SUPPLY FANS. The two supply fans are located as shown in the drawings. Apparatus No. 1, for the classroom supply, is a single single inlet, double width, top horizontal discharge, full housed fan, running at 278 R. P. M. and having a capacity of 41,000 cu. ft. per minute. This fan is beltdriven by a 20 H. P. electric motor, with a synchronous speed of 900 R. P. M. Apparatus No. 2, for the assembly room supply, is a single inlet, single width, to horizontal discharge fullhoused fan running at 260 R. P. M. for the toilet rooms. This is a single inlet, single width, top vertical discharge, full-housed fan, running at 480 R. P. M. and delivering 4,500 cu. ft. per minute. It is belt-driven by a 2 H. P. motor, with a synchronous speed of 900 R. P. M. All of the air-tempering heaters, preheaters and re-heaters are of the Vento type. The sections are of the regular pattern, 40 in. high and spaced 5 in. on centers. They are erected in a vertical position and assembled in groups as follows: This fan has a capacity of 22,000 cu. ft. per minute, and is belt-driven by a 10 H. P. motor, having a synchronous speed of 900 R. P. M. EXHAUST FANS. Apparatus No. 3 (north side classroom exhaust fan) is a single inlet, single width, top vertical discharge, fullhoused fan, running at 240 R. P. M., and having a capacity of 22,000 cu. ft. per minute. The fan is belt-driven by a 71⁄2 H. P. motor, with a synchronous speed of 900 R. P. M. Apparatus No. 4 (south side classroom exhaust fan) is a single inlet, single width, top vertical discharge, fullhoused fan, running at 260 R. P. M., with a capacity of 24,000 cu. ft. per minute. A 10 H. P. motor is used with this fan, belt-connected, having a synchronous speed of 900 R. P. M. Apparatus No. 5 is the assembly room exhaust fan, and is a single inlet, single width. top vertical discharge, fullhoused unit, running at 235 R. P. M. and having a capacity of 22,000 cu. ft. per minute. It is belt-driven by a 71⁄2 H. P. motor, with a synchronous speed of 900 R. P. M. Apparatus No. 6 is the exhaust fan The two-air washers which are included in the equipment are of the Carrier type, and have capacities of 40,000 and 22,000 cu. ft. of air per minute, respectively, with a velocity of air through any part of the washer of not over 500 ft. per minute, Each washer is provided with a system of humidity control arranged for maintaining a constant relative humidity in the rooms throughout the winter. The washers are guaranteed to remove not less than 98% of the solid matter entering the apparatus, to saturate the air leaving the apparatus when the air is heated in the washer; to maintain a relative humidity of 50% or less to 30% in the building when the room temperature is maintained at 70° F. during weather below 50° F. outside; and to cool the air in summer, when recirculating the water over and over again, through a range of temperature equal to 75% of the difference between the entering wet and dry bulb temperature. The architects of this building are Ingham & Boyd, Pittsburgh. The engineers are the Richard B. Kimball Co., New York. The contractors for the heating and ventilating work are G. F. Higgins Co., Pittsburgh, Pa. The Investigation of the Physical Conditions of a Room DESCRIPTION OF NEW APPARATUS DESIGNED TO MEASURE HEAT LOSSES, ORGANIC IMPURITIES IN AIR AND FOR MAINTAINING UNIFORM TEMPERATURES IN EXPERIMENTAL ROOMS. BY A. H. BARKER, (Abstract of paper read at the annual meeting of the Institution of Heating and Ventilating Engineers, London, February 9, 1914.) The author said that in previous papers he had expressed the opinion that experimental means of investigating the physical conditions of a room were very defective; the knowledge of the transmission co-efficients of building materials was likewise defective, and the figures in current use considerably in error. He had also previously explained why it was difficult to get accurate figures for that purpose, and had detailed what he regarded as the features in room air which produced feelings of comfort, and the healthful climate which, in his view, it should be the object of all heating and ventilating engineers to produce. The paper continued: As far as health is concerned, and perhaps comfort as well, all the physical conditions which go to produce a satisfactory climate should be within the purview of the heating engineer. His object should be less to heat the room and less to change the air in it than to produce a "good climate." Warming at room and changing the air in it are to be regarded as only among the means to effect such an end. THE WORD "CLIMATE" NOT SATISFACTOR ILY DEFINED. The word "climate" has not been satisfactorily defined. We all know what it means in a general way, but nobody seems to know what it means in a specific way. The doctors who talk learnedly on the subject of different climates probably in many cases have very hazy notions what is the physical difference between, say, the climate of Hastings and that of Buxton, taking the names of two health resorts at random. The difference in temperature may be negligible, the differences in pressure practically none, the differences in purity of air non-existent or at least indistinguishable by chemical analysis. The differences in mean wind velocity may be little or nothing; the quantity of ozone in the air probably does not differ as between the two places by the millionth part of one per cent. The humidity may be identical. In spite of such identities, doctors gravely pronounce in favor of one or the other climate as being preferable in the case of a disease whose nature they possibly understand as little as they understood the climate. ELEMENTS OF ROOM CONDITIONS. It is with the