Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 233
. In using it as a radial averaging instrument, the range oftracing is equal to a ring formed bv two circles of 1 inch and 13 inchesrespectively. By connecting the tracing arm with a heavy brass roller the instrumentcan further be used as a Rolling Planimeter. … Fig. 17.—Universal Planimeter with Roller. , Roller for the Universal Planimeter (i.e. the part AB of above illustra-tion).—The roller maybe connected very conveniently with the tracing frame,allowing areas of any length and a width of n inches to be measured withthe pattern Paregol, and of 22 cm.…
