The first experiment was carried out by Mr. W.W. Evans, on the Southern
Railway of Chili, in 1857, and he informs your committee that in 1860,
when he left that country, the ties were still good and in serviceable
condition.
We give herewith, in Appendix No. 16, an interesting letter from Mr. E.
Pontzen to Mr. Evans, on the subject of the Boucherie process.
Experiments Nos. 2 to 16, inclusive, were all tried with various
modifications of the sulphate of copper process as introduced by Mr. W.
Thilmany in this country. They date back to 1870 (experiment No. 2),
when Mr. Thilmany was working and recommending the methods of vital
suction and of the Boucherie hydraulic pressure system. After describing
the foreign methods of injection with sulphate of copper, he states in
his first pamphlet (1870): "This process resulted very satisfactorily,
but it was found that the sulphate of copper became very much diluted by
the sap, and when the same liquid was used several times, the decaying
substance of the sap, viz., the albumen, was reintroduced into the wood,
and left it nearly in its primitive condition."
He accordingly proposed a double injection, first by muriate of barytes,
and, secondly, by sulphate of copper, forced through by the Boucherie
process, and it is presumed that the ties of 1870, in experiment No. 2,
which showed favorable results when examined in 1875, were prepared by
that process.
Subsequently Mr. Thilmany changed his mode of application to the Bethell
process of injecting solutions under pressure in closed cylinders, and
probably the paving blocks for experiment No. 3 were prepared in that
way. The chemical examination of them by Mr. Tilden, however, showed the
"saturation very uneven; absorptive power, high; block contains soluble
salts of copper, removable by washing."
It was expected that the double solution, by forming an insoluble
compound, would prove an effective protection against the _teredo_.
Experiments Nos. 4, 5, 6, and 8, however, proved the contrary to be the
fact.
The process, when well done, gave moderately satisfactory results
against decay. A pavement laid in the yard of the Schlitz Brewing
Company, in Milwaukee (experiment No. 7), was sound in 1882, after some
six years' exposure. A report by Mr. J.F. Babcock, a chemist of Boston
(experiment No. 9), indicated favorable results, and the planks in a
ropewalk at Charlestown (experiment No. 15), laid in 1879, were yet
sound in 1882.
The experiments on railroad ties (Nos. 10, 11, 12, 13, 14, and 16),
however, did not result satisfactorily. They seemed favorable at first,
and great things were expected of them; but late examinations made on
the Wabash Railroad, on the New York, Pennsylvania, and Ohio, and on the
Cleveland and Pittsburg Railroad, have shown the ties to be decaying,
and the results to be unfavorable.
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.
Whether the process will prove more convenient and economical than the
original Boucherie process can only be determined by practical
application upon an extensive scale.
A considerable number of modifications and appliances for working the
Boucherie process have been patented in this country; but none of them
seems to have come into practical use, probably because of the necessity
for operating upon freshly cut logs, and the inconvenience of such
applications.
The table on this page gives a record of various experiments with
miscellaneous substances.