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.