both hands, and pulled with all his strength. The resistance by friction having been nearly all eliminated by the oil, the handle straightened out, and the engineer found himself back in the tender. There were no further arguments on the oil question.

Mr. W. F. Durfee.-The variation in the amount of piston friction may be explained possibly, in some degree, by the varying cylinder condensation due to the varying point of cut-off of the

It is a well known fact that steam, as it expands, has a certain amount of it condensed in the cylinder, and if the cutoff varies, the quantity of water resulting from such condensation will vary also in accordance with a certain law. In the case of a vertical engine this water on the down stroke of the engine will be pretty evenly distributed around the circumference of the piston. In a horizontal engine most of the water will lie along the bottom of the cylinder, and the piston is running away, so to speak, from the condensation that takes place on the surface of the cylinder. The piston, except at its bottom, where it bears on the cylinder, gets very little benefit directly from the condensation of the steam on the surface of the cylinder, whereas in a vertical engine, the internal condensation taking place all over the surface of the cylinder, the water on the down stroke runs down and distributes itself evenly on the circumference of the piston. I have known a vertical engine of a large size to run a number of years without any lubricants whatever being applied, and the cylinders and valve faces have remained in very excellent conditionquite as good, and in some cases better than the corresponding parts of horizontal engines in which oil was liberally used an equal length of time. That is a practical point which, to my mind, is in favor, and very much in favor, of the vertical over the horizontal form of engines.

Mr. Thos. S. Crane.- Mr. Durfee has anticipated the remark I was about to make. Nearly all the engines in the country thirty years ago were run without lubrication. A tallow pot was kept on the hot steam chest to keep it fluid, and once in a while the engineer would give a little dash of tallow to the cylinder through a valved oil cup. From 1857 to 1861 many engines were put out without any means of lubrication at all. If desired in the mill where they were operated, the tallow cup would be put on. I have seen those engines taken apart after ten or a dozen years of wear, with the piston rings and the valves in perfect order, without having been lubricated at all. It was claimed that the lubricant corroded the

scraped joints; and it was admitted that a cylinder must always be lubricated, if the practice were commenced.

Mr. J. F. Holloway.-In the discussion in regard to the friction piston packing, it seems to me that a very important element has been overlooked. It is well known there are a great variety of piston packings in the market, and it is claimed by men who have invented packings of various kinds, that the peculiarity of their piston packing is that they dispense with a large amount of the friction. It seems to me that to carry on a discussion in regard to piston packing friction which does not designate the kind of packing used, would be like the play of Hamlet, with Hamlet left out. There are, as I said before, a great variety of packings, some better than others, no doubt; and the amount of friction which is produced by this internal pressure of the ring against the interior surface of the cylinder, varies not so much with the lubrication or the want of it, as with the character of the packing used in the cylinder. It was the practice a few years ago, and is still to a certain extent, to use packing rings, which are set out by springs and set screws in the piston head. I think, in those days, it was the general feeling among engine runners, that whenever there was anything wrong with an engine, the first thing to do was to set out the packing rings, and pretty generally it was done. Whenever a new engineer took hold of an engine, if it did not go to suit him, he would take off the cylinder head and set out the packing. I remember a few years ago we undertook to introduce some of the self-setting packing rings on propeller engines on the lakes. With these upright engines, the engineer had to work pretty lively to keep them from getting on the center, and the complaint was, that the engines moved so easily with this packing in, that they could not handle them. Consequently the steam packing was taken out, and springs and set screws were put in. (Laughter.) Now, unless we take some specific packing, and test it, we cannot discuss the subject of lubrication intelligently.

Prof. Jas. E. Denton.-I am familiar with the fact that engines have been run without cylinder lubrication in many instances in the past. I have in mind a 10 H. P. plain side valve engine which ran ten years without cylinder oil, at 60 lbs. boiler pressure, at about the period mentioned by Mr. Crane.

The Sellers firm advise the running of their steam hammers without cylinder lubrication.

A majority of the tug boats now belonging to the Pennsylvania

R. R., and plying between New York and New Brunswick, used no oil in their cylinders for several years without damage. I have not however been able to find in any of these instances conclusive evidences that there is not a considerable increase in the friction of the sliding surfaces in the cylinder and steam chest whenever a lubricant is dispensed with.

