in that it can be used to carry off the foul air in warm weather when no pulsion is required, by heating only the coils in the foul air shafts.

All ventilation is costly, and so far as we now know, the more perfect systems the most costly.

The best ventilation now in use is that made by the use of machinery, creating the powers of pulsion and aspiration by the forcing and suction fans; for the reason that the power is under mechanical control, is therefore more thoroughly reliable, subject to less modifications from the conditions of the surrounding atmosphere, (heat and cold, dryness or humidity, variations by changes of the force or direction of the wind); and, not least among the advantages when register faces only are used,—depriving the occupants of any degree of control. The whole control of the ventilation may be in the hands of one man, under the direction of one head, which should be guided by the anemometer and thermometer, instead of the feelings of attendants or inmates. It is claimed for this method that when there are several hundred persons to be supplied with warmth and air, and there is an engine in use for other purposes, that it is as cheap as any other good method.

To combine the methods of mechanical pulsion and aspiration by heated temperature in the foul air flues, is to be highly recommended, because it utilizes and economizes the heat created for other purposes, and is therefore cheaper; its difficulty lies in the fact that the aspirating power would likely be the weaker and less reliable and steady, while it in fact needs to be the stronger..

The amount of air used by each person varies very greatly in fact, as well as by the estimates of authorities; an adult, not in exercise, will not require the amount of air needed when at labor, and very much less will be needed when asleep. Children, though more sensitive to evil conditions, require much less than adults; probably a child of ten will need less by one-half; invalids or hospital patients need much more pure air; 2,000 cubic feet per hour is considered a low estimate of the amount of pure air that should be introduced in a room for each person, especially if not in robust health. Morin's tables give the lowest estimates we have seen; for prisons 30 cubic feet per minute to each occupant, and for schools 10 cubic feet; other authorities double this. That the amount required when asleep is much less than when awake and active, we may know by the sense of discomfort felt on enter

ing a poorly ventilated, occupied sleeping apartment. The very small amount of air used by animals in hibernation establishes the fact; the amount of carbonic acid thrown off is therefore much less by the person when in a passive state, than when in activity; the tolerance of bad air by night in dormitories is very great.

Cold air inlets for furnaces should be very full size, and depends for capacity a good deal upon the directness of the flow; the outside air is not as pure at the surface or below as it is some feet above, unless there is a nice greensward or pure earth exposure; therefore, as a rule, the air preferably should be taken from several feet above the surface, and not from confined areas, or stagnant corners, as is often done; this is especially true in cities.

The register faces, through which the warm air passes into apartments with the flues between, should, if practicable, connect with cold air flues or a modulating reservoir, so as to reduce the temperature if needed, in order to avoid any opening of windows. As a rule, the windows in a building interfere with, and obstruct the ventilation astonishingly, frequently destroying the proper working of the entire system; the opening of a window in one apartment injuring the ventilation not only in the room in which it is situated, but neighboring ones also, and affecting the whole building.

Wrought iron as a material for furnaces is thought better than cast, and the fire brick or soapstone superior to either, yet much more expensive. The warm air flues, if they can be made to warm the floors and walls in passing are a gain, the cooling effect of cold floors, walls and windows being great. The more efficient the powers of pulsion or aspiration the smaller the flues and registers may be. If practicable, connection should be made with foul air flues by registers with tightly fitting valves at the tops of rooms, for use in warm weather; these should be tightly closed in cold weather when warm air is needed to be introduced in the rooms, as the foul air should, in all cases, be drawn from the bottom of the room when artificial heat is brought in. Register faces should only be used at the bottom of rooms so that the opening to the flues may never be closed.

Carbonic acid evolved by respiration will define itself all through rooms nearly equally; experiments have not settled the question whether it is found more largely at the bottom or top of rooms; the fouler, heavier, poisonous effluvia, settles towards the bottom

or in stagnant corners; a rapid circulation is desirable in all parts of a room. The filtering of air through spray or passing it over a body of water so as to precipitate street dust and coal smoke impurities is, perhaps, desirable in cities, though in considering this, the fact must be recognized that the dryness promotes and dampness reduces ventilation, and also that dryness disperses while dampness carries foul gases.

It may not be out of place to suggest a partial remedy for use in those buildings in which cold flues are made and nothing done to create a current; by cutting into the flue and introducing a gas jet or a petroleum lamp, a five-foot gas burner in a ten-by-ten flue will give a fair ventilation to a room for four or five persons.

