Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/527

493&#93; CHA powdered coal, is extremely strong, pure, and fragrant. Corn-spirit, merely shaken with coal, loses its bad flavour; and, if honey be add- ed, it becomes a sweet and plea- sant liquor. Even the tainted fla- vour of ardent spirits, when im- pregnated widi any vegetable oils, may in a similar manner be de- stroyed : and, if the spirit be dis- tilled, the residuum is said not to be brown ; so that no inconveni- ence will arise from carrying the distillation too t;y — Tin were produced by every kind of coal, whether fossil or charred ve- getable substances ; though the latter appear to us, in many re- spects, preferable to • There are considerable differ- ences in the coals cf various ve- witii respect to their ha- bitude to fire : the very light coals of linen, cotton, some fi quickly catch tire from a spark, and soon consume : the more ones of woods, and roots, an on tire with greater difficulty, and burn more slowly; the coal's of the black berry-bearing alder, of the hazel, willow, and lime-tree, are the most proper for making gun- powder and other pyrotech compositions. For die r. metallic calces, those of he wood, as oak and beech, are ferable ; because these appear to contain a larger proportion of the inflammable principle, and perhaps in a more fixed state. C as common fuel, those of the heavy woods afford the gre, and require a most abundant supply of air, in order to keep them buni- on the contrary, the coals of the light woods retain a glowing heat, till they are consumed, with- out a strong draught of air ; the bark usually crackles while burn- CHA - I ing, which is seldom the case with the coal of the wood itself. Charcoal is likewise cf consider* able service to different artists, for polishing brass and copper- plates, after they have been rub- bed clean with powdered pumice- stone. Horn-plates may be po- lished in a similar manner, and a gloss afterwards given them with tripoli. — Coals of different sub- stances are also used as pigments : hence the the shops. its of this kind are not only incorruptible, but also p ntage of a full colour, and work freely in all the forms, where powdery pig- ments are emplqyi but they ought to be carefully prepared, by thoroughly burning the substance iu a close vessel, and afterwards re- ducing the coal tp a tine powder. — In drawing outlines, the artist avads himself of pieces of char- coal, the marks of which may be easily rubbed out. For this pur- pose, the smaller branches of a tree, such as the willow and vine, are usually preferred j and which, being freed from the bark and pith, afford the best drawing pencils. Dr. Lewis remarks, that the shells and stones of fruit yielded coals, so hard diat they would with difficulty mark on pa- per, while those of the kernels of fruit were very soft and mellow. All these experiments must be con- ducted in proper vessels, closely covered (the barrels of old guns, or pistols, may occasionally serve as substitutes). The Doctor levi- gated various coals into fine powder, mixed them with gum-water and oil, and applied them as paints, di- luted with different degrees of white. When laid on thick, they all appeared of a strong, full black ; nor