On tlie Preservation of Timber. 
15 
Bethell's Paint. — Mr. Bethell, in his patent of 1853, after 
cliaro^ing the wood with a soluble salt of zinc or copper, runs a 
truck-load of the sleepers into a drying-house, through which 
all the smoke and gaseous products evolved during the combus- 
tion of the fuel are passed, and after being cooled down he 
paints them with tar, or melted pitch, or bitumen, or rosin, or 
any description of varnish, or gutta percha dissolved in any 
spirit or oil, or with any material which will make a water-tight 
covering to the wood. 
Sidphuret of Antimony and Copper in Varnish. — Key and 
Guibert employ a pigment formed of 10 parts of sulphuret of 
copper, 2 parts of sulphuret of antimony, and 5 to 30 parts of 
the best varnish, with which they paint the surface of the wood. 
Asphalte. — VVestwood and Baillie apply a preparatory coating 
of black varnish and afterwards an asphalte or bituminous com- 
position, by which they insure the adhesion of the latter with 
increased tenacity. 
Greenshields modifies this plan by previously soaking the 
timber in a solution of alum and common salt, and adds tallow- 
elaine to the asphalte. 
Vitreous Compounds. — Madame Boulard proposes to employ a 
peculiar vitreous composition with different colouring matters 
and applied in the usual way. 
Glue and Tannin. — Clark states that he partially impregnates, 
while coating the timber by applying a solution of gelatine or 
glue, and by then soaking it, after being dried, in a solution of 
tannin, forms an artificial leather in the pores and on the surface 
of the wood. 
Electro-coating of Metal. — A modification of this use of external 
agents has been patented by the Messrs. Oudry, who clean the 
timber and cover it with a slight layer of varnish or fatty body ; 
they then drive into the wood barbed copper pegs at different 
points and expose the whole to an electro-chemical bath, by 
which means they succeed in depositing the metal uniformly- 
over all the surface. They have since modified the plan by first 
coating the timber with any isolating material, which assists in 
preserving and rendering it waterproof. 
Staining and Ornamenting Wood. 
Staining Wood. — The staining of wood has been most suc- 
cessfully accomplished by MM. Renard and Perrin. These 
gentlemen introduced into wood all the dyes and preparations of 
alum which have been applied to cloth. Madder, cudbear, cam- 
peachy, or Breizil wood, give different shades of red or violet ; 
madder, indigo, or campeachy, with the addition of nitrate of 
