capacity do you have? So there can be no law laid down for boilers for steam engines or boilers for other purposes. In steam boilers for steam engines you will find in the market to-day probably a ratio of ten to one between the different amounts of water prescribed. You will find in use vertical boilers with very little water in them and other boilers, like the Scotch boiler, with a great deal of water. One has a great reserve of power in emergencies and the other has not. So that the amount of water you put in a boiler depends on how much fluctuation you expect in the demand for

steam.

XXII. TOPIC No. 16.

Should not the opening through the seat of all radiator valves be equal to the inlet and outlet, and should they not be constructed so that no water will be held in the radiator by the seat of the valve?

Mr. Barron:--I would like to ask if there is any one here who has had much experience in using gate valves on radiators and what that experience has been. I have used them and found fair results. I would like to know if others have done the same?

Mr. Gormly:-I would say I have had some experience in the use of gate valves in water radiators and have found them to work very successfully, except in places where it was necessary to run the temperature very high and say 25 or 30 pounds pressure. In that case I found that the gates had a tendency to rattle and made the jobs noisy. I never used them on steam, so I can say nothing for them in that respect.

Mr. Payne: Wherever I have found it necessary to set a radiator at a distance from the riser and having to carry the connecting pipe over the floor to the radiator, I generally try to use a gate valve with a wood wall. I have found very good results from them and I think it is about the best method unless we can use an angle valve. In regard to corner radiator valves I had the same trouble. of which Mr. Quay has spoken in regard to the seat being raised up on the valve. I ordered some corner valves and they were made in this way, they were put on the job and of course we had to take them off and get the off-set radiator valve. I am sure I cannot see why manufacturers should send out valves made in this manner, because I think they are worse than nothing. I think this question almost answers itself. I hardly imagine that any person will want to use a valve of a less opening than the inlet and outlet, though in a great many cases we do use it, but the nearer the opening of the valve approaches the inlet and outlet I should think we all agree would be the better.

The President:-There is the latter portion of this question, Mr. Payne that no water be held in the radiator by the seat of the valve.

Mr. Payne:-Most decidedly.

XXII. TOPIC No. 17.

Which are the most effective, float or expansion automatic air valves?

Mr. Barron: From my experience none of them are effective. (Laughter). There is no question but nearly all the makes of valves are used and give very good results. In the flat where I live there are three different makes and they give no trouble. In the office I use another make and it gives no trouble. The valves are not uniform. You get from a manufacturer a valve to-day and it is all right. Next week you get a valve and it is not right.

It has a float that will not let water out-water will come out, and all the skill in the world will not make that valve work. I think it is due to the fact that valves are not made uniformly; they do not have fine jigs and all that sort of thing with which to turn out fine work. I think that if the construction of air valves were confined to the state of Connecticut they would be all right. (Laughter). Mr. Payne:-Answering the question, I think a combination of the two is very desirable.

XXII.-TOPIC No. 18.

What is the best method of heating and ventilating schoolhouses accommodating about 200 pupils?

No discussion.

XXII.-TOPIC No. 19.

What are the relative merits between flue radiators and other types?

No discussion.

XXII.-TOPIC No. 20.

What should be the proper form and area of chimneys for house heating boilers in proportion to their grate surface?

Mr. Cary: I think that we have an authority on the subject of chimneys with us, Mr. William Kent, and I would suggest that he be called upon to answer this question. I do not know of any one who can do it as well as he.

The President:-Mr. Kent, gentlemen, is an authority on the

subject of chimneys, as I think we all know. I have stolen some of his thunder.

Mr. Kent: The only extent to which I am an authority is that it happened twelve or fifteen years ago that I studied up all the different formulæ on chimneys and all the tables and compared them with a great deal of existing practice, and from that deduced a formula and table which has been very widely received by the profession since, and I have seen no reason to modify the table except to extend it and make it larger. With regard to the question, "What should be the proper form and area of chimneys for house heating boilers in proportion to their grate surface?" First, the proportion to the grate surface. They should not be proportioned according to the grate surface at all. That is one of the troubles that we have had in chimneys for all time. We will build a boiler and a chimney and make the area of the chimney one-eighth of the grate surface and get along all right, and then we will get another coal and find that that coal is better burned with one-half of the grate surface, and then the ratio is one-quarter the area of the grate, and the chimney works all right still. If you get it down to one-eighth you will find no end of trouble. The chimney must be proportioned to the maximum amount of coal that is intended to be burned on the grate. Sometimes you will burn five pounds of coal per square foot of grate per hour. At other times you will burn four or five times that much; in locomotive practice you will burn twenty times as much. But the chimney must be made large enough to take out the gases, and the gases do not depend so much on the amount of grate surface as on how fast you drive the air through. In steam engine practice we have an arbitrary figure called the horse power. I do not think they adopt that in heating practice. But the formula that I have given and the table that I have given for horse power of chimneys I would say would be exactly applicable to house heating boilers, if for horse power we substitute five pounds of coal per hour. I have not the formula in my head but you can find it in Prof. Carpenter's book and in my own, and nearly all the prominent boiler makers publish this chimney table of mine, so that if you take that chimney table and instead of so many horse power multiply it by five and the number of pounds of coal burned per hour, that chimney will be big enough.

