After the feed storage was got to work, one boiler ran twenty-two days and nights continuously, and on opening out it was found absolutely devoid of scale or dirt. "I caused two tests to be made of eighteen hours each, during which the coal was accurately weighed and the water measured through a meter I had previously checked with the following results: "When working without thermal storage, the evaporation reduced to 'from and at 212 degrees Fahrenheit was equal to 10.95 pounds of water per pound of coal, and on the second test, when the thermal storage was at work, the evaporation was raised to 12.21 pounds. "Of course, you must bear in mind that this particular apparatus was only designed for feed storage, as steam storage was not required under the special conditions which had to be dealt with in this case. "Sketch No. 3 of the storage vessels, to work in connection with refuse destructors, shows four thermal storage vessels, the number required in this case. "You will, of course, observe that any possible effects of radiation, about which I am not at all frightened, are minimized, as the cylinders here radiate against each other, so that only one-quarter of the total surface, or, say, one cylinder, will be under the influence of losses from radiation. "I have arranged this plant so that there is a wooden gallery in the roof, and into this gallery all the various handles are brought for working the apparatus. I have taken this precaution so that should any joint break the men in charge are perfectly safe, and being in the gallery they can control the valves and blow the vessel off, any escaping steam passing out through louvres in the roof. The boilers for this plant are not shown. "You will observe the thermal storage vessels are completely finished in the riveting machine, not a single rivet being put in by hand, and, owing to the form of the dished ends, there is not a single stay in the whole vessel, so that they are absolutely free to expand in any direction without doing injury by tearing themselves to pieces. All the valves, etc., are arranged so that any one, or all vessels, can be cut out of use." In conclusion, I will say that, of all the methods of storage available, the storage battery would, on theoretical grounds, be the best because of its forming the last link in the chain, thereby giving the economies. of continuous working to all that precede. Unfortunately, it involves such large losses in itself as to nearly, if not quite, nullify the advantages it would otherwise present. And, again, its extreme cost above all other methods renders it unavailable in any complete storage project. We are, therefore, compelled to go back of the engine for our equalization schemes, and put up with the losses due to variable load upon all that follows. Fortunately, the losses which we can overcome at this early stage are quite considerable, and we have a number of methods at hand. Of these the gas engine -involving a gas storage-seems to give the best results. Very closely following this, comes Halpin's combined feed and steam storage, followed by feed storage and steam storage. Below is given, in tabular form, the cost to produce for one year one electrical horse-power, with coal at $1.75 per ton and $3.50 per ton; also, the saving effected by the various methods over present methods in a station having a mean load twenty-five per cent of its maximum. HALPIN'S COMBINED FEED AND STEAM STORAGE SYSTEM, IN PROFESSOR STINE: In the discussion of this very able paper, I had hoped to be preceded by two gentlemen upon whom I naturally supposed would devolve the duty of taking up one, at least, of the three principal methods of storage proposed. For reasons which possibly need not be stated fully, I concluded to devote myself to a discussion of the storage battery side of the question. I am aware that this is a subject which, possibly more than the other two, is demanding wide-spread attention throughout the country; and we are all awaiting with eagerness the results of this revival of interest in the storage battery. It is with this feeling that I discuss the storage battery phase. I have assumed that the recent articles that have so fully worked out the economies effected by the storage battery in connection with European plants, have shown us that, as the paper has stated, in some cases a storage battery may effect a decided economy, considering the convenience, and a partial economy as relates to dollars and cents. It is well known that Europe has far excelled America in the development and applications of the storage battery. This has not been entirely due to apathy manifested in this country towards the storage battery, but rather to positive prejudice. This prejudice has been so marked in the past that those interested in the development of the storage battery have been accorded derision instead of encouragement. In such bad repute have they been held that no scientist dared risk his reputation in thorough investigation of this class of electrical apparatus. As a consequence, their development has rested largely with a class of well-meaning men who have lacked the proper scientific knowledge and experience to do justice to their work. Their efforts being so largely of a hit-or-miss style, and so little scientific, has caused the history of storage battery development to be filled with chapters of failures rather than successes. What real good has been accomplished by these persevering, but untrained, workers through years of toil and failure could have more quickly and easily been accomplished had men of competent scientific ability taken hold of the subject as they should. But a change seems to be taking place; the storage battery is rapidly becoming an important factor in the economies of electrical engineering. But since a widespread interest in the use of accumulators has been developed, it is necessary to regard the question of their economy from the standpoint of caution. It is well to recognize that the American storage battery is at present insufficiently developed to meet this demand. This criticism is given only in the desire to present the subject truthfully. Just here, we must learn an important lesson from the past. There is no longer a question but that the use of storage batteries will effect a considerable saving under proper conditions, provided the storage battery employed be reliable. At this stage, if the expectations based on |