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Fresh Air. 
 
THE VENTILATION 
 
 OF THE 
 
 School Room, 
 
 — BY — 
 
 Wm. J. Baldwin, m. am. soc. c. e., 
 
 H 
 MEM. AM. SOC. MECHS. ENGS. 
 
 EXPERT 
 
 AND 
 
 CONSULTING ENGINEER. 
 
 HEATING AND VENTILATION 
 
 {^Copyrighted, igoi.) 
 
 PRICE, ONE DOLLAR. 
 
 Published by the Author, 
 
 107 W. 17TH Street. 
 
 New York. 
 
[the library of 
 
 j CONGRESS, 
 
 Two CoHiM Received 
 
 SEP. 25 1901 
 
 COPVRIQHT ENTRY 
 
 <9c^. // /q o/ 
 CLASS O^OCXa. N#. 
 
 I COP Y a 
 
 3 ^^ 
 
 TO 
 
 ABRAHAM ABRAHAM, Esq. 
 
 OF BROOKLYN, 
 IN CONSIDERATION OF THE INTEREST HE TAKES 
 IN THE SUBJECT. 
 
 c • « e e 
 
 • c s • » c 
 
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IN 1897 the author published a little blue book, 
 called "Data for Heating and Ventilation," 
 and in its preface he promised to continue his 
 efforts in a similar line at a later date, provided 
 the endeavor he then made was appreciated. 
 
 The demand and the appreciation for the "blue" 
 book was greater than his anticipations, and the 
 many letters asking to be remembered when an- 
 other book was issued, induced him to produce a 
 red hook for the year 1899, and call it "An Out- 
 line of Ventilation and Warming." 
 
 He now issues his little "white" book under 
 the title of T/ie Ventilation of the School Room 
 (1901) and he trusts that in the future he may be 
 able to continue his work in similar lines. 
 
 The author has the honor to be the pioneer 
 x\merican writer of a book of reference on steam 
 heating, etc. This book known. as "Baldwin on 
 Heating" from the press of John Wiley & Sons, 
 has now reached its 15th edition ; something that 
 no other engineering work ever printed in America 
 has attained. 
 
 (3) 
 
THE VENTILATION OF THE SCHOOL ROOM. 
 Perfect Ventilation ? 
 
 T PRESUME the word "perfect" should never 
 * be associated with the word "ventilation." 
 
 What is "perfect ventilation?" 
 
 If one lived in a tube, taking air at the bottom 
 and discharging it at the top, and the air was 
 taken from the top of one of the highest moun- 
 tains, presumably it would satisfy the person who 
 is looking for " perfect ventilation." 
 
 Under the ordinary conditions of our lives, in 
 our homes, at our business, in school, in the thea- 
 tre, we have to take what we can get in the matter 
 of ventilation, or more properly speaking, air^ 
 fresh or foul and make the most of it for the time 
 being ; and the only way we can help ourselves, is 
 by simply avoiding the places, when it is possible, 
 where we know the ventilation to be either very 
 bad or none at all, and patronize the places in 
 
 (5) 
 
6 THE VENTILATION 
 
 which there is some systematic attempt at ven- 
 tilation. 
 
 We cannot live in tnbes, and we therefore live 
 in houses, in fellowship with our kind, breathing 
 the same air with them and helping to contaminate 
 it, and an analysis of the air taken at the outlet 
 will be a fair sample of what we breathe, each per- 
 son having added his or her quota of contamina- 
 tion ; the same mingling with the mass : although 
 at the same time, through some properly arranged 
 inlet and outlet, there may be passing a stream of 
 air, the inlet presumably fresh, and the outlet 
 more or less contaminated . 
 
 This is all we can hope for while we live to- 
 gether, and our effort should be to secure " good " 
 or "fair" results under the normal conditions of 
 human life, and not look for an ideal condition 
 that is impossible to attain. This is why the 
 word perfect should be omitted in a ventilating 
 specification, as no one can attain it. 
 
 I may now ask "what is ventilation?" (in 
 contra distinction to "perfect ventilation" as 
 quoted above.) This question may be answered 
 
OF THE SCHOOL. 7 
 
 L by saying, that any means whereby the air of 
 habitations can be maintained at some common 
 standard of purity, can be termed "ventilation." 
 
 The "standard" can be placed higher or lower 
 as the local conditions may seem to require, or the 
 persons interested can afford. 
 
 Movements of confined air, which simply pro- 
 duce a sense of cooling, must not be confounded 
 j with true ventilation. 
 
 A room or building may be well ventilated from 
 a hygienic standpoint, and still be deemed uncom- 
 
 * fortable to live in by being over or under-heated. 
 If it is over-heated, the unthinking person is apt to 
 
 • sa}^ the ventilation is bad, while as a matter of fact, 
 it may be that only the warming lis improperly 
 
 idone ; and this is why the question of warming and 
 ventilating have to be considered together in all 
 cold climates. 
 
 I am not, however, going to consider the ques- 
 tion of warming here, any farther than is necessary 
 to properly present the question of fairly good or 
 good air in habitations, schools or other inclosed 
 space. 
 
8 THE VENTlIvATlON 
 
 I have made tests in a hospital as to the quantity 
 of air that was moving through it, and found that 
 the average amount of air per bed was between 
 7,000 and 8,000 cubic feet per hour. At the same 
 time, the physician in charge declared that the 
 ventilation of the hospital was '' abominable." 
 His opinion was not based on the chemical analy- 
 sis of the air. It was based on the fact that the 
 room was too warm. A room receiving but 1,000 
 cubic feet of air per bed might pass as "fairly 
 well" ventilated provided the temperature was 
 comfortable. 
 
 I only cite the case of the physician to show how 
 educated persons may err on the subject of ventila- 
 tion, when the personal feelings alone are the 
 instruments with which one measures the standard 
 of purity. 
 
 "What is the standard of purity at which air 
 should be maintained ? ' ' The necessity for a stand- 
 ard of purity implies, of course, that individuals 
 contaminate the air of habitations, and that suffi- 
 cient fresh air must be admitted and an equal 
 amount expelled or withdrawn until the air within 
 
OF THE SCHOOL. 9 
 
 the building is kept at a degree of purity very 
 nearly equal to the purity of the outside air. This 
 is ventilation, but it has not answered the question 
 of a working standard of purity. 
 
 The writer knows of many buildings that are 
 even as yet being used as schools or places of edu- 
 cation, that are almost, if not entirely, without 
 ventilation in the proper sense of the term. 
 
