by
pressure, or by sawing a log nearly through in the middle, raising it at
the center slightly, so as to open the joint, placing a strip of tarred
rope or a rubber band just inside the periphery of the cut log, and
letting it spring back, so as to form a tight joint by pressing upon the
rope or band. An auger hole bored diagonally into the cavity so formed
then served to admit the solution under pressure.

This process, applied with a solution of about one pound of sulphate of
copper to one hundred pounds of water, has been extensively applied in
France for many years, with satisfactory results. It was found, however,
that to be successful it must be applied to freshly cut trees in the log
only, and that this involved so much delay, moving about, waste, and
annoyance, that it has now been abandoned. These difficulties would be
still greater in this country, and in the Northern States the process
could not be applied at all during the winter (or season for cutting
down trees), as the solution would freeze.

On this page is a list of the experiments which your committee have been
able to learn about, as having been made with sulphate of copper in this
country.

RECORD OF AMERICAN EXPERIMENTS.

SULPHATE OF COPPER, OR BOUCHERIE.

--+--------------+----+--------+----------+----------+----------+---------------
| | | | Material |Subsequent| |
No| Locality |Year|Process.| Treated. | Exposure.| Results. | Authority.
--+--------------+----+--------+----------+----------+----------+---------------
1|Chili, S.A. |1857|Boucher.|Poplar |R.R. track|Favorable |W.W. Evans
| | | | ties | | |
2|Cleveland, O |1870|Thilmany|Ties | " " |Favorable |J.R. Conrad
| | | | | | to 1875 |
3|Washington |1872| " |Paving |Laboratory|Unfavor. |W.C. Tilden
| | | | blocks | | |
4|Pensacola |1874| " |Live oak |Teredo |Failure |W.H. Varney
| | | | | | |
5|Charleston, SC|1875| " |Pine block| " | " |Q.A. Gillmore
| | | | | | |
6|San Francisco |1876| " | " " | " | " |C.S. Stewart
| | | | | | |
7|Milwaukee |1876| " | " " |P