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enough water was being used and hence humidification effects were only slight or nil.

15. The Drying Surfaces of the house were those ordinarily present, such as rugs, varnished furniture, clothing, wall paper and varnished woodwork - all of which, as it is well-known, have a most remarkable capacity for absorbing moisture, at least in the first few days of artificial humidification attempts. When all of these have reached a condition of moisture saturation in general keeping with that of the air, these factors practically cease to be of importance as atmospheric dehydrating agents.

16. Auxiliary heating by Natural Gas applicances was used quite extensively because of the severity of the weather and the shortage of coal, and it early became apparent that the burning of natural gas in a room, in itself, had a marked influence on humidity relations, its use being accompanied by a concurrent rise, invariably, in the humidity readings. Therefore, so far as the efficiency of the humidifying device was concerned, only such readings as were made when a minimum amount of, or no, gas-heating accompanied were taken.

Summary of Devices Used.

It will be seen that the total number of devices used in these air-conditioning experiments in the abode in question (in addition to the building construction with the amounts of insulation and air leakage indicated) were (1) an ordinary, hot-air furnace, coal heated; (2) gas-grates, gas-stoves, and one overhead gas-heating plate -all burning natural gas; (3) standardized thermometers, one

hung in each room; (4) an eightinch ordinary electric fan placed in the basement opening of the cool-air inlet at the side of the base of the furnace; (5) a humidifying apparatus connected to the water supply; (6) a pan to catch the overflow from the humidifying apparatus; (7) the city water supply, which ranged betwen 14 and 25 pounds' pressure, as gauged in the basement, and (8) a pocket sling psychrometer with accompanying psychrometric chart and some distilled water (placed in covered tumblers in each room for moistening the wet-bulb thermometer). Other essentials in conducting the experiments were observations as to weather conditions, including official local reports corresponding to the hours when the home readings were made, notations as to the number of persons present, and the presence or absence of temporary disturbing factors.

Summary of Experimental
Findings.

Tables showing the results of the experiments are omitted because of lack of space, but the following summaries give the essential facts of each table:

A. EXPERIMENTS IN ROOMS HEATED BY DIRECT GAS-HEATING APPLIANCES (GRATES, STOVES AND PLATES).

In 24 experimental readings made in "comfortable living rooms", the expertments made on 13 different days (between January 10 and February 17) with outdoor temperature ranging from 0° to 38° F. and outdoor relative humidities ranging from 63 per cent to 91 per cent and wind velocities from four to twentysix miles per hour, it was found that the relative humidities within the rooms ranged from 37 per cent to 68 per cent (all but four scattered readings falling between 40 per cent and 55 per cent. While this does not constitute an ideal condition (60 per cent relative humid

ity), it conforms to the conditions which are usually laid down as practical of obtainment. It would, therefore, seem that no artificial humidification is needed in rooms thus heated (direct heating by grates, stoves and heating plates burning natural gas in the air of the rooms).

B. EXPERIMENTS WITH HOT-AIR FUR

NACE.

In 10 experimental readings made in "comfortable living rooms" (as regards temperature), made on 7 different days (between January 4 and February 4) in which heating was by the ordinary hot-air furnace, with outdoor temperature ranging from -6° to 16° F., outdoor relative humidities from 63 percent to 87 percent and wind velocities from two to thirty-two miles per hour, it was found that the indoor relative humidities ranged between 15 percent and 50 percent (all but two falling between 15 percent and 33 percent. Hence these experiments bear out the statements made by others that the heating of premises by such indirect methods as the hot-air furnace results in great aridity and shows the necessity for providing for humidification of the heated air.

C. EXPERIMENTS WITH COOL ROOMS (592° to 35° F.)

In 15 experimental readings made on 11 different days in rooms whose temperatures ranged between the limits stated and which were miscellaneously heated (hot-air furnace and gas appliances) with outdoor temperatures ranging from -5° to 30° F., outdoor relative humidities ranging between 56 percent and 95 percent and wind velocities from four to forty miles per hour, the indoor relative humidities ranged between 30 percent and 64 percent, nine falling between 44 percent and 64 percent. These experiments simply show that as temperatures decrease below the point of comfort in living rooms there is some compensation in the fact that the relative humidity increases to an amount which may be equivalent to the ideal (60 per cent). The cold, damp atmosphere resulting, however, is not to be advocated.

D. EXPERIMENTS IN ARTIFICIAL HUMIDIFICATION USING HOT-AIR FUR

NACE.

