374 TEREDO NAVALIS IN NOVA SCOTIA — MURPHY. 
by repelling the attacks of insects and preventing the propaga- 
tion of fungi. 
“Thirdly. It arrests the vegetation or living principle of the 
tree, after its separation from the root, which is one of the pri- 
mary causes of dry rot, and other species of decay. 
“The attention of the author of the paper referred to, 
was first called to this subject in 1841, in consequence of 
having practiced the process, to some extent, for Mr. John 
Braithwaite (M. Inst. C. E.), on the Eastern Counties Rail- 
way. The works, in that case, were of the most primitive 
and incomplete description; nevertheless they answered the 
purpose, and the sleepers, prepared at Heybridge, eleven years 
ago, are as sounl and perfect as the day they were laid down, 
although they are of Scotch fir, and not of very good quality. 
Since that time, being extensively engaged in preparing timber, 
many improvements have been made in the machinery and ap- 
paratus, and in the method of preparation. 
“Creosote is at present used for preparing timber, either under 
pressure in strong closed cylinders, or by placing the timbers in 
open tanks, and keeping the solution up to a temperature of 
120° to 150° until the required quantity is absorbed. Creosote 
has the property of crystallizing when the temperature is below 
35°, and it becomes a hard compact mass of salts. It was in con- 
sequence of this peculiarity, and the difficulty of using it in the 
winter season, that peat was resorted to; and was done in the 
first instance by making a common fire-place at one end of the 
reservoir, and running a flue under the bottom. This system 
was, however, exceedingly dangerous, because the oil came in 
contact with the heated iron plate, and the temperature could 
not be raised beyond 70° or 75°, or only just sufficient to enable 
the work to be continued conveniently during the cold weather. 
The experiment was then tried of allowing high pressure steam 
to blow into and upon the creosote in the reservoir; by this 
means the temperature was raised as high as was required, and it 
has continued to be used. Where a steam engine is used for 
working the pressure pumps, the waste steam can be employed 
to heat the creosote, by passing it through a coil of pipe laid in 