The temperature of flues for outflow should be at least one-half higher than that of the rooms they exhaust from, in which case the air will pass a 12x12 register at the rate of two to three cubic feet per second, and will suffice to give pure air to five or six persons; increasing the warmth of flues will increase the outflow and thereby increase the capacity for occupancy. Some authorities give twelve square inches of outlet as sufficient for each person. Discretion should be used in determining all these questions, as they are practical ones.

An assembly room, occupied by a number of persons considerably in excess of ordinary rules, should have excessive powers of aspiration in its plans of ventilation, as very swift currents in the flues could scarcely be so injurious as the opening of windows on a crowded assembly; this throws drafts of cold air on a part, and injures the real ventilation to the other part, of the audience. The desideratum here sought for is an absolute sufficiency of air of the requisite degree of purity and warmth, "that it may be distributed through the room so as to be imperceptible; the strictly natural means must not be wanting, and the various artificial means should simply supplement them."

GENERAL DEBATE ON THE PAPERS.

The PRESIDENT (Mr. Lord): This finishes the programme, as far as the presentation of papers is concerned. All the papers are now for discussion to the extent of five minutes for each speaker. Mr. Pendleton, member of the State Board of Charities of Rhode Island, will open the discussion.

Mr. PENDLETON: I have been requested to speak upon the economy of Rhode Island in regard, more particularly, to our insane asylum. In the month of May, 1869, when the Board of Charities was established in Rhode Island, the law provided that we should receive inmates at the Workhouse and the Asylum for the Insane on the first of July, giving us one month to make preparation. The farm, with a farm house, had already been purchased. Of course our other buildings had to be erected pretty rapidly, and we threw up wooden buildings,-two for the insane, one for males, and one for females,-when the cost was much more than it would be at present; we expended about $6,000 apiece for those wooden buildings; we also erected a cottage for the more violent insane, dividing it equally between the sexes, at an expense of about $10,000. We put up a building for the deputy superintendent at an expense of $2,500. Since that time we have erected two additional buildings at an expense of about $5,000, upon a very economical plan, yet they are substantial buildings and we feel satisfied with them. They are brick, covered with slate; the window sills are capped with granite; they have hard pine floors, and, upon the whole, are very respectable buildings, of one story, ventilated with cast iron pipes running up through the floor from the cellar. We are now erecting a hospital building for the insane, which we expect will cost about $6,000. The whole expense of the buildings, then, will be about $42,000. We have now 250 inmates, which would make the cost about $160 per capita. We are now about erecting buildings for our Reform School, but we do not expect to get those for the same price per capita, though we have some two hundred and fifty-five inmates in the school. Our State Prison we all thought a very extravagant building; still, we are proud of it. It cost about $350,000, and is perhaps as good a building as can be found anywhere in the country; it now contains

200 inmates, and will accommodate perhaps 400. Our Workhouse is built of stone, four stories high; our Almshouse we are very sorry to show to anybody, and would avoid taking them through it; but we intend soon to have something better. It is kept clean, however, and well ventilated.

Dr. BYERS: Is it the purpose of your State to take the reform school boys out of the city of Providence, to the farm at Cranston?

Mr. PENDLETON: It is. Some people object that Rhode Island should provide for these boys on the same farm with the convicts and the insane; yet it has been generally thought by our citizens that this objection was sentimental. The boys will be as far from the prison or workhouse as formerly. This farm contains about 440 acres; and the part given up to the boys will be reached by a railroad, without bringing them in contact with the insane, at all; and I do not think they will ever come in contact with the others on the farm.

Dr. BYERS: I rise to speak of a single line in the paper prepared by Bishop Gillespie, in which attention is called to the inexpensiveness of good taste in the arrangement of public buildings. This is not a fact to be wondered at, when we consider that what is cheap is the kind usually left out in building. Light is cheap, so is air, and yet we often build to the exclusion of both. General utility in these buildings is the thing too often disregarded, while utility and tasteful arrangement are not inconsistent, nor necessarily expensive. But, unless we are going to reduce the inmates of our institutions to a very remarkable degree, we shall have to give up the family, or cottage system. I believe a thousand boys, or a thousand insane persons, can be more successfully managed under one administration, and one roof, than when divided among cottages and families. The difficulty is always in getting others to carry out the ideas of the superintendent of the institution. Where everything comes under his eye, errors can be remedied; but where scattered all about, difficulties occur constantly; so that I have doubted much if we shall make progress with the family system. Mr. C. H. BOND, of Connecticut: I have had some experience with boys in the House of Refuge at Philadelphia, and in the training of vicious girls in Connecticut. Perhaps boys could be well handled on the congregate plan, but for girls the cottage plan is the best. I do not quite agree with Mr. Howe in making distinctions; nor in grading or placing them in his method. We have