regard to the smallest size of plant in which a charging machine can be profitably worked.

gar.

Mr. GREENOUGH-My opinion agrees with that of Mr. FullaI think that where a stack of sixty retorts is operated it will pay to put in a drawing machine. I believe Mr. Fullagar thinks it will pay in works with fifty retorts.

On motion of Mr. Wood a vote of thank was tendered to Mr. Greenough.

Mr. A. C. Wood, of the Syracuse (N.Y.) Gas Light Company, then read the following paper on

IMPROVED FURNACES.

Mr. President and Gentlemen of the Association :

At the Annual Meeting, in May last, of the Central New York Gas Engineers' Association, I gave the members thereof a description of the new plant erected by our company during the previous year.

In that description I related our experience in the working of the "Stedman-Stanley Furnaces," and reported the results obtained after using them up to that time-some four and one-half months. This statement was published in the American Gas Light Journal, with the proceedings of the Central New York Association; and when, a few weeks ago, our worthy President and irrepressible Secretary importuned me to present for your consideration a paper bearing upon this same subject I declined, stating that as I had already given our gas friends our experience with regenerative furnaces, and that the information I could impart was in the hands of all who read the Journal, it was neither desirable nor expedient to repeat it.

The reply was, five additional months' use of the new furnaces had elapsed since the meeting of the Central New York Association, and that a statement brought down to, say, October 1st, giving our experience with the furnaces during the nine months' of use would be of interest to the members of the Association, and the President then directed me to prepare such a statement and present it at this meeting.

I have therefore obeyed his orders, and will proceed to give

you our working experience with the "Stedman-Stanley Regenerative Furnaces," for nine months, ending Sept. 30th, 1885.

In the paper before alluded to I gave a description of the construction and modes of operating these furnaces, which need not be repeated here. Suffice it to say that the Stedman-Stanley furnace aims to utilize the waste gases, which have left the retort chamber, to the fullest extent consistent with strong and durable construction; and before permitting them to pass away into the chimney they are conducted back and forth between the front and rear ends of the bench, in contact with a series of parallel flues, from which the air for combustion is supplied. The flues for heating the air for the combustion of the furnace gases are uppermost in the series, and consequently are subjected to the greatest heat. The air for the combustion of the coke is heated in the lower series of the flues, and the waste gases are finally conducted, transversely, under the ashpan, and evaporate water to furnish the steam necessary to keep down the clinkers and mitigate the intense heat, which would otherwise destroy the furnace linings. The steam as it rises from the ashpan mingles at once with the heated air from the primary air flues, and together they ascend through the body of coke in the furnace.

Referring to the cuts, the waste gases are lettered A on one side and B on the other; and at the flue below the ashpan it will be seen that they appear on both sides. The supplementary air flues are lettered S, and the primary air flues P. The numbers indicate the successive flues into which the waste gases, and also the air supplies, successively pass. The furnace is made of various depths, to suit the structures where it is built. Not less than 32 feet in depth of fuel can be relied on, however, for generator work. The deepest furnace is in a basement of 13 feet height, and the shallowest where an excavation of only 3 feet could be allowed. In this case, by raising the inlets to the supplementary air supply sufficient space was made between them and the grate bars to maintain a good working depth of fuel and produce excellent results. A greater depth of fuel insures more uniform quality of the gases from the generator.

The retorts are 14 in. by 26 in., and 9 feet inside, six to each bench; and a stack of seven benches was erected. On Decem

ber 11, 1884, we charged for the first time three of these benches. These three benches have been under continuous fire from that

date up to the present time. Others of the benches, put in use in December, January and February, were let down later in the season. The average number of retorts in daily use for the whole period was 201⁄2. About 63 per cent. of our whole make of gas was made in the new benches, the balance being made in ordinary benches with ordinary furnaces. As our whole make of gas passes through the same station meter, we can only credit the coal carbonized in the new benches with the yield of gas obtained from all the coal used; so, upon this basis, we give you the production of gas in the new benches.

The yield of gas per pound of coal used for our whole make, for nine months ending Sept. 30th, was 5.072. We know that the yield was more than this in the new, and less than that amount in the old, benches, and at least 5 per cent. could be safely added to the above yield for the production of gas in the new benches; but we will take the figures as they are without any estimates or speculations. With this understanding we have the following results, obtained in operating these benches with the improved furnaces, for nine months, from Jan. 1st to Sept. 30th inclusive. The amount of coal carbonized was 10,640,942 pounds; the number of days was 273; average number of retorts in use, 201⁄2; average charge of coal per retort, 3162/3 pounds; average charge of coal per bench, 1,900 pounds; average charge of coal per bench per day, 11,400 pounds; the amount of gas manufactured was 53,970,858 cubic feet; the average yield of gas per pound of coal, whole make, 5.072 cubic feet; average yield of gas per retort per charge, 1,606 cubic feet; average yield of gas per retort per day, 9,636 cubic feet; and average yield of gas per bench per day, 57,816. The coal used was Westmoreland, with an average of 5.3 per cent. of West Virginia cannel, which gave us an average of 19.3-candle gas, tested with an ordinary Argand burner. This gave us, per retort per day, 185,975 candle feet, and per bench per day, 1,115,850 candle feet. This production would have been increased but for reasons set forth in the statement before alluded to-i. e., "There were many interruptions in the working of the new benches incident to starting up and operating a new and comparatively untried apparatus ;" and, too,