128 
PHYSICAL AND MATHEMATICAL SECTION. 
Annual Meeting, March 29th, 1881. 
E. W. Binney, F.RS., F.G.S., President of the Section, 
in the Chair. 
The following gentlemen were elected officers of the 
Section for the ensuing year : — 
JOSEPH BAXENDELL, F.R.A.S. 
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E. W. BINNEY, F.R.S., F.G.S. 
ALFRED BROTHERS, F.R.A.S. 
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JAMES BOTTOMLEY, D.Sc., F.C.S. 
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JOHN A. BENNION, F.R.A.S. 
“On the Motion of Developable Cylinders,” by James 
Bottomley, D.Sc., F.C.S. 
I have not seen, in any works on Dynamics, the following 
problem treated. A perfectly flexible surface is rolled up 
so as to form a cylinder. The external edge is fixed and 
the cylinder is allowed to roll down an inclined plane, under 
the action of gravity, to determine the motion. As ex- 
amples we may take rolls of tape or ribbon. I suppose the 
lamina to have thickness, but this thickness to be indefi- 
