71 
It would appear that a cheaper, if not more expeditious, method of 
preventing the adulteration of the solution could be found by passing- 
only clear water through the logs at the beginning of the treatment, 
continuing this process until the sap has been removed, and only*then 
introducing the antiseptic solution. The water, alter passing through 
the logs, would be allowed of course to run to waste. 
The removal of the sap might, perhaps, bo expedited and made more 
complete by using a weak solution of borax, instead of pure water, at 
the beginning of the operation. 
In France, where the Boucherie process was for many years used ex- 
clusively for impregnating wood with'vulphate of copper, the rule was 
to continue the treatment until every portion of the end from which 
the solution escaped showed the proper reaction when tested with fer- 
ro-cyanide of potassium. It was also a rule not to stop the operation 
until the solution escaping from the end, when tested by chemicals, 
showed a strength of two-thirds of the original solution, the wood re- 
taining almost all the sulphate of copper at the beginning of the treat- 
ment, and gradually less, so that the solution flowing from it showed a 
corresponding increase in strength. The time required for thoroughly 
impregnating wood by this process was found to vary with the state of 
the atmosphere, with the dimensions of the log, and with the quality of 
the timber. A humid and mild atmosphere was the most favorable, 
while dry and cold weather retarded the process. During freezing 
weather operations had to be suspended. 
As to the influence of dimensions on the time required for treatment, 
it may be assumed that the time required is directly proportional to 
the diameter of the log and to the square of its length. It may also 
be assumed as being inversely proportional to the hydrostatic pressure 
applied. 
Timber in which the annual rings do not differ much in width, such 
as beech and hemlock, is more readily impregnated than timber in 
which the heart is much more compact than the sap-wood, as in oak. 
No attempt should be made to treat timber which is not perfectly sound 
throughout its whole section and length. 
With fresh-cut beech logs intended for ties it took on an average 
about forty-eight hours to complete the impregnation. Logs of greater 
length and of other kinds required as much as one hundred hours for 
treatment. In cases where the impregnation was found not to be com- 
pleted at the end of one hundred hours it was customary to reverse the 
position of the logs and to force the solution through in the opposite 
direction. 
This process has been most extensively used in France, and to a 
smaller extent in Austria and Germany. Iu England it has never been 
applied, because nearly all timber used there is introduced from abroad. 
In the United States it has been used, so far as I am aware, in but few 
instances. 
