22 



Scientific Proceedings, Royal DuhUn Society. 



be capable of slipping from end to end through that eye, and of 

 being held to that eye in either of these two positions. When the 

 cross-rod is slipped to one end of its range the foot would work the 

 lower of the cogged wheels, and would drive the machine level, 

 and when the rod is slipped to the other end the foot would work 

 the other cogged wheel, and would drive the machine ' geared up.' 

 The slipping of the cross-rod could be effected by continuing the 

 longer of the connecting-rods upwards so as to bring it within 

 reach of the rider, and by providing spring-clutches to hold the 

 cross-rod in its place when it has been slipped to either end. 



The third- contrivance is one which we described at a former 

 meeting of this Society, and which we would ask leave to describe 

 again with a view to its being placed on record. It is a contrivance 

 for applying balance gear to a cranhed axle. Balance gear — that 

 is, gearing which allows the driving wheels of a tricycle, traction- 

 engine, &c., to travel at unequal velocities while both continue to 

 be driven — has hitherto been applied to a straight axle lying be- 

 tween those wheels. We wish to point out that it may be applied 

 to a cranked axle, so that it is possible to apply it to a tricycle, 

 the main axle of which is to be acted on directly by the feet — an 

 arrangement which we believe would in many cases be preferable 

 to the method hitherto employed of adding a countershaft for the 

 feet to work on. This we propose to do as follows : — The cogged 



Yvx. 1. 



wheel a is keyed to the axle of one of the driving wheels of the 

 tricycle, a acts on h and &', cogged wheels keyed to an axle pass- 

 ing through a tube on which the right foot acts. 1/ acts on c, c on 

 d, d on e and e', keyed to an axle passing through a tube on which 



