114 MR. F. C. CALVERT AND MR. R. JOHNSON 
lever. The machine consists of a lever H with a counter- 
poise B and a plate C, on which the weights are gradually 
placed. The fulcrum L bears on a square bar of iron A, 
passing through supports E. The bar A is graduated at 
a, and has at its end a conical steel point F, 7mm. or 0°275 
of an inch long, 5mm. or 0°197 of an inch wide at the base, 
and 1:25mm. or 0:049 of an inch wide at the point which 
