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must preserve the wood. I have no doubt of its efficiency, used on wood work in wheel pits, or any other place where wet or dry rot is liable to occur; such as floors near or on the ground. Kerosene, or burning oil, is now being largely used for cleansing furniture and wood work in houses.

The PRESIDENT. There is one question I would like to ask Mr. FRANCIS. On page 18 you say that the corrosive sublimate will penetrate farther in green lumber that is full of moisture than in dry lumber; although lumber in a green state will not take up as much of it as when dry. Would you recommend green lumber for kyanizing rather than dry lumber?

Mr. FRANCIS. Well, that is one of those things there seems to be no absolute rule about, and it seems difficult to say. I have shown an instance here of a post that had been kyanized that has been in the ground forty-one years. I consider that as good a specimen of kyanizing as can be found anywhere. That post was purchased two years before it was kyanized, and it was purchased for another purpose ; and, having that timber on hand, it was allowed to be seasoned two years before it was kyanized. Then it was kyanized and put in the ground, and it was in the ground forty-one years, and when it was taken up not very long ago it was found to be perfectly sound. That was a remarkably good specimen. Now, I think under those circumstances it would show that it might be well perhaps to season the timber pretty well before it is kyanized. That is my own individual opinion ; but when you come to speak of the exact fact, whether it is better to kyanize green lumber or better to kyanize dry lumber, I do not think that anybody is able to say whether it would be better or not. Most of the lumber of the Locks and Canals Company comes in a green state, and of course they have to kyanize what is sent to them ; but sometimes we have lumber sent to us which is unsound. That lumber cannot be preserved, and for that reason we throw it out. There was something like four hundred thousand feet board measure of spruce sent to us from the

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city of Boston for the new Cambridge bridge; four-inch plank, spruce. Well, that is a pretty large quantity of timber. Some of it came to us unsound, and it was thrown out. It is no object for us to throw out any lumber, it does not interest us one particle; but at the same time people who are interested in the preservation of timber should be careful to see that lumber treated in that way, or by any other process, is good to begin with. That is one of the secrets of its success.

Mr. S. N. BOURNE. What kind of wood is that post you speak of having been in the ground so long?

Mr. FRANCIS. That is a spruce post.

The PRESIDENT. In 1882 the Pacific Mills had occasion to lay a basement floor in the main mill, and about two hundred thousand of spruce plank were sent to the Locks and Canal Company for kyanizing. That floor was laid. The plank were laid upon sand and fastened to six-by-six timbers. They were bedded in the sand, and the level of that floor is a little below the level of the ground outside of the mill walls. The plank that have been examined since that time, and some have been examined this year, show the plank and timber to be perfectly sound to-day, and the floor was laid about nine years ago. It is not a moist place. In many spots I think you would find the sand perfectly dry under that floor. There are places, however, where there would be moisture. We found that the plank were in such good condition this year in that place that we have used more of it for bridges and in other places since we bought the first lot. If there are no further questions to be asked of Mr. FRANCIS, we will take up the next paper.

Mr. ROBERT MCARTHUR. I would like to ask Mr. FRANCIS what kind of wood he would recommend for covering bridges.

Mr. FRANCIS. We recommend softer wood, usually spruce. Spruce is the kind that comes to us more than any other. .

The PRESIDENT. We will now proceed to the next pay by Mr. SAMUEL D. CRAFTS of Boston, on Wood Vulcanizi.

WOOD VULCANIZING.

BY SAMUEL D. CRAFTS, Boston, Mass.

Having been invited to address you on this subject, it gives me pleasure to comply, especially as anything which tends to the preservation of our fast-depleting forests is a matter of great importance and interest to all.

It is not, however, the broader view of this question which is of present moment to us, or in the discussion of which I will take up your valuable time, but the preservation of wood by the process carried on by The Haskin Wood Vulcanizing Company of New York, at their works, foot of East 19th Street, in that city.

While efforts toward prolonging the life of timber may have claimed the attention of former ages, it was not until the present century that anything practical was attempted in this direction. Knowing the antiseptic powers of corrosive sublimate, John W. Kyan reasoned that, if he could but remove the sap and fill the pores thus emptied with this salt of mercury, that wood must be indefinitely preserved. Others followed, with the same idea of getting rid of the decaying elements of the sap; and creosote, sulphate of copper and other chemicals have lent their aid to the bringing about of the desired result. The principle of all has been the same; viz., the injection into the vessels of the wood of some mineral material, which, by combining with the albumen of the woody tissue, prevents its decomposition and gives it a foreign character.

Great credit should be given to pioneers in any line of improvement, not only from the actual benefit derived from their researches, but from the fact that new heads and bands are enlisted in the perfecting of the new ideas, or in the evolving of new methods of producing the desired results.

This process of vulcanizing deals with methods entirely overlooked in the scramble for something with which to stop nature's tendency to decay. It has been found that wood has in it the elements to preserve itself. Heat, the great chemical agent of the universe, has been called to our aid, and by its intense application not only are the germs of decay destroyed, but from its chemical action antiseptic substances are evolved which render decay impossible, even if any life were left in the fungi-breeding sap. It is a fact beyond dispute that intense heat destroys the vegetable principles of the sap, and with it all the germs of decay.

It is well known to chemists that wood contains fifty-three per cent. of liquid matter called sap, and that, if the wood is placed in a still or retort under three hundred to five hundred degrees of heat, the sap flows off in the form of an oily, tarry, resinous, antiseptic liquid, which the chemist separates into pyroligneous and acetic acids, wood alcohol, creosote, and a dozen or more minor chemical constituents seldom heard of in commerce. This result is all produced by the simple application of a high degree of heat to the contents of the wood.

This being a well-established fact, it is very evident that the vulcanizing process, using the same degree of heat, produces precisely the same chemical change in the sap; but, being prevented by the application of an atmospheric pressure of one hundred and seventy-five to two hundred pounds to the square inch, nothing is allowed to exude from the wood while subjected to this high temperature, and it becomes thoroughly filled with the newly formed antiseptic. The wood is subjected to this extreme heat for hours, the liquid permeating the fibres of the wood through and through, the albumen becoming coagulated and the pores filled with the new substance. The wood is then allowed to cool slowly, and by the solidifying of its gums and resins its fibres are made more cohesive, and, as it were, cemented together. At no time in this process is there any possibility of a weakening of the fibres by the pulling apart or opening of the pores, as no vacuum is created, but, on the contrary, the fibre of the wood is kept in place by the intense pressure which is maintained until the lumber is cooled. It is thus that the lumber has been increased in strength, for there has been no separation or straining of the fibre. The fibres become more rigid in their relation to each other, the elasticity is increased, and the resistance to crushing force and transverse stress very materially augmented, facts which have been proven by extensive laboratory tests. (Reference is made to tables herewith appended.) The wood also becomes more uniform in its character, and this is caused by the forcing of the contents of the wood, when in its fluid state, throughout its pores.

We have stated the theory, now let us examine into its practical results. The works have been in operation nine years, and we have yet to learn of the least evidence of decay in a single piece of vulcanized wood. Spruce ties which have been subjected to the severest tests for nearly nine years, being covered in the ground (made land) in the tracks of our yard and exposed to extremes of moisture and heat, on being taken up last spring were found to be as sound as when originally laid, and do not show the slightest tendency to decay; and, where there was a crack in the wood, which, as you all know, is where decomposition frequently first sets in by reason of its holding the moisture, there was not the thickness of this paper in discoloration even. Vulcanized yellow pine ties which have been in use in the switch yard of the New York Central at the Grand Central Depot for seven and three-quarters years do not show the least tendency to decay, and even the sap wood is in

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