In 28 experimental readings made in "comfortable living rooms", the experiments made on 10 different days (be

tween January 13 and February 5) with outdoor temperatures ranging from -2° to 24° F. and outdoor relative humidities ranging from 56 percent to 91 percent and wind velocities from three to twenty-nine miles per hour, it was found that the relative humidities within the rooms ranged from 29 per cent to 58 per cent (all but seven scattered readings-the lowest of these 29 percenfalling between 38 percent and 58 percent. This is, for practical purposes, the normal condition desired. This experiment, therefore, shows that it is practical, with only the outlay described, to humidify artificially the average size and type of residence and include proper humidity as an element in the "comfortable living rooms".

E. EXPERIMENTS IN

ARTIFICIAL HUMIDIFICATION WHERE BOTH HOTAIR FURNACE AND DIRECT HEATING GAS APPLIANCES WERE USED.

It is thought advisable to include the four readings which come under this head, as it was sometimes found necessary to augment the heat coming from the furnace by the gas-grates or gasstoves available. This was usually due to the fact that the furnace had been allowed to cool down inadvertently. The four experimental readings were made in "comfortable living rooms", on four different days (between January 13 and February 2), with outdoor temperatures ranging from 14° to 22° F., with outdoor relative humidities ranging from 66 percent to 90 per cent and wind velocities from 10 to 13 miles per hour. It was found that the relative humidities within the rooms ranged from 41 percent to 46 percent-the "normal" condition. These readings serve to show again how readily the burning of natural gas in the atmosphere of the room increases or maintains an atmospheric humidity. The findings are in line with those obtained in the A group of experiments.

Observations and Deductions.

I. The "comfortable living room" atmosphere may be defined as one in which there is (1) a barely perceptible circulation of the air, yet without draft; (2) temperature not depressingly high nor uncomfortably low with heat more or less evenly diffused throughout

the rooms; (3) a degree of humidity which is neither high enough to be depressing nor low (dry) enough to be irritating, and (4) the absence of obnoxious gases, as those escaping from stoves grates and, obviously, dust, smoke or disagreeable odors. We may standardize the principal items in the above, and thus be more certain of a "healthful" as well as a

or

"comfortable" atmosphere: The air should move at a velocity of about one foot per second; its movement should be varied in direction; and it need not be over 68° F. in temperature, provided the degree of saturation with water vapor amounts to about 40 to 50 percent.

2. In air-conditioning buildings such as residences the chief problems to be considered and controlled are as follows:

(1) Movement of the mass of air to overcome stagnation and stratification (indirect heating, as by the hot-air furnace, easily accomplishes this while great improvement can be observed by the added use of the electric fan).

(2) Prevention or control of heat loss from the bulding through the two chief sources: (a) direct filtration of heated air outward and ingress of cold air into the building (these air changes take place rapidly about doors, windows, baseboards, floors, and especially chimney flue openings) and (b) direct conduction of heat through walls, window panes and floors (these are usually sufficiently insulated against by proper building construction, which includes intervening "dead" air spaces).

(3) Loss of water vapor which may have been added to the air for bringing up the humidity requirements.

It will be seen, therefore, that the question reduces itself practically to one of heat and humidity control, part of which is accomplished by correct building construction and the balance of which may be secured by the usual

type of hot-air furnace and a humidifying device.

3. Unless double windows are used and outer walls are efficiently insulated, there will be an accumulation of moisture on the roomside of these otherwise cold surfaces. Surfaces of the interior of rooms

must approach in temperature that of the room atmos-. phere or moisture deposits may occur. In the residence described, window panes, only, became steamed or frosted. Unquestionably, double windows would have avoided this. However, there is no evidence that such condensation upon windows or walls become a hazard to the health of occupants.

4. It was found that a small electric fan turned on for an hour or so three times a day was sufficient to "get the heat out of the furnace", and along with it any added humidity.

5. When outside temperatures mount above the freezing point (32° F.), at least in the locality in which these experiments were made, it does not appear that artificial humidification of residential atmosphere is necessary. This means, therefore, that, on the whole, the season making such humidification desirable in this part of the country is not only briefer than is commonly supposed, but that during the cold season many days occur when the outside temperature is above the freezing point. With the persistence of outside temperature below the freezing point, indirect heating methods, such as the hot-air furnace, produce an excessively drying tendency, or "dryingness" of the air which should be corrected, both on account of the damage to fur

niture and decorations as well as for health reasons.

