16 Mr. C. Vernon Boys [March 7, 



lateral stability, the spokes are carried not to the centre, but to the 

 two ends of the hub, thus lying on two cones. Such a wheel is 

 abundantly strong in its own plane : it can withstand the jars and 

 shocks of a bad road without a groan, but once subject it to a serious 

 side strain, such as I can with ease put upon it with a jerk of my 

 wrists, and the wheel will crumple up like an umbrella in a storm. 

 Till this year there has been no change in the principle of construc- 

 tion, though in detail many improvements have been carried out and 

 are largely adopted. By the use of hollow rims a stiffer and lighter 

 wheel can be made ; thick-ended, crossed, and laced spokes are em- 

 ployed, and other details modified. Essentially, however, the " spider " 

 wheel as a structure is the same as it was when first introduced. 

 Suddenly, two radical changes are presented to us. Mr. Otto, whose 

 great work I shall describe in its projDer place, has devised a wheel 

 on a new system, in which the spokes that form the structure lie in 

 the plane of the rim, in which position they are best able to withstand 

 direct shocks. Such a wheel would be unstable, but requires very little 

 to keep it true. Delicate spokes not screwed up very tight are therefore 

 placed on either side, so that a side strain is met by the whole 

 strength of the spokes on one side, which are not, as hitherto, weakened 

 by the pull of the spokes on the other. On this system much nar- 

 rower wheels can be made than was possible before. The other 

 change, due to the same inventor, is still more striking. He has 

 found, contrary to the opinion of every one, that wheels, either of his 

 narrow type or of the usual form, can be made and will remain true 

 when the spokes are made elastic by being bent into a wavy 

 or slightly spiral form. If only these wheels will stand the 

 test of time — and I see no reason why they should not — one of the 

 greatest discomforts and probable causes of injury from which the 

 cyclist suffers, the vibration and jolting due to a bad road, will have 

 been removed. 



The bearings in a bicycle are perhaps more to be admired than 

 any single part. Instead of allowing the axle to slide round in its 

 bearings, hard steel rollers or balls are introduced, so that the parts 

 which are pressed together roll over and do not slide upon one 

 another. Any one who has trodden on a roller or a marble must have 

 found in a possibly unpleasant manner the great difference between 

 rolling and sliding friction. I can now give for the first time the 

 result of an experiment, only completed this morning, which shows 

 the extraordinary perfection to which this class of work has attained. 

 I have observed how much a new set of balls, which I obtained direct 

 from the well-known maker Mr. Bown, has lost in weight in travelling 

 1000 miles in my machine. Every 200 miles I cleaned and weighed 

 the balls with all the care and accuracy that the resources of a 

 physical laboratory will permit. The set of twelve when new weighed 

 25-80400 grms., after 1000 miles they weighed 25*80088 grms., the 

 loss being 3 "12 milligrams, which is equal to ~ grain, that is in 

 running 1000 miles each ball lost -J- grain. This corresponds to a 



