6 
On the Preservation of Timber. 
XI. By puncturing tlie timber and filling the holes with solid 
preservative materials, as suggested by Kemp. 
XII. By carbonizing the surface. 
XIII. By the use of external applications or coatings. 
History. — ^The first attempts to preserve timber from decay 
consisted in applying fatty and resinous substances extemalh", in 
order to protect the surface from the action of the atmosphere, 
which either induced fermentation or conveyed those insects which 
were equally destructive. 
These plans are all more or less defective, as the application or 
external coating peels oflF, and at all events proves no protection 
against the fermentation, which commences sooner or later in the 
interior of the timber. It is stated, however, that a coating of 
hydraulic lime has been more successful. 
The first patent secured in this country dates as far back as 
1728, but no further steps appear to have been taken in this 
direction until upwards of a century afterwards, when Mr. Kyan 
in 1832 introduced his process of soaking or boiling timber in a 
solution of corrosive sublimate, Avhich patent, with some modi- 
fications, is still extensively employed. 
j\La.TEEIALS TEOPOSED or tried. — During the interval which 
has elapsed, a great variety of chemical agents have been sug- 
gested or tried, of which the following is a list : — 
Bichloride mercury. Xitrate potash. 
Chloride of tin. Carbonate ditto. 
„ mangapese. Sulphate lime. 
„ zinc. „ magnesia. 
Sulphate copper. . „ bar^ tes. 
„ iron. Carbonate ditto. 
„ zinc. Bicarbonate lime. 
Xitrate iron. Alum. 
Pyrolignate ditto. Caustic lime. 
Acetate lead. Sulphuric acid. 
Sulphate soda. Sulphurous ditto, 
ilanganate and permanganate Arsenious ditto. 
ditto. PjToligueous ditto. 
Carbonate ditto. Tar and its products. ' 
Silicate ditto. Tannin. 
Muriate ditto. Tannin and gelatine. 
Phosphate ditto. Gutta percha. 
„ ammonia. Oils, wax, tallow. 
Eesin, &c. 
Mechanical Operations. 
Class I. Immersion. — The slowness with which even the most 
mobile liquid penetrates wood is a serious objection to any plan 
of simple immersion or soaking, such as that proposed by Kyan, 