 The principal of a ladies' seminary in Greater 
 New York, while showing the mother of a pro- 
 spective pupil her institution, explained the ad- 
 vantages of having large dormitories divided into 
 small rooms, with partitions that did not run to the 
 ceiling, by saying, *'We get the most perfect ven- 
 tilation thereby — a free movement of the air from 
 one room to the other ; " and when it was suggested 
 that the air of one room was probably no better 
 than the air of the other room, she explained, that 
 "As soon as the pupils retired, they covered their 
 heads with the bed clothing, and that all the win- 
 dows were opened for about ten minutes, thus re- 
 moving every particle of contamination.^'' That 
 was her standard. 
 
lO THE VENTILATION 
 
 Twenty years ago, fifteen years ago, and prob- 
 ably not more than ten years ago, the Public 
 Schools of New York were almost without ventila- 
 tion. At the present time, however, whatever may 
 be said against the school system of New York, it 
 cannot be said that they are not making a most 
 determined effort to secure a good standard of pu- 
 rity in the air of the rooms. QWe may differ with 
 them in their methods, and be disappointed in the 
 results sometimes obtained, but nevertheless, the 
 present management deserve the highest commen- 
 dation for their efforts. 
 
 PBTTENKOFER'S EXPERIMENTS. 
 
 Pettenkofer has demonstrated by careful scien- 
 tific cabinet experiments on an individual, 28 years 
 of age, whose weight was 132 pounds, the amount 
 of carbonic acid that the person would add to the 
 atmosphere in which he lived and breathed in a 
 given time. 
 
 He found that "in repose " the individual added 
 .00424 cubic feet of carbonic acid per hour (reduced 
 to the volume of 32 degrees Fahrenheit) /^r/^?^/;^^/ 
 
OF THE SCHOOL II 
 
 weight of his body ; and that under what he con- 
 sidered "gentle exercise,'' he added .0059 cubic 
 feet (per hour per pound weight of his body) ; and 
 that the amount reached .01227 for "hard work :" 
 all of which reduced to correspond to a person 
 weighing 142 pounds (assumed average weight of 
 adult human beings) would amount to .6 cubic feet 
 of carbonic acid for a person " in repose ;" .9 for a 
 person at "gentle exercise;" and 1.8 per hour 
 when doing ' ' hard work. ' ' 
 
 A STANDARD OF PURITY. 
 
 With the foregoing in view, what should the 
 standard of purity be ? and the amount of air ad- 
 mitted per person to maintain it ? 
 
 Able authorities are of the opinion that when the 
 CO2 is maintained at .0002 in excess of what is 
 found in the outer air, that it is at least good ; in 
 which case there will have to be admitted 3,000 
 cubic feet of fresh air per person per hour while 
 "in repose" 4,500 cubic feet for persons at " gen- 
 tle exercise ; " and 9,000 cubic feet for persons at 
 '' verv hard " or laborious work. 
 
12 THE VENTILATION 
 
 This certainly seems to be a liberal standard to 
 maintain, and the best authorities now seem to 
 think it is ample in cold climates in winter, as the 
 cost of ventilation must enter into the question, 
 particularly when a great number of persons have 
 to be provided for in comparatively restricted 
 space, such as hospitals, schools, etc. 
 
 It is customary in hospitals to provide for a min- 
 imum admission of 3,000 cubic feet of air per bed 
 per hour, with mechanical means of increasing the 
 admission to 6,000 cubic feet of air per bed per 
 hour, when it is deemed necessary. This amount 
 of air (3,000 to 6,000 cubic feet per bed per hour) 
 seems to cover the contingencies and insure a 
 standard, in which the excess or coincident CO2 
 will be about .0002. Of course, when half this 
 qua itity of air is admitted, other things being the 
 same, the increase of coincident CO2 will be 
 doubled, and will become about 4 parts in 10,000. 
 
 MASSACHUSETTS' LAW. 
 Under what is known as the ''Massachusetts? 
 Law," which provides for the admission of 1,800 
 cubic" feet of air per hour per child in the 
 
OF THE SCHOOL. 13 
 
 schools (without regard to weight,) the additional 
 vitiation (carbonic acid) will be about .0003 CO2 
 when the average weight is about 90 pounds, 
 which, of course, secures what may be termed a 
 £-ood standsLvd of purity, without an excessive cost 
 of maintenance. 
 
 PURE CARBONIC ACID NOT A VITIATION. 
 
 This treatise does not intend to convey the idea 
 that a certain percentage of the carbonic acid 
 (CO2) in the air, in its pure state, is a vitiation, as 
 from ,0002 to .0004 of CO2 is nearly always present 
 in what is considered pure outside air, at least in 
 the neighborhood of cities. It does imply, how- 
 ever, that coincident CO2 or the carbonic acid 
 added by the lungs within doors, is the measure of 
 the vitiation, as in proportion to it all the other 
 emanations from the animal system, such as aque- 
 ous vapor, etc., must and do exist, and that by 
 measuring the excess of carbonic acid, which is 
 easily done, a comparative conception at least of 
 |.he other contaminations can be formed. 
 
14 THE VENTILATION 
 
 TEST FOR CARBONIC ACID. 
 
 Careful tests for carbonic acid in the air should 
 be made by a chemist or one who has made a study 
 of the subject. A crude comparative test, however, 
 can be made by a layman in the following manner: — 
 
 Procure a jar of lime water, made by placing a 
 small quantity of ordinary burned lime in a vessel 
 of water. After it has slaked and stood for a time 
 the excess of lime will settle, leaving a clear and 
 pure lime water on the top. Decant the clear 
 water and it is ready for use. 
 
 Procure a large necked bottle and make two 
 holes in the cork. In one hole place a tube running 
 near to the bottom of the bottle, the other hole 
 being open. Attach a small bellows to the open 
 end of the tube. Go into the open air and force 
 air into the bottle with the bellows until the water 
 becomes turbid : counting the number of strokes of 
 the bellows. Then enter the suspected room with 
 a fresh bottle full of lime water and renew the ac- 
 tion of the bellows until the water becomes as tur- 
 bid as before : counting the strokes of the bellows. 
 Then, if it is found that it takes only half as many 
 
Fig. I. 
 
OF THE SCHOOL. 15 
 
 strokes of the bellows to produce the same result 
 inside as it did outside, the general conditions may 
 be assumed to be good and the amount of carbonic 
 acid in excess can be reasonably supposed to be no 
 greater than the original quantity of carbonic acid 
 outside. If, however, one fourth the number of 
 strokes of the bellows produced the same result, 
 then there would be four times the quantity of car- 
 bonic acid inside that there was outside, or three 
 times as much " in excess. " 
 
 The carbonic acid combines with the lime in the 
 water and makes insoluble carbonate of lime. 
 This, of course, is a crude method, but with prac- 
 tice, fairly accurate estimates can be obtained. The 
 bellows should be opened to its full capacity each 
 time so that the measure will always remain the 
 same. 
 
