[satterly] 



NEW VIBRATION EXPERIMENT 



91 



The long cylinders quoted in A are twice as long as the short 

 cylinders quoted in B and one quarter of 1.47 is nearly .38. 



The moments of inertia of the glass cylinders could not be 

 quickly calculated as some were rods and others tubes of different 

 wall thicknesses. 



II. — Solid brass cylinders were tried next. They were balanced 

 on a fixed glass cylinder. The results were as follow^s: 



II. — Solid Brass Cylinders 

 Diameter of Fixed Glass Cylinder 2.51 cms. 



Mean 1.65 



Check by calculation for No. 6 of the above table, v^ubstituting 

 in Equation (2) we get 



T = 2t 



12 4 



= 2, 



V gX.62 



For No. 1 above 

 / 15.32 



1/ 



9.5+ .5 

 £X .62 



= 1. 13 sec. 



r = 27r 



V 



+ —(.23)- 

 12 4 



gX1.02 



^2, 



V 



19.5+.06 

 gXl.02 



= .»/ sec. 



5è 



Neglecting the - — -correction for the thick cylinder would lower 

 4 



the calculated period about 1 per cent., with the thin cylinder the 

 error is negligible. 



