100 Mr II. M. Stoker on the China-stone anl 



Chin a- stone ... 25 parts 



Soda . . . . 6 ... 



Borax .... 3 ... 



Nitre , . . . 1 ... 



Of this frit, when ground, 26 parts are taken, and added to 

 or mixed with — 



26 of ground China-stone, 

 31 ... white-lead, 



7 ... flint, 



7 ... carbonate of lime, &c., 



3 ... oxide of tin, 



in which the biscuit is dipped prior to the last application of 

 heat. The colours to be laid on the ware are applied and 

 burnt in prior to the formation of the glaze, an article often 

 requiring a separate burning for each different colour, thus, 

 especially in gilded articles, entailing an additional amount 

 of cost and labour. 



The China-stone increases the strength and sonorosity of 

 the article, while the ground flint gives whiteness and density 

 to the base of plastic clay : earths are by themselves infu- 

 sible, but on the addition of silex or silica, another name for 

 quartz, we form a silicate, to which, if we add a third of earth, 

 with an alkaline base, we form a body verifiable and uniformly 

 translucent. 



As it may not be uninteresting to my readers, I shall briefly 

 attempt to describe the mode in which the China-stone and 

 China-clay are treated, prior to their being turned, twisted, 

 and flattened, to form the numberless articles in which they 

 greet the eye. 



The China-stone is ground to a fine powder by means of 

 a number of stones which are kept rotating on the bottom 

 of a paved vat, when it, as well as the clay and ground flint, 

 are mixed with a certain quantity of water, by a process 

 termed "bluging," till of the consistence of cream, when it is 

 passed in a state of slop or slip through a series of cambric or 

 lawn sieves kept rapidly revolving by a water-wheel, each pint 

 of clay slip wcighingtwenty-fourounces, while that of the flint 

 or China-stone weighs thirty-two ounces ; it is then passed 

 through a very fine silk sieve, after which these ingredients 



