383 



• K NOW 1^ EDGE » 



[Mahch 3, lW»i 





Voar article, altbouKh tcllinfr aa a lot about the dye, doe* not itato 

 the nctaal colour. Wn« not the Imporial |iur|ileof the Cu-mn red ? 

 1 hare neon it so depicted in many jHiintinf^. A. J. Mabti^c. 



TOBACCO AXD SCIENCE. 



[207] — J. I'- Grail [199] makes some inquiry under this head. 

 1 will maku some others. When smoking a cigarette (with a mouth- 

 piece), if, after inhaling the smoke, you remorc the cigarette, 

 holding it horizontally, you will sec that a little smoke e8ca|>e8 from 

 the mouthpiece and ascends ; the smoke which remains in the 

 mouthpiece does not ascend, bat falls to the lower part and there 

 remains. Why ? 



When smoking, no matter whether pipe, cigar, or cigarette, after 

 inhaling puff it out immediately, and the smoke which comes out of 

 the mouth, as well as that which gently rises from the pipe or the 

 lighted end of cigar or cigarette is of a delicate pale blue ; but if, 

 after inhaling, you retain the smoke in your mouth for two or three 

 seconds before exhaling it, it will be of a pale dirty-brown colour. 

 Why should it be so ? , A. T. C. 



THE HADIUMETEK. 



[298] — On exposing a radiometer to direct rays of coloured light, 

 obtained by a sciopticon lantern and coloured gelatine sheets, I got 

 the following results ; the vanes of the radiometer in each case 

 starting from a state of rest. 



Bed light : garc 39 revolutions in 1 minate. 



Green „ : „ 30 ,, „ „ 



Blue „ : ,.33 „ „ 



Dii turning up the light a little — 



Red light : gave 40 revolutions in 1 minute. 



Green „ : „ 43 „ ,, 



Blue „ : ,,40 

 On turning down the light — • 



Bed light : gave 43 revolutions of the vanes in 1 minute. 



Green „ ; ,.40 „ „ „ „ „ 



Blue „ : „ 37 „ „ „ „ ,, 



These proportions appear constant, and would they not show that 

 the red rays in the spectrum of solar light have most energy, and 

 blue and violet the least ? When I tried yellow light, produced in 

 the same way, I got neerly as many revolutions of the vanes as 

 with white light ; I suppose this was owing to the yellow sheet 

 allowing other rays to pass through. Can you advise any book on 

 the subject? J. S. Gla'dstosh. 



STOTE-WAKMED HOUSES. 



[299] — I have read in your issue of the 3rd instant an article on 

 the heat from American stoves. Now, sir, I trust that you will 

 permit me to give my very long experience of these invaluable houee- 

 warmers. I lived in Canada and the United States from 1832 to 

 1878, in houses wholly heated by stoves. In 1834 a coal stove was 

 Jirought out in Troy. State of New York, to bnm anthracite coal. 

 1 procured one of these stoves and placed it in the entrance-hall of 

 my house. That house was 6-t by 38 feet, and this stove, althengh 

 far inferior to the "Crown Jewel" stoves, manufactured by the 

 Detroit Stove Company, now on view at Kensington, heated every 

 part of my large honse, which was situated on the bank of the St. 

 Lawrence, on a bay nine miles wide, whore the outside tempe- 

 rature was frequently 38° below zero. We kept a tin evaporator 

 en the stove to throw o6E sufficient moistnre, and, daring the whole 

 time this stove was in nse, we never had one case of sickness. I 

 never had one day's illness in America, and I may say that since 

 my return to England I have been half the time sick ; this I 

 attribute entirely to the absurd way in which the English attempt 

 to heat their houses. With the best coal fire, in an ordinary room, 

 we are roasted on the side next the fire and cold on the opposite. 

 Every passage and room we enter has a different temperature. We 

 need not, therefore, be astonished at the enormous number of 

 bronchial, long, and rheamatic diseases so prevalent in England. 



JCSIICB. 



[.100^ — May I ask Mr. W. Mattieu Williams one question through 

 the median] of your paper Y It is not for the sake of contrtDversy, 

 but to satisfy my own mind on the matter of " Stove Heating!" 

 Supposing the atmosphere inside a stove-heated room to be 50° 

 (u*ing Mr. Williams' fignrea), the amount of vapour required to 

 saturate air of this hoat is sufficient to support a column of 361 

 inches of merctiry, and this is easily supplied, " for an English house 

 IB enveloped in a foggy atmosphere, and encased in damp surround- 

 ings." In the open air the temperature is 32 ; therefore, if the fire 

 were allowed to go out, would it not follow that because the quantity 



of vapour in the room would be double the amount of that in tb^ 

 open air, condeDsation of the excess uf rapoor would take place?— 

 Your^ Ac., G. G. D. 



