Experiment No. 6 was made by Mr. Ashbel Welch, former President of this Society, and consisted in boring hemlock track sills 6 x 12 with a 1-1/8 inch auger-hole 10 inches deep every 15 inches.  These were filled with common salt and plugged up, as is not infrequently done in ship-building, but while the life of the timber was somewhat lengthened, it was concluded that the process did not pay.

Salt has been experimented with numberless times.  It is cheap, but is a comparatively weak antiseptic, its atomic weight being 58.8 in the hydrogen scale, as against 135.5 for chloride of mercury.

Experiment No. 9 is included in order to notice the well-known and most ancient process of charring the outside of timber.  In this particular case, the fence posts after charring were dipped for about three feet into a hot mixture of raw linseed oil and pulverized charcoal, which probably acted by closing the sap cells against the intrusion of moisture, which, as is well known, much hastens decay.  The posts, which had been set butt-end upward, were mostly sound in 1879, after 24 years’ exposure.

Experiments Nos. 41, 42, 43, and 44 did not, however, result as well, and numberless failures throughout the country attest that charring is uncertain and disappointing in its results.

Much ingenuity has been wasted in devising and patenting machinery for charring wood on a large scale to preserve it against decay.  The process, however, is so tedious in comparison with the benefits which it confers, and the charred surface is so objectionable for many uses, that nothing is to be expected from the process upon a large commercial scale.

In 1857-58 Mr. H.K.  Nichols tried sundry experiments (No. 10), at Pottsville, Pa., upon timber which he endeavored to impregnate with pyrolignite of iron by means of capillary action.  Similar experiments had previously been thoroughly tried in France by Dr. Boucherie, but the result has not been found satisfactory.

In 1858 the Erie Railway purchased the right of using the Nichols patent, and erected machinery at its Owego Bridge shop for boring a 2 inch hole longitudinally through the center of bridge timbers.  This continued till 1870, when the works were burned, and in rebuilding them the boring machinery was not replaced.  The longitudinal hole allowed a portion of the sap to evaporate without checking the outside of the timber, and undoubtedly lengthened its life.  It is believed there are yet (1885) some sticks of timber in the bridges of the road that were so prepared in 1868 or 1869.

In 1867 Mr. W.H.  Smith patented a method of preserving timber, by incasing it in vitrified earthenware pipes, and filling the space between the timber and the pipe with a grouting of hydraulic cement.  This was applied to the railroad bridge connecting the mainland with Galveston Island (experiment No. 12), and so well did it seem to succeed at first that it was proposed to extend the process to railroad trestlework, to fencing, to supports for houses, and to telegraph poles.  But after a while the earthenware pipes were displaced and broken, the process was given up, and Galveston bridge is now creosoted.