Nov. 



1883.1 



♦ KNOWLEDGE ♦ 



277 



" Let Knowledge grow from more to more." — Alfked Tenntson. 



Only a small proportion of Letters received can possibly be in- 

 serted. Correspondents must not be offended, therefore, should their 

 letters not appear. 



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The Editor is not responsible for the opinions of correspondents. 



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 AND DIRECTED ENVELOPE BE ENCLOSED. 



SIB WILLIAM HEKSCHEL. 



[082] — With reference to letters 947 and 956, as to the statement 

 by "A Fellow of the Royal Astronomical Society" that Sir 

 William Herschel lost an eye observing the sun, I beg to point out 

 that in Webb's "Celestial Objects" (3rd ed., p. 19) it is stated 

 that " Galileo probably thus blinded himself wholly, and Herchel I. 

 in part." A. H. S. 



[In Smyth's " Bedford Cycle," Vol. L, p. 87, it is stated that 

 Sir W. Herschel lost the sight of one eye in this way. — R. P.] 



[983] — On my return home I lose no time in redeeming the 

 promise to Colonel Herschel, given by me in Letter 956, p. 233. If, 

 then, he vrill turn to p. 87 of Vol. I. of Smyth's " Celestial Cycle " 

 (the " Prolegomena " to the "Bedford Catalogue") he will find 

 its author saying, apropos of observing the sun : — " Nor is it wholly 

 without danger. The illustrious Sir William Herschel lost an eye 

 in this service, and I myself had a narrow escape from a similar 

 disaster, by neglecting to reduce the aperture of the instrument." 

 As Admiral Smyth was 34 years old at the time of Herschel's 

 death, he may well have seen him face to face. Whether, though, 

 he wrote the words I have quoted from personal knowledge, or 

 from'hearsay, I have no means of deciding. 



A Fellow of the Royal Astronomical Society. 



TRICYCLES (AN ERROR CORRECTED). 



[984] — In No. 103, page 241, it is stated that Messrs. LaiTetto 

 and Barrow rode on a tricycle 18 miles in 25 minutes. That would 

 be at the rate of 43A miles an hour. It is probable tliat 1 hour and 

 25 minutes is meant. That is (circa) 12J miles an hour. 



James Montague. 



LARGE V. SMALL WHEELS FOR TRICYCLES. 



[985] — I have read with considerable interest the correspondence 

 upon this subject now publishing in your paper. There is, however, 

 one question, and that the most important of all — safety — which 

 both parties appear to have entirely overlooked. Increased speed 

 is a very good thing, but it is not worth purchasing at the cost of 

 increased risk of accident. I am now fast approaching sixty years 

 of age, weigh considerably over fifteen stone, and have just returned 

 from a ran tljrough Gravesend, Ramsgate, Dover, St. Leonards, 

 Eastbourne, Brighton, Worthing, Portsmouth, Southampton, Win- 

 chester, Reading, Slough, and through Watford back into Hertford- 

 shire. 



I ride for health, exercise, and recreation, and to mo speed 

 occupies a very secondary place in comparison with safety. I ride 

 .'i 50-inch Sparkbrook National, geared to 48 inches, or nearly level. 

 Wlion I am in the saddle my pedals have 4i inches clearance, and 

 iriy saddle is 37 inches from the ground, or 12 inches above the axle. 

 'I'lio centre of gravity being so low, my weiglit acts as ballast, and 

 the chances of an upset are very small indeed, so that I can turn 

 even sharp corners with safety. Place me upon a machine with 

 86-inch wheels and ray saddle will be exactly on a level with the 

 tops of the wheels, and my weight, so far from serving as ballast to 

 steady the machine, would in that elevated position simply tend to 

 overthrow it. This fact alone is sutlicicnt to condemn suiall wheels 

 in my estimation. I sh.ill be glad to hear from Jlr. Browning what 

 is his opinion upt>n this, to nie, all-important imiut. \V. W. D. 



[986]— In view of the letters and articles which have lately 

 appeared in Knowledge upon the subject of " Tricycle Wheels," 

 perhaps I may be allowed a little space for the same subject. 



