ratus spoken of by Mr. Durfee, I should think that it would depend a great deal upon the cost of the development of the water power and of the plant which is put in to create the friction and produce the heat. The relative cost of steam power and water power is a very complex question, and depends upon so many variable quantities, that it cannot be established for any one locality, and the cost of steam power depends upon the amount of exhaust steam which can be used for various heating purposes. It depends upon the cost of coal in the different localities. The cost of water power depends upon the development of the power and the cost of the dam and canals, etc., and upon the cost of the installation of water wheels with their feeders, wheel pits, raceways, etc., which in large plants are very often more expensive per horse power than in small plants. While in the case of steam power the cost of power is less for large plants than for small plants, so that we have just the reverse, usually the cost decreasing with the increase of power in steam plants, and the cost increasing with the increase of power in water appliances. On the Merrimac River, the case which has been cited, which has Lake Winnepesaukee and several other lakes as a reservoir, the high water in the tail-race will decrease the power very much, during a freshet. I had occasion to see how many days the water was high enough to decrease the power 33 per cent., and in the year 1886 there were twenty-five days when the power was decreased 33 per cent. on account of high water in the river, thus requiring a plant 50 per cent. larger than is required .ordinarily. If a mill was dependent on water power then they must put in a water appliance sufficiently large to develop the required power at the low head, so that the cost of water power in that case is increased by the cost of the plant. There are other advantages which have been touched upon in the use of steam for power-the greater uniformity of regulation which Professor Thurston spoke about, and then there is a practical question, when we are using water power with no steam plant, if there is an irregularity of the flow, there are days when the mill must be closed, and in that case the best help will leave the mill and go to other places where they get. steady employment. Then in the case of irregular flow you must have steam plant to make up the deficiency or else stop the mill, so that you have the cost of a double plant, whereas if you were dependent entirely on steam, you would have only the cost of one plant. About the heating power of the coal, it would have been a good deal better if we could have had the pounds of dry steam consumed per indicated horse power, but I could not get those figures. I think I have touched upon nearly all the questions that were asked, CCCXIV. A FOUNDRY CUPOLA EXPERIENCE.* BY FREDK. A. SCHEFFLER, ERIE, PA. (Member of the Society.) UNFORTUNATELY the writer was unable to attend the meeting at which his first paper was read under the above title, nor to give time in closing the debate upon it to answer fully the able discussion made by Mr. H. I. Snell and others. Hence this brief answer to the questions asked at that time. As Mr. Snell kindly took the trouble to inquire into some matters of importance which I had not the forethought to include in the article, an effort will be made in this way to make clear all of the points raised. In the first place the proportions of the charges of fuel and iron made at the time the paper was written cannot be ascertained, but as the cupola is to-day doing practically the same work, the information as to the charges at this time will answer, as these do not vary excepting under certain circumstances. The first charge or bed of fuel is 2,000 lbs. of coke (this is not the best of coke), then 2,500 lbs. of iron, then 200 lbs. of fuel, then 2,000 lbs. of iron-the fuel and iron being reduced as each successive charge is made. very The distance of the tuyeres from the bed was given in the original paper, and is 24 inches. There had always been trouble with the old cupola in having the tuyeres too low down, so the new one was made to insure the melted iron remaining below the bottom of same. In regard to the measurement of the blast, I would say that the gauge was connected by a -inch rubber tube to the top of the blast box around the cupola, and the top of the gauge about 30" above the top of the blast box, the gauge being located only 3' distant. The pressure of 12 oz. has been found to be too high, *This paper is in continuation of the paper by same author presented at the Nashville Meeting, May, 1888, and published with discussion as No. CCXCIX., on page 496, Vol. IX. Transactions. as with this cupola and a blast of only 9 oz. the iron is melted faster than it is required. Of course the pressure is gradually increased to 9 oz., and does not reach this amount until about the middle of the heat, when it is gradually reduced. Only 4-oz. pressure is used at the beginning of the heat. Heats to the amount of 40,000 lbs. can be easily taken off, and it is very frequently done, and in considerably less time than was required for the old cupola when melting 34,000 lbs. The location of the gauge was not changed from that which it occupied when connected to the old cupola, as it is situated directly between the two cupolas-the connecting pipe being simply transferred from the old to the new one, so that any chance for a differential reading to occur was entirely dismissed. The larger diameter of the new cupola may have something to do with the increased amount of blast, as there is undoubtedly a greater total area between the pieces of coke and iron forming the charges than there was when the old cupola was used. The charging of both cupolas was the same in proportion to the amount to be melted. I certainly think that excellent work was performed by the old cupola, for more was required of it than its real rated capacity, but something even better was desired, and it was certainly realized. The proportion of iron melted to fuel consumed is from 7 to 8 lbs. of the former to 1 lb. of the latter. Probably if more expensive fuel was used the proportion might be increased somewhat, but I doubt whether it would make sufficient difference to pay for the increased cost of the fuel. If any of the members can throw some light upon this subject I am sure it will be appreciated. DISCUSSION. The Chairman.-Mr. Snell, do you wish to add anything to the discussion which was had at the last meeting? Mr. H. I. Snell.-I do not know that I have much to add to the discussion of this paper. Mr. Scheffler does not exactly answer the questions I asked. He has given the height of the tuyeres in the new cupola, and I asked for those in the old one. I suppose that perhaps they were too low down in the first case, and that partially accounted for the difference in the amount of iron melted. in the new cupola with the same blower as used on the old one. He says that the increased amount of blast was probably due to the larger area of the cupola and the greater distance between the particles of coal and iron. That, I think, conveys an erroneous impression. If he means the amount of increased pressure per square inch, it should have been more in the smaller cupola than it would have been in the larger one, from the fact that the pressure of blast from a fan blower diminishes as the delivery is enlarged after the enlargement exceeds the capacity of the fan. The amount of iron that he melts in the new cupola is about the usual proportion per pound of fuel. The old cupola that he complains of shows a great deal better practice in the amount of iron melted than I have met with in any examinations of cupolas I have ever made, and I took the trouble of making a comparison with some of about the size of the old cupola described in Mr. Scheffler's paper, and I will read a little of the data that I obtained. Here is N. S. Bouton's enpola in Chicago, 43 inches in diameter, that was charged with coke on an eight ounce blast. It melted 8.4 pounds of iron with one pound of coke, and was charged similar to the charge Mr. Scheffler reports in his new cupola, that is: Bed, 800 lbs. coke, 2,000 lbs. iron, 200 lbs. coke, 2,000 lbs. iron, Repeating to the last charge, 200 lbs. coke, 3,500 lbs. iron. They melted 10,764 lbs. per hour. Mr. Scheffler's old cupola is, I believe, 44 inches in diameter. In Tatum & Co.'s cupola, in Cincinnati, which was 44 inches in diameter, they required 17 ounces per square inch of blast, and melted only 6 pounds of iron to one pound of coke, and melted only 8,430 pounds per hour. In another cupola, that of the American Bridge Co., in Chicago, a 44-inch cupola, eight-ounce blast, 6.3 pounds of iron for one pound of coke, and melting only 7,764 pounds per hour. In looking over the question of cupolas, I have come to the conclusion that with about five or six thousand cupolas in this country, and every one of them charged in the best manner by men who have had experience of from thirty to forty years in charging cupolas, in every known and unknown method, and finally adopt |