Description of the Rotascope. 



279 



FIRST SERIES, 



With the sharpest point of the axis downwards. 



SECOND SERIES, 



With the more obtusely pointed pivot downwards, having a great- 

 er naoraent of friction. 



It appears from the above tables, that my instrument at the time 

 these trials were made, had a material difference in the friction of its 

 two points. The following table shovi^s, at a view, the differences of 

 time for each weight, the ratios between those differences, and the 

 greater times, and the differences between those ratios themselves 

 taken successively. 



As the differences in favor of the smaller pivot, increase with the 

 total amount of time ; and as there is an increasing ratio between the 

 differences and the whole amounts of time given by the smaller pivot, 

 it would lead to the conclusion that friction increased with the in- 

 crease of velocity. The difference between the theoretical and the 

 experimental results in the higher velocities, might, it is true, lead to 

 the supposition of such an increase, but it could not be with certainty 



