the highly refined engines, and the ultimate results that are shown in his paper, are not so widely different, and that will be, I think, a matter of some surprise to many, until they investigate the matter in the direction and to the extent in which Dr. Emery has investigated it. The common idea is, that to get the best results, you must get the most refined mechanism, and considerable money is often spent in that direction without knowing how much in other respects, the total value of the saving is brought down to the results obtained by the plainer and more common machines.

Referring to the water power question, I know very little about that, except that it occurs to me that it is hardly a fair comparison that Dr. Emery has made between the steam engine and water power, in the location which he has selected. I think it would have been better to have said that he had made the comparison with a place where there would be a good water power if there was water. If you go to all the expense of arranging for using water, and then half the year you do not have water, of course that must add largely to the ultimate cost of water power. PROF. JOHN H. BARR-I came down here this afternoon to hear the third reading of this paper. I had the privilege a short time ago of hearing a dress rehearsal of it, and read it to-day on the cars. I hope this, however, is not the final reading as it is one of the things that grows on me. I thank you for the privilege of taking part in this discussion, though Dr. Emery has left. little to discuss. The previous gentlemen have expressed their appreciation of this valuable paper to the engineering profession, in which I wish to concur.

I noticed a reference to the condition of affairs at the Calumet and Hecla Mines. My first engineering experience was gained at the Calumet and Hecla Mine, and, while I was there in a subordinate capacity and perhaps not entirely competent to judge of things, I think it quite probable, if not certain, that the conditions have by this time been so modified, that a different policy might be pursued with economy, so far as distribution of power is concerned. The great work done at Calumet by Dr. Leavitt, is of the highest interest to engineers, and if he has kept his eye rather constantly on columns e and f of the table given in this paper, it can be said that few men have done as much with a pound of coal as he.

The Falls of St. Anthony is cited as an exceptional case where nature has greatly favored the locality in water power; and while its water power had a very important influence in the development of the city located near it, I doubt if its present influence is as great as most people think. I believe that steam mills at other places can now compete on very fair terms with the mills on the water power at St. Anthony. The supply of water is so variable that all the more important mills have to have large steam plantssteam plants sufficient to practically run the entire mill. The in

terest, and all costs except running expenses, go on for this part of the plant, whether the mill is run by steam or water. The cost for labor also is largely maintained whether run by steam or water, because the engineers have to be employed throughout the year in order to have them when needed. The value of land and high taxation, or rent, puts these mills at a disadvantage, largely compensating the gain due to running by water part of the time.

MR. C. O. MAILLOUX:-In using engines for electrical station purposes, the tendency of modern practice, even with slow speed engines is to do away with the jack-shaft and to use the power either by belting from the engine direct or by attaching the armature direct to the shaft. Hence in a large number of cases the power of the engine will all be utilized excepting a very small percentage necessary for its own friction; and one need not, therefore, allow ten per cent. more for loss in jack-shaft or other intermediate transmission. This, of course has a direct bearing on the initial cost of the engine and the cost of maintenance, and indirectly upon the total cost of power per annum.

In regard to the utilization of water power when used to generate electricity to transmit to a distance, there is one factor that appears to me to be of importance, as affecting the question whether a given transmission scheme is financially practicable or not. I refer to accessory machinery and apparatus, particularly that needed for regulation and control, the importance and the cost of which I think is often underrated if not neglected, in making estimates on the cost of machinery necessary to utilize the energy of water power by transmission to distant points. I met a party some time ago who is operating an electric railroad by water power, and was not particularly happy over it, even though the power cost him but little. He said the principal trouble was in the great flunctuation of pressure, the voltage varying from 300 to 600. If several cars happened to start, or to be going up grade at the same time, the voltage would come down to 300, but if some of the cars stopped, the dynamo would raise the E. M. F. up to 600 or more. I asked myself, while thinking over this case, what would be the result when transmitting 5,000 horsepower electrically, from a generator driven by a turbine, supposing the load was suddenly and totally relieved by the circuit being opened through a main fuse blowing out, or a break in the wire, or supposing it were suddenly thrown on, without giving time for the governor to act; or again suppose the load were constantly fluctuating as it does on most railroad circuits. It occurred to me that something would happen of interest to science, and possibly the coroner also. We can hardly have fly-wheels sufficiently large to take care of these fluctuations, as they must be of enormous size. Calculations show just what would have to be their weight and proportions to prevent any serious variation of speed, when the whole load is thus thrown on or off. There are to-day many places where available and cheap water

power is unused for the sole reason that no efficacious and satisfactory regulation has been found to compass the fluctuations of load occurring on railway and power circuits. At Oswego they use a resistance, so that when the load is thrown off from the working circuit it is thrown on an idle resistance, which is not a very economical means of handling the difficulty, to say nothing of its cost. Hence, even assuming that we can overcome all other difficulties, of a financial or engineering character, in connection with a transmission scheme, we must put into our estimate a very liberal allowance for accessories, to enable us to secure a successful transmission and control of the energy, and leave the energy at the other end where it has to be utilized, in such form that it can be used as successfully and as satisfactorily to the customer as the electricity obtained from a central station operated by

steam.

I have always found the principal difficulty of electrical transmission projects to be, to dispose of the electrical energy after it is transmitted, and especially to distribute it, or deliver it to the consumer in a satisfactory manner.

PROF. FORBES-I would say that in the case of the Niagara transmission that question has been thoroughly threshed out and we have got a fly-wheel, not at all gigantic in comparison with the revolving arinature, which completely takes care of that. In two seconds the regulator will have acted and the fly wheel will have taken care of it up to that time.

