20 
On the Preservation of Timber. 
90 degrees to 100 degrees of Fahrenheit, and we force this warm solu- 
tion into the cylinder containing tlie timber, with the usual precautions. 
" By mixing- the tar with these solvents we render it perfectly fluid, 
and suitable for use in preserving timber, whereas, heretofore, in order 
to obtain a preserving liquid of sufficient fluidity to be successfully 
employed for this purpose, it has been necessary to distil the tar, and so 
separate from it bodies which, although they have considerable pre- 
servative properties, render tiie tar too thick for use. Or, instead of 
separating the acetic acid portion of the liquid products, where the 
acetic acid is present in comparatively small quantities, we neutralize 
the acid by means of carbonate of soda, or otherwise, and we dissolve in 
1 gallon of the liquid about 1 lb. of caustic soda, or 2 lbs. of red liquor 
salt, and mix it gallon for gallon with the tar, warming up the mixed 
liquors to about 90 degrees to 100 degrees of Fahrenheit, and pro- 
ceeding as before. In this way we render useful the proportion of pre- 
serving material which would otherwise be lost in the acetic acid liquid. 
"In all these different methods the temperature may be varied con- 
siderably witliout affecting the result ; and when it is not an object to 
collect the gas in distilling the waste timber, a lower heat and slower 
distillation will increase the production of the liquid product. 
" We would remark that, when sleepers or bearers are distilled which 
have originally been submitted to the creosoting process, we obtain, in 
addition to, and mixed with the' tar formed by the distillation of the 
wood, the dead oil originally used in the preparation." 
Kesults of Distillation. — I submitted some of the waste 
sleepers to distillation at Gateshead, and quote some of the 
results by way of illustration : — 
1. A decayed Scotch fir sleeper, when distilled slowly, at a 
moderate heat, gave 25 88 per cent, charcoal, and 58*82 per cent, 
tar and pyroligneous acid : distilled rapidly at a high heat, E 
obtained 17"30 per cent, charcoal, and Gl'72 per cent, tar and 
pyroligneous acid. 
2. A larch sleeper, in a state of very great decay, slowly 
distilled, at a low heat, furnished 23 00 per cent, charcoal, and 
58'77 per cent, tar and pyroligneous acid ; and rapidly distilled 
at a high heat, the produce was 17'31 per cent, charcoal, and 
G2 78 per cent, tar and pyroligneous acid. 
3. While an elm sleeper, comparatively sound, treated in a 
similar manner, gave — 
Slow firing. Quick firing. 
Charcoal 'ZG-li .. .. 13-49 
Tar and pyroligneous acid .. 51-80 .. .. 66-16 
These sleepers were taken at random from a heap lying near 
the line, and they had not been creosoted. 
Products of Distillation. Gas. — When rapidly distilled 
at a high heat and in small pieces, the proportion of gas is much 
