[= co 19 moe 
— 
© 
a 
Description of the Rotascope. 279 
FIRST SERIES, 
With the sharpest point of the axis downwards. 
Square | Diff. be- 
q 
t. in persed Ratios to} roots of | tween | Theoretical | Difference between 
Ibs. Vezoad 115 No. of jratios and times. observed and theoret- 
Ibs. roots. ical results 
82” | .7130| .7071|/—.0059;} 81”.3165| — 0.6900 
115 (1.0000/1.0000/+.0000/115 .0000 0 .0000 
162 |1.4087/1.4142)+-.0055)162 .6330) + 0 .6330 
1.7043) 1.7320) +.0277/199 .1800} + 3 .1800 
220 |1.9130|2.0000/+-.0870/230 .0000;} +10 .0000 
SECOND SERIES, 
With the more obtusely pointed pivot downwards, having a great- 
et moment of friction. 
4 | 58” | .7160} .7071/—.0089| 57”.2751| — 0.7249 
1} 81 |1.0000/1.0000/--.0000} 81 .0000) .+ O .0000 
2) 114 |1.4074|1.4142/+-.0068]}114 .5502| + 0 .5502 
3/137 11.6913]1.7320)+.0407|140 .2920| + 3 .2920 
4| 152 |1.8765!2.0000|+..1235/162 .0000} +10 .0000 
N= pg ae ee 
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 
baie points. The following table shows, at a view, the differences of 
ime for each weight, the ratios between those differences, and the 
seater times, and the differences between those ratios themselves 
taken successively. 
Ratios of the differ- . 
ences compared with) Differences of the ratios. 
the greater times, 
m- 
10 ‘ ‘ 
Rp genie 
yb. | 827 — §67=2424— 62=.2926, . . 1... 
1... 115° — 81 =3434—115=.2956).2956—.2926=.0030 
2.. (162 —114 =48498--162=.2962).2962-.2956=.0006 
3.. 1196 —137 =59 59-196 =.3073/.3073-.2962=.0111 
4. | 22 —152 =6868+220=.3090!.3090-.3073=.0017 
As the differences in favor of the smaller pivot, increase with the 
‘otal amount of time ; and as there is an increasing ratio between the 
differences and the whole amounts of time given by the smaller pivot, 
"Would lead to the conclusion that friction increased with the in- 
‘tease of velocity. ‘The difference between the theoretical and the 
*xperimental results in the higher velocities, might, it is true, lead to’ 
supposition of such an increase, but it could not be with certainty 