 Figure i shows the arrangement I have describ- 
 ed, and in the hands of a school teacher will furnish 
 at least an approximation of the amount of vitiation 
 in a class room. 
 
 COST OF VENTlIvATION. 
 
 What does ventilation cost? The person who 
 has to provide ventilation for a crowded building in 
 
1 6 THE VENTILATION 
 
 a cold country, has also to assume the responsibil- 
 ity for the fuel bills, and were it not for this ques- 
 tion of fuel, there is no reason whatever why we 
 should limit ourselves in the amount of air passed 
 into or through a building, up to a point of mak- 
 ing it draughty. 
 
 A pound of coal burned under a boiler is equiva- 
 lent to warming 486,000 cubic feet of dry air, one 
 degree Fahrenheit, when the initial temperature of 
 the air is zero ; while at 14 degrees above zero, it 
 will warm 500,000 cubit feet of air one degree : and 
 at 70 degrees above, 562,000 cubit feet of air — in 
 each case one degree Fahrenheit. 
 
 This establishes the fact, therefore, that 500,000 
 cubit feet of air (in round numbers) can be warmed 
 one degree Fahrenheit for the cost of one pound of 
 coal, or 5,000 cubit feet of air can be warmed 100 
 degrees for the cost of one pound of coal. This is 
 the fuel cost of ventilation. It follows the immut- 
 able law of equivalents and cannot be changed 
 materially. 
 
 In the neighborhood of New York, it has been 
 found that an average rise of temperature of about 
 
OF THE SCHOOL. 1 7 
 
 40 degrees Fahrenheit is sufficient to cover the 
 ranges for an ordinary winter ; and that an average 
 of 50 degrees is sufficiently high for any point 
 within the United States, so that the average 
 amount of air that can be warmed by the burning 
 of a pound of coal in the East, North, West and 
 Middle States of the Union will be between 10,000 
 and 13,000 cubit feet. 
 
 With coal at $5.00 a ton of 2,000 pounds (a fair 
 average for the whole United States) it will require 
 20c per hour for fuel to maintain the warmth of 
 every one million cubit feet of air passed through a 
 building, taking one day with another throughout 
 the winter. 
 
 In the case of hospitals, in which the heating is 
 to be maintained day and night, say through 180 
 days of a year, the fuel for the same time will be 
 $864 for every million cubic feet of air passed in 
 an hour. This, of course, does not include interest 
 on the plant, labor, service etc., which increases it 
 to about $2,000. per season per million cubit feet 
 of fresh air passed into the building every hour. 
 As the plant grows larger this can be reduced to 
 
1 8 THE VENTII^ATION 
 
 probably $1500. per year for each additional million 
 cubit feet of air admitted per hour. This is the 
 cost of ventilation for hospitals. 
 
 This estimate will be considerably modified in 
 the case of schools as of course the schools are not 
 run continuously. The fuel cost per hour, how- 
 ever, will remain about the same (20c for each 
 million cubit feet of air passed through the build- 
 ing). An eight room school will require about 
 1,000,000 cubic feet per hour — during sessions — for 
 all purposes, increasing at about the ratio of 100,000 
 cubic feet of air per room as the school building 
 becomes larger. 
 
 HORSE-POWER REQUIRED FOR 
 VENTILATION. 
 When the power or heat required is expressed in 
 horse-power, it is equivalent to about 33. 3 centen- 
 nial horse-power {continuously) per million cubic 
 feet of air warmed and passed through the building 
 in an hour. 
 
 HOW TO SECURE VENTILATION. 
 The savage made a hole in the' roof of his house 
 to let out the smoke. This was the first attempt 
 
OF THE SCHOOL. IQ 
 
 at ventilation and very little improvement was 
 made on this primitive method until about 600 
 years ago when the fireplace and chimney appeared, 
 and this sufficed for dwellings until abont Frank- 
 lin's time, when he invented the ''aspirating stove;" 
 the waste heat of which drew a measure of air out 
 of the room : which air was renewed the best way 
 possible, through window and door cracks and 
 porous building materials. 
 
 The early chimney was as a general thing so 
 large that when the doors and windows were closed, 
 the air to supply the fire came down one side of the 
 chimney, while the smoke w^ent up the other side, 
 and this circulation went on even after the fire was 
 out (though in a subdued measure) ; thus securing 
 "accidental ventilation." 
 
 In the latter part of the 17th century systematic 
 ventilation was undertaken by Sir Christopher 
 Wren in the British House of Parliament, London. 
 It was a little better than "some holes in the 
 ceiling." 
 
 About 1723 Desaguliers improved the foregoing 
 system by connecting the holes or tubes with heated 
 
20 THE VENTII^ATION 
 
 chimneys. This is the first well authenticated 
 account of ventilation by "heat aspiration." 
 
 About the year 1736 Desaguliers again improved 
 the ventilation of the British House of Parliament 
 by the use of centrifugal fans, which were very 
 similar to the "housed" pressure fan or blower of 
 to-day. This is probably the first well authenti- 
 cated account of the use of "pressure" and "ex- 
 haust" fans to buildings. 
 
 It is only within the last forty years, however, 
 that a great and well defined stride has been made 
 in the development of systematic ventilation for 
 habitations. The little that had been done by 
 persons previous to that time was in special cases 
 and only in notable buildings, such as the Capitol 
 at Washington and some hospitals and asylums, 
 and it is probable that General Arthur Morin, Di- 
 rector of the Conservatory of Arts and Trades, 
 Paris, was the first to disseminate and give a clear 
 understanding, in his writings, of the true princi- 
 ples of modern systematic ventilation, and I suggest 
 for the consideration of all students a translation of 
 his work on " Warming and Ventilation in Occu- 
 
OF THE SCHOOL. 
 
 21 
 
 pied Buildings," a translation of which by Mr. Clar- 
 ence B. Young, appeared in the annual reports of 
 the Board of Regents of the Smithsonian Institute 
 for the year 1873 and 1874. 
 
 He recommended as the amount of air to be 
 changed every hour to preserve the healthful con- 
 dition of the room, as follows : — 
 
 Hospitals : 
 
 For ordinary cases of sickness 
 For surgical and lying-in cases 
 During epidemics . 
 
