Proceedings of the Polytechnic Association. 1075 



diiferent kinds, he gave the following data, which are generally 

 accepted as accurate : 



Kesistance IK Pounds pek Ton on Diffeeent Roads. 



Iron floor 8 lbs. per ton 



Stone tramway 12 lbs. per ton 



Paved road 33 lbs. per ton 



Macadamized road 46 to 65 lbs. per ton 



Oravel 147 lbs. per ton 



In the case of the velocipede, allowing the resistance to be forty- 

 six pounds per ton, the velocipede and the rider to weigh together 

 one tenth of a ton, and the effective work of a man to be one-eighth 

 of a horse, or 4,700 pounds raised one foot high per minute, then the 

 velocity attained should be about ten miles per hour. This is more 

 than a man can accomplish by merely walking. It will be seen, 

 however, that if the resistance should be as great as that on a gravel 

 road, the utmost power of a man would drive the machine only about 

 three miles per hour, wliich is less than he could walk. 



Dr. Vanderweyde. — In the velocipede we have a wheel say ten 

 feet in circumference, and a crank of but ten or twelve inches. Bj- 

 moving our feet up and down to the extent of twelve inches, we pro- 

 pel ourselves a distance often feet ; and, meantime, our entire weight 

 is supported by the saddle of the velocipede. Surely, we are enabled 

 to gain a great deal by this. 



Mr. J. S. Whitney. — It is all very well to talk of the velocipede 

 being a useful machine ; but when we consider the constant mental 

 strain which is kept up, owing to the amount of watchfulness required 

 to maintain the proper balance, it will be obvious that riding a veloci- 

 pede becomes very hard work. The amount of watchfulness required 

 will be seen from the fact that one of our best velocipedists, who is 

 also a very powerful man, tells us that merely passing over a nail in 

 the floor has a perceptible effect on the machine. In addition to this 

 there is the liability of getting spilt, for I can myself testify that in 

 my attempts at riding the velocipede I found myself in some very 

 undignified attitudes. 



Dr. Vanderweyde. — Tliose who skate well make no such mental 

 exertion. A poor skater is in constant danger, but to a good skater 

 the keeping of his balance is a second nature, and he does it uncon- 

 sciously and without effort. It will be the same with the velocipede ; 

 when a man has become thoroughly expert he will be in no danger 

 of fallinff. 



