velopment of the hydraulic plant, thereby entirely changing the conditions.

55. The writer has not hesitated to recommend an original expenditure of $200 per horse-power for a combined hydraulic and electric plant near large cities, where not only the customary income due to incandescent and are lighting and the use of small motors at high rates would be available for comparatively short hours, but where the industries were such that large units of power could be sold at remunerative prices on a 24 hour basis. Even higher costs for development would appear to be warranted in some locations, but there is no general rule on the subject. The allowable expenditure in a particular case can only be deter mined from calculations based on the actual conditions.

DISCUSSION.

THE PRESIDENT:-Members of the Institute, you have heard the very interesting paper which has been presented by Dr. Emery. I think the impression which many of you have received is the same as my own-of surprise that there is so little difference between the total cost of power for the different classes of steam engines. Any one who has been called upon to make a selection of a steam plant and has received from fifteen to twenty bids from different builders, together with the claims for economy made by each, has been much in doubt as to the wisdom of a final judgment. I must confess that I myself have often been confused by the conflicting claims, and I think the paper which has been presented to-night will aid every engineer in settling these oftentimes puzzling questions.

The conclusions which Dr. Emery has reached in the matter of the use of water power in plants for the electric transmission of power is similar to that which I arrived at some time ago. Before I go into any details, however, I shall ask Professor Forbes, who I see is present, and who by reason of his experience and his present connection should be well qualified, not only to give us his views upon steam plants, but particularly upon combined hydraulic and electric plants, to say a few words upon this subject. I see that we have also with us some members of the American Society of Mechanical Engineers whom we wish to hear.

PROF. GEORGE FORBES-Mr. President, since you are good enough to call upon me to make some remarks I will rise, but I fear that I shall not have a great deal to say that will be of any value. The paper was only put into my hands a short time before I arrived here, and it is one which requires a good deal more attention than from hearing it read or the slight glance I was able to give it before arriving here. But everybody, I am sure, must appreciate, even from hearing the abstract read what enormous importance this paper is going to be to us all. No doubt there are many others here, who have been in the same position in which I have been placed in the course of the last year, who have had to make a special examination of this very question, and all those who have had to deal with the utilization of large quantities of water power, estimating the value which that water power is to those who are exploiting it, must have been forced to do what they could to estimate the value of the horse-power when developed in the most economical means by steam power. I have in these investigations during the last year had the good fortune to be assisted by the experience of some of the most experienced engineers in this country, including one whom we all respect, who is mentioned by the author of this paper, Mr. Leavitt; and I would only say generally that the conclusions which have been come to by myself, and those who have given me their assistance agree

extremely well with the conclusions at which Dr. Emery has arrived. I must say that Dr. Emery has put the case in a much more general way, and much more applicable to a great variety of circumstances that actually do exist in practice than any estimates I have ever seen of the actual cost of the horse-power, and consequently it is possible for us in any particular case that we are considering, to pick out the conditions which most nearly approach what is in the case that we are studying. And while I may say that some estimates I have seen of the cost of a horsepower per annum, especially on a ten hours' a day service come out a little below what Dr. Emery has produced, I must add that in those cases certain items of expenditure have been omitted, and in the cases where a lower estimate has been arrived at, the compiler has been professedly trying to produce the lowest figure which the users of water power would ever have to contend against.

I would feel that it is hopeless, without having given a great deal of time to prepare remarks on this paper, to say anything much to the point. But I would ask the author one or two questions about it. In the first place as to the cost of the coal, I noticed that the heat producing power of the coal is assumed to be the same in all cases. Now I fancy that these tables may lead to a little misunderstanding in the minds of some. I imagine some one taking up this table and saying: "Now what will it cost us at such and such a place to produce a horse-power per annum? There is coal purchasable at this place at $2.00 per ton. There is also coal purchasable at $4.00 per ton. He will natur

ally say: I will choose the coal at $2.00 per ton. That gives him a certain definite price on this estimate; but, of course, the slack at $2.00 per ton would only produce about one-half the heating power of coal at $4.00 per ton. In giving the price of coal it seems to me it ought to be mentioned what the calorific power of the coal is, and I would ask Dr. Emery whether he has in all these cases considered the calorific power of the coal practically the same.

I would ask Dr. Emery whether he considers that 500 horsepower is a sufficiently big amount to be considered. I mean are the standing expenses of a 500 horse-power plant sufficiently divided over the power to make it fair? If you went to 10.000 horse-power, for instance, would the standing charges be less in proportion to the horse-power, or is 500 horse-power sufficient to take up the whole of the value of the fixed expenditure? That is to say; are all the brains, and all the bodies that are at work on the plant fully occupied with 500 horse-power or would a larger unit modify the result?

I will not take up the time of the meeting with remarks which I feel are not of very great value and I will only make a few remarks about the supplementary portion relating to water power. The cost of putting in the plant has been taken at probably $140