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AN ILLUi&IRATED. ^ 



I ^ MAGAZlNEoFS^ENCE 



PlJVlNUf WfORMD -EXACTllDESC RIBEa; 



LOXDON : FRIDAY, FEBRUARY \ 1882. 



Contents of No. 14. 



FAQS. 



The Air of Stove-Heatod Rooms. 

 Bv W. MattienWillinms ^''5 



Young on Ihc Son. Ht the Mitor . 280 



Found Links.— Part til. Hv Dr. 

 Andrew WilnOD. P.B.S.E., .(:o 38S 



lotelliaenec in .Ininmb ■2S9 



.Mights with a Thrco-inth Telescope. 

 By " A Fellow of the Royal Astro- 

 nomical Society." (ftiu.'tratrJ.) 290 



Brain Troubles : Partial loss of 

 .S|)eech , 291 



liKviKws : Srieneo Ladders -Science 

 (or All— The Science of the Stars . 293 



Ibo Effects of Tolrtoco.— Part I. By 

 Dr. Mnir Howie 292 



Professor Grant on Motoorolopy .!. 29* 



PAGB. 



Easy Lessons in Blowpipe Chemistry. 

 - -Lesson II. Bv Lieut.-Colonel 

 W. A. Ross, late "R.N 29S 



Ellluvia and Health; The Use of 

 Fleas, &c. ; Fish "Sounds." By 

 W. Mattieu Williams 295 



—Volcanic Projectiles, 4o 296-302 



Star Map for Febmarv 297-300 



Queries .'. 303 



Replies to Queries 303 



.A-nswers to Correspondents 304 



Notes on Art and Science 30tt 



Our Mathematical Column 3V 



Our Chess Column 309 



Our Whist Column 309 



THE AIR OF STOVE-HEATED ROOMS. 



By W. M.iTTIEU WiLLI.YMS. 



%S WHATEVER opinions may be formed of the merits of 

 * \ the exhibits at South Kensington, one result is 

 unquestionable — the exhibition itself lias done much in 

 directing public attention to the very important subject of 

 economising fuel and the diminution of smoke. We sorely 

 need some le,ssons. Our national progress in this direction 

 has been simply contemptible, so far as domestic fireplaces 

 are concerned. 



To prove this we need only turn back to the essays of 

 Benjamin Thompson, Count of Rumford, published in 

 London just eighty years ago, and find therein nearly 

 all that the Smoke Abatement Exhibition ought to teach 

 us, both in theory and practice — lessons which all our 

 progress since 1802, plus the best exliibits at South j^Ken- 

 sington, we have yet to learn. 



This small progress in domestic heating is the more 

 remarkable when contrasted with the great strides we 

 have made in the construction and working of engineering 

 and metallurgical furnaces, the most important of which 

 is displayed in the Siemens regenerative furnace. A 

 climax t<:) this contra-st is afforded by a speech made by 

 Dr. Siemens himself, in which he defends our domestic 

 barbarisms with all the conservative inconvincibility of 

 a Ijom and bred Englishman, in spite of his German 

 nationality. 



The speech to whicli I refer is reported in the "Journal 

 of the Society of Arts," Dec. 1', 1881, and contains some 

 curious fallacies, probably due to its extemporaneous 

 < haracter ; but as they have been (juoted and adopted not 

 only in political and literary journals, but also by a maga- 

 zine of such high scientific standing as Mature (see 

 <-ditorial article Jan. !), p. 219), they are likely to mislead 

 many. 



Ha\-ing already, in my " History of Modem Invention, 

 ac," and in other places, expressed my great respect for 

 Dr. Siemens and his benefactions to British industry-, the 



spirit in which the following plain-spoken criticism is made 

 will not, I hope, be misunderstood either by the readers of 

 Knowledge or by Dr. Siemens himself. 



I may further add that I am animated by a deadly hatred 

 of our barbarous practice of wasting precious coal by burning 

 it in iron fire-baskets half buried in holes within brick walls, 

 and under shafts that carry 80 or 90 per cent of its heat 

 to the clouds ; that pollute the atmosphere of our towns, 

 and laake all their architecture hideous ; that render scien- 

 tific and efficient ventilation of our houses impossible ; that 

 promote rheumatism, neuralgia, chilblains, pulmonary di- 

 seases, bronchitis, and all the other " ills that flesh is hf>ir 

 to " when roasted on one side and cold-blasted on the other ; 

 that I am so rabid on this subject, that if Dr. Siemens, Sir 

 F. Bramwell, and all others who defend this English abomi- 

 nation, were giant windmills in full rotation, I would 

 emulate the valour of my chivalric predecessor, whatever 

 might be the personal consequences. 



Dr. Siemens stated that the open fireplace " communi- 

 cates absolutely no heat to the air of the room, because air, 

 being a perfectly transparent medium, the rays of heat pass 

 clean through it." 



Here is an initial mistake. It is true that air which 

 has been artificially deprived of all its atjueous vapour is 

 thus completely permeable by heat rays, but such is far 

 from being the case with the water it contains. This 

 absorbs a notable amount even of bright solar rays, and a 

 far greater proportion of the heat rays from a comparatively 

 obscure source, such as the red-hot coals and flame of a 

 common fire. Tyndall has proved that 8 to 10 per cent, of 

 all the heat radiating from such a source as a common fire 

 is absorbed in passing through only 5 ft. of air in its ordi- 

 nary condition, the variation depending upon its degree of 

 saturation with aqueous vapour. 



Starting with the erroneous assumption that the rays of 

 heat pass "clean through" the air of the room. Dr. Siemens 

 went on to say that the open fireplace ' ' gives heat only by 

 heating the walls, ceiling, and furniture ; and here is the 

 great advantage of the open fire ; '" and, further, that " if 

 the air in the room were hotter than the walls, condensa- 

 tion would take place on tliem, and mildew and fermenta- 

 tion of various kinds would be engendered ; whereas, if 

 the air were cooler than the walls, the latter must be 

 absolutely dry." 



Upon these assumptions, Dr. Siemens condemns steam 

 pipes and stoves, hot-air pipes, and all other methods of 

 directly heating the air of apartments, and thereby making 

 it warmer than were the walls, the ceiling, and furniture 

 when the process of warming commenced. It is quite true 

 that stoves, stove pipes, hot-air pipes, steam pipes, &c., do 

 this : they raise tho temperature of the air directly by 

 convection ; i.e., by warming the film of air in contact 

 with their surfaces, which film, thus heated and expanded, 

 rises towards the ceiling, and, on its way, warms the air 

 around it, and then is followed by other similarly-heated 

 ascending films. When we make a hole in the wall, and 

 burn our coals within such cavity, this convection proceeds 

 up the chimney in company with the smoke. 



But is Dr. Siemens right in saying that the air of a 

 room, raised by convection above its original temperature, 

 and above that of the walls, deposits any of its moisture 

 on these walls .' I have no hesitation in saying very posi- 

 tively that he is clearly and demonstrably wrong ; that 

 no such condensation can possibly take place under the 

 circumstances. 



Suppose, for illustration sake, that we started with a 

 room of which the air and walls were at the freezing- 

 point, 32° F., before artificial heating (any other tempera- 

 ture will do), and, to give Dr. Siemens every advantage, we 