Such increase of friction may not be distinguishable in many kinds of engines. Thus the 10 H. P. engine mentioned above was so strongly built and its smooth running of so little importance, that the valve might have offered 50% increased resistance and not attracted notice. The Sellers steam hammers have no unbalanced valve to show increased labor on a valve stem if the friction increases, and the same was the case with the tug boats. Those of the latter having unbalanced slide valves could not be run without oil, and Messrs. Sellers do not attempt to run their slide valve engines without oil. Again, take a stoutly built directacting pump; they are often run without cylinder oil, and apparently do as well as with a lubricant. But if a pump with a steamthrown slide valve is run at its maximum speed as an air pump, the use of a cylinder lubricant largely affects the speed with which the valve can be made to move back and forth, and the speed of the piston of the pump is affected proportionally. Now, a similar effect, which evidently is caused by a reduction of friction, is produced by oil on the steam valve of any pump, but as the speed of the pump is controlled by the resistance of the water or by the throttle, we have no means of knowing that the valve works harder without oil. I ceased using oil in the cylinder of a modern high speed engine, having a partially balanced slide valve, driven by two eccentrics with a considerable number of intermediate connections. At the end of three weeks, no cutting had occurred in the cylinder or valve seats, all surfaces being highly polished in fact, but the valve gear ran very noisily. So much "clanking" occurred in its joints that it could be heard in the next room. On re-applying oil, drop by drop, the "clanking" ceased entirely at the 40th drop, but would return after about 3 hours of running if only 40 drops were fed. This behavior repeated itself over a period of several weeks, and was made the means of comparing the difference of lubricating value of several cylinder lubricants.

If this engine had been of less delicate valve gear, or one in which more or less noise went unnoticed, it would not have been

noted that the absence of cylinder lubricant made any difference in valve friction. My belief is, therefore, that absence of cylinder lubricant creates increased friction, which results in increased wear, but that there is not always the means of making ourselves aware of the existence of the increased friction. I think the general tendency of practice is to use but a few pounds tension in cylinder packing rings, and therefore it is rarely that the increase of friction of a piston can make itself known until the cylinder is opened. But many engines with unbalanced valves could not be operated at all without a cylinder lubricant, and their behavior gives unmistakable evidence of any increase of friction. In a locomotive, for instance, whenever the reverse lever is unnotched and held by the hand, the latter becomes a fulcrum through which the resistance of the slide valve must act, and any increase of friction of the valve is thereby made apparent to the engineer at once. I gradually reduced the feed of oil to the cylinder of a 16 x 24 locomotive, with an unbalanced slide valve of 80 square inches area, running 100 miles with each successive reduction of feed. When the rate of feeding became equivalent to about 250 miles to the pint, 27 miles of running so increased the friction of the valve that one man could not hold the reverse lever steady enough to set it to a particular notch, whereas with oil fed at the rate of a pint to 150 miles, the lever could be managed with one hand. The record of the apparatus herein presented, in showing greater friction as the oil used is less in amount, is therefore thoroughly in accord with practical observation.

I

Regarding difference in types of packing rings, I incline to the belief that for equal tension there is not so great a difference as is often claimed, but the ring which has been thus far used in the apparatus is certainly one that is becoming very general. admit, however, that attention should be paid to different forms in planning further experiments. Mr. Schuhmann's point regarding the interference of the upper and lower rings is a sound one, and it is intended to learn the effect of running one of these rings. The relative effect of the different amounts of oil, is however, probably independent of this change.

Mr. Crane cites an instance where apparently excessive moisture in the steam gave results opposed to my finding, wherein the introduction of wet steam greatly reduced the friction. He does not provide data to determine whether there was undoubted increase of friction in the cylinder and steam chest. What he

describes as "bad lubrication " may have meant "groaning some slight noise, often constituting the engineer's measure of lubricating value, but which is not necessarily indicative of a change of friction, which was the element measured in my appara

But assuming that no such distinction holds, I can only account for his results, by conceiving that the wetness of his steam, in the case of the uncovered pipe, interfered with the uniform distribution of the cylinder lubricant.

The latter would tend to concentrate itself in the liquid portion of the inflowing steam, and this action in the case of triple expansion engines running "light" under throttle (so that the steam entering the third cylinder is largely condensed) has been known to interfere seriously with the lubrication of the intermediate and low cylinders, when no difficulty was experienced with the high cylinder. I do not suppose that the amount of moisture in Mr. Crane's case approximated in degree to that used in my experiment, so that the lubrication still depended mainly upon the oil. It is only when the amount of moisture becomes so excessive that the oil is no longer the principal liquid in the cylinder that the results obtained in my own experiment would apply. I have met very contradictory opinions amongst engineers regarding the influence of moisture upon cylinder lubrication. To settle the question experiments should be made with superheated steam and with steam of various degrees of moisture, and it is hoped that this may be undertaken in the future use of the apparatus under notice.

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