bleaching do use mineral oil mixed with sperm on their looms without harm; and such a mixture is safer in respect to spontaneous combustion than pure sperm. An admixture of twenty-five per cent high grade mineral oil with sperm and thirty-five per cent with lard oil appears to prevent spontaneous combustion, while seventy per cent added to boiled linseed oil does not serve such purpose. It has also been proved by the use of nitro-sulphuric acid that an oil which yields a minimum quantity of the tarry brown gum, which is supposed to be the cause of stain, may bear a very high fire-test and a very low rate of evaporation.

We hope soon to be able to furnish in one case, at a small cost, a simple set of instruments, by which every manufacturer can test for himself the flashing-point, rate of evaporation, anti-frictional qualities, and specific gravity of oils offered for sale; and possibly a bottle of acid, by which the tendency of a mineral oil to stain may be detected, and by which the adulteration of lard or olive oil with cottonseed oil, petroleum, or other adulterants, can surely be ascertained.

Owing to circumstances that have occurred, the undersigned is compelled to say that any circular that has been issued prior to this date (Jan. 30, 1879) alleging that, in this examination, certain oils have proved to be "the best" and are "entirely free from stain," was so issued without any authority from him, and the allegations rest entirely on the assertion of those who issued them. Were he himself now a user of oil, he would cause such oils to be tested again before purchasing them.

The undersigned has been as careful as possible to avoid making statements that would lead to a preference for any single oil, until all the facts could be placed together before the members of the association for themselves to choose.

Members of the association are invited to call at the Institute of Technology to inspect the frictional tests in regard to which, it may be added, that all the evidence that can be obtained tends to the belief that a high flashing-point and an evaporation of less than five per cent in twelve hours at 140° are sure indications of the best lubricants, if durability, as well as efficiency, be considered.

The question has been asked several times, why so high a standard of heat as 140° F. has been adopted. The answer is, that at this standard, although the evaporation takes place somewhat more rapidly than at 100°, it yet takes but very little time, when a volatile oil begins to wear out, to bring the heat of a bearing up to 140°. This may be easily proved by the use of a thermometer applied in the manner described at the meeting.

Two or three matters referred to in the meeting call for an addi

tional word. Further investigation proves the benefit of treating hose with paraffine wax to prevent mildew. Messrs. N. Boynton & Co., 87 Commercial Street, are fully prepared to do this work promptly and cheaply.

One of our members has had excessively oily belts treated by Mr. E. R. Flint, and considers them worth fully one-half their original value after the treatment.

The compound of coal-ashes, hair, and calcined plaster, had been long used by Mr. Hiram Kilburn, but could only be applied to pipes when cold, and then with some difficulty, because it sets very quickly. His attention having been called to the mixture of sawdust and flourpaste at the meeting, he mixed some flour with the ashes, and now finds that this compound can be applied to pipes when hot, the flour retarding the setting, and causing the material to be very porous. Sour flour answers the purpose best.

In respect to the saving of the "suint," or grease of the sheep's wool, it appears that in Europe, where naphtha is less easy to procure and dearer than it is here, " bi-sulphide of carbon" is used, of which the manufacture has been very recently established in Ohio.

This fact is named for the information of some of the woollen manufacturers, to whom this Report will be sent, who have asked the question.

Respectfully submitted.

BOSTON, Jan. 30, 1879.

EDWARD ATKINSON.