in connection with buildings that have a system of ventilationnothing to do with dwelling constructions at all. We have worked under a guarantee as to a given amount of air and the circulation, and we are held down in Massachusetts by a law which compels the circulation to be practically perfect. We are bound to comply with the Massachusetts law, and while it is not stated in the law, it is stated in the requirements of the police. department that the air in any part of the room shall be within .0006 as pure as it is out of doors. Naturally we have got to work to get a pretty good distribution or we do not get our money; so that anything I said in regard to the inlet and outlet, etc., referred only to buildings which have a system of ventilation embodied with them.

Mr. Kenrick:-Referring to what Mr. Wolfe has said, the last job I settled in Massachusetts the committee required a certificate from the state that was satisfactory to them in every respect before we could get a cent. They not only take the temperature through the sides of the room but they have a thermometer right in the center of the room, and not only in regard to circulation must the requirements be fulfilled, but the temperature of the incoming and outgoing air is figured against us.

Mr. Payne: Is it not a fact that, if you take a room with only one side exposed and you blow your air in from outside wall and exhaust it from the floor on the same side, you will get a more uniform temperature in the room than if you blow it in from the inner wall toward the cooler wall and take it out from the bottom of inner wall? It looks to me as if that is so. I would like to know if it is correct. I have a theory, and I have not had the opportunity of testing it, that if the air is blown in from the outside wall of a room, where there is only one exposure, and exhausted from the floor on the same side it will give a better average temperature throughout the room than if it is blown from the inside wall towards the outside and then exhausted on the inside wall also. The reason is that you blow the air over towards the cooler wall and it drops down and becomes cool and passes along the floor to the exhaust; whereas, if you blow it towards a warm inside wall and it drops down, the cooling effect will not be as great and your exhaust register being at the base of the cool wall will draw the cooler air off quicker and warmer air will pass along the floor.

The President:-Can any one answer that question. If not it will have to be brought up at the next meeting.

XXII.-TOPIC No. 24.

Up to what point will large piping effect an economy for heating purposes?

No discussion.

XXII. TOPIC No. 25.

What is the relative fuel economy of different systems of school house heating and ventilating?

No discussion.

XXII.-TOPIC No. 26.

Are float traps discharging to atmosphere more reliable than pot traps?

Mr. Barron:-I suppose you see that the object of the question is to find out whether there is such a thing as a reliable steam trap, and I am afraid that that question cannot be answered at present.

Prof. Carpenter:-In other words, I suppose you mean that it is doubtful whether there is any trap that is perfectly reliable.

XXII.-TOPIC No. 27.

Should not the form of hot air registers be changed so as not to reduce the area and efficiency of shallow flues?

Mr. Jellett:-Mr. President, I think the form of hot air registers as used at present should be changed. I believe the old-fashioned slide register was more satisfactory in delivery of air than the present register. But the design of the old-fashioned register could not be used today. People would not have it. The present registers have, in most cases, three valves in a register twelve inches wide. In order to make a clearance for those valves, the form of the register box has to be deepened, the result being that the entire depth through the register is 21 to 2 inches; add to this the fact that the castings are made square, forming a square edge on the inside, and there is also a great deal of resistance. It has been my practice to make the outlet register two and a half times the area of the flue itself and round the top of the flue so as to guide the air towards the opening in the face; but I find that there is considerable resistance and a very decided variance in the delivery of the air over the face of the register. We take the average of the anemometer readings over the face and it varies very considerably. The suggestion was made a year or two back that the inner side of the castings be tapered; that is, that the thickness of the metal be tapered on the inside very similarly to the tooth of a gear for example, narrowing so as to form a funnel and enlarging to the opening of the register-enlarging from the inside out. In doing this you could reduce the friction of air passing over the surface, but until we can get some other form of a valve and reduce the depth of the casting, I do not think this would be any great

benefit. We are all called upon to put up flues in very narrow spaces; we are limited as to depth and as to width. Therefore we cannot afford to give up any of the space. It strikes me that if some form of register was devised by which the entire back of the register could be hinged at the top, when the register is open, swing back the entire depth of the flue and allow the air to come in, it would be an advantage. Some such register as this need have nothing but the face and the flat valve at the back and one valve for the entire register; that valve, opening always in the direction of the incoming air, serving as a guide for the air, driving it forward. I offer that as a suggestion, because I do not believe that the present registers are as efficient as they should be. I think we lose a great deal of our efficiency in the delivery of air through registers, particularly at low velocities. If any other member has a suggestion to make of a better form of register than that I would like to hear from him.

XXII. TOPIC No. 28..

What is the cause of priming or foaming in house heating boilers?

