290 SCIENCE IX SHORT CHAPTERS. 



artisans or other tenants of small houses, I do not advocate depend- 

 ence on this ; but, on the contrary, regard them as more properly 

 constituting landlord's fixtures, and recommend their erection by 

 owners of small house property in London and other large towns. A 

 workman who will pay a trine extra for such a garden, is likely to be 

 a better and more permanent tenant than one who is content with 

 the slovenly squalor of ordinary back premises. 



I base this opinion on some experience of holding small houses in 

 the outskirts of Birmingham (Talbot Street, Winson Green). These 

 have small gardens, while most of those around have none. They 

 are held by weekly tenure, and, during eighteen years, I have not 

 lost a week's rent from voids ; the men who would otherwise shift 

 their dwelling when they change workshops, prefer to remain and 

 walk some distance rather than lose their little garden crops ; and 

 when obliged to leave, have usually found me another tenant, a 

 friend who has paid them a small tenant-right premium for what is 

 left in the garden, or for the privilege of getting a house with such a 

 garden. 



A small garden is one of the best rivals to the fascinations of the 

 tap-room ; the strongest argument in favor of my canvas conservato- 

 ries, and that which I reserve as the last, is that they are likely to 

 become the poor man's drawing-room, where he may spend his sum- 

 mer evenings, smoke his pipe, contemplate his growing plants, and 

 show them in rivalry to his friends, rather than slink away from an 

 unattractive home to seek the sensual excitements that ruin so many 

 of our industrious fellow-countrymen. 



As above stated, I have not been able practically to test the filter- 

 ing capabilities of the canvas, owing to my residence out of town, but 

 since the above was written, i.e. on last Wednesday evening, I visited 

 the Houses of Parliament, where, as I had been told, the ventilation 

 arrangements include some devices for filtering the air by cotton wool 

 or otherwise. 



I was much interested on finding that the long experience and 

 many trials of Dr. Percy and his assistant engineer, Mr. Prim, have 

 resulted in the selection of the identical material which I have 

 chosen, and with which the above-described experiments have been 

 made. A wall of- such canvas surrounds a lower region of the 

 houses, and all the air that is destined to have the privilege of being 

 breathed by British legislators is passed through this vertical screen, 

 for the purpose of separating from it the sooty impurities that con- 

 stitute the special abomination of our metropolitan atmosphere, and 

 that of our great manufacturing towns. The quantity of sooty matter 

 thus arrested is shown by the fact that it is found necessary to take 

 the screens down once a week and wash them, the wash water coming 

 away in a semi-inky condition. 



I anticipate that the conservatory filters will rapidly clog, and, 

 therefore, require washing. This may easily be done by means of a 

 jet from a hand-syringe directed from within outward, especially if 

 the slope of the roof is considerable, which is to be recommended. 

 The filtering screen of the Houses of Parliament is made by sewing 

 the canvas edges together, to form a large continuous area, then 

 edging the borders of this with tape, and stretching it bodily on to a 

 stout frame. This method may be found preferable to that which I 

 proposed above, and cheaper than I have estimated, as only very 



