. 

 Then, when the porous mould has 

 dried the clay partially, the mould 

 is taken away in pieces and the 

 vessel is removed. The addition of 

 handles, spouts, or embossments, 

 .separately made in moulds, are 

 now stuck on, completing the shape. 



Casting is done by pouring 

 liquid clay or slip into a mould, 

 and, when sufficient of the moisture 

 has been taken away by the porous 

 mould, the remainder of the slip 

 is poured out, leaving a coating of 

 clay of the required thickness 

 inside. When partially dry this 



shrinks away from the mould, 

 allowing its removal, when it can 

 be treated and finished. Handles, 

 spouts, feet, and knobs are applied 

 in the clay state. 



The piece is now ready, when 

 dried to white hardness, for the 

 biscuit or bisque oven, the first 

 fire, which changes the clay into 

 earthenware or porcelain, the 

 quality of the piece depending very 

 largely upon this. The oven is a 

 circular, dome-shaped structure 

 about 16 ft. in diameter, with a 

 narrow doorway, through which the 

 ovenmen carry the " saggars " 

 filled with clay articles until the 

 oven is completely packed. The 

 doorway is then bricked up and 

 luted with clay, the fires around 

 six or eight are lighted, and are 

 maintained for about 48 hours at 

 least. As the firing draws to com- 

 pletion the whole interior glows 

 with a fierce heat. The fireman 

 draws from several proof -holes test- 

 pieces previously arranged, by 

 which he can tell the state of the 

 oven, and at the proper moment 

 the fire-holes are closed up and the 

 whole allowed to cool gradually ; 

 this takes as long as sometimes 

 longer than the time required for 

 firing. The pieces have meanwhile 

 undergone a wonderful change, 

 accompanied by a diminution in 

 height, thickness, and weight. 



Glazing and Printing 

 When they are drawn from the 

 oven and have passed through the 

 bisque warehouse for sorting, they 

 are ready for the dipping-house, 

 where they are glazed. Glaze is a 

 compound of alkalis and earths 

 to which lead is added, the mixture 

 being first melted together and 

 ground with water. This is then 

 placed in an open tub, and the 

 dipper proceeds to plunge the piece 

 of ware into the bath, the porosity 

 causing an even coating to adhere 

 to the surface. The next stage is 

 the glost-oven, where each piece 

 lias to be carefully separated from 

 its neighbour, so that during the 

 firing of the glaze no touching or 

 sticking together shall result. The 

 placing in saggars and firing of the 

 oven is similar to that of the bisque 

 oven. The glost fire is not so fierce 

 as the biscuit, and is sustained only 

 long enough to accomplish the 

 complete fusion of the surface. 

 Decoration, other than clay em- 

 bossments and relief figurings, is 

 sometimes under the glaze and 

 sometimes over it. 



Printing is a form of decoration 

 which has done as much for pottery 

 as it has for literature. The print- 

 ing press used is the ordinary type 

 of copper-plate press with rollers. 

 The printer fills a copper plate 



POTTERY 



engraved with the pattern with 

 colour, bossing off all the colour 

 except what remains in the en- 

 graved lines. Then he places a 

 piece of prepared tissue paper upon 

 the plate, which has been brushed 

 with a solution of soap. Both 

 copper and paper now pass under 

 the press rollers, and, when re- 

 moved, they are warmed upon the 

 printer's stove and the paper gently 

 pulled off. The colour has left the 

 engraved lines and adhered to the 

 paper. The print is then trimmed 

 of any superfluous paper by the 

 transferor and laid accurately upon 

 the ware, being rubbed firmly 

 down on to it with a flannel boss. 

 The colour being mixed with an oil 

 vehicle, and the paper prepared 

 with a water medium, the applica- 

 tion of a damp sponge or the im- 

 mersion of the piece of ware in 

 a tub of water removes the paper, 

 leaving the pattern upon the ware. 

 This process is used both over and 

 under the glaze. In the latter case 

 a hardening-on kiln of a dull-red 

 heat is required to remove the oil 

 and fix the printed pattern to the 

 ware before it undergoes the glaz- 

 ing process at the dipper's hands. 

 The well-known willow arid pheas- 

 ant patterns arc done in this way. 

 The painter uses a great variety 

 of colours, all metallic oxides, and 

 for overglaze, fluxes or colours con- 

 taining glaze in the mixture are 

 required. Thus, from gold is ob- 

 tained crimson, from cobalt blue, 

 from chromium green, from iron 

 red, from antimony yellow, etc., but 

 great experience is necessary, as 

 the purity of tone, and sometimes 

 even the colour, does not appear 

 until after firing. Great difficulty is 

 felt by all ceramic decorators, as 

 some colours will not mix with 

 others, but will in the fire react to 

 their mutual destruction. 



Method of Gilding 



Gold for the best work must be 

 of the purest quality. It is amalga- 

 mated with mercury and ground in 

 a mill to powder, then mixed with a 

 special oil, and applied sometimes 

 as a print, but also in a freehand 

 manner as painting is done. Edge 

 lines and bands are put on circular 

 pieces by using a hand wheel. After 

 firing in the enamel kiln, gold has to 

 be burnished with an agate or 

 blood stone, or if a dull surface is 

 required, scoured with fine sand. 



The enamel kiln is the last pro- 

 cess of manufacture. It is a muffle 

 or closed-up wagon-shaped box of 

 fireclay slabs, around which fire is 

 allowed to play until the whole, 

 with its contents carefully arranged 

 on iron slabs, assumes a bright-red 

 heat, or cherry-red heat, as it Ls 

 technically known. Kilns filled one 



