INTRODUCTION 5 



chain was used to convey the power from the foot to the disk. The first 

 form of this instrument has been described in detail in a former publica- 

 tion by Benedict and Carpenter. 1 A second apparatus was constructed 

 during the summer of 1911 by Mr. W. E. Collins, mechanician of the 

 Nutrition Laboratory, and carefully tested. The original ergometer 

 leaves little to be desired in the way of accuracy, constancy, and sub- 

 stantial construction, but as certain modifications have been made in 

 constructing the second instrument, a detailed description of this ergom- 

 eter seems desirable. 



DETAILED DESCRIPTION OF THE BICYCLE ERGOMETER. 



For the latest form of bicycle ergometer, which is shown in fig. 1, a 

 high-grade bicycle frame, with sprockets and pedals, was purchased. 

 Instead of the ordinary sprocket-chain, a special chain was used in which 



Fia. 1. Side and top views of ergometer II. 



the minimum resistance and maximum flexibility were secured by roller 

 bearings in the links. The rear wheel was replaced by a hub of the type 



1 Benedict and Carpenter, U. S. Dept. Agr., Office Expt. Stas. Bui. 208, 1909, p. 11. 



