28 



♦ KNO^A^LEDGE ♦ 



[June 9, 1882. 



Ifttn-g to tl)t eiiitor. 



If retpcmtibU for l\e opimont of 1,1$ eorrttponJenl: 

 - icriptt or to eorretpond rilk thfir teriteri. AH 

 f04nbU, comitltntly n'M /ull end eltar ital4- 



m*mit oftXt wr\t*r'$ SManijif J 



AH EJtlifr^ eommuHifaiitnu tiould It adjrttted to 

 •ii SwtMfM communicaXitnu i« tJit i*ublia\«rt. at tl 

 Krw*. WC. 



AU BtmMancn, CXt^tl, and Port- 

 ttrart. Wfian t Sou. 



•«• All Utttrt to Ike Editor trill i> Xumtered. For ronoenirnot of 

 fondnlt, rin r^rrrin} to any leHtr, triU oblige b) mentioning i 



Ordert ekould be node payable 



ndti, 



AULettm 

 EXOKXICGI. 

 the daf qf publieat%on. 



tfkt^A it appeare. 



Qaeriee to the Editor rkirk require attention in the current ieeve ^ 

 IJreaek the Pnblieking Office net later than the Saturday preceding 



ne mint be concise; thpT mnst be dr»wB 

 1 the form tdopted fcr lettera here, «o thot tber may Ro untouched to the 

 Tmter* ; private comraunicationB, therefore, ae we'll as' queries, or repbes to 

 DPrie* (intended to appear aa such) should be written on separate leaves. 

 (U.) tettera which (either because too ioni;, or unsuitable, or dealing with 

 utiera which others hate discussed, or for any other reason) cannot find place 



" In knowledge, that man only is to be contemned and des 



(t*t« of truisition '>'or is there anything more 



than fiiity of opinion."— Jorarfjy, 



** There is no harm in making a raistalie, but great harm in 

 me > mas who makea no mutakes, and I will show von 

 Dothing."— Z<«iii7. 



" God'a Orthodoxy ii Troth."— CJar/es Kingiley. 



adverse to 

 making none. 



0\\x CorrrsponiJrnre Columns. 



TOBACCO AND COXSUMPTIOX. 



[418]— In letter Xo. 411, pnge 030, Mr. W. B. Wickcn proposes 

 the use of tobacco a-s a preventive and cure for consumption. 



The fact that the Tnrks are comparatively free from consumption 

 is, I believe, beyond doubt ; and it may be, though I do not think 

 80, that their habit of inhaling the smoke into the lungs keeps away 

 that dreadful disease. On the other hand, how is it that consump- 

 tion is so prevalent in our own counti^j- ? Wo are a great nation of 

 smokers, and if we do not make it a point of inhaling tho smoke 

 into cor lungs, a fair percentage of it mast necessarilv find its way 

 to the organs of breathing. Personally, I do not i.lnr'r .niv f^n'th in 

 tobacco as a care for consumption, for Ibelir-.- l,:is 



more to do with it than anything else. As a ; i,/, 



possibly, be of service, by keeping the cells of ; ,,,1 



thereby prevent the accumulation of morbid hni.i.n-. I ur,.i,r(i 

 smoke has, undoubtedly, some soothing effect, and alluys irritatinn 

 of the lungs; for I find that when my laboratory is filled with arid 

 fames, that I have no inclination whatever to eongh, as lung as I 

 use ray pipe. 



With regard to the tobacco used by tho Turks, I may say that I 

 have never smoked a stronger kind than that used with the nar- 

 gillah. When on a visit lately to Constantinople, I one day ordered, 

 ont of cariosity, a cop of coffee and a nargillnh. The latter, how- 

 ever, soon proved too much for me, thoQgh tho smoke was drawn 

 through three yards of tubing and about sii inches of water. 

 After passing through so much, the smoke was still so powerfully 

 noiions, that one fiuff satisfietl mo fully, and I was glad to resign 

 the pipe to a stander-by, who finished it in happiness. The tobacco 

 used with the pipe is different from that used for cigarettes. 



In Spain, too, the smokers draw tho smoke into their lungs, and 

 will frequently engage in a very spirited argument before emitting 

 it again. They seem to have no difficulty whatever in swallowing 

 the smoke— in fact, it is their usual custom ; bat their tobacco is not 

 unlike chopped hay in mildness. 



In conclusion, I will repeat that Englishmen consume a great 

 deal of tobacco, and yet consumption is very prevalent amongst us. 

 1 believe that it is to oar changeable and humid climate that tho 

 cause must be assigned, and this applies not only to consumption, 

 but to all the diseases that the chest and lungs are subject to. 

