April 21, 1882.] 



KNOWLEDGE • 



531 



to hall and staircase, and through the rooms into the final 

 shaft or chimney. The openings into and out of the rooms 

 being adjustable, they may be so regulated that each shall 

 receive an equal share of fresh warm air ; or, if desired, the 

 bed-room chimney valves may be closed in tlie daytime, and 

 thus the heat economised by being used only for the day 

 rooms : or vice versd, the communication between the 

 upcast shaft and the lower rooms may be closed in the 

 evening, and thus all the wai-m air be turned into the bed- 

 rooms at bed-time. If the area of the entrance apertures 

 of the rooms exceeds that of the outlet, only the latter 

 need be adjusted ; the room doors may, in fact, be left 

 wide open without any possibility of " draught," beyond 

 the ventilation current. 



So far for winter time, when the ventilation problem is 

 the easiest, because the excess of inner warmth converts 

 the whole house into an upcast shaft, and the whole outer 

 atmosphere becomes a downcast. In the summer time, the 

 kitchen fire would probably be insufficient to secure a 

 sufficiently active upcast. To help this there should be in 

 one of the upper rooms — say an attic — an opening into the 

 chimney secured by a small well-fitting door, and altogether 

 enclosed within the chimney, a small automatic slow com- 

 bustion stove (of which many were exhibited at South Ken- 

 sington, that require feeding but once in twenty-four hours), 

 or a large gas-burner. The heating-chamber below must now 

 be converted into a cooling-chamber by an arrsmgement of wet 

 cloths presently to be described, so that all the air entering 

 the house shall be reduced in temperature. Or the winter 

 course of ventilation may be reversed by building a special 

 shaft connected with the kitchen fire, which, in this case, 

 must not communicate with the house shaft. This special 

 shaft may thus be made an upcast, and the rooms supplied 

 ■with air from above down the house shaft, through the 

 rooms, and out of the kitchen vid the winter heating- 

 chamber, which now has its communication with the out- 

 side air closed. 



Reverting to the first^named method, which I th ink is 

 better than the second, besides being less expensive, I 

 must say a few concluding words on a very great supple- 

 mentary advantage which is obtainable wherever all the air 

 entering the house passes through one opening, completely 

 under control, like that of our heating-chamber. The great 

 evil of our town atmosphere is its dirtiness. In the winter 

 it is polluted with soot particles ; in the dry summer 

 weather, the traffic and the wind stir up and mix with it 

 paiticles of dust, having a composition that is better 

 ignored, when we consider the quantity of horse-dung that 

 is dried and pulverised on our road-ways. All the dust 

 that falls on our books and furniture was first suspended 

 in the air we breathe inside our rooms. Can we get rid of 

 any practically important portion of this 1 



I am able to answer this question, not merely on 

 theoretical grounds, but as a result of practical experi- 

 ments. On March 19, 1879, I read a paper at The 

 Society of Arts, recommending the enclosure of London 

 back-yards with a rooting of " wall canvas," or " paper- 

 hanger's canvas," so as to form cheap conservatories. 

 This canvas, which costs about threepence per square yard, 

 is a kind of coarse, strong, fluffy gauze, admitting light and 

 air, but acting very effectively as an air filter, by catching 

 and stopping the particles of soot and dust that are so fatal 

 to urban vegetation. I made a series of experiments, which 

 are described in the Journal of the Society, March 21, 

 which proved this filtering action, and after these, when 

 my paper was announced, was told that similar experi- 

 ments had been made in the Houses of Parliament. I 

 went there accordingly, and obtained some very interesting 

 information from Mr. Prim, the assistant engineer to 



Dr. Percy, who superintends the ventilation arrangements 

 of the whole building. 



There I found that, after trying many materials, they had 

 finally selected the same as I had, but were using it rather 

 differently. The air supplied to the building is passed 

 through a succession of screens of this material, all kept 

 moist by the trickling of water over them. In the summer, 

 the outer air is thus cooled as well as filtered. The 

 effectiveness of the filtration is proved by the fact that the 

 screens become so clogged with sooty abominations, that 

 they have to be regularly washed once a fortnight, and the 

 water in which they are washed becomes of inky blackness. 



I propose, therefore, that this well-tried device should be 

 applied at the entrance aperture of our heating chamber, 

 that the screens shall be well wetted in the summer, in 

 order to obtain the cooling effect of evaporation, and in the 

 winter shall be either wet or dry, as may be found desir- 

 able. The Parliament House experiments prove that they 

 are good filters when wetted, and mine that they act 

 similarly when dry. 



By thus applying the principles of colliery ventilation to 

 a speciallj-constructed house, we may, I believe, obtain a 

 perfectly controllable indoor^climate, with a range of vari- 

 ation not exceeding four or five degrees between the 

 warmest and the coldest part of the house, or eight or nine 

 degrees between summer and winter, and this may be com- 

 bined with an abundant supply of fresh air everywhere, all 

 filtered from the grosser portions of its irritant dust, which 

 is positively poisonous to delicate lungs, and damaging to 

 all. The cost of fuel would be far less than with existing 

 arrangements, and the labour of attending to the one or 

 two fires and the valves would also be less than that now 

 required in the carrying of coalscuttles, the removal of 

 ashes, cleaning of fire-places themselves, and the curtains 

 and furniture they befoul by their escaping dust .and smoke. 



It is obvious that such a system of ventilation may even 

 be applied to existing houses by mending the iU-fitting 

 windows, shutting up the existing fire-holes, and using the 

 chimneys as upcast shafts in the manner above described. 

 This may be done in the winter, when the problem is easiest, 

 and the demand for artificial climate the most urgent; but I 

 question the possibility of summer ventilation and temper- 

 ing of climate in anything short of a specially-built house 

 or a materially-altered existing dwelling. There are doubts 

 -less some exceptions to this, where the house happens to 

 be specially suitable and easily adapted, but in ordinary 

 houses we must be content with the ordinary devices of 

 summer ventilation by doors and windows, plus the upper 

 openings of the rooms into the chimneys expanded to their 

 full capacity, and thus doing, even in summer, far better 

 ventilating work than the existing fire-holes opening in the 

 wrong place. 



I thus expound my own scheme, not because I believe it 

 to be perfect, but, on the contrary, as a suggestive project 

 to be practically amended and adapted by others better 

 able than myself to carry out the details. The feature 

 that I think is novel and important, is that of consciously 

 and avowedly applying to domestic ventilation, the prin- 

 ciples that have been so successfully carried out in the far 

 more difficult problem of subterranean ventilation, in 

 which I have had some practical experience. 



Eclipse Map of Egypt.- — This map, promised for the present 

 number, vrill be given next week. It seemed desirable to the 

 Editor to supplement the mere track of the shadow's centre with 

 the elliptical shadow outlines for each of nine stations indicated 

 along the track. A figure will also be given explaining the simple 

 geometrical construction for determining the shape and position of 

 this elliptical shadow, as well as the position of the sun in the sky 

 at the time of central eclipse at each station. 