 Prisons 
 
 Workshops : 
 
 Ordinary occupations 
 Unhealthful occupations 
 
 Barracks : 
 
 During the day 
 
 At night .... 
 
 Theatres ..... 
 Assembly-rooms and halls, for long 
 
 receptions .... 
 
 Halls for brief receptions ; lecture 
 
 rooms. .... . 1,059 
 
 Primary Schools .... 42 — 4,530 
 
 Adult Schools ..... 833 — 1,059 
 
 Cubic Feet. 
 
 2,119—2,472 
 
 3,532 
 
 3,709 
 
 1,766 
 
 2,119 
 3,532 
 
 1,059 
 1,413—1,766 
 1,413—1,766 
 
 2,119 
 
2,2 THK VKNTIIvATION 
 
 I am unable to say why he placed a higher pro- 
 portion of air for primary schools than for adult 
 schools. It may be an error of the translator's. 
 
 It will be noticed that his quantities of air do 
 not fall so far below what is considered very fair 
 practice of the present day. 
 
 MIXING THE AIR— OR MIXING VALVES. 
 
 Morin was probably the first to point out the im- 
 portance of keeping the quantity of air admitted to 
 a building constant^ while making its temperature 
 variable ; the variations in temperature being to 
 suit the changes in the outside temperature. 
 
 The only general method in vogue previous to 
 about 20 years ago was to close the register when 
 the room was sufficiently warm ; which, of course, 
 not only cut off the heat supply, but the air supply 
 as well, interrupting the fresh air supply and 
 nullifying ventillation. 
 
 This, however, is changed now in many build- 
 ings that are systematically ventilated. 
 
 General Morin called attention to the necessity 
 of the " mixing valve " in the following words : 
 

OF THE SCHOOL. 23 
 
 "During the period of artificial heating, it is 
 proper to reserve means of mixing with the warm 
 air, supplied with the heating apparatus, cool air, 
 the amount of which may be regulated by conven- 
 ient registers. For this purpose the warm air sup- 
 plied by the heating apparatus should be received 
 in a special register or mixing-chamber, into which 
 the cold air should also enter before passing into 
 the distributing pipes." 
 
 The usual method of accomplishing the fore- 
 going, now followed in the United States, is shown 
 in the cut. (Figure 2 and Figure 2'). 
 
 The dampers "b" "b" are connected with a 
 rod and operated from the room by hand-pulls, or 
 automatically operated by pneumatic pressure con- 
 trolled by a thermostat. 
 
 Various modifications of this method of mixing 
 warm and cold air are in use; and those intro- 
 duced here are ^simply to show the principle in- 
 volved. 
 
 WARMING AND VENTILATION OF A 
 
 SCHOOL. 
 The usual school room for from 40 to 50 pupils, 
 as now commonly designed, has a floor space 
 
24 THE VENTILATION 
 
 of about 24 feet by 32 feet, with light on at least 
 two sides of the room ; the general endeavor being 
 to have the sitting so arranged that the light will 
 come in over the left shoulder of the pupil. A 
 sketch of such room is shown in Figure 3. 
 
 Provision should be made for the admission of at 
 least 100,000 cubic feet of fresh air to one such 
 room in an hour. It may be that it will not all be 
 required, even to comply with what is known as 
 the "Massachusetts' I^aw," (30 cubic feet per child 
 per hour.) 
 
 The admission of this air should be above the 
 head-line, and one inlet register is sufficient. 
 
 Experiments have demonstrated that the neces- 
 sary flue for such a room should have a cross sec- 
 tion of not less than 3 feet in its smallest part, and 
 that 4 feet is probably the limit required, the latter 
 being the size now adopted by the writer. 
 
 It is the custom in New York City schools to 
 leinforce the warm air system by a direct system, 
 the object being to maintain the heat of the room 
 by direct radiation when the fans are not running. 
 
y CLOAK-ROOM 
 
 ^ 
 
OF THE SCHOOL. 25 
 
 such as at night, etc. , using the fans only during 
 the hours of school. 
 
 It has been found that when a quantity of air 
 equal to 100,000 cubic feet is admitted to an ordin- 
 ary school room in an hour, that this amount of 
 air can be admitted and withdrawn without appre- 
 ciable draughts, at a temperature sufficiently low 
 to prevent the room from being overheated. Under 
 this condition of ample quantity and low tempera- 
 ture, it has been found, except in exceedingly cold 
 parts of the United States, that direct radiation can 
 be dispensed with and still give comfortable condi- 
 tions at all parts of the room. 
 
 It is not desirable, however, from a point of 
 economy of maintenance, to admit such large 
 quantities of air when the school is not in session ; 
 therefore, in the construction of a heating and ven- 
 tilating apparatus for a school, it is desirable either 
 to provide a reasonable quantity of direct radiation 
 or to design the flues and the indirect portion of 
 the heating apparatus in such a manner that suffi- 
 cient air will pass through the flues by natural 
 draught to maintain the heat when the school is 
 
26 THE VENTILATION 
 
 not in session, but with a greatly reduced quantity 
 of air and with a very much increased temperature 
 above what is necessary when the school is in 
 session. 
 
 A register of 50^ greater area than the cross sec- 
 tion of the air flue, when placed above the head- 
 line, the lower edge being 7 to 8 feet from the floor, 
 will not cause inconvenience as long as the tem- 
 perature of the entering air is above the air of the 
 room, although the velocity of the air may be 4 or 
 even 5 feet per second. 
 
 In the matter of withdrawing air from a school 
 room, the air should be taken from as near the floor- 
 line as possible, and preference should be given to 
 a register that will 'be low and wide rather than the 
 reverse. Building construction, of course, some- 
 times interferes with the proper shaped flue to 
 secure the best results. The architect, however, 
 should endeavor to make the flues wide, so that 
 the register can be low, and no objection should be 
 made to having the register partly in the base- 
 board, as appearance should give way to utility in 
 schools. 
 
OF THE SCHOOL. 27 
 
 The lower or "floor vent registers" can be in 
 the same wiall or group as the heat registers with 
 the outlet at the floor, and it is probably the best 
 position for them. 
 
