196 



CHINA-n^ARE. 



lent workmanship, as vases, busts, figure*, and models, all 

 IDU edges and tooling remain as sharp and clear as in fine 

 sculpture. There is great probability that a sight of the 

 biscuit china, suggested to Mr G. Cumberland, of Bristol, 

 the idea of manufacturing tiles of a body of clay and 

 ground silica ; by pressing linen of different fineness upon 

 the clay, for the formation of the teeth, and then baking 

 them till vitrified. (Vide Nicholson'* Journal, 8vo. vol. 

 xxv. p. 237.) Slight inspection of biscuit ware will-suggest, 

 and its bibulous nature on immersion in water will demon- 

 strate, its porosity, rendering it inconvenient for containing 

 fluids, and easily destructible by decomposition ; yet pro- 

 perly adapted to retain the fluid medium of the components 

 of the glase, which has been employed from earliest times to 

 assist the durability, and improve the general appearance. 

 The thin fabric of most vessels, as well as the components 

 ot the body, will not allow the fluid glaze to be applied 

 while they are in the clay state, as the water would cause 

 the shape to alter, and either sink beneath its own weiebt, 

 or bilge out and burst. English china, as at present com- 

 pounded, if attempted to be formed by once baking, would 

 so contract in the body as not to appropriate all the glaze 

 which would be in ridges on the surface. And this will ap- 

 ply to any china whose components of the body greatly dif- 

 fer from those of the glaze. When the most ready em. 

 ployment of felspar in body and glaze becomes generally 

 known, then will English china, probably, be made atone 

 baking. 



Ornamenting biscuit ware is accomplished by painting 

 and printing, with the distinction of blue, because that 

 colour was first employed ; though now, in both branches, 

 mot other colours are used. 



Blue painting, or biscuit painting, is now practised on 

 only very common earthenware ; and in rude patterns, 

 traced by camel-hair pencils, on the surface of tea-ware 

 and jugs. The colours for this manipulation are thus pre- 

 pared ; 



Blue calx, 9 or S; fritt, 91 or 92. 



For enamel use 12 flint, and 6 copper. 



Blue printing is the nune for the manipulations of tak- 

 ing impressions (in colours, blue, green, pink, and brown,) 

 from copper-plates engraved in a style peculiar to the artists 



of the pottery districts ; and of sizes varied to the differeut 

 vessels. The press is made very strong and large, similar to 

 that used for beautiful copper-plate printing for embellish, 

 ments ; usually with cast-iron cheeks and roller*, and an 

 iron lever, not a cross. The press is placed within four 

 feet of a stove-plate, kept constantly heated, that when the 

 copper-plate is laid thereon, its engravings may more easily 

 admit the colour as it is rubbed over it. The printer has 

 his thumb and finger protected by a thick slip of leather, 

 and cleans his plate from the scalding colour with a stuffed 

 leather boss, not bis hand, as other copper-plate printers. 



The blue colour is blue calx, 37 ; Hint, 4-2 ; nitre, ; bo- 

 rax, 13 ; well ground together ; (and in similar proportions 

 for other colours ;) the tint being heightened or lowered by 

 the quantity of the calx. 



Sroitm. Litharge, 37 ; crude antimony, 37 ; manganese, 

 18; and blue calx, 8; calcine and grind well together for 

 use. 



Black. Red lead, 60 ; antimony, 25 ; manganese, 15 ; cal- 

 cine, then grind with blue calx, 40 ; oxide of tin, 5 ; and 

 calcine for use. 



Mulberry. Manganese, 54 ; blue calx, 26 ; nitre, 14; bo- 

 rax, 6 ; calcine over pulverized nitre ; then grind well with 

 glass, 18 ; flint, 10 ; for use. 



The colour is well mixed on a very hot iron plate, into a 

 fluid, called technically an oil, prepared thus: over a slow 

 fire, in a vessel kept loosely covered, for two hours boil 

 one quart of pure linseed oil, then add one pint of pure 

 rape oil, and two ounces of capivi balsam, and boil two 

 hours longer. When a little cooled, (to 160) add, of am- 

 ber oil, white lead, and clean pitch, severally half an ounce ; 

 resume the boiling, and continue forty-five to seventy-five 

 minutes, according to the strength of tint for which it is 

 wanted. Some printers prefer to the latter ingredients, 

 one ounce of oil nf tar, and one ounce uf balsam of sul- 

 phur, very carefully introduced, else the whole will bo 

 spoiled by coagulation. 



The printer places his plate on the stove, rubs in the 

 colour, with a broad pallet knife scrapes off the excess, and 

 then with his boss cleans the plain sides, and places it on 

 tiie bed of his press ; he next brushes the sheet of tissue 

 paper over with a solution of soft soap and water, puts it 

 on the plate, rolls it between the rollers, and the instant 

 the return of the press leaves it dry by the hot plate, he 

 carefully takes it off, and examines that the impression is a 

 good one, and that the colour properly adheies. Thus he 

 proceeds till his quantity is taken off. Messrs. Machin & 

 Potts, Burslem, under the security of a patent, use engraicd 

 rollers for the purpose, instead of plates Their machinery 

 is, at present, not exhibited to strangers ; but the sugges- 

 tion seems taken from calico printing, with which branch 

 Mr Potts was some years connected. 



A cutter (a little girl, training up for the next manipula- 

 tion,) takes the impression, cuts away all the white paper, 

 then separates the impression into its parts, which she 

 places in the order most readily facilitating their applica- 

 tion to the ware. 



A transferer, with considerable tact andjudgment, places 

 on a biscuit vessel the several parts in their proper ar- 

 rangement ; and then, with a rubber of flannel, six to six- 

 teen inches long, and firmly rolled and tied together, with 

 the ends a little loose, she rubs the paper upon the article, 

 with much force, often resting one end in the right arm-pit, 

 until it cannot again be taken off. The dry and absorbent 

 porosity of the ware aids the adhesion of the colour in the 

 oil, and when the task is completed, each vessel is taken 

 off the board on which it was placed by the transferer, im- 

 mersed in water, and with soft soap and a brush the paper 

 is washed off, and leaves in the ware only the mineral 

 colour, and a little of the oily medium. The ware is kept 

 in a heated room to evaporate much of the water imbiber] 

 in washing off the paper, which is requisite to prepare it 

 for the fluid glaze; and also, is heated to a red heat, to 

 harden on the colour, and volatilize the oily particles, else 

 the glaze would not adhere. 



Baking china and earthenware, glazed. The porous na- 

 ture of vessels baked only biscuit, would allow many fluids 

 to permeate, which being an inconvenience, while it faci- 

 litates their destruction by decomposition, the necessity of 

 an impermeable covering, is provided for in a glaze ; and 

 this has been attempted to be effected by several different 

 processes. 



When common pottery was manufactured in Stafford- 

 shire, the dust of lead ore was shaken from a bag, on the 

 outside, in the clay state, and afterwards manganese was 

 mixed with it. Glazing with salt was the next improve- 

 ment, and then washing; and, finally, biscuit-dipping. 

 For some years, only raw glazes were used ; their compo- 

 nents only being mixed, without fritting, prior to grinding; 

 but, as the desire for improvement increased, the method 

 adopted to make glass and vitreous colours, suggested the 

 practice of fritting the components. There is a physical 

 necessity for the components of the glaze to be adapted to 

 those of the body, which is varied according to the judg- 

 ment or opinion of the manufacturer. The degree of ex. 

 pansion and contraction depends on the density and com- 

 pactness of the body, which must be carefully regarded, or 



