On the Preservation of Timber. 
19 
Eaw Material for Creosote, &c. — The contrary, however, 
is the striking characteristic of that material which I now propose. 
The beneficial action of creosote is now universally recognised, 
the mode and facility of its application is well understood, and 
there is practically no limit to the present and future source of 
supply, as well as economy, in the waste old sleepers and timber 
of your extensive railway system. 
Process of Conversion. — The process of converting this old 
timber to this useful purpose consists in subjecting it to dry 
distillation in suitable close furnaces or retorts, and condensing 
the volatile liquid products by an arrangement similar to that in 
use at gas-works. The further details will be best given in the 
words of the specification of the patent for this improvement. 
" In order to obtain tar and other products from old or waste railway 
sleepers or bearers, we proceed as follows •. — 
" We remove all adhering dirt or other foreign matters from the old 
or waste railway wood, sleepers, or bearers, before subjecting them to 
distillation. This waste timber may be used whole, or it may be first 
cut into small faggots, and we prefer that it should be air-dried for 
some time previous to distillation. The clean and dry old and waste 
timber, either whole or cut into smaller blocks, we submit to dry 
distillation, and for this purpose we prefer to employ the arrangements 
and apparatus now in common use for making coal gas, merely washing 
the gas with a weak solution of soda before passing it into the lime 
purifiers. This gas, which is obtained in addition to the tar and other 
products, is suitable for use for illuminating purposes. 
" The retorts are heated up to a cherry or bright red heat, and we 
find tlie higher the temperature the better for our general purposes. 
"We charge each retort with about one hundredweight of the timber 
prepared as above described. We drive the distillation as rapidly as 
possible, and we work olF the charge in from two to three hours 
according to the kind and state of the timber. The charcoal is 
withdrawn, and the fire extinguished by water or charcoal powder. 
The gaseous products require more lime for purification than coal-gas, 
but they possess the great advantage of being free from sulphur 
compounds, and may be used either alone or mixed with ordinary 
coal-gas. The liquid products of the distillation, which are arrested 
in the hydraulic main, principally consist of the tar and acetic 
acid, and these may be separated and treated in the usual manner, in 
which case the tar, when distilled, will furnish the compound known 
under the name of dead oil, which may be employed at once for the 
preservation of new sleepers and bearers in the ordinary manner. But, 
instead of distilling the tar, for the purpose of obtaining the dead oil, 
we prefer, according to the second part of our intention, to mix one of 
the following saline solutions with it in about equal volumes, viz., a solu- 
tion of caustic soda of about 1'13 specific gravity, or the liquor known 
in the alkali trade under the term of red liquor, with a specific gravity 
of about 1*30. We heat these mixed fluids to a temperature of from 
C 2 
