Dec. 24, 1885] 



NA TURE 



179 



consists of a band of steel lined with leather encircling a 

 drum m the driving-axle. By a hand-lever this can be 

 tightened with great foree. In some central-geared 

 tricycles a band-brake can be applied with the foot to the 

 crank-axle. 



Pedals. — When bicycle cranks are used the pedals are 

 mounted on pedal pins bolted to the cranks, \yith 

 cranked axles they are made in two halves. Ball bearings 

 are frequently emplojed. Both rat-trap and rubber 

 pedals are made : the latter are more slippery than the 

 former, but absorb more vibration and so are more 

 comfortable. The combination pedal with rat-trap plates 

 on one side and rubber on the other is due to the author. 

 A common cause of danger in bicycle ridmg is the 

 slipping of the feet from the pedals when driving with 

 much power, which puts the weight so far forward as 

 to throw off the rider in front. Pedals to grip the feet 

 have been devised, but some forms are apt to hold the 

 feet so firmly as to make a sudden dismount occasionally 

 impossible. The author has invented a pedal in which 

 by bell-crank levers the foot is only held when pressure 

 is exerted. 



Fittings, &-T. — Of the fittings and accessories the 

 varieties are far too extensive for enumeration ; but many 

 display an amount of ingenuity that will well repay an 

 inspection of them. The manufacture of these fittings 

 forms separate trades, which employ a large amount of 

 capital and labour. 



The Chairman having complimented the author on the 

 excellence of his paper, invited discussion. 



Mr. C. Vernon Boys, referring to the undoubted going 

 powers of the small .Safeties, thought that in addition to 

 the reason given in the paper the facts that the wind 

 resistance was enormously reduced and that the rider 

 could work in a position of comfort, without straining 

 himself to ride as high a wheel as possible, had a great 

 deal to do with the observed result. He thought that on 

 a racing path the wind resistance of the spokes was the 

 chief opposition to the motion of the machine. 



He pointed out that the method of turning the Otto as 

 described by the author, though employed by some, was 

 essentially bad, tending to rub the tyres off one of the 

 wheels, and explained the perfect method by which the 

 wheels are made to turn simultaneously in opposite 

 directions, by which no strain is put upon the tyres and 

 only half the space is required for turning. 



He thought too much preference had been given the 

 clutch as compared with the dift'erential gears for driving 

 tricycles, and pointed out that in starting round a curve 

 owing to the fact that the wrong wheel — the inner one — 

 alone drives, more strain is thrown upon the steering- 

 wheel, causing it to slip, than it ever experiences in 

 ordinary riding when one wheel of a differentially-geared 

 machine meets with greater resistance from mud or other 

 causes than the other. 



He mentioned the fact that Mr. Burstow, the inventor 

 of the centre-cycle, had shown him nearly two years ago 

 a double-acting clutch such as the author considered to 

 be even more perfect than the differential gear, but he 

 did not know how it was constructed. 



Passing on to the Oarsman tricycle, Mr. Boys said that 

 though apparently a hand-worked machine it was in 

 reality driven chiefly by the muscles of the legs and body, 

 and the stroke was only completed by the arms ; and also 

 that though a clutch-driven machine it had the advantages 

 of a differentially-geared machine, in that when turning 

 a corner the two cords could be pulled to different extents, 

 and each wheel could at all times be driven. 



He gave his experience of the elastic spokes. Since 

 Christmas he had ridden a pair of wheels 3,800 miles, and 

 had tested thein most severely, but as yet they showed 

 no signs of becoming untrue or losing their elasticity. 



He had made further tests of the wear of balls, letting 

 them run 1000 miles without being opened, after which 



he found that the wear was about one-fifth the rate of that 

 previously observed. This, he considered, went to show 

 that the wear, such as it was, was almost entirely due to 

 a very small amount of grit which it is impossible to 

 prevent from entering the bearing from the screw however 

 carefully it may be cleaned. However, the result last 

 obtained showed that the loss of weight of each ball in 

 travelling 1,000 miles, during which it turned on its own 

 axis about 1,400,000 times was less than i/iooo grain. 

 This, he thought, showed that those who found fault with 

 ball bearings did so very rashly. 



Mr. Sampson referred to a machine shown at the 

 Inventions Exhibition on the lines of the Otto, but 

 driven with a chain and with definite worm-gear for 

 steering, which was worthy of attention. 



Mr. Dalby, speaking as a rider, said he was sure that 

 the author of the paper had not set the invention of the 

 balance gear at its true value, that he had done special 

 pleading on behalf of the clutch system After severely 

 criticising the arguments of the author, he attributed the 

 poisibility of the modern tricycle mainly to the balance 

 gear. 



Mr. F. Warner Jones thought that more might have 

 been said on the principles of cycle construction. The 

 paper had been mainly descriptive of machines, and very 

 little of first principles was to be found in it. 



He agreed that the wind resistance was so much less 

 felt on the small safeties than on a full-sized machine, 

 that this should be considered an important factor in the 

 cause of their good qualities. But he did not quite agree 

 with Mr. Boys as to the way in which this acted. In any 

 case the seat must be about seven inches behind the 

 pedal axle to enable the rider to work in a proper position. 

 With a saddle so placed on an ordinary bicycle the 

 position became dangerous when descending a hill, but 

 owing to the construction of the safety bicycles this 

 position could be attained with perfect safety, the rider 

 being more between the wheels. On a high machine the 

 wind acted with a greater leverage, throwing more 

 pressure on the hind-wiieel in proportion than in a Safety. 



The Safety bicycles with the steering-wheel in front 

 were safer than the others owing to their greater length, 

 and the fact that the rider was so far back, but they 

 were not so fast, as less weight was on the driving-wheel. 

 The rider could not be placed far enough back to put as 

 much weight on the driving-wheel unless the pedal a.xle 

 were divided. By adapting the swing frame with the 

 divided pedal axle to such a class of machine, as much 

 weight as desired could be placed upon the driver, and 

 the advantages of the dwarf bicycles and of the Otto 

 secured'in one machine. 



Concerning the Otto there seemed an anomaly— that 

 they were better hill climbers when the wheels were as 

 high as 56 in. than when smaller. As it was necessary 

 for the centre of gravity to be over the points where the 

 wheels touched the ground, there was a limit to the 

 steepness of hill which could be surmounted. 



He quite agreed with Mr. Boys as to the good qualities 

 of the elastic spokes. He considered they were correct 

 in principle. 



Mr. Boys showed that even in the case of the steepest 

 hills the amount by which the points of contact of the 

 wheels with the ground were advanced was so small as 

 to produce none of the effects supposed by Mr. Jones. 

 In fact the hill-climbing power of the machine was 

 perfectly well known. 



Mr. Phillips felt sure that the slow pedalling was a far 

 more important factor than the diminished wind resist- 

 ance in the cause of the excellence of the Safeties. He had 

 not intended to represent that the clutch gear was as good 

 as the differential, but that at present the differential was 

 greatly superior ; he however believed that some device 

 of the kind that he had spoken of— a perfect and instant- 

 aneous double-acting clutch— would be better than either. 



