vessel, a free space being preserved, and the dome kept empty, so that the Creosote is not drawn through the exhaust pipe. The Creosote is raised to a temperature a little exceeding 212° Fahrenheit instead of 120° Fahrenheit as heretofore. The exhausting process is continued until all the water is extracted from the timber in the form of vapor, drawn through the dome, condensed by passing through the worm of the condensing apparatus, and collected in the receiving tank, where the quantity extracted can be measured. With charges of very wet sleepers, the author has succeeded in withdrawing water equal in volume to 50 gallons per load of timber, and replacing this water with an equal volume of Creosote by the action of the air pump alone. If necessary, however, the pressure pump can be afterwards applied in the usual way.

A slight additional cost, and a few hours' additional time are necessary for dealing with very wet timber by this process as compared with the ordinary

method. But the expenditure in time and money is not so great as would be required by stoving the wood before Creosoting. If, in the absence of artificial methods, timber be stacked for six months, as it should be, the interest on capital represents a certain expenditure also. The author ventures to suggest that this is not always taken sufficiently into account, in giving out contracts for creosoted timber. Other conditions being equal, dry timber is at a disadvantage in the competition, as far as price is concerned, with timber just landed. Yet a small extra expenditure in this particular would frequently be repaid to the consumer twenty or thirty-fold in the prolonged duration of the wood.

Conclusion.-In conclusion the author would remark that with regard to certain points mentioned in this paper, upon which some controversy has at times arisen, he has been careful to advance no opinion which he has not confirmed, either by the opinions and investigations of eminent authorities, or by careful and

reiterated experiments. Many hundreds of experiments have been in fact carried out at the laboratories of the author's firm at Silvertown during the last five years, with the especial object of investigating the properties of the tar oils and other antiseptics, and their behavior in contact with timber. To Mr. Royle, Mr. Bendix, and Mr. Holmes of the chemical staff of his Silvertown Works he has to return his best thanks for their skilled assistance, and particularly to Mr. Bendix, who has been more especially entrusted with the conduct of these experiments. To Mr. Gabbett he is indebted for the drawings exhibited.

The Treatment of Timber by Antiseptic Methods has been acknowledged by some of the greatest engineers of this country to have been useful to the art of constructive engineering. It may be made even more useful in the future than it has been in the past. All that the advocates for its still more extended development can desire to claim will be, that their methods and investigations

may be seriously examined, and from time to time decided upon, in accordance with the results which science and experience may bring to light.

DISCUSSION.

Sir Joseph Bazalgette, C. B., President, said the subject of the paper was an exceedingly practical one. Timber, in the majority of countries, was the most available material for constructive and engineering purposes, and in some countries it was almost the only material which could be used. The great defect in its use was its want of durability. Anything, therefore, which could remedy that defect, and give durability to the timber, must be a subject of great interest to the engineer. The author in the paper had given the result of thirty-four years' experience, together with his researches into what had been done ages before, and the whole had been placed before the members in a manner showing that he had devoted very great ability and attention to the subject.

Although the author was commercially engaged in that branch of engineering, he was sure the members would feel that the paper had risen considerably above the commercial element, and had clearly shown that science could be, and had been, brought to bear on industrial art, so as to improve it and make it of great value.

Mr. Boulton remarked that the subject of his paper was one which had occupied his attention for many years. He hoped he had clearly explained the analytical investigations by which he had sought for some clue to what was a rather complex labyrinth, namely, the kind of substance which was the best to put into timber for its preservation. He had employed many of those substances, and the conclusion at which he had arrived was that, supposing the substance to be a good antiseptic, whether, as in former times, corrosive sublimate, sulphate of copper, or chloride of zinc were used, or whether creosote oils, there was always a close connection between the durable results of the anti