DEL 



DEL 



temporal, judges of the courts at West- 

 minster, and doctors of the civil law. 



DELIVERANCE, a criminal brought to 

 trial, to which pleading not guilty, he 

 puts himself on God and his country ; the 

 clerk of the crown wishes him a good 

 deliverance. 



DELFT ware, a kind of pottery of 

 baked earth, covered with an enamel or 

 white glazing, which gives it the appear- 

 ance and neatness of porcelain. Some 

 kinds of this enamelled pottery differ 

 much from others, either in their sustain- 

 ing sudden heat without breaking, or in 

 the beauty and regularity of their forms, 

 of their enamel, and of the painting with 

 which they are ornamented. In general, 

 the fine and beautiful enamelled potte- 

 ries, which approach the nearest to por- 

 celain in external appearance, are at the 

 same time, those which least resist a 

 brisk fire. Again, those which sustain a 

 sudden heat are coarse, and resemble 

 common pottery. The basis of this pot- 

 tery is clay, which is to be mixed with 

 such a quantity of sand, that the earth 

 shall preserve enough of its ductility to 

 be worked, moulded, and turned easily ; 

 and yet that its fatness shall be sufficient- 

 ly taken from it, that it may not crack or 

 shrink too much in drying or in baking. 

 Vessels formed of this earth must be 

 dried very gently, to avoid cracking. 

 They are then to be placed in a furnace 

 to receive a slight baking, which is only 

 meant to give them a certain consistence 

 or hardness. And, lastly, they are to be 

 covered with an enamel, or glazing, 

 which is done by putting upon the ves- 

 sels thus prepared, the enamel which 

 has been ground very fine, and diluted 

 with water. 



As vessels on which the enamel is ap- 

 plied are but slightly baked, they readily 

 imbibe the water in which the enamel is 

 suspended, and a layer of the enamel ad- 

 heres to their surface ; these vessels may 

 then be painted with colours composed 

 of metallic calces, mixed and ground 

 with sensible glass. When they are be- 

 come perfectly dry, they are to be placed 

 in the furnace, included in cases of baked 

 earth, called seggars, and exposed to a 

 heat capable effusing uniformly the ena- 

 mel which covers them. This heat gi- 

 ven to fuse the enamel, being much 

 stronger than that which was applied at 

 first to give some consistence to the 

 ware, is also the heat necessary to com- 

 plete the baking of it. The furnace and 

 colours used for painting this ware, are 

 the same as those employed for porcelain. 



The glazing, which is nothing but white 

 enamel, ought to be so opaque as not to 

 show the ware under it. There are many 

 receipts for making these enamels ; but 

 all of them are composed of sand or flints, 

 vitrifying salts, oxide of lead, and oxide 

 of tin ; and the sand must be perfectly 

 vitrified, so as to form a glass consider- 

 ably fusible. Somewhat less than an equal 

 part of alkaline salt, or twice its weight 

 of oxide of lead, is requisite to effect such 

 vitrifications of sand. The oxide of tin 

 is not intended to be vitrified, but to give 

 a white opaque colour to the mass ; and 

 one part of it is to be added to three or 

 four parts of all the other ingredients ta- 

 ken together. From these general prin- 

 ciples various enamels may be made to 

 suit the different kinds of earths. To 

 make the enamel, lead and tin are oxyd- 

 ed together with a strong fire ; and the 

 sand is also to be made into a frit with the 

 salt or ashes. The whole is then to be 

 well mixed and ground together. The 

 matter is then to be placed under the 

 furnace, where it is melted and vitrified 

 during the baking of the ware. It is next 

 to be ground in a mill, and applied as 

 above directed. 



Concerning the earth of which the 

 ware is made, pure clay is not a proper 

 material when us^d alone. Different 

 kinds of earth, mixed together, are found 

 to succeed better ; pieces of ware made 

 of cl<ty aione are found to require too 

 much time to dry, and they crack and 

 lose their form, unless they are made ex- 

 ceedingly thick ; an addition of marie di- 

 minishes the contraction of the clay, ren- 

 ders it less compact, and allows the water 

 to escape, without altering the form of 

 the ware in drying. It affords also a bet- 

 ter ground for the enamel, which appears 

 more glossy and white than when laid on 

 clay alone. The kinds of clay which 

 are chiefly used in the composition of 

 delft ware, are the blue and green. A 

 mixture of blue clay and marie would 

 not be sufficiently solid, and would be 

 apt to scale, unless it were exposed to a 

 fire more intense than what is commonly 

 used for the burning of delft ware. To 

 give a greater solidity, some red clay is 

 added ; which on account of its ferru- 

 ginous matter possesses the requisite 

 binding quality. The proportions of 

 these ingredients vary in different works, 

 according to the different qualities of 

 the earths employed. Three parts of 

 blue clay, two parts of red clay, and five 

 parts of marie, form the composition used 

 in several manufactories. See ESTAMEL. 



