374 TEREDO NAVALIS IX 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 D 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 