6. Heating of rooms by naked (natural) gas flames (grates, stoves, etc.) results in an amount of atmospheric humidity which is apparently sufficient (forty percent to sixty percent saturation). It was not determined whether this increased humidity comes from the oxidation of hydrogen in the gas or whether it is any more than would result from the presence of any form of naked fire in the

room.

in

7. Very few precision struments are needed to measure the quality of a healthful atmosphere. Some of these the householder may do away with and rely upon "primary sense impression" and "comfortable room temperature" as guides. No doubt a little increased watchfulness, or increase in the acuity of the senses, is necessary and may be cultivated.

8. The effectiveness of any humidifying device is a very relative matter. Much depends upon the control of the heat-loss and moisture-loss through filtration leaks, direct conduction and evaporation. It is conceivable that in quarters insulated against such losses, any humidifying device, in time, would succeed in completely saturating the atmosphere with moisture. Under these conditions, for example, the moisture which a mouse exhales with each breath would in time humidify to saturation a large auditorium. Hence the question of the efficacy of humidifying devices appears be: "What will supply enough moisture in a few hours' time to bring about a relative humidity of from forty percent to sixty percent in spite of the chances for losses which exist in the ordinary place

to

of residence?" As the experimenter's observations, which correspond with those of others, are to the effect that it requires from a few to twenty or more gallons of water per day (depending upon the temperature of the air to be heated and its rate of escape from the building) to get enough water vapor into the air, it is obvious that some continuously operating device connected with the water supply of the building is the most. practical solution. An atomizing device can be made to accomplish this.

9. Observations in a number of experiments bore out the statements of others that when relative humidity mounts to from 45 to 60 percent, "room comfort" becomes "O. K," even when thermometers about the rooms record as low as 60° F. While this indicates that a lower temperature than is customary is comfortable under properly humidified air conditions, it does not mean that any less "heating", i. e., consumption of coal, is taking place, since the heat is simply being used at the furnace to evaporate the moisture which comes in contact with the heated air and the furnace box.

It does, however, render the living atmosphere more healthful and comfortable since it does away with the necessity of excessive heating (70° to 80° F.) in order to feel comfortable on cold days. The cost in fuel is probably about the same.

10. The apparatus needed to bring about "proper air conditions" by the householder is (1) a hotair furnace of ordinary type and an arrangement for air circulation in the rooms and back to the furnace (this return being accom

plished either by registers between floors or by loose door and floor constructions, or by leaving stairway doors ajar); (2) a humidifying device, costing about twentyfive dollars, with from three dollars to five dollars additional cost for its installation, the same to be connected to the hot-air furnace, (3) a small portable electric fan, costing about ten dollars - the same one used in the summer season for cooling and ventilation; (4) a couple of thermometers

costing about one dollar each, and (5) a hygrometer or psychrometer, costing from four to ten dollars. The cost of the amount of water used is insignificant, while the cost of electricity amounts to a few cents a day at the most (the use of the fan for four to six hours). The time necessary for regulating the humidifier and the fan should be made to correspond with that of tending to the furnace, at which place all three are under control.

NO CHRISTMAS SEAL CAMPAIGN THIS YEAR; GENERAL RED CROSS FUNDS SUPPORT TUBERCULOSIS WORK.

No Red Cross Christmas Seal campaign will be held this year. In line with the request of President Wilson and the Council of National Defense that financia! campaigns be reduced to the smallest possible number, the National Tuberculosis Association and the

American Red Cross have joined hands in a membership campaign for the Red Cross, to be known as the "Christmas Roll Call". Each member secured in the Christmas Roll Call will be awarded ten Red Cross seals and be given antituberculosis literature.

To provide for the development of the anti-tuberculosis campaign without abatement, the War Council of the American Red Cross has appropriated to the National Tuberculosis Association the sum of $2,500,000 to finance the tuberculosis work of the country. This money will be distributed by the National Association to the various state associations and through them to their respective local societies and committees. This arrangement insures to each state and local association, which last year derived an income from

the sale of Red Cross Seals, an amount equal to the gross amount realized from the 1917 seal sale.

The plan of campaign as outlined contemplates close co-operation between anti-tuberculosis agencies and the Red Cross in an effort to make the Christmas Roll Call uni

versally successful. The arrangement is distinctly a war measure and is not to be understood at this time in any way as a permanent program.

The controversy between medicine and morals is not really controversial if we look at it squarely. It is simply a question of utilizing a new type of public health machinery. Instead of using the sanitary engineer to drain a swamp as we do in malaria, we have to use the lawyer and the social worker in controlling liquor and prostitution and other evils. The analogy is scientific enough and the public is beginning to see it.Major William F. Snow, in American Journal of Public Health, Vol. VIII, No. 9 (September, 1918).

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