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III.— 0^ GEAEING POE BICYCLES AND TEICYCLES. By 

 GEOEGE JOHNSTONE STONEY, D. Sc, E. E. S., and 

 GEOEGE GEEALD STONEY. 



[Read, December 18, 1882.] 



The making of Bicycles and Tricycles has "become an enormous 

 industry, and the pecuniary value of patents affecting paltry 

 details, if they can be brought largely into use, is consequently 

 great. The bicycle industry is so overloaded with patents of this 

 kind that no purchaser can obtain a machine with every improve- 

 ment which he may reasonably desire, and the best makers are 

 very much hampered. The inconvenience to the public in this 

 case, which accompanies benefit to a few, has suggested to us that 

 it may be of advantage to communicate the three following con- 

 trivances to the Royal Dublin Society, with a view to rendering 

 them incapable of being made the subjects of patents. 



We have been impressed very much with the advantage of a 

 small wheel in mountain rides, which are those which we chiefly 

 practise. But on the other hand, when one comes down into the 

 plain, the small wheel becomes unsatisfactory, as it prevents the 

 rider attaining the speed which would otherwise be his natural 

 pace under those easier circumstances. We have hitherto ridden 

 machines of a size selected with a view to strike a compromise 

 between these opposed requirements, but a much better result 

 would be obtained if we could get a wheel which would become 

 small and powerful on the hills, and large and swift in the level 

 country. A wheel which could be geared to two or more speeds 

 presents the same advantages. And there are two ways in which 

 we should propose to accomplish this. In both we should prefer a 

 very small wheel, say of 36, or at . most 40 inches diameter, to be 

 driven level, as the technical phrase is, that is, ungeared when 

 ^ climbing up hills, and to be geared tip so as to furnish a higher 

 speed on easy ground, 



I. The first of these contrivances is adapted to a machine with 

 some such levers as the ' Xtraordinary ' and the 'Facile.' The 

 hub of the bicycle wheel is to be made tubular, for the purpose of 



