The age-herald., 1901-11-24

of the air supplied, which is much the l same thing.
 It Is further pointed out that currents
 of unequally heated air are not only un- l hygienic. but that they seriously inter- fere with the transmission of sound from the stage or platform, the finer qualities | of the singers or speakers voice being | often quite lost as result Even more | important is the question of air impurity. Not only does each member of the audi
 ence influence the temperature. but he l takes to himself a proportion of the vital I properties of the air. and returns to 1t his own semi-poisonous exhalations, be-
 sides throwing off Q certain amount of
 what Professor Woodbride aptly calls | personal debris" With the imperfect
 method of downward ventilation" as it | is called, just described. it will be seen
 that large part of these noxious ele-
 ments-which in the main cause the
 greater part of the immediate discomfort
 to an audience in an i'll ventilated room | cannot be eliminated from the atmos-
 phere immediately surrounding the l breather.
 By substituting upward ventilation, so
 called, for downward. however, it is ev- | ident that the amount of fresh air needed
 to maintain a definite standard of purity
 would, in the first place. be much less
 Professor Woodbridge, for example, gives !
 candles of course, represent the human
 audience: An otherwise tight small
 chamber has been fitted with a perfo-
 rated floor and ceiling; candles have
 been closely placed upon the floor and 1 lighted and the chamber has been fur
 nished with just enough air through the | floor to bring and keep the candle flames at full brilliancy. When the same air
 quantity was supplied through the per-
 forated ceiling, the flames dwindled al-
 most to the point of extinguishment, the | candles were smothered and softened, | dropped, and bent double in their own
 vitiated air and heat brought back upon them by the downward movement of
 the ventilating air. Gas jets equal in
 number to the candles were then used, and supplied with air by Athe upward
 method until the flames reached their
 maximum brflliancy, and when again the | direction of the ventllating current was | changed. the quantity of air remaining
 constant. the flames became small, pale,
 and sickly."
 | The necessary air supply being so much
 smaller with upward ventilation, the
 problem of the ventilating engineer. Pro- | lessor Woodbridge points out, is to sup | ply the required amount without drafts; 1 but the ingenuity necessary in accom- plishing this result is so considerable that
 1t is only recently that the problem has | been even approximately solved. Without going into the exact details of the spe- cial method recommended by Professor Woodbridge, it is perhaps sufficient to say that the plan which furnishes the
 most complete results requires an air chamber beneath the auditorium, in which | the pressure shall be such as to produce | a regular flow of fixed velocity through | openings discharging into specially de- signed box-shaped legs on the theater chairs-in the case of theater-or into la hnv Of
 the pews of a church. Thus the air does
 not strike directly upon the legs or ankles | of the persons in the audience, but 1t is generally diffused horizontally beneath | the seat, so as to make an equable and practically draftless body of pure air, cooler than that above the audience.
 which rises to take the place of the warm
 air and breathed air, which, in turn. rises away from the occupants of the chairs | or pews and passes out at the ceiling. | In theaters the suggested outlet is in the
 rear, above the gallery.
 l The results obtained by this method of upward ventilation have in many cases beensextraordinary. Thus in the hall of
 the Massachusetts Institute of Technol- ogy the "increment''-or increase during l the occupation of the hall-of carbon di-
 oxide, the presence of which Is an indi- l cation of certain poisonous clements in l the air attending its use by many breath l CTS. sank from 14S6 under previous con | ditions to 192. The experiments were ex- | tended with similar results to the legis- l lative halls of the Maine state house, the new chambers of Massachusetts and
 Rhode Island Legislatures. and the Sen
 ate Chamber, the House of Representa-
 tives and the Supreme Court in Washing | ton.
 l More typical, however, are the results l obtained in several of the large Boston
 theaters. In one of these, for example, near the close of performance when the seats were we'll filled and many persons were standing. the carbon di-oxide incre- ment has been found to be less than 1.6
 in 10000 parts of air. Admittedly. the in-
 crement is greater in the balconies than in the orchestra floor, due. of course. to l the fact that they intercept air rising from the floor and do not except in rare