object of attempting to define some of the features in room conditions which go to make up the tout ensemble of satisfactory or unsatisfactory heating or ventilation, that the writer has been endeavoring to devise instruments for analysing the various conditions of room air. He said he regarded the elements of room conditions which need to be considered as the fol lowing: (1) The air temperature. (2) The mean radiant temperature. (6) The extent and velocity of the air currents and their general direction. To these might perhaps be added (7) The electrical condition of the air in the room. He was not inclined to attribute any considerable importance to the amount of ozone in the air. APPARATUS TO MEASURE HEAT LOSSES. The first instrument described by the author was one erected in the laboratories at University College, but which he had not had time to take a complete set of readings from, owing to it having only recently been completed. The apparatus has a double object; first, the determination of the rate of loss of heat through walls and windows-that is, the co-efficient known as "K"; second, the total loss of heat from the room in which the apparatus was placed. It is an automatic apparatus, the prin FIG. 1.-BARKER'S APPARATUS FOR DETERMINING COEFFICIENTS OF HEAT escapes from the guard ring can not escape in any other way than through the enclosed area of plate. ARRANGEMENT OF EXPERIMENTAL CHAMBER FOR DETERMINING HEAT LOSSES. The author's method for the determination of "K" is exactly similar in general outline. He showed on the screen a large diagram of a rectangular chamber, open at one side and carefully protected against loss of heat on all the other sides. It is formed of an iron M-Recording instrument. N-Connecting rod. S- -Mercury thread. V-Electricity meter. maintained, say, 30° above the temperature of the external air. If the interior of the room outside the chamber is maintained at precisely the same temperature as the interior of the chamber, the author said it is evident there will be no loss of heat from the room into the chamber, or vice versa, because the temperatures of the two sides are the same. If the room is maintained at exactly 30° above the outer air by independent means, such as radiators or gas flame, or otherwise the means making no differ ence then, if the interior of the cham-. ber is maintained at exactly the same temperature as the room, it ensures that whatever heat is supplied to the inside of the chamber can only escape through the wall. This heat is supplied to the interior by electrical means, and if the total number of units supplied to the interior of the chamber in any given time is measured accurately, the amount of heat lost in that time through the wall is thereby determined, with a given difference of temperature. That, said Mr. Barker, is the fundamental basis of the instrument. The appliances coupled with it are merely the automatic means for securing the uniformity and identity of temperature which is necessary within and without the chamber. As arranged in the laboratory, the means for maintaining the room at a constant temperature is by burning gas and controlling the supply of gas by an electrical thermometer, which turns on the gas when the temperature falls a fraction below the desired temperature, and turns it off when the temperature rises above that level. UNIQUE ELECTRIC THERMOSTAT MAINTAINING CONSTANT ROOM TEMPERATURE. FOR This is effected by an apparatus working on the following principle: The thermometer is an alcohol one very carefully made; at the top of the column there is a thread of mercury, which is pushed along the tube by the expansion of the column of alcohol and pulled back by its contraction. In the tube there are three platinum wires fused, numbered 1, 2, 3. The thread of mercury is long enough to make electrical contact between 1 and 2 or between 2 and 3, but just too short to make contact between 1 and 3. When the temperature is exactly 60°, or any other temperature for which the thermometer is constructed, the mercury thread lays evenly between 1 and 3, but is not in contact with either. When the temperature rises a fraction of a degree, the mercury thread is pushed along the tube a small distance, so as to make contact between wires 1 and 2. This puts into circuit a battery, which is so coupled up as to energize an electro-magnet, which pulls down an armature and closes the gas cock. When the temperature falls meter coupled to a recording instrument, which marks on a chart the amount of gas consumed at any given time. This is accomplished by fixing a small crank on one of the spindles of the meter, and coupling the crank-pin by a connectingrod to a pen, which traces a wavy line on a cylinder, with vertical axis, which is rotated by clockwork. By this means the amount of gas consumed up to any point of time can be exactly determined, and knowing the calorific value of the gas, the total heat lost from the room is given accurately. The readings on the curve give what might be called a by-product of the experiments-namely, the heat lost from the room during the time under consideration. MEANS FOR MAINTAINING INTERIOR OF CHAMBER AT SAME TEMPERATURE AS ROOM. The next part of the apparatus consists of means for maintaining the interior of the chamber at exactly the same temperature as the room. This is secured by fixing in the chamber a large air thermometer, another one being fixed in the room itself. The two are coupled together by a glass tube, in which a thread of mercury separates the air in the two thermometers. When these are at exactly the same temperature, the thread of mercury occupies a mid-position; but if either air bulb is at a higher |