 The question of ceiling ventilation and ceiling 
 or upper side wall registers in a school room is a 
 very unsettled one. In winter time, it is probably 
 unnecessary to have them, although this does not 
 always satisfy, and for this reason it is customary 
 to place another ventilating register in the same 
 vent flue as the floor register but near the ceiling. 
 This brings the ceiling outlet too close to the inlet 
 or heat register, resulting in robbing the room of 
 its heat, and the "short-circuiting" of the fresh 
 air current when the upper register is open. For 
 this reason perhaps it would be well to have a 
 double set of vent registers and vent flues to each 
 room when possible ; the lower vent registers being 
 placed near the floor in the flue group with the 
 heat flues, and the upper vent registers near the 
 ceiling in another group remote from the heat. 
 This will admit of both floor and ceiling ventila- 
 tion at the same time. It will also prevent the 
 
28 THK VKNTII^ATION 
 
 intensity or draught of the Floor '' vent " from be- 
 ing interfered with when the upper vent is opened, 
 and it will prevent short-circuiting to a very great 
 extent. 
 
 All schools designed for forced ventilation should 
 also be arranged so that in case the forcing or fan 
 mechanism gets out of order, that air and heat suf- 
 ficient will still enter the rooms by natural meth- 
 ods to keep them comfortably warm, so that it will 
 not be necessary to dismiss the school through 
 temporary injury to the fan or motor. 
 
 Figure 3 shows the ground plan of a typical 
 school room, arranged for seating from 40 to 50 
 pupils ; and the object of introducing these dia- 
 grams here, is to discuss the question of a standard 
 relation between the school room and its warming 
 and ventilation. 
 
 The tendency lately is to provide what may be 
 called a " breathing wall." This wall may be on 
 the long or the short side of the room, though pre- 
 sumably it is best to have it on the short side and 
 the wall between the school room and the cloak 
 roomlis best taken for this purpose. If it can be 
 
OF THE SCHOOL. 29 
 
 arranged by the architect that it is not a construc- 
 tion wall, all the better. 
 
 When this wall is used, easy access is obtained 
 for the warm air through the flues to both the 
 school room and its corresponding cloak room, as 
 shown by the arrows ; the flues simply opening on 
 opposite sides of the same wall. 
 
 When the wall "a" is used as a " breathing " 
 or flue wall, as occasionally happens, it complicates 
 the entire matter by having to carry both heat and 
 vent flues across the cloak room, and for this reason 
 alone it should not be used as a/' breathing wall." 
 
 An advantage also of using the wall between the 
 cloak room and the school room as the breathing 
 wall is that the space underneath the lower cloak 
 room can be taken as a heating chamber, or if 
 there is any reason why this room cannot be used 
 as a heating chamber, the heating chamber can be 
 constructed on the opposite side of the wall by tak- 
 ing a portion of the basement room usually used as 
 a play room or for toilet rooms. 
 
 Reference to Figure 4 will show the arrangement 
 of the radiators or heaters required for a two-story 
 
30 THE VENTILATION 
 
 school building. There is sufficient room, how- 
 ever, in the ordinary breathing wall to carry ample 
 flues for three stories, but that is about the limit 
 
 for the size flues required for ordinary school 
 rooms. 
 
 For a two-story school, it is necessary to find 
 room for four large flues, aggregating not less than 
 3 square feet each, and for four small flues (two 
 heats and two vents) the large flues for the school 
 rooms and the small flues for the cloak rooms. 
 
 Another story will about take up the remaining 
 blank space in the flue walls, requiring, of course, 
 a rearrangement of t^^e flues as shown here. 
 
 Flue Hj (Figure 3) shows the heat flue for the 
 first story, and alongside of it is flue H2 which 
 sends warm air to the second story. Their relation 
 to the radiators is shown m Figure 4. 
 
 The small flues H2 and Hj show the flues in 
 their relation to the cloak rooms. 
 
 The flues V, in like manner (Figure 3) show the 
 main ventilating flues, Vj being the first story flue, 
 and V2 the second flue. 
 
 I will say that the second story vent does not 
 run down, as shown in Figure 3,lbut the space in 
 
1 
 
OF THE SCHOOL. 31 
 
 the wall is required for it, and sometimes the un- 
 der part of it is used as a heating flue so as to save 
 wall space. 
 
 Figure 5 is a simple section through the base- 
 ment and first floor of the same school building, 
 showing the relation of the heating chamber to the 
 hot air flue, with the radiator, cold air duct, and 
 the position of the hot air or inlet register (the 
 lower edge of which is now always placed above 
 the head-line.) To determine the height of the 
 register, one wants to be guided by two conditions : 
 (i) that the register must be sufficiently far above 
 the head-line so the air will not inconvenience 
 one, and (2) to be sufficiently far from the ceiling 
 to prevent a dark streak which soon appears there- 
 on (caused by the invisible dust carried in with 
 the fresh air), when the register is very close to the 
 ceiling. 
 
 Figure 5 is a vertical section through the hot air 
 duct, the fresh air inlet " F. A.," showing how 
 the air passes to the radiator to be warmed, and 
 through the upper part of the switch valve, thence 
 through the flue to the register. 
 
32 THE VKNTII.AT10N 
 
 When the room is sufficiently warm, the switch 
 valves "d " and " d' " change their position so that 
 ^' d " is closed and " d' " is open, when the passage 
 of air will be through the lower valve, thus permit- 
 ting cold air to pass into the room. 
 
 By fixing these valves "d" and " d' " at any in- 
 termediate position, mixed air will pass up the flue, 
 usually at a little above 70 degrees, keeping the 
 room at the constant and desired temperature. 
 When these contrivances (switch valves) are auto- 
 matically operated by a proper system of thermos- 
 tatic control, the variations of a class room can be 
 kept within 2 degrees Fahrenheit. 
 
 Figures 2 and 2' show modifications of the switch 
 valve ; Figure 2 showing a good arrangement of 
 valve as automatically controlled, while Figure 2^ 
 shows the hand-controlled swatch valve. It is 
 nothing but a piece of sheet iron fastened in the 
 flue at the point shown and arranged to be drawn 
 against the upper opening by a hand-pull within 
 the school room. The valve divides the flue so 
 that cold air from below can pass up and mingle 
 with the warm air from above the radiator, and 
 
OF THE SCHOOL. 33 
 
 thus pass into the room. The objection to the 
 hand-controlled mechanism, however, is that the 
 teacher and those concerned will never think of 
 adjusting it until the room becomes, I will say, a 
 little too warm, and that again they will not think 
 of changing it until the room becomes a little too 
 cold, so that it is alternately a little too hot and a 
 little too cold, to the annoyance and discomfort of 
 all concerned. The theory is right, but the prac- 
 tice is wrong, and the only relief from the annoy- 
 ance of it, is automatic control, which practically 
 anticipates the requirements of the room. 
 
 Figure 2 shows the clean-out at the bottom of 
 the flue, which is very necessary. 
 