FOSSILS IN METEORS. 



rSOl] — Referring to the articles "Meteoric f>rganisnu," and 

 " No Organic Matter in Meteors," in No. 12 of Knuwledce, I beg 

 leave to point out, in order to prevent erroneous notions aboat 

 German men of science to arise among English students, especiaDj 

 among the readers of your truly excellent journal, that the start- 

 ling discoveries of Dr. Uahn, and the extravagant theories based 

 thereon, were, immediately after their first api>carance before the 

 public, very ably discussed and thoroughly refuted by the eminent 

 geologist. Professor Zittel, of Munich, in a paper which appeared^ 

 if I am not mistaken, a twelvemonth ago in the AwjshHrg'r AUgt- 

 meine 'Leiiung. Dr. Hahn is, I am given to understand, not at all 

 a geologist, bat a medical man ; I may be further permitted to state 

 that he is neither half insane nor a fool, but an eager amatear, 

 whom it would be more charitable and just to describe as possessed 

 by a rather ludicrous illusion concerning the real valne of tba 

 strange results his cherished "scientific" obser\'ation8 have led 

 hjm to. — Yours, Ac, Gkbjian Fbiexd or Ksowlkoge. j 



MANUFACTURE OF GAS FROM WOOD— ARRANGED 

 SQUARES. 



[302]. — To make it intelligible how wood-gas (p. 346) can take 

 place of coal-gas for illnminating, F. C. S. should have added : foif 

 every l.CJO feet of commercial gas, 4t gallons of naphtha are osed^ 

 This being rich in carbon makes a bright, of an otherwise dull light* 



The numbers in the Villa Alboni inscription, I take the Latin to 

 ?ay, add up horizont.illy, vertically, and diagonally (the maximum 

 number of ways) to 369. This is found to be the case, and the total 

 to be 3,321.— Yours. Ac. C. T. B. 



6, Prince's-terrace, Brighton. 





EYESIGHT OF DOGS. 



[303] — In an article on " Intelligence in .\nimals," in Kxow- 

 LBDGE, No. 2, page 29, there is the following remark, which I am 

 surprised no one has already commented on, in alluding to dogs 

 being near-sighted : — This writer says " We believe that there 

 could not be quoted a single instance tending to show that a do^ 

 has been able to see aa well as a very near-sighted man." My 

 experiences with dogs leads me to quite a different conclusion. 1 

 had a retriever bitch which certainly saw better than a near- 

 sighted man. To give one instance. Out shooting one day I hit a 

 partridge very hard, which flew over a gate across a field, and fell 

 into a cover some 200 yards off ; the retriever, with its fore paws on 

 the top of the gate, watched the bird. As soon as it fell she jumped 

 over the gate, and ran straight to where the bird had fallen, and in 

 a few minutes returned with it. Surely she was not near-sighted ? 

 I have often seen dogs notice game some distance off when they 

 could have neither smelt nor heard them. A gentleman much inte- 

 rested in conrsing tells me that he believes that many, if not most, 

 dogs see remarkably well. Of course, dogs like Skye terriers, 

 whose eyes are much covered with hair, cannot see so well aa 

 those which have shorter hair. One reason which may make dogs 

 at times appear near-sighted is, that their eyes are so near the 

 the ground that long grass, or any other obstacle, will prevent them 

 from seeing an object which to a person of ordinary height is dis- 

 tinctly visible. — Yours. Ac, G. S. S. 



COMPARISON OP THE SEXES. 



[304] — According to Huxley, the blood of men contains a larger 

 proportion of " solid constituents" (these include the "corpuscles") 

 than that of women; although, he odds (instructively), "the 

 difference of sex is hardly at all exhibited by persons of flabby, or 

 what is called lymphatic, constitution." (Physiology. Lesson lii.. 

 Sec. 17.) According to McKendrick, whereas the diameter of a 

 single muscle-fibre is -j^th of an inch in an adult male, in an adult 

 female it is only rxis^^ °' *° ''"^'' ( ' Outlines of Physiology, ' p 79) 

 The same author, on p. 82, remarks that smallness in the si^e o1 

 fibres, and fineness in the distribution of capillaries, and greatness 

 of contractility, are concomitant circumstances. Thurman, a write* 

 quoted in Bastian's " The Brain as an Organ of Mind," says. " Mv 

 own observations fully confirm those of preceding writers as to thi 

 average weight of the adult male brain being about 10 per cent 

 greater than that of the female. i.(i.,about 49oi. to44oz." 'Thesami 

 writer adds (see Bastian, p. 356), " For this purpose I haveexaminei 

 ^nd oompared the average brain weight fur men and women at tbi 