A small machine geared to two speeds has these advantages, (1), 

 lightness; (2), ease in climbing hills. Having small wheels which 

 run round faster, the machines have the disadvantage of greater 

 friction. The supporters of large wheels urge in their favour, (1), 

 less friction ; (2), more comfortable riding on rough roads. The 

 opponents say that large wheels have the disadvantage of (1) 

 greater weight, and (2) less adaptability to hill riding except by 

 gearing down. 



Now, the question is, taking all the pros and cons for each side, 

 which is the best machine? that is, which gives the greatest possible 

 speed with the least possible fatigue ? We often wonder how there 

 can be any diversity of opinion on this point, considering that there 

 are so many tricyclists capable of judging. But, the fact is, each 

 tricyclist can only judge of the particular machine or machineshe 

 has ridden, and very few men who hold opposite opinions are riding 

 machines by the' same maker. Besides this, one might add that 

 what suits one man may be most unsuitable for another. One 

 could hardlv expect a man " born almost without muscles" to ride 

 a large and"hea\-y machine, but one can partly understand a strong 

 rider like " Sigma" having a contempt for " geared-up castors.'' 



However, the few considerations which follow may help to guide 

 any one who has not ridden to the choice of a machine suitable to 

 himself. 



Consider first the small wheels geared high. The first advantage 

 — viz., lightness — is so obvious, that I need hardly mention it. 

 Although we cannot say that the weight of the wheel varies as its 

 diameter, we can say small wheels are lighter than large ones. 

 Now, on hills the weight of the machine is an important considera- 

 tion, and tricycle riders in general ivill certainly "go for" any- 

 thing which takes off the weight without lessening their speed. 

 The convenience of changing gear for hills applies more to weak 

 than to strong riders, but even to strong riders it is of importance 

 for very steep hills. Much has been said of the connection 

 between the " dead point" and hill-climbing. Some have asserted 

 in Knowledge that the " dead point" occurs more frequently with 

 small wheels than with large ones. It does not. The dead point 

 has only to do with the pedals. It is the point where one pedal is 

 up and the other down, and therefore no power is being applied. 

 But if a machine with small wheels is geared up to the same speed 

 as one with large wheels, that means that the pedals of both 

 machines are going ronnd at the same rate. The small geared 

 wheels move round faster than large ones, and thus more friction 

 is caused. This is a cause of complaint that will lessen every year, 

 for ball-beai-ings are being continually improved. Still the fact 

 remains that in small wheels geared up and having the most perfect 

 bearings, the friction is greater than in large wheels. But is this 

 not compensated by the less weight of the small wheels ? In hill- 

 climbing the large- wheeled tricycles may be geared down, bat there 

 is still the extra weight of the wheel. 



The last point in favour of the large wheels is that of comfort. 

 On rough roads there is no doubt that large wheels go more 

 smoothly, and with less jerking over stones or similar obstacles ; 

 but in England the roads are generally speaking good, and by 

 thick rubber tires we can take away mnch of that inconvenience. 



Leaving this for the consideration of your readers— that is, if 

 you choose to insert it, Thomas B. Walker. 



ANTHROPOMETRY. 



[987]— In reply to " Uallyards" [970] I would say that the con- 

 clusion as to tallness or shortness being a racial peculiarity is due 

 to the Anthropometric Committee of the British Association, and 

 not to myself. At the same time, if a humble outsider may say so 

 without " pre-sumptuousness, I fully concur in their conclusion. 

 Races of men </» differ noticeably" in height, e.g., Japanese and 

 Patagonians, Finns and Swedes, Bushmen aud Zulus, Esquimaux 

 and Red Indians. Increased food aud ease of life no doubt tend to 

 make individual members of each race attain the highest develop- 

 ment of that race, but they do not, apparently, tend to make 

 Japanese (for example) grow' as tall on the average as lowland 

 Scots, unless (perhaps) the favourable conditions be extended over 

 a very long space of time, .and (probably) be accompanied by 

 special selective action, sexual or natural. If "Hallyards" will 

 read the Report of tho Anthropometric Committee, aud also the 

 writings of Dr. Beddooa, Dr. Tliurnam, Prof. Rollestone, and other 

 ethnologists, he will, probably, bo convinced that size and shape 

 of bono is a remarkably constant racial feature, and he may, per- 

 haps, be surju-ised to find how wonderfully such small personal 

 peculiarities often persist from generation to generation. 



As to " Hallvards' " two particular examples, I should like 

 to ask him, first, how docs he know that the Lowland Scots 