 Perhaps some of our medical contributors will give us their ex- 

 perience in this matter, which I am sure is of great interest to 

 many. I would just say one thing, and that is, that rather than 

 believe the Turk's freedom from tubercular diseases is duo to tho 



manner in which they use tobacco, I ehoiJd say it is because of 

 their abstinence from intoxicating liijuors. 



W. 0. TKOSiiER, F.C.S. 



THE LATE MR. DUNMAN. 

 [tlOJ^The recent death of Mr. T. Dnnman has already boon 

 noticed in your columns. Ue may be said to have sacrificed his 

 life to his self-denying zeal in the work of popular education, and 

 to an intense interest in tho teaching of Science. Will yon allow 

 me to mention that a fund is being raised to help his widow to 

 place herself in a position to support herself and lior two children ? 

 Several members of the Council of the Working Men's College are 

 on the Committee, and I am authorised as treasurer to receive con- 

 tributions. — R. B. Litchfield, 4, Brjanston-street, Portman- 

 square, W. 



TRICYCLES. 



[420]— In reply to H. R. L., I fear I can add little to tho infor- 

 mation I have tried to give in my two articles on recent tricycles, 

 which have so lately appeared "in K.vowLKiXiK, but if tho writer 

 will ask for details of any particular machine lie may find wanting 

 in what 1 have written, \ shall be very glad to furnish tho infor- 

 mation to the best of my power. JonN Browning. 



MILDNESS OF THE SEA COAST. 



[421] — The cfloct of the near neighbonrh.iod of tho ocean in 

 moderating cold seems to be well illustrated by comparing the 

 minimum temperature for Valentia, given in your weather reports 

 for three weeks, ending April 29, with those observed at this station 

 — Killarney — distant inland from Valentia 50 miles. 



The minima here were loiter than at Valentia on those 21 days 

 as follows : — (The amount is given in whole degrees) — 5, 8, 4, 2, 1, 

 0,6, 8,-1, 4, —1, 1,2,2,0, l,e, 8, G, 1, 1. 



The mean difference is 3°. This is a somewhat striking exempli- 

 fication of the well-known effect of the moderating influence of tho 

 presence of the sea. I may add that the instrument used here has 

 a Kew verification. It would be, I think, an improvement to give 

 the hour of tho barometer readings in your Weather Reports. 



G. R. Wy.n.ne. 



THE "COLD SNAP" IN MAY. 



[422]— Permit mo to suggest as a reason for the low tempera- 

 ture of u week in May thet there is usually formed in that month 

 a region of high barometric pressure in the north, causing prevalent 

 easterly winds over England. JYequently this wind is light and anti- 

 cyclonic, and, after a period of cloudy skies, there is a clear sky for 

 several nights. This, with the comparative calmness of the atmo- 

 sphere, promotes rapid radiation from the earth. The ground tempe- 

 rature falls decidedly below freezing-point, and tho air is cooled 

 rapidly in the stratum next the earth. 



I believe in this direction must be sought the cause of the cold 

 snap. Later on in the season tho amount of heat received from the 

 sun in its longer ])eriod above the horizon is sufficient to prevent the 

 excessive loss by radiation experienced in May, even in the clearest 

 calmest Hummor iiiglits. (i. R. WvNNE. 



POPULATION OF TllH EARTH. 



[423] — On a globe 2 ft. diameter, the Dead Sea appears as a 

 small coloured dot, but if it were frozen over there would bo room 

 on its surface for the whole living human race, allowing six stjuarc 

 foot for each person, and were they suddenly to bo engulfed, it 

 would merely raise the level of tho lake by some four inches. 



One hears at times very wild statoirionts as to tho depth tho 

 earth would bo covered if all the ])eoplo who have lived were laid 

 side by side on its surface, estimates running from four feet 

 upwards; but if we suppose the earth to have been as populous as 

 now for 0,000 years (200 generations), the whole number could have 

 been decently buried in graves 5j It. x 2 ft. within tho British 

 Isles, and some 7,000 square miles to spare. 



I have taken tho present jioiiulation, as ^,'lvtn by tho Germau 

 statisticians, at 1,450 millions (nearly). W. W. M. 



STAR SPECTROSCOPE— GLASS STYLOGRAPHS— MAGNI- 

 FYING POWER. 

 [424] — With a good 4-in. Cooke, jirovided with a Maclean's star- 

 spectroscope, but mounted on an ordinary altazimuth tripod, with- 

 out slow motions, the fuintnoss of star-spectra, and especially the 

 unsteadiness of tho motion, made it extremely hard to determine 

 the best focus. The way I succeeded is simple, and may bo useful. 

 Slide out tho prisms and replace the concave cylindrical lens, fit the 

 instrument as usual in the place of the eyepiece, focus on tho PeJ© 



