used, because very injurious to machinery if continued long in

use.

The volatile portion of these oils cleaned bearings, when first applied, just as naphtha or kerosene will; but the next step was that the heat of the bearings continued, or perfected, the distillation of the oil, threw off the volatile portion in vapor, and left the heavy portion on the machine. This heavy portion could only lubricate by being kept fluid at a high degree of heat. Hence it followed that those mills which used these low-priced but really very dear oils could only be worked by the use of an excess in quantity, and by maintaining the heat of the bearings at a somewhat high degree. They therefore combined the maximum of danger with the minimum of economy, and I am glad to say that they seem to have disappeared, — at any rate, they are not offered to our members, as their dangerous and worthless character is sure to be detected.

I would here suggest that Mr. Waite be asked to give some of his further results with respect to durability of oil; and I also suggest that in view of the fact that Mr. Waite's report, which was to have been printed in the last copy of our proceedings, and which was excluded on account of the burning of the plates for the illustrations in the fire which occurred,- that that report be asked to be contributed to the Board of Government, to be by them published, if they see fit, in this report. Mr. Waite, I think, would like to give us some further experience of his in regard to the durability of oils tested under similar conditious to these.

Mr. WAITE. I have little to say except to give you an account of a few experiments in applying results shown at the last meeting. First-to show the importance of using a fluid oil in preference to a thick one. In one of the spinningrooms at the mill, we have substituted for Downer's heavy spindle oil, the Downer extra 32°. The oil was not changed on any part of the machine but the spindle bearings. With the same power and the same work, the speed of the top rolls increased from eighty-one to eighty-six turns per minute, showing a gain of six per cent in speed by using a lighter oil.

I have also tried experiments on heavy bearings with this light oil. I have put it on one of the heaviest and worst bearings in the mill. A hole was bored in the box-cover, a copper cartridge cap was cemented into the bottom so as to come as

near as possible to the journal without rubbing. This was filled with water, and a thermometer was placed in the water to show the temperature of the box.

I started with a gallon and a half of oil. The box was packed with asbestos, and as fast as the oil worked through it was caught in a drip-pan below, and used over again.

In running through once it lost about three pints, and continued losing until, after running through ten times, it had shrunk to less than a quart. The experiment lasted a month, and the thermometer showed the box to be from twelve to fifteen degrees above the temperature of the room. After the oil had been used once, a sample was taken for testing on the lubricating machine, and it was found that the oil had gained in lubricating value. A sample taken after the oil had been twice used showed an additional gain, but from this point the oil continued to lose slowly, until the end of the experiment.

Some heavy spindle oil was tried under the same conditions. In running through once it lost about a quart, but after that lost very little.

The man in charge of these bearings tells me that a gallon and a half of oil, used over and over in this way, usually lasts about eight months, showing a durability eight times as great as the light oil. The oil, like the other, showed a gain in lubricating value after being used two or three times. The thermometer in the box indicated from fifteen to twenty degrees above the temperature of the room, — showing that the thin oil was the better lubricant although the more expensive one. At the last meeting I spoke of rough bearings, and said that the bearing surfaces may become so smooth by continual friction that the oil is easily pressed out from between them. Since then I have had opportunities for proving this, and, in the case of a number of hot boxes, all trouble was immediately stopped by draw-filing the surface of the shaft.

Mr. GEORGE DRAPER. You have said nothing about the bearings being injured. If the bearings are subject to be injured by the fact you have spoken of, which would wear the bearings out the sooner, the thin or the thick?

Mr. WAITE. I think there is less wearing in the case of the lighter. You cannot tear the particles of metal apart without occasioning an increase of heat. In the case of the light oils there was a decrease of heat.

case.

There is one question that has not been looked into, and that is the influence of velocity on oils. A thin oil cannot be used to lubricate slow-moving surfaces. Although "extra 32° " oil was found to work well on the heavy bearing before mentioned, it could not be used on the top rolls of a spinning frame, notwithstanding the pressure was much less than in the former For this purpose an oil having more body must be used. Mr. GARSED. Suppose you had a crank-pin of steel, and phosphor-bronze boxes, and could not keep them cool by ordinary oil, i.e., by either sperm oil or mineral oil, nor by any that you could find. Then what would you do if you had a crank-pin of a twenty-five-inch cylinder engine that was very difficult to keep cool? The boxes are phosphor-bronze, and the pin is steel, apparently fitted as well as modern practice can make it, and yet the greatest difficulty to keep it cool, so much so that a man stands oiling every five minutes. Now, what would you recommend to cool that pin?

