known over here as the "Munich furnace." Mr. William Farmer, who built those works, was the designer of that furnace, which was very successful indeed. It consumed less than II pounds of coke per 100 pounds of coal carbonized. It would not be germane to the subject under discussion to tell why these furnaces were not continued there, but it was at least co-equal with, and certainly prior to, the advent of the "Munich furnace" in America. The value of Mr. Steinwedell's paper, though considerable, would be still greater, perhaps, if he had given his views on the proper proportion, or best proportions of the various parts of the furnace to the bench in general. Some well informed gas engineers hold differing views upon these points, especially as to the most suitable area of grate, and if additional facts upon that part of the matter could be brought out at this meeting, I am sure these Proceedings would become of great value to us all. In conclusion, Mr. President, permit me again to compliment Mr. Steinwedell on his good judgment in the selection of his subject, and the able manner in which he has acquitted himself of his task.

MR. NORRIS-There is an apparent typographical error on page 50, where it is stated that the clinker bars are 5 feet long by 3 inches by 34 inches. I presume it means 3/4 of an inch.

MR. STEINWEDELL-Yes, sir.

MR. NORRIS-Mr. Steinwedell speaks of testing the bench daily for leaks by a lighted torch. This is a detail with which I am not. entirely familiar. And further along, there is an apparatus described for testing for carbonic acid. As I understand the apparatus the pressure to which the gas is subjected after the absorption of carbonic acid is slightly less than before that absorption. This, I presume, introduces a slight error, though perhaps in some cases not a serious one. If, however, the absorption of carbonic acid is about 19 per cent., then the pressure to which the gas is subjected must be about four-fifths of what it was before, and if I grasp the action of the apparatus the consequent error would be very considerable. Moreover, the gas is collected in contact with the absorbent reagent, and its readings must be unreliable.

MR. MACBETH-Has Mr. Steinwedell had any trouble from the overheating of the middle bench of 9's?

MR. SOMERVILLE-It struck me, being one of the old-fashioned company managers, while listening to the reading of the paper, that to make this furnace successful we would have to have men far higher in intelligence than the present stokers. I have never run one of these furnaces, but, from what Mr. Steinwedell said, it seems there is frequently a failure to get the best results from want of knowledge. I should judge from his description that to

make these furnaces successful depends greatly on the men you have in the retort house, or that the furnaces require superior intelligence and further direction, along with careful watching of your apparatus. With a stoker looking at the gauges for CO: and CO, and things like that, it would be impossible to run them. In fact, we would require college men to watch the stoking. I would like to ask Mr. Steinwedell if he has that class of people in his place, or if it requires that type of workmen.

MR. A. E. FORSTALL--I think Mr. Somerville has made rather a mountain out of a molehill. I have run regenerative or recuperative benches for a good many years without much assistance outside of the ordinary retort house foreman. I think the first requisite in starting to operate the bench is to teach your foreman what you are supposed to be doing. That is, you want to give him a certain amount of knowledge as to gaseous firing. He wants to know that in the generator of that bench you are making carbonic oxide, a gas which is to burn again in the combustion chamber to produce the heat in the bench. And you also want to tell him how to fire the benches, that you don't want your furnace hot to make your bench hot, otherwise he will get all your heat in the furnace and no heat in the bench. At the same time I don't think the regenerative benches can be run satisfactorily without a certain amount of supervision from the superintendent of the works. That supervision will only take a very few minutes every day, as by keeping a record of the damper openings, the primary and secondary openings, and of all the changes made, the superintendent can tell exactly the condition of things in the retort house by a very slight amount of supervision. I have also found it well to put in a pretty good man, that is a selected fireman, to take care of the furnaces and have charge of them entirely. I would pick out as good a fireman as I could and pay him regular fireman's wages, and let him have entire charge of the furnaces. As I have said before two or three times, we were not supplied with a chemist at our gas works, so we ran the benches by a set of rough and ready rules, descriptions of which can be found both in the proceedings of this Association and of the American Gas Light Association. It is hardly worth while for me to say that you do not need a college man to fire or run your benches. If you have a good superintendent who will give 10 minutes a day to that branch of the work, the benches can be kept in perfect running condition, the heats being kept up and the fuel account down, with the aid of the ordinary retort house foreman.

MR. BARRET--Following the same line on which Mr. Forstall has just spoken, we have the additional fact, taking Mr. Somer

ville's statement of what the requirements are, that, as we improve in our product from necessity, it does require more skilled labor. Take the same thing in other lines. The old slide valve engine can be run by almost anybody, but the complicated engines of today take a better class of superintendence. I don't think the criticisms so far of Mr. Steinwedell's paper are legitimate. The paper seems to me a very plain description of how to run a regenerative bench. I think the issues so far taken are side ones entirely.

MR. CHOLLAR-So far as I am concerned, I will have to admit that my experience in the operation of regenerator fired benches is slight, but Mr. Steinwedell has told us in a very few words how such benches can be operated successfully without regard to their construction. His paper is applicable to all kinds of regenerators. Now, what is the difference between regenerator and recuperator benches, as mentioned in the technical works and in the Associations, is a question I would like to know something about. If somebody can give a clear, distinct definition, that would draw the line sharp in respect of showing the difference between the one and the other, I would like to hear it.

THE PRESIDENT-It is part of the business for which this Association is organized to determine that and other questions.