Mr Cary: I am not so well acquainted with house heating boilers as I am with boilers of larger capacity, that is, running may be from 25 to 50 horse power. They are both boilers, and I do see that the conditions in one would be different from those in the other. They are both vessels in which you put water and put a fire under the water to generate steam. The conditions are generally the same. The matter of priming and foaming is very often confused by people. Priming is sometimes called foaming and vice versa. Priming is essentially the drawing of water along with the steam as the boiler is in operation. Foaming is caused by some chemical change in the boiler, or from other sources, such as the introduction of oil with the feed water in the boiler, and certain chemical impurities in the water will cause the boiler to foam in a similar manner to soap; as you rub soap in a basin you produce a froth or foam, and this sometimes occurs in marine boilers where salt water is introduced in boilers that have been using fresh water or the reverse. I do not see how foaming could occur under any other conditions. Those are the principal conditions which would produce foaming. Priming would be caused by an insufficient evaporating surface. If the steam leaves the water at too great a speed it will pick up water with it, on the same principle as the old rope well in which we revolve an endless rope into the well and the water is picked up and clings to

the rope. When steam leaves the water rapidly it picks up little particles of water with it and carries them on, being held in suspension by the velocity. If your evaporating surface is too small this will occur. If you force your boiler you get in the end about the same results. If you force it too far it will cause a violent agitation on the surface and the water will be picked up from the crests of the little waves formed, dashing up against the side of the boiler around the evaporating surface, or the steam will be driven from the surface of the water too rapidly to produce dry steam. These are the conditions in larger boilers and I do not see but that the explanation will apply to house heating boilers as well.

Mr. Dean:—I wish to tell of an accident the effects of which I saw and which might possibly explain similar cases in other boilers. I called at a residence and was looking at the heating apparatus. The man was showing his new boiler to me and also an old one lying at the side of the cellar. It was not very old either, but it had been discarded. Upon inquiry I learned that while using the old boiler he had heard a noise in the cellar and started down. When he got to the stairway he found he could not go down because water was flowing from the safety valve. An examination of the boiler showed that there was no chance for circulation of the water, and consequently the hot fire which he had at the time the accident happened simply lifted the water right up and blew it out of the boiler through the safety valve. It being a pipe boiler when the water got out the fire very soon spoiled it.

Mr. Kenrick:-I would say that I had a case within a month caused entirely by core sand. In the first place we supposed the priming was caused by oil. With that in view, the boiler was blown off fifteen times. Finally we made a surface blow, made an examination of the water, and found it was core sand in the water which, probably in blowing off, was left as a deposit in the sections and then in filling up the boiler it floated on the surface; but by making two surface blows the boiler was made perfect.

XXII.-TOPIC No. 29.

Is indirect radiation satisfactory in hot water heating?

No discussion.

XXII. TOPIC No. 30.

Which is the best method for return of condensation from fan heaters to boilers, gravity or non-gravity?

Mr. Connolly: To promote discussion in regard to this question

I understand from Mr. Barron that he said gravity would be more economical. Am I right?

Mr. Barron:-If the circumstances would allow you to do it.

Mr. Connolly:-I bring up the point that non-gravity would be better. The hotter you bring the water back to the boiler the better results you get, and it would be more economical.

Mr. Payne: That depends on the amount of steam you have got to expend to get the water back.

XXII.-TOPIC No. 31.

What is the relative difference in economy between automatic return traps, pumps and receivers, and gravity return of water of condensation?

Mr. Barron:-(Referring to topics 30 and 31.) Both these topics should be taken together, for while there is a slight difference we all know that there is a good deal of difficulty in returning the water from fan heaters if you do not use a pump. It is sometimes tried to return the water by gravity and sometimes by automatic drips. Then the relative economy of the three ways—if you can return satisfactorily, of course--the gravity is the most economical. If you cannot, I should think the automatic trap was the next most economical; that is, if you can make the trap work and you have a first class man and can monkey with it all the time, and in that case the pump becomes the most economical because it insures satisfactory work.

Mr. Dean:-I would like to ask why they cannot return by gravity.

Mr. Barron:-You know, as fan heaters are generally located, Mr. President, the fan heater is usually on the same line as the boiler floor. Of course you can return where it is convenient to locate them in that way, but that is not often the case.

Mr. Payne: I had occasion to express an opinion for a church society regarding the best methods in which to arrange their heating. They intended to adopt a blower system, and the specification as drawn up by several heating concerns called for quite an elaborate outlay for pumps and receivers, etc., and I advised them as the most simple method to put their boilers in a pit, giving sufficient head-room; after looking the matter over they decided to do so, but they found, if they put the pit down it would cost them $3,000 to make it water tight, so they decided to have the pumps, traps, etc. Of course we all know that a gravity apparatus is best, but the conditions are not always such as to permit that.