DOMESTIC VENTILATION. 71 



the Society of Arts, March 19th, 1879, recommending the 

 inclosure of London backyards with a roofing 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 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 desirable. The Parlia- 

 ment 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 

 specially constructed house, we may, I believe, obtain a per- 

 fectly controllable indoor climate, with a range of variation 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 combined with an abun- 

 dant 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 labor of 

 attending to one or two fires and the valves would also be l3ss 

 than that now required in the carrying of coal-scuttles, the 

 removal of ashes, the cleaning of fireplaces, and the curtains 

 and furniture they befoul by their escaping dust and smoke. 



It is obvious that such a system of ventilation may evea be 

 applied to existing houses by mending the ill-fitting windows, 

 slmtting 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 tempering of climate 

 in anything short of a specially built house or a materially 

 altered existing dwelling. There are doubtless 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 an4 

 windows, plus the upper openings of the rooms into the chim- 

 neys expanded to their full capacity, and thus doing, even iu 