Mr. WAITE. I think possibly it may have become polished. These hard surfaces running against each other would tend to polish each other in time, and become very smooth. I would recommend that the crank-pin be roughened a little, and then you would have no difficulty in using the thinnest oil you could get.

Mr. GARSED. There is a groove cut at angles across the boxes from the outside, probably one-sixteenth of an inch deep by a quarter of an inch the other way, to hold the oil.

Mr. WAITE. One groove will not do. If you have a number of very fine scratches, each one acts the same as a large groove.

Mr. GARSED. The reservoir of oil must be distributed in very small portions around this pin, is that the idea?

Mr. WAITE. Yes, sir.

Mr. GARSED. But you want these grooves to hold the oil to prevent this wearing, or otherwise the cylinder becomes polished.

Professor ORDWAY. There are some points respecting this machine that Mr. Woodbury has not alluded to. It might seem strange that we have been so long in getting at apparently a few small results. I took hold of this matter without any prejudice at all, and soon found there was no machine that would give us any thing like uniform results. One was thrown

aside after another, until last summer I had this machine made by Browne and Sharpe. One of its excellences is that it is made as true as a machine can be. The disks were made of very hard steel, very highly polished, and perfectly true, so that when they are put together with a little oil between it is necessary to use force to separate them. This machine was calculated to run with two disks, both turning, and the friction was to be shown by the difference in velocity between the two . disks. The upper one ran by friction, and the lower one by power. We soon found that the heat would have to be taken into account. It seemed desirable to modify the machine, and put on a direct dynamometer, so that we could weigh the power. Mr. Woodbury had this bronze box made, to put on in place of the upper steel disk. This gives us a chance to cool the bearings at all times, or keep it at a definite temperature, and allow it to rise as fast or as slowly as you please. We have now this apparatus, which is a grist-mill to grind oil, in fact. No oil can get out except what passes between the two stones of the mill. A great many machines have failed from this circumstance: that oil in going around the shaft is wiped off by the edge of the bearing box, and there stays for a while, until there comes a time when a little of it will work in, and then all at once drops down your dynamometer, which shows a sudden change in the amount of friction, or amount of speed. This is the case with all machines that have half round bearings. They will go with great uniformity for a time, and then all at once there is a change, and then it comes up again where it was before, and then there is another change. That is owing to the fact that it is utterly impossible for any machine with half round bearings to keep the oil perfectly fed, and keep it from working out irregularly. The advantage of this machine is that that cannot happen. The oil must all go out by the centrifugal force. We are hoping to arrange it by and by so that we can tell what the endurance of an oil is. We can feed in a certain quantity, and know what will come out in a certain time. We shall make experiments upon the oils, and determine how much will wear out in a given time. This must, of course, be taken into account in determining the economy.

It took some time to build this machine. It came last fall when I was very busy, and could not be seen to until Mr. Woodbury could spare the time to take hold of it. He has

attended to it ever since with great constancy and fidelity. In the first place, it was necessary to get his bearing, and get it perfectly true. It was no easy matter to get that made as it should be. He has worked upon that for some time, and he has had a great deal of patience, and has finally got it into a very good condition, and every point about the machine has been worked out with scientific accuracy. Of course this has taken time, and the experiments which he is now making have been going on only for a short time. He has got, for the time. he has been making experiments, a great many results. We are beginning to get at some data which will serve as a basis of calculation. The only point we have had time to attend to, so far, is this point, as to the fluidity of the oil. It is certainly true that the fluidity of the oil is a very important point in lubricating power; and the point to be determined is whether that is the only point. I don't think it is the only point. It is the largest factor altogether, but there are other things undoubtedly. In the case Mr. Waite has mentioned, it seems to me that possibly in using the mineral oils, when there is an increase in the lubricating power after their being used a while, it is because there is an evaporation of the light oil; when that is entirely out, the lubricating power is increased. I have yet to determine whether taking a lubricating oil, and adding a small quantity of naphtha, it would increase or decrease the lubricating power. My feeling is that probably it would decrease the lubricating power; I should not be willing to say whether it would or not, except after a long series of trials. There is one thing certain, that oil which has a low lubricating power may be increased in lubricating power by heat; but Mr. Woodbury's experiments seem to show that there is a limit to this rapid increase. We see up here [on the chart] these lines are getting nearly straight. It would seem as though after the bearings got up to one hundred and ten we need not expect any great increase of the amount of friction. This may be true only with low pressure. The lard oil we see goes in almost a straight line. In all these other cases we begin to come to a parallelism with the ordinate axis; and I suppose that the curve will be different in each case. We see in those Mr. Woodbury has tried, it works up this way pretty fast, and comes nearer and nearer to a parallelism. One point he has to determine with reference to the various animal, vege