 Figure 6 is a vertical section through the same 
 wall as Figure 5. This section, however, is through 
 the vent flue Vi (Figure 3) while Figure 5 is a ver" 
 tical section through the heat flue Hi (Figure 3.) 
 
 Figure 6, therefore, is a vertical section through 
 the main vent flue of the school room, and the 
 heat and vent flues are shown in separate illustra- 
 tions rather than in the conventional manner so as 
 to overcome confusion of ideas, if possible ; Fig. 
 5, being the section through the heat flue. 
 
34 'THE VENTILATION 
 
 I might say that the pink, of course, in the il- 
 lustration, indicates heat, and that the green indi- 
 cates foul or vitiated air, while the blue indicates 
 fresh air, or air that is relatively cold, such as at 
 the windows. Red also represents the primary 
 source of heat, or the radiators. 
 
 The ordinary course, therefore, of the fresh air, 
 is from the inlet through the radiator and through 
 the flue to the room, thence making a circuit to 
 the windows and becoming lightly cooled, (indi- 
 cated by blue,) thence passing to the floor and be- 
 coming vitiated and passing out at the flues marked 
 in green, Figure 6. 
 
 The warm air as it leaves the register will rise 
 to the ceiling and expand and flow out under the 
 same ; the windows of the building supplying the 
 power to keep up the circulation within the room, 
 and they perform a very important function in the 
 mixing of the air. The glass of each window be- 
 ing cooler than the temperature of the internal air, 
 made so by the temperature of the external air, 
 causes the downward movement of the air to the 
 floor, across which it flows to the point of outlet. 
 Every child within the room also becomes a factor 
 for air moving. His or her body is warmer than 
 the air so that there is an upward current of air at 
 each child, and this upward current carries the 
 
 
OF THE SCHOOL. 35 
 
 exhalations with it to the ceiling, there to mix with 
 the warm fresh air, flow across the ceiling to the 
 various w^'ndows, down at each window, and across 
 the floor towards the outlet. It may be said that 
 the child is breathing the floor air, which is passed 
 to the ceiling over its body, and this to a great ex- 
 tent is true ; but the question must here be asked, 
 "is this floor air foul?'' and it may be answered 
 in the negative, so long as it is known that a 
 reasonable per capita of fresh air has been admitted. 
 
 It is utterly impracticable to bring fresh air 
 directly to the lungs of each child or person in a 
 crowded or partially crowded room, and all that is 
 practicable is to admit sufficient fresh air per person 
 to secure a dilution or standard of purity which is 
 reasonably good, and which in fact, can be made 
 very good if sufficient fresh air is admitted. 
 
 The conditions in any school room are analogous 
 to admitting a tiny stream of ink to a reservoir of 
 water, while at the same time you admit a very 
 large ^quantity of pure water to the same tank, 
 allowing an equal quantity to overflow. If there 
 are any fish in this tank, it is possible, by admit- 
 
36 THE VENTILATION 
 
 ting sufl&cient pure water, to keep them in good 
 health, and they will not be poisoned by the small 
 stream of ink, provided the water in the tank is 
 kept well agitated ; and in the case of the school, 
 the cold of the windows and the heat of the bodies 
 of the children are the agitators. These two forces 
 produce an agitation which keeps the mixture at a 
 nearly constant and equal condition of freshness 
 (or foulness), at every part of the room. 
 
 There seems to be an idea that it is preferable to 
 have the heat flue as near the outside wall and 
 windows as possible, and that the vent flue should 
 be as near the inside or warm corner of the room 
 as possible. I am not convinced that much is 
 gained in choice of positions. When the heat flue 
 is near the outside wall, the air is projected along 
 the wall and made to turn at the short side of the 
 room, and in that way to help the circulation. It 
 may be claimed there is an inert patch at the ceil- 
 ing in the warm corner of the room if this is carried 
 out. If such is the fact, then it would be better 
 to have the inlet or hot air flue in the warm corner 
 
OF THE SCHOOL. 37 
 
 of the room, as it would be the means of stirring 
 up this inert patch. 
 
 These ideas are put forth because we are apt to 
 find persons arguing from both sides of this ques- 
 tion, and my own opinion is that there is very little 
 gained or lost, no matter what relative positions 
 the inlets and the outlets have, provided the outlet 
 or vent is pretty near what may be called the warm 
 comer of the room. 
 
 When 100,000 cubic feet of air are admitted 
 through the hot air flue Hj in an hour, and drawn 
 out through the vent flue Vi in the same time, it 
 is very reasonable to assume that the conditions 
 within that school room are good, and when this 
 quantity of air is passed through a school room, 
 not only will the air be kept at a fair standard of 
 purity, but an equality in temperature will be 
 maintained so nearly alike between the ceiling and 
 the floor that they will not vary 4 degrees, and this 
 in the outer corner of the room at "X," in what 
 may be called the focus of two windows. 
 
 When large quantities of air at low temperatures 
 
38 THE VENTII^ATION 
 
 are admitted to a room, a wonderful uniformity of 
 temperature is the result. 
 
 When small quantities of air are admitted, at 
 high temperatures, great uneven ness of tempera- 
 ture prevails. 
 
 When large quantities of air are admitted to a 
 room, such as will be required in a school room, if 
 one puts his hand over the inlet register, the 
 temperature of the air will feel cool to the touch. 
 This is because the air is coming in considerably 
 below the blood temperature, but still sufficiently 
 high to maintain the temperature of the room. If 
 it came in at a higher temperature, it would simply 
 overheat the room, and either the temperature or 
 the quantity of air admitted would have to be 
 lessened. 
 
 Supplementary direct radiation is sometimes 
 used in school rooms, usually in the form of a coil 
 of 2 or 3 pipes placed on the outside walls under 
 the windows. 
 
 There are two reasons for these coils. They 
 may be necessary in very cold or exposed places so 
 as to prevent too great a down draft at the win- 
 
OF THE SCHOOL. 39 
 
 dows, but this interferes with air mixing and diffu- 
 sion, as it reverses the window current. The other 
 reason is on account of the extreme expense of 
 maintaining the heat of a school building at all 
 times by indirect radiation. In other words, an 
 attempt is made to use the indirect radiation and 
 ventilation during the school session, and to keep 
 the building warm or partially warm at night by 
 the direct coils. This, however, is hardly ever 
 carried out, and the alternate use of coils at night 
 or in the early morning and afternoon, and ventila- 
 tion during the school hours becomes a dead letter, 
 as it will not be properly attended to, so that there 
 is nothing but a confusion of the heating system 
 and general annoyance. 
 
