48o 



NATURE 



{March 20, 1884 



friction there, but of preventing wear in a place wliere 

 any shalce is highly objectionable. One of his ball-heads 

 is on the table. 



The frame of the bicycle, consisting merely of the fork 

 and backbone, is made of thin steel tube, the type of all 

 that is light and strong. Indiarubber, besides being used 

 for the tyres of all machines, has been worked into every 

 part of the structure to diminish, so far as is possible, 

 that perpetual and wearying vibration of which all 

 bicyclists so bitterly complain. The number of improve- 

 ments in every detail is so great that any attempt to enu- 

 merate them is out of the question. Suffice it to say that 

 the modern bicycle is the perfection of all that is perfect ; 

 as a machine for racing, as a machine for hurrying over 

 good and level roads nothing can approach it. Unfortu- 

 nately, however, there is ever present danger, and danger 

 of the most objectionable sort, for the most skilful rider 

 knows too well that should he strike a stone of even an 

 ordinary size he must expect to be pitched over the 

 handles, and come with a crash to the ground. It is true 

 that in general no harm is done, but such a fall may 

 bring any one to a sudden and horrible end. 



Manyhaveattempted, whilestill retaining the advantaoes 

 of the bicycle, to make these involuntary headers impossible 

 by modifying in some way its construction. One of the 

 earliest attempts in this direction is well named the 

 " Extraordinary." On it the rider is placed much further 

 behind the main wheel, but can still employ his weight to 

 advantage, as the treadles are placed below him and are 

 connected by levers with the cranks. In another safety 

 bicycle a third wheel is carried in front, just above the 

 ground, so as to resist at once any tendency to tilt for- 

 ward. In another type much smaller wheels are em- 

 ployed, and the feet, now nearer the ground, are con- 

 nected with the cranks, by levers in the " Facile," or by a 

 hanging pedal in the "Sun and Planet." There is a 

 bicycle with two large wheels — one in front of the other — 

 which two can ride, which should be both safe and 

 rapid. 



By far the most curious and utterly unintelligible of all 

 machines of the bicycle type is Mr. Burstow's " Centre- 

 cycle." So incomprehensible did this machine seem to 

 me that I took the trouble one afternoon last week to 

 ride to Horsham to see it in its native place, h careful 

 examination has convinced me that it is not only correct 

 in its design, but that it is in many respects the most 

 wonderful cycle at present made. There is on the table 

 a model Plympton skate. When this is level, it runs 

 straight ; when inclined either way, it wheels around in 

 a manner that was so familiar a few years ago. The four 

 wheels of the Centre-cycle are a counterpart of the four 

 wheels of the skate ; when the frame leans either way, 

 they turn in an appropriate manner, or, conversely, when 

 they turn, the machine leans in the proper direction. It 

 might be thought that a thing with five wheels is more 

 nearly allied to a tricycle than to a bicycle ; but this is 

 not so, for the Centre-cycle, when ridden skilfully, has 

 rarely more than one wheel on the ground ; the leaning to 

 one side in turning a corner (tricycles unfortunately must 

 remain upright), and the general action is essentially 

 that of a bicycle. The great peculiarity of this machine 

 is the power that the rider possesses of raising or lowering 

 any wheel he likes. Now that I have mounted it you 

 will see that 1 can rest on one, three, four, or five wheels 

 as I please. In consequence of this power of lifting the 

 wheels, a rider can travel over an umbrella without 

 touching it, lifting the wheels as they approach, and 

 dropping them as they pass, after the manner of a cater- 

 pillar. 



Whatever difficulty I may have had in doing justice to 

 the bicycle, the corresponding difficulty in the case of 

 tricycles is far greater. The number of makers and the 

 variety of their work is so great that it would be sheer 

 madness on my part to attempt to describe all that has 



been done. Those who wish to see the great variety of 

 detail which chiefly constitutes the difference between 

 one make and another must go to one of the exhibitions 

 of these things which are now so common. 



All I shall attempt will be an explanation of the leading 

 principles which are involved in the design of a tricycle. 

 For this purpose it will be necessary for me to mention 

 occasionally some particular machine ; but in justice to 

 the hundreds to which I cannot even refer, I wish it to be 

 understood that those named, though typical, are not of 

 necessity better than any other. 



Till a few years ago the bicycle was the only velocipede 

 which was worthy of the name. Inventive genius and 

 mechanical skill have given rise to a series of machines 

 on three wheels on which any one can at once sit at ease, 

 and which require but little skill in their management. 

 Men who do not care to risk their necks at the giddy 

 height of the bicyclist, ladies to whom the ordinary 

 bicycle presents difficults which they cannot well sur- 

 mount, each find in the tricycle the means of obtaining 

 healthy and pleasant exercise, and of enjoying to a cer- 

 tain extent the advantages which the bicycle affords. 

 Thanks to the perfection of the modern tricycle, cycling 

 has become one of the most popular institutions of the 

 day. 



It is first necessary to know what combinations of three 

 wheels will, and what will not, roll freely round a curve. 

 The few possible arrangements determine the general 

 forms which a tricycle can take. A wheel can only travel 

 in its own direction ; no side motion is possible without 

 the application of considerable force, entailing strain and 

 friction of a most injurious kind. In any combination, 

 then, of three wheels, each must be able, in spite of the 

 united action of the other two, to move in its own direc- 

 tion. There is on the table a model in which the three 

 wheels can take every possible position. To begin with, 

 two large ones are placed opposite to, but independent 

 of, one another, and parallel, and a snail one, parallel to 

 the others, is mounted between them at one end. This 

 arrangement rolls along in a straight line with perfect 

 freedom; on twisting the plane of the third wheel it is 

 also free to roll round a curve whether the little wheel is 

 before or behind. If I shift the position of one of the 

 large wheels so that, though still parallel to, it is no 

 longer opposite, the other, then, though they can freely 

 move in a straight line, they can by no possibility be in- 

 duced to roll round a curve. It is clear, then, that two 

 wheels that are parallel cannot be employed in a tricycle 

 unless they are opposite one another. The only class of 

 people who frequently appear to be familiar with this fact 

 are nursemaids, who always tip up the front of a peram- 

 bulator in turning a corner. 



If one wheel is in front of and another behind a third, the 

 combination can only roll round a curve when the front and 

 rear wheel are turned to proportionate extents ino[)posite 

 directions. The model is so arranged now ; if either of 

 the little wheels is not turned to exactly the right amount, 

 they can no longer roll, they can only be dragged round 

 a curve. It is not sufficient that two parallel wheels 

 should be opposite one another, they must be able to turn 

 at different speeds. I have now the two large wheels 

 keyed on the same axle, so that they must of necessity 

 turn together ; this combination is ready enough to go 

 straight, but no amount of encouragement by the steering 

 wheel will induce it to go in any other direction. 



Bearing these facts in mind, it will not be difficult to 

 follow the development of the tricycle. It would seem 

 impossible in the first arrangement (that with two wheels 

 opposite one another, and a third, or steering wheel, 

 before or behind between them) to drive both sides, for 

 the wheels must be able to turn at different speeds ; let 

 therefore one be free to go as it pleases, if the other only is 

 driven, we have at once a very common form of tricycle, 

 in which one wheel drives, one steers, and one is idle. 



