This applies to the sulphate of copper and barium process. Mr. Thilmany
has patented still another combination, in which he uses sulphate of
zinc and chloride of barium, which has been noticed under the head of
burnettizing.
Experiment No. 17 was tried on the Hudson River Railroad. It consisted
of 1,000 sap pine ties, which had been impregnated in the South, by the
Boucherie process, with a mixture of sulphate of iron and sulphate of
copper, under Hamar's patent. These ties were laid in the tunnel at New
Hamburg, a trying exposure, and when examined, in 1882, several of them
were still in the track. The process, however, was found to be so
tedious that it was abandoned after a year's trial, and has not since
been resumed.
In 1882 Mr. H. Fladd, of St. Louis, patented a method which is the
inverse of the Boucherie process (experiment No. 18). To the cap
fastened to the end of a freshly cut log he applies a suction pump, and
placing the other end into a vat, filled with the desired solution, he
sucks up the preserving fluid through the pores or sap cells of the
wood.
Quite a number of experimental ties have been prepared in this way, with
various chemical solutions, chief of which was sulphate of copper, and
there is probably no question but that the life of the wood will be
materially increased thereby.
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