DRY′ERS (Painter’s). Prep. 1. Litharge (best) ground to a paste with drying-oil. For dark colours.
2. From white copperas and drying oil; as the last.
3. From sugar of lead and drying oil. The last two are for pale colours.
4. From white copperas and sugar of lead, of each 1 lb.; pure white lead, 2 lbs. For ‘whites,’ and opaque light colours, greys, &c.
Dryers are employed, as the name implies, to increase the drying and hardening properties of oil paints. A little is beat up with them at the time of mixing them with the oil and turpentine for use.
DRY′ING. See Desiccation, &c.
DRY′ING-OIL. See Oils.
DRY-ROT. A peculiar disease that attacks wood, and renders it brittle and rotten. It is generally caused by dampness and the subsequent development of the spores of fungi, particularly those of Merulius lacrymans and vastator and Polyporus destructor. The dry-rot principally attacks ‘ill-seasoned’ timber, and more particularly that of ships and badly ventilated buildings.
Prev. Various means have been proposed to prevent the attacks of dry-rot and to arrest its progress when it has commenced, among which the process called ‘Kyanizing’ (Kyan’s patent) is that most generally known and most extensively adopted. It consists in immersing the timber in a bath of corrosive sublimate. The process termed ‘Paynizing’ (Payne’s patent) consists in first filling the pores with a solution of chloride of calcium, under pressure, and next forcing in a solution of sulphate of iron, by which an insoluble sulphate of lime is formed in the body of the wood, which is thus rendered nearly as hard as stone. Wood so prepared is now largely employed in our public works and railways. Sir W. Burnett’s process (patented in 1836) consists in impregnating the timber with a solution of chloride of zinc. Mr J. Bethell’s process (patented in 1838) consists in thoroughly impregnating the wood with oil of tar containing creasote and a crude solution of acetate of iron, commonly called ‘pyrolignite of iron.’ The impregnation is effected in a strong cylindrical vessel, connected with a powerful air-pump, so that in the first instance a vacuum being formed, and subsequently a pressure of several atmospheres applied, the liquid may as much as possible be forced into all the pores of the wood. The above processes for ‘seasoning’ preserve the timber not only from dry-rot, but from the influence of the weather and the attacks of insects and worms.
“The construction of air-drains or passages around wood-work to be preserved is, where the method is applicable, a great aid to the preservation of wood. Dry-rot is both prevented in new buildings and cured in old ones by filling up the spaces between the floor-joists with ‘tank-waste’ from alkali works. This can also be applied to the ends of beams resting in walls.”—Chemical News.