Planimeter with case, Allbrit, stainless steel / plastic / leatherette, made by Stanley & Co, England, c. 1949
Allbrit Planimeter - blacked and stainless steel rods with plastic roller and vernier, in black velvet-lined leatherette case. This planimeter has an unusual short form of tracing arm, probably used for graphs of a fixed scale. It has a steel bounded white plastic roller which accumulates the distance travelled and increments a counter wheel via a small worm drive.
One side of the tracing arm is marked "1 REV = 10 " ", JCB and "2.21.711". The other side of the tracing arm is marked "10735", the blackened steel supporting arm is marked "Made in England"