 For this reason it is better, when possible, to 
 omit the direct radiation from a school room. If 
 it is used, it should never be used except in con- 
 nection with an automatic shut off system. 
 
 It is necessary, however, to practice economy in 
 the warming of schools, for should the ventilating 
 system be run during the 24 hours, or even during 
 16 hours of each day, the cost of warming the 
 
40 THE VENTILATION 
 
 school is either doubled or trebled, as the case may 
 be. This is a great cause for complaint with 
 schools : — the fuel bill is simply enormous, as the 
 full million or two million or three million cubic 
 feet of air (according to the size of the school) that 
 is admitted each hour, has to be warmed from the 
 outside to the inside temperature, and then allowed 
 to escape at the latter temperature, tending to 
 warm all out-of-doors. 
 
 This can be avoided, however, to a very great 
 extent, by providing an internal or night circula- 
 tion. This is rarely carried out in its entirety, 
 though a modification of it is sometimes used, 
 whereby the cold air inlets and the ventilating 
 outlets are all closed ; the class room doors opened, 
 so that the air from the class rooms is allowed to 
 pass down through the halls and stairways to the 
 basement, and enter the chambers through a door- 
 way from the hall, as at "b.'* Fig. 4. 
 
 This, however, has its disadvantages as some 
 rooms will warm and some rooms will not, due to 
 local conditions. 
 
 To insure inside or night circulation, therefore, 
 
OF THE SCHOOL. 4I 
 
 in its best form, there should be a night circulating 
 flue arranged from each room. This is shown by 
 dotted lines in Fig. 5 and by blue on Fig. 7 which 
 latter is a section through this flue. It is best ar- 
 ranged so as to start on a cold side of the room, 
 as shown in Figure 3 at "c." It drops to the 
 basement, as shown in Figure 7, and passes un- 
 der the basement floor, returning to the heating 
 chamber as shown by the flue lines and ar- 
 rows. At this time, the fresh air inlet (F. A.) is 
 closed and the regular vent flues 'shown in Fig. 6 
 are closed so as to prevent the escape of heat or 
 air in that direction. It will be noticed by Figure 
 7 that one operation from each school room can be 
 made to accomplish this result, by the use of a pull. 
 In the vent flue there are three dampers, arranged 
 on a single pull. The dampers are shown in what 
 might be called the "night position." In other 
 words, the regular ventilating flues are shut off" and 
 the night or internal circulation flue is opened. 
 The janitor, or some one appointed for that pur- 
 pose, should enter the room at a few minutes before 
 9 o'clock in the morning, unhook the pull from 
 the wall and drop the dampers until they assume 
 
42 THE VENTILATION 
 
 the position shown in Figure 6, when full ventila- 
 tion is obtained for the day session. 
 
 I consider the drawings here shown to be a fairly 
 full expositionof the most recent principles involv- 
 ed in school room ventilation. They are the result 
 of experience^ and all those who have made a study 
 of the question are gradually being forced to the 
 same conclusions. 
 
Card by the Author. 
 
 THE author offers his services as an Expert and Designer 
 of heating, cooling and ventilating plants, power houses 
 and general engineering. 
 
 He has had thirty years experience, both practical and the- 
 oretical, with a thorough knowledge of all the minutia of detail 
 of construction. His experience enables him to assure econ- 
 omy, both in design and maintenance. 
 
 Below are a few of the buildings for which he has furnished 
 plans, specifications, etc. 
 
 OFFICE BUILDINGS. 
 
 Manhattan Co.'s & Merchants' Bank Building, New York. 
 
 ' ' Number Seven Wall Street, ' ' New York. 
 
 ' ' Robert Hoe ' ' Building, Broadway, New Y'ork. 
 
 Malley Building, New Haven, Conn. 
 
 Temple Bar Building, Brooklyn, N. Y. 
 
 Mechanics Bank, Brooklyn, New York. 
 
 Hanover Fire Insurance Co.'s Building, New Y'ork. 
 
 Lawyers' Title Insurance Co.'s Building, New Y'ork. 
 
 Washington Building, New Haven, Conn. 
 
 Winchester Building, New Haven, Conn. 
 
 Exchange Building, New Haven, Conn. 
 
 Clayton Block, Denver, Colorado. 
 
 The Metropolitan Telephone & Telegraph Co.'s Building, New Y'ork 
 
 Chusman Building, Denver, Colorado. 
 
 Southern New England Telephone Co.'s Building, Bridgeport, Conn. 
 
 Joseph Butteuweiser Building, New York. 
 
 Tribune Building, New York. 
 
 GOVERNMENT BUILDINGS. 
 
 Ellis Island U. S. Immigrant Station, N. Y. Harbor. 
 
 U. S. Immigrant Hospital, N. Y. Harbor. 
 
 U. S. Immigrant Baths, N. Y'. Harbor. 
 
 U. S. Immigrant Dormitories, N. Y'. Harbor. 
 
 U. S. Army Mess Hall, David's Island, N. Y. Harbor. 
 
 TJ. S. Army Barracks, David's Island, N. Y'. Harljor. 
 
 Marine Barracks, Navy Yard, Brooklyn, N. Y. 
 
 INSTITUTIONS. 
 
 New York State Reformatory, Elmira, N. Y. 
 Military Academy, Peekskill, N. Y. 
 Insane Asvlum, Wilmington, Del. 
 
 (43) 
 
44 A CARD TO THE PUBLIC. 
 
 County House, Hares Corners, Del. 
 
 Madame De Hirsch Home for Working Girls, New York. 
 
 Hebrew Orphan Asylum, Brooklyn, N. Y. 
 
 Home for Aged & Inform Hebrews, New York. 
 
 Leake & Watts Orphan Asylum, New York. 
 
 Hebrew Orphan Asylum, Newark, N. J. 
 
 SCHOOLS. 
 
 Vanderbilt Memorial, Yale University, New Haven, Conn. 
 
 George Street Public School, New Haven, Conn. 
 
 Norton Street Public School. New Haven, Conn. 
 
 Public School No. 3, Paterson, N. J. 
 
 St. Agnes' School, Brooklyn, N. Y 
 
 Holy Family School, New Bedford. Mass. 
 
 Phelps Memorial (Yale University) New Haven, Conn, 
 
 Peekskill Military Academy, Peekskill, N. Y. 
 
 State School, Cold water, Mich. 
 
 Trinity School, New York. 
 
 Locust Valley Public School, L. I. 
 
 Hicks ville Public School, L. I. 
 
