May 6. 1854.] 



NOTES AND QUERIES. 



415 



LONDON, SATURDAY, MAYS, 1854. 



AN ENCYCLOPEDIA. OF VENTILATION. 



" The House \_of Commons'] met to-day [21th April] 

 after the Easter holidays — and honourable members, on 

 entering, seemed highly to appreciate the unusual luxury 

 of a little fresh air." — The Times, 28th April. 



The failure of some late attempts to ventilate 

 public buildings invites me to set forth an Ency- 

 clopaedia of ventilation — at a cheap rate, and in a 

 compendious form. 



Aware of the abilities and celebrity of many of 

 the writers on this subject — from Whitehurst 

 and Franklin to Reid and Gurney — I must ward 

 off the imputation of self-conceit by expressing 

 my belief that the errors of those who have failed 

 should be chiefly ascribed to excessive cleverness ; 

 to unadvised attempts at outwitting nature! I 

 hope to escape that snare. In the execution of 

 my humble task, I shall entirely rely on common 

 sense and common experience. 



Air is essential to human life, and as respiration 

 destroys its vital qualities, the ventilation of rooms 

 which are intended for habitation should be a 

 primary object in all architectural plans. 



Architects, however, seldom provide for the 

 ventilation of rooms otherwise than as they pro- 

 vide for the admission of light. Now the pro- 

 perties of light and air, with reference to our 

 domestic requirements, differ in some important 

 particulars — of which it may not^be amiss to give 

 a brief enumeration. 



Light moves with uniform velocity : air is 

 sometimes quiescent, and sometimes moves at the 

 rate of thirty miles an hour. Light diffuses itself 

 with much uniformity : air passes in a current 

 from the point of its entrance to that of its exit. 

 Light, whatever be its velocity, has no sensible 

 effect on the human frame : air, in the shape of a 

 partial current, is both offensive to the feelings 

 and productive of serious diseases. Light, once 

 admitted, supplies our wants till nightfall : air 

 requires to be replaced at very short intervals. 

 Light may be conveniently admitted from above : 

 air requires to be admitted on the level of the 

 sitter. Light, by the aid of ground glass, may be 

 modified permanently : air requires to be va- 

 riously adjusted according to its direction, its 

 velocity, the seasons, the time of the day, the 

 number of persons assembled, &c. 



An attentive consideration of the above cir- 

 cumstances leads me to certain conclusions which 

 I shall now state aphoristically, and proceed to 

 describe in more detail. 



A room designed for a numerous assemblage of 

 persons — as a reading-room, a lecture- room, or 

 a school-i*oom — should be provided with aper- 



tures, adapted to admit spontaneous supplies of 

 fresh air, in such variable quantities as may be 

 required, on at least two of its opposite sides, and 

 within three feet from the floor ; also, with aper- 

 tures in the ceiling, or on a level therewith, to 

 promote the exit of the vitiated air. The aper- 

 tures of both descriptions may be quite distinct 

 from those which admit light. 



Suppose a room to be twenty-four feet square, 

 and sixteen feet in height, with two apertures for 

 light on each side, each aperture being three feet 

 wide by eight feet in height, and rising from the 

 floor. There are not many rooms constructed on 

 a plan so favourable to the admission of fresh air 

 — but it has some serious defects. 1. The air 

 would enter in broad and partial currents. 2. It 

 would not reach the angular portions of the room. 

 3. The vitiated air might rise above the apertures,, 

 and so accumulate without the means of escape. 



Now, suppose the same room to have its aper- 

 tures at eight feet from the floor, and so to reach 

 the ceiling. The escape of the vitiated air might 

 then take place — if not prevented by a counter- 

 current. But whence comes the fresh air for the 

 occupants ? There is no direct provision for its 

 admission. The elevated apertures are utterly in- 

 sufficient for that purpose ; and the perpetual re- 

 quisite is no otherwise afforded than by the occasional 

 opening of a door J 



It being thus established that the same aper- 

 tures can never effectually serve for light and 

 ventilation, I propose with regard to reading- 

 rooms, lecture-rooms, and school-rooms, which 

 require accommodation for books, maps, charts^ 

 and drawings, rather than a view of external ob- 

 jects, that the windows should be placed in the 

 upper part of the room — that the admission of 

 fresh air should be provided for by ducts near the 

 floor — and the escape of the vitiated air by open- 

 ings in, or on a level with, the ceiling. 



The number of windows, and their size, must 

 depend on the size of the room. If windows are 

 to admit light only, a smaller number may be suf- 

 ficient, and they may not be required on more 

 than one side ; a circumstance which recommends 

 the plan proposed, as we can seldom have win- 

 dows on each side of a room, or even on two of 

 its opposite sides, but may devise a method of so 

 admitting air. 



Rejecting the use of windows as a means of 

 ventilation, and rejecting artificial currents of 

 every description, I propose the substitution of air- 

 ducts of incorrodible iron, to be inserted horizon- 

 tally in the walls of at least two opposite sides of 

 the room, within three feet from the floor, and at 

 intervals of about four feet. The ducts to be six 

 or eight inches in diameter, according to the size 

 of the room. The external orifice of each duct to 

 be formed of perforated zinc, and the internal 

 orifice, which may be trumpet-shaped, of perfc— 