THE PRESIDENT:-I think in the larger plants where five or six thousand horse power units are used, there will be less difficulty possibly than is anticipated, because as a ule where transmitting from a single source of such large units to distributed work for stationary purposes, there is a certain averaging up of the duty which will prevent such sharp variations of the load as have been indicated, and hence I do not think there will be somuch difficulty on the large water power transmissions; still, these variations have to be guarded against, and it is more difficult to meet them in a water plant than in a steam plant.

If any other gentlemen wish to discuss the paper we will be glad to hear from them. Possibly some remarks may be prepared by members subsequent to this meeting; if so, I shall try to have them received at the next regular meeting, or they can be presented to the Editing Committee. Emery will reply to some of the comments which have been made.

Dr.

DR. EMERY:-I can only say that I feel very much gratified with the complimentary remarks that have been made in regard to the paper and the way in which it has been appreciated by those present. It is unfortunate that the paper is so long that few have had time to study all the points in their different bearings and relations to each other, and I am quite sorry that one whom we esteem so highly as Prof. Forbes should have received

a copy only an hour before the meeting. I should have been very much pleased to have his remarks, excellent as they were, based upon a more thorough study of the paper. I quite agree with him on the point he makes in regard to the quality of the fuel. That matter should be emphasized in every way. At the same time it is not neglected in the paper. I will read Section 25, page 133, upon that point:

"In column m is shown the weight of water which it is assumed will be evaporated per pound of coal. The assumption is 8 pounds, except in the last case where it has been fixed at 9 pounds. Although 9 and 93 pounds evaporated can be obtained under actual conditions readily with boilers of good proportion and construction, it is thought that 8 pounds is as much as can be depended upon in average practice. It is in fact greater than is obtained in most cases, though less than is claimed in exceptional ones. This rate must be considered somewhat in relation to the price of coal. If cheap coal is to be used which will not give 8 pounds evaporation, the results must be sought in the column of the table applying to coal of a higher price.'

The last clause of the quotation, it will be seen, exactly covers the point made by Prof. Forbes in regard to cheaper coals. They will not give 83 pounds evaporation. The better grades of anthracite coal of buckwheat size, will rarely evaporate over 8 pounds of water from actual pressure and temperature, and for the poorer qualities 7 pounds or even less can only be depended upon. If, therefore, such coal cost $2.00 per ton, the results in the table should be mentally interpolated between those for $2.00 and $3.00 per ton. A glance at the figures in the two columns will show that any such difference will not appreciably alter the relative performances of the different engines if the same coal be used in all cases. The absolute results for a particular engine would of course be changed.

The next question is, whether or not 500 horse-power is a sufficiently large unit for general consideration. Prof. Forbes did not use the term unit, but I think that will express his meaning. I used 500 horse-power as being more generally applicable than a larger unit. It is in fact much larger than the average, but sufficiently large to secure maximum performance in the engine. The results would not be materially changed if we were to consider larger plants as multiples of a 500 horse-power plant. The cost of fireman would not change at all, and though one engineer on watch might care for an engine of more than 500 horse-power in a large plant, a chief engineer would also be employed at a higher salary, so that the labor account would not be greatly modified. The table is therefore about right for any large plant. PROF. FORBES:-For how small a plant is it right?

DR. EMERY:-It would be presumptious to say that it is exactly right for any engine. It cannot be expected that the friction of the engine, the weight of steam or coal used per hour, the cost of

supplies, of wages, of interest, and of fuel will in any particular case exactly coincide with the assumptions in the table. I have attempted to cover a great deal of ground and have been obliged to generalize. I have stated all the details of the generalizations and show at some length that considerable changes in the assumed facts would not materially affect the comparative results for the different engines. Absolute results for any particular case can be obtained by substituting the particular conditions, using for ready reference the formulæ at the heads of the columns. Do not misunderstand me. I have assumed very probable conditions, collated by references and by personal recollections based on a very lengthy experience, so that the results are approximately right for average conditions. Recurring to the original question I do not think that the operating expenses of a steam plant of 2,500 horse-power, or containing several units of that size would vary from one of 500 horse-power, or made up of several units of that size, sufficiently to predict in advance which would have the advantage. As already stated, one engineer on watch would take care of more horse-power in large units, but the number of men required to do the overhauling on the spare engine, and the salary of a chief engineer or general superintendent, would balance or more than balance the apparent saving for attention. For electric lighting work the principal saving due to the use of 2,500 horse-power or other large units, would be in the cost of real estate and buildings. In New York City, for instance, the area is limited, land is high priced, and the larger units take less floor space, so that considerably more engine power can be crowded into the same space, and this may make considerable saving in first cost.

Prof. Forbes, in the short time he has had to examine the paper, has not quite understood my first remarks in relation to the cost of water power. Moreover, the preliminary statement in the supplement to the paper is necessarily incomplete, and was rendered much more so in attempting to abstract it. Prof. Forbes says, "The cost of putting in the plant has been taken at probably $140 per horse-power without electrical transmission." I wished to be understood that $140 per horse-power was about the maximum amount that could be expended to develop a water power on a 10-hour basis in competition with steam, and I showed that the expenditures on the Merrimack had reached this sum, and that if they could be recalled they would not now be warranted. It was not intended to intimate that water power could not frequently be developed for a less sum. The supplement is directed particularly to the question of allowable expenditure when interest on the first cost is considered. I of course agree

with the general statement that the cost of developing water power when there is a high head and no dam to be built is comparatively small. I have simply emphasized the fact that all waterfalls are not thus advantageously located. I recently report