1128 



WHITE LEAD 



WHEAT-FLOUR ; To detect Adulteration of. Potato-starch is insoluble in cold water, 

 unless it be triturated in thin portions in a mortar. If pure wheat-flour be thus 

 triturated, it affords no trace of starch to iodine, as the former does, because the 

 particles of wheat-starch are very minute, and are sheathed in gluten. 



Bean-flour digested with water at a heat of 68 Fahr., and triturated, affords on 

 filtration a liquid which becomes milky on tho addition of a little acetic acid, by its 

 reaction on the legumine present in the beans. 



British Wheat returned as sold in various (150) Market Towns of England and Wales 



in each month. 



WHEEIi CARRIAGES. This article is omitted from this edition to make room 

 for articles more directly connected with the subjects legitimately belonging to it. 



WHEEL ORE. See BOURNONITE. 



WHETSXiATE is a massive mineral of a greenish-grey colour ; feebly glimmer- 

 ing ; fracture slaty or splintery ; fragments tabular ; translucent on the edges ; feels 

 rather greasy ; and has a spec. grav. of 2722. It occurs in beds, in primitive and 

 transition slates. Very fine varieties of whetslate are brought from Turkey, called 

 honestones, which are in much esteem for sharpening steel instruments. See HONES. 



WHEY (Petit lait, Fr. ; Molken, Ger.) is the greyish-green liquor .which exudes 

 from the curd of milk. Scheele states, that when a pound of milk is mixed with a 

 spoonful of proof spirit, and allowed to become sour, the whey filtered off, at the end 

 of a month or a little more, is a good vinegar, devoid of lactic acid. 



WHISKY. A spirit obtained by distillation from corn, sugar, or molasses, though 

 generally from the former. It is extensively manufactured and used in Scotland and 

 in Ireland. See USQUEBAUGH. 



WHITE XiEAD, Carbonate of lead, or Ceruse. (Blanc de plomb, Fr. ; Bleiweiss, 

 Ger.) This is the principal preparation of lead in general use for painting wood and 

 the plaster walls of apartments white. It mixes well with oil, without having its 

 bright colour impaired, spreads easily under the brush, and gives a uniform coat to 

 wood, stone, metal, &c. It is employed either alone, or with other pigments, to serve 

 as their basis, and to give them body. This article has been long manufactured with 

 much success at Klagenfurth in Carinthia, and its mode of preparation has been 

 described with precision by Marcel des Serres. The great white-lead establishments 

 at Krems, whence, though incorrectly, the term white of Kremnitz became current, 

 on the Continent, have been abandoned. 



In Germany the manufacture of white lead is conducted as follows : 



The lead mostly comes from Bleiberg ; it is very pure, and particularly free from 

 contamination with iron, a point essential to the beauty of its factitious carbonate. It 

 is melted in ordinary pots of cast iron, and cast into sheets of various thickness, ac- 

 cording to the pleasure of the manufacturer. These sheets are made by pouring the 

 melted lead upon an iron plate placed over the boiler ; and whenever the surface of 

 the metal begins to consolidate, the plate is slightly sloped to one side, so as to run off 

 the still liquid metal, and leave a lead sheet of a desired thickness. It is then lifted 

 off like a sheet of paper; and as the iron plate is cooled in water, several hundred- 

 weight of lead can be readily cast in a day. In certain white-lead works these sheets 

 are one twenty-fourth of an inch thick ; in others half that thickness ; in some, one 

 of these sheets takes up tho whole width of tho conversion-box ; in others, four sheets 

 are employed. It is of consequence not to smooth down the faces of the leaden 





