Little is known in England of the inventions which have arisen in foreign countries not already mentioned.
M. Szerelmey, a Hungarian, proposed, in 1868, potassa, lime, sulphuric acid, petroleum, &c., to preserve wood.
In Germany, the following method is sometimes used for the preservation of wood: Mix 40 parts of chalk, 40 parts of resin, 4 of linseed oil; melting them together in an iron pot; then add 1 part of native oxide of copper, and afterwards, carefully, 1 part of sulphuric acid. The mixture is applied while hot to the wood by means of a brush, and it soon becomes very hard.[15]
Mr. Cobley, of Meerholz, Hesse, has patented the following preparation. A strong solution of potash, baryta, lime, strontia, or any of their salts, are forced into the pores of timber in a close iron vessel by a pump. After this operation, the liquid is run off from the timber, and hydro-fluo-silicic acid is forced in, which, uniting with the salts in the timber, forms an insoluble compound capable of rendering the wood uninflammable.
About the year 1800, Neils Nystrom, chemist, Norkopping, recommended a solution of sea salt and copperas, to be laid upon timber as hot as possible, to prevent rottenness or combustion. He also proposed a solution of sulphate of iron, potash, alum, &c., to extinguish fires.
M. Louis Vernet, Buenos Ayres, proposed to preserve timber from fire by the use of the following mixture: Take 1 lb. of arsenic, 6 lb. of alum, and 10 lb. of potash, in 40 gallons of water, and mix with oil, or any suitable tarry matters, and paint the timber with the solution. We have already referred to the conflicting evidence respecting alum and water for wood: we can now state that Chapman’s experiments proved that arsenic afforded no protection against dry rot. Experiments in Cornwall have proved that where arsenical ores have lain on the ground, vegetation will ensue in two or three years after removal of the ore. If, therefore, alum or arsenic have no good effect on timber with respect to the dry rot, we think the use of both of them together would certainly be objectionable.
The last we intend referring to is a composition frequently used in China, for preserving wood. Many buildings in the capital are painted with it. It is called Schoicao, and is made with 3 parts of blood deprived of its febrine, 4 parts of lime and a little alum, and 2 parts of liquid silicate of soda. It is sometimes used in Japan.
It would be practically useless to quote any further remedies, and the reader is recommended to carefully study those quoted in this chapter, and of their utility to judge for himself, bearing in mind those principles which we have referred to before commencing to describe the patent processes. A large number of patents have been taken out in England for the preservation of wood by preservative processes, but only two are now in use,—that is, to any extent,—viz. Bethell’s and Burnett’s. Messrs. Bethell and Co. now impregnate timber with copper, zinc, corrosive sublimate, or creosote; the four best patents.
We insert here a short analysis of different methods proposed for seasoning timber:—