In regard to the best form for chimneys I do not know; I do not think anybody else does. The form of the chimney I have found generally depends on geographical considerations. In Erie, Pa., they build chimneys broad at the top and narrow at the base. In other places they are narrow at the top and wide at the bottom.

They are all good. The only thing is to make them high enough. Our old rule was to make the chimney 80 feet high and as much higher as the owner will pay for. There is one thing that I hope engineers will continue to do and that is to hammer the architects. Architects will never know how to build chimneys. They will always make them too small in area. They may make them high enough; you can scarcely ever have a chimney too big; but you may have it too little. I have never yet found a case where the table I have given was found to give too small an area.

Prof. Carpenter:-I would say that I took the liberty to compute a table from Mr. Kent's formula which I adapted to steam heating boilers, and it is given in connection with the discussion so that it can be used. (See Table X.) I also printed it in my book. I printed.

TABLE X.

DIAMETER OR SIDE OF CHIMNEY IN INCHES REQUIRED FOR VARYING AMOUNTS OF DIRECT STEAM-RADIATING SURFACE.

250

2.5

7.4 7.0

6.7

500

5.0

750

7.5

1,000

10.0

1,500

15.0

2,000

20.0

3,000

4,000

5,000

6,000

7,000

6.2 6.0 6.0 9.6 9.2 8.8 8.2 8.0 6.6 7.3 11.3 10.8 10.2 9.6 9.3 8.8 8.5 12.8 12.0 II.4 10.8 10.5 10.0 15.2 14.4 13.4 12.8 12.4 11.5 17.2 16.3 15.2 14.5 14.0 13.2 30.0 20.6 18.5 18.2 17.2 40.0 23.6 22.2 20.8 19.6 19.0 17.8 50.0 26.0 24.6 23.0 21.6 21.0 19.4 60.0 28.4 26.8 23.4 22.8 21.2 20.2 19.5 30.4 28.8 25.5 24.4 23.0 21.6 20.8 32.4 30.6 28.6 26.8 26.0 24.2 23.4 22.2 90.0 34.0 32.4 30.4 28.4 27.4 25.6 24.4 23.4 100.0 37.0 34.0 32.0 30.0 28.6 27.0 25.4 24.6 38.4 36.2 35.0 33.0 31.0 29.2 43.0 42.0 41.0 37.0 35.0 34.0 50.0 48.0 46.0 43.0 41.0

For other kinds of heating multiply the radiating surface by the following factors: Hot-water heating 1.5, indirect steam 0.7, hot-blast heating 0.2. it two ways—with the argument in horse power and also the number of square feet in direct radiation. Practically we get about onethird of a pound of steam condensed from a square foot of radiation per hour, so that very nearly one hundred feet of direct radiation requires about the same amount of steam as one horse power. Hence it is very easy to reduce horse power to square feet of direct radiation and then, by multiplying by the other constants which are given, we can change from direct to indirect. The chimney formula has been found very satisfactory in my practice.

Mr. Wolfe:-Do you not believe that every chimney has a round draft? In other words, is the corner of a chimney of any use? Of course, in our business it is not so much in the draft of a steam boiler as it is for moving air. I have found the draft coming down in the corners and going up in the center and two or three different drafts at the same time in the same chimney, and in noticing factory chimneys it has seemed to me that all smoke coming from the top takes a spiral form, and as to the form of the chimney, don't we get the best results the nearer we keep to a circle? I ask that simply as a matter of information. I do not know; but I would like to.

Mr. Dean:-I will give a case that I had at one time. I was putting in a boiler for 900 feet of steam radiation. The owner asked me if the chimney was large enough. The opening seemed to be at least 12 inches square. I said, "Yes, it is plenty large." But later developments showed that there had been a fireplace in the room above and that an opening from it extended down into the cellar and instead of being 12 inches square the opening was perhaps 12 by 20. When we started to connect the boiler I put my head through the opening and looked up the chimney and it looked to be about two inches wide by two feet. As a matter of fact it was four inches by 24 inches. I told the owner I did not think the boiler would work with that chimney. He said he would change it if necessary-it was on the outside wall-but to go ahead and connect the apparatus up and try it. We made the connections and when we made a fire it was only about fifteen minutes until the boiler was blowing off. It was just as good a draft as I have ever seen on any chimney. I thought possibly it was due to the fact that there was a large opening at the bottom so that when the smoke went in it had a chance to distribute itself and enter this narrow flue at its full area.

Mr. Payne:—I once connected a boiler to a chimney which measured 4 by 30 inches the whole way out. It was not a success.

Mr. Dean:-I should like to ask the gentleman if the smoke pipe was simply the chimney or if there was a large opening made so that the smoke would have a chance to squirt out.

Mr. Payne:—It was 4 by 30 inches from the base to the top.

Mr. Kent: I was once called in to find the trouble with a boiler that had not enough draft and I found that it was connected with a chimney eight inches square. I found that right alongside of the chimney was another chimney also eight inches square separated from it by a 4-inch wall, and I recommended that they take out the 4-inch wall and turn it into an 8 by 20-inch chimney. This was done and it was a complete success.