24 Scientific Proceedings, Royal Dublin Society. 



A machiiie provided with the balance gear and guiding arrange- 

 ments we propose might have the rider's weight brought almost 

 entirely over the driving wheels, in which case his position might 

 be made secure by two safety-wheels mounted like castors, one in 

 front of one driving wheel, the other behind the second driving 

 wheel. Or perhaps better still, the lever which applies the break 

 might; be made to act on connecting bars which would at the 

 same time give the proper, inclinations to the two safety- wheels. 

 One arrangement for accomplishishing this is represented in the 

 adjoining figure. It would, as in Blood's patent, give a greater 

 inclination to the wheel travelling on the inside of the curve along 

 which it is desired to travel so as to secure continuous rolling. In 

 the figure, is a fixed centre round which the system of connecting- 

 rods is made to turn, and there are pivots at a, h, c, d : ma and nd 

 are projections rigidly connected with the wheels to be guided, as 

 in the guiding apparatus of the ' Coventry' tricycle. 



A tetracycle built in this way would make only two tracks on 

 the road, which is a great convenience. We may observe that we 

 have not foimd a high position for the rider to be a source of 

 danger ; while it gives an advantage in touring, and looks better. 