 Roslyn Public School, L. I. 
 
 Glen Road Schoo', Boston, Mass. 
 
 Blairsville Ladies' Seminary, Blairsville. Pa. 
 
 St. Mary's Parish School, Charlestown, Mass. 
 
 RESIDENCES. 
 Hon. William A. Clark's Mansion (Fifth Avenue) New York. 
 Mr. Charles W. Clark's Residence, Butte, Mont. 
 Mr. Howard B. Tattle, Naugatuck, Conn. 
 Mrs. B. T. Williams, Hartford, Conn. 
 Mr. H. H. Cook (Fifth Avenue) New York. 
 Gen. F. R. Halsey (53rd Street) New York. 
 Mrs. Edward Perkins, Hartford. Conn. 
 St. Luke's Rectory, Brooklyn, N. Y. 
 Mr. H. B. Hollins, Islip, N. Y. 
 Mr. W. Bayard Cutting, Oakdale, N. Y. 
 Dr. John N. Tilden, Peekskill, N. Y. 
 St. John's Rectory, Elizabeth, N. J. 
 Dr. Fredk. Hyde, New York. 
 
 Y. M. C. A. BUILDINGS. 
 
 Y. M. C. A. Building, New Haven, Conn. 
 Y. M. C. A. Building, Des Moines, Iowa. 
 Y. M. C. A. Building, Cleveland, Ohio. 
 
 PRINTING HOUSES. 
 
 New York Realty Co.'s Building, Rose Street, N. Y. 
 H. C. Hallenbeck, Pearl & Park Streets, New York. 
 
 HOSPITALS AND MEDICAL BUILDINGS. 
 
 The (new'* College of Physicians and Surgeons of the City of New York^ 
 Vanderbilt College, now Medical Department of Columbia University, 
 
 L.ofC. 
 
A CARD TO THE PUBLIC. 45 
 
 The Sloane Maternity Hospital, (old and new) New York. 
 
 The Vanderbilt Clinic. New York. 
 
 New Laboratory, College Physicians and Surgeons, N. Y. 
 
 Wm. J. Syms Operating Theatre, (Roosevelt Hospital) N. Y. 
 
 Columbia College Medical I»epartinent (westerly extension) Bacteriology. 
 
 Clinical Building, Yale Medical Department, New Haven, Conn. 
 
 Immigrant Hospital, Ellis Island, New York Harbor. 
 
 Orthopedic Hospital, New York. 
 
 Columbia College Medical Department, (easterly extension) Museum Bldg 
 
 Insane Asylum, Kalamazoo, (Sup ) Michigan. 
 
 Maternity Hospital, New Haven, Conn. 
 
 Newark City Hospital, Newark, N. J. 
 
 DRY GOODS STORES. 
 
 Messrs. Abraham & Straus, Great Department Store, Brooklyn, N. Y. (1898). 
 
 The W. & J. Sloane Carpet Store, New York. 
 
 Le Boutiller's Dry Goods Store, 23rd Street, New York. 
 
 Astor Estate Building, 552, 554, 556 Broadway, N Y. City. 
 
 Swan Building, 339 Broadway, New York. 
 
 Easterly Extension Abraham & Straus' Department Stores. Bklyn. (19(X)). 
 
 " Edward Malley Co.'s Department Store,' ' New Haven, Conn. 
 
 Mendel & Freedman Department Store, New Haven, Conn. 
 
 W. & J. Sloane (new) Building, 19th Street, (1898) New York. 
 
 Abraham & Straus' Power House, (2000 H. P.) Brooklyn, N. Y. 
 
 THEATRES. 
 
 American Theatre, New York. 
 
 Public Theatre, Ogdensburg, New York. 
 
 Music Hall, New Haven, Conn. 
 
 CHURCHES. 
 
 Cong. Shearith Israel Synagogue, New York. 
 
 All Angels P. E. Church, New York. 
 
 St. Francis Xavier (R. C.) Church, Brooklyn, N. Y. 
 
 Baptist Church, New York. 
 
 Mormon Temple, Salt Lake City, Utah. 
 
 St. Luke's P. E. Church, Brooklyn, N. Y. 
 
 Temple Mishkan Israel Synagogue, New Haven. 
 
 St. Agnes' Church & School Buildings, Brooklyn, N. Y. 
 
 FACTORIES. 
 
 Lemair Schwartz Factory Building, N. Y. 
 
 Bamford Mill, Wilkesbarre, Pa. 
 
 Barber Underwear Factory, Peekskill, N. Y. 
 
 Reed & Carnrick's Chemical Factory, Jersey City, N. J. 
 
 American Stone Co.'s Plant, Portland, Me. 
 
 Haines Piano Factory, N. Y. 
 
46 A CARD TO THK PUBI^IC. 
 
 BANKS. 
 
 The Importers' & Traders' Bank, New York. 
 Manhattan Co.'s Bank, New York. 
 Merchants' Bank, New York. 
 Astor Bank, New York. 
 Mechanics Bank, Brooklyn, N. Y. 
 
 COURT HOUSES. 
 
 Livingston County Court House, Geneseo, N. Y. 
 St. Lawrence County Court House, Canton, N, Y. 
 
 PRISONS. 
 
 New York State Reformatory, Elmira, N. Y. 
 State Prison, Ionia, Michigan. 
 State Prison, Jackson, Michigan. 
 County Jail, St. J^awrence Co., N. Y. 
 
 LIBRARIES. 
 
 Carnegie Library, Atlanta, Ga. 
 Torrington Library, Torrington, Conn. 
 
 Hundreds of other large buildings and residences throughout the United 
 
 States. 
 Consulting Engineer Electric Subway Companies, N. Y. 
 Mechanical Engineer Empire City Subway Company, N. Y. 
 
 iTERMS FURNISHED ON APPLICATION. 
 
\HE Author is the pioneer writer in 
 America on the suhjeot of Steam 
 Heating. 
 
 His work "BALDWIN on HEATING," 
 has reached the 16th edition. Price $2.50. 
 
 His work "HOT WATER HEATINQ 
 AND PITTING " is in the 3rd edition. 
 Price, $2.50. 
 
 His " BLUE BOOK " is Data for Heating 
 and Ventilation. Price, 50 cts. 
 
 His "RED BOOK" is An Outline of 
 Ventilation and Warming. Price, $L00. 
 
 They are standard American works of 
 reference on these subjects. 
 
J^ 
 
 •\ 1909 
 
SEP 2B jpj- 
 
 !£sr%t 
 
LIBRARY OF 
 
 CONGRESS 
 
 0020975^52*