MR. FERRIER-I want to call attention to the statement in the paper that "the excess equals 5 times the excess of oxygen." I suppose it was meant that excess of air is 5 times the excess of

oxygen.

MR. STEINWEDELL-Regarding Mr. Egner's question as to the saving, I think the reason why recuperative benches are not used in a great many places is, as he said, that you can not go down very deep with economy, on account of water or poor soil for foundations, and probably on account of the fact you can get gas coal so much cheaper in some localities than you can in others. For instance, some companies get gas coal for $2 a ton delivered, while others get it for $5 a ton delivered. That would be quite an item, whether you are firing with coke or coal, and whether it is worth while to invest the extra amount of money in a recuperator in consideration of the saving effected. Regarding whether it is best to admit live steam under the grate bars, or to use water in the ashpit, it might be said there are many different methods of doing so. In some cases water is run into the recuperator through a system of return pipes connected and acting as a feedwater heater, so that the water is heated before it reaches the ashpit. In such case you will be saving that amount of heat and find cold water would lower the temperature of the waste gases. In regard to grate area and

cross section of flues, etc., I think that would come under the head of the designing of recuperative furnaces, and it would be a very good idea for this Association to have a paper on that subject. I don't remember ever having seen one on that subject. Mr. Norris's question, concerning the apparatus for testing carbon dioxide, was as to within what degree of accuracy that would be. Several slight inaccuracies come in there, but I could not explain them very well without the use of a blackboard. The theory is, assuming 760 mm. to be the normal height of the barometer, as CO: is absorbed in the upper bulb a diminution of the pressure occurs. Supposing that I per cent. CO2 is absorbed, the loss in pressure would be 7.6 mm. of mercury. Respecting the lighted torch, that is only used in looking over the bench. You take a lighted torch and pass it around outside of the bench. If there is a leak-sometimes it can not be seen-the flame will be drawn inward. It is in order to detect by the draught a leak in the bench. The probable reason that the middle retort gets warmer towards the end of any particular watch is that it is midway of the upper and lower retort, and so, naturally, as it is nearer the center of combustion, it would have a little higher temperature than the outside retorts. Concerning the intelligence of a retort house hand, although it is better he should know what he is doing, it is only necessary to the results that he should know, in the matter of apparatus for testing for carbon dioxide, how to read the scale. It is not necessary for him to know why, although he will pick that up naturally from time to time. I have been asked why sand should be kept on top of the bench. In one case a severe crack occurred on the top of the retort house stack, and it was the custom in that works to keep a supply of sand and a shovel on top of the bench; by shoveling in sand the crack was stopped and any further mischief prevented. The difference between a regenerative and a recuperative bench, as I look at it, is about this. There is no such thing as regeneration in a bench. You only use the waste heat as it goes into the chimney to recuperate. I don't think I have used the term regenerator in my paper in any place, and the reason that I say recuperator is that you save the heat of the waste gases as they go to the chimney. No regeneration takes place in any sense. I think that is as near as I can answer Mr. Chollar's question.

MR. CHOLLAR-Explaining the difference between regeneration. and recuperation, we may possibly need regeneration, but we won't get it. If we get good recuperation we will be well satisfied.

MR. A. E. FORSTALL-I think that as the word regenerative is commonly used, it is synonymous with recuperative. That is, when

we speak of a regenerative bench, we are using, as Mr. Steinwedell says, an incorrect term, but we are using it in the meaning of recuperative. At least that has always been my understanding of a regenerative bench. There is, however, a distinction between a recuperative bench and a generator bench. The recuperative bench is the generator bench to which the recuperators are added. The generator bench is merely a bench in which the heating is done by an indirect process in which the fuel is burned by a direct process. In the ordinary direct way with the free firing bench, the combustion of the fuel is completed in one operation. It is burned at once to carbonic acid. In the regenerative bench the fuel is taken through another step. The fuel is burned in the furnace to carbonic oxide, then the carbonic oxide is burned in the combustion chamber to carbonic acid. Some question whether there is any advantage in recuperation at all. They claim that all you need is to have generative firing without recuperation, that you will get just as good results, or results that are so nearly as good that the extra cost of recuperation is not warranted. I think Mr. Chollar had the distinction between a generator bench and a recuperator bench in mind when he spoke of the difference between regenerative bench and recuperative bench.

MR. CHOLLAR-My question had direct reference to a regenerative bench as compared with a recuperative bench or furnace, not a comparison between a generative bench and a recuperative bench.

MR. EGNER-When I first read Mr. Steinwedell's paper I was impressed with the thought that it was as good and as practical a paper as we had ever had before this Association, and I think when the gentlemen return home and read it over carefully they will agree with me. I think its influence will go beyond this room, and that it does not really require such an education as we generally suppose a college man to have. It is a very practical thing in simple language, and I was impressed by its value from my travels to and fro through this country, in seeing so many who did not seem to understand just exactly what was the best for them to do. When I saw this paper the thought came to me, Mr. Steinwedell has just hit the nail right square on the head. I think his paper is as good as any we have ever had before this Association.

MR. J. R. LYNN-Mr. Steinwedell replied to a question put to him in reference to the different heats in the middle retort of a bench of 6's, and the central one in the bench of 9's. I don't think under any consideration, in a bench of 6's or 9's, you could get any other result than that the middle or center retorts would be hottter than the others.