1884.] on Bicycles and Tricycles in Theory and in Practice. 23 



a time. These arrangements have the further advantage of enabling 

 the rider to disconnect the treadles from the wheels whenever he 

 pleases. Tricycles on which two, three, or a whole family can go out 

 for a ride together involve few new principles, and I shall not, for 

 this reason, have a word to say about them. 



There remains one machine forming a class by itself more distinct 

 from all others than they are from one another. It is not a bicycle 

 in the ordinary sense of the word ; it is not a tricycle, for it has only 

 two wheels. This machine is from a scientific and therefore from 

 your 2)oint of view more to be admired than any other. It is called, 

 after its inventor, the " Otto." The Otto bicycle and the Otto gas- 

 engine will be lasting memorials to the ingenuity of the brothers 

 who invented them. 



No machine appears so simple but is so difficult to understand as 

 this. Tricyclists who have been in the habit of managing any machine 

 at once are surprised to find in this something which is utterly beyond 

 them. They cannot sit upon it for an instant, for so soon as they are 

 let alone it politely turns them off. When at length, after much 

 coaxing, they can induce it to let them remain upon it, they find it 

 goes the way they do not want. Riding the Otto, like any other 

 accomplishment, must be learnt. Some seem at home on it in half an 

 hour, others take a week or more. It is not surprising that that quick 

 perception in which ladies have so much the advantage of men 

 enables them to quickly overcome the apparently insurmountable 

 difficulties which this machine presents to the beginner. 



The rider, when seated, is above the axle of two large equal wheels, 

 being then apparently in unstable equilibrium : he would of necessity 

 fall forwards or backwards if some movement of recovery were not 

 possible. The Otto rider maintains his balance in the same way as 

 the pedestrian. If he is too far forward, pressure on the front foot 

 will push him back ; if too backward in position, pressure on the rear 

 foot will urge him forward. That this must be so is clear, for what- 

 ever turning power he applies to the wheels, action and reaction being 

 equal and opposite, they will produce an equal turning effect upon 

 him. The steering of this machine is quite peculiar. In the ordinary 

 way both wheels are driven by steel bands at the same speed : so long 

 as this is the case the Otto of necessity runs straight ahead. When 

 the rider desires to turn he loosens one of the bands, which causes the 

 corresponding wheel to be free ; if then he touches it with the brake 

 or drives the other wheel on, it will lag behind and the machine will 

 turn. It is even possible to make one wheel go forwards and one 

 backwards at the same time, when the machine will spin like a top 

 within a circle a yard in diameter. 



There being no third wheel the whole weight is on the driver, the 

 whole weight is on the steerers ; the frame, which is free to swing, 

 compels the rider to take that position which is most advantageous, 

 making him upright when climbing a hill and comfortably seated 

 when on tlie level. Owing to a curious oscillation of the frame which 



