328 
W. F. STAN LEY & CO. LTD 
Quote Stanley’s ‘A’ Catalogue 
“ALLBRIT” RULE-FORM PLANIMETERS 
The Rule-Form Planimeter is designed for the measurement of areas and mean heights 
of figures larger than can be covered conveniently by the polar planimeter. 
In this design the measuring wheel travels on a uniform matt surface instead of on the 
diagram or drawing which is being measured, and thus its rotation is not influenced by 
surface irregularities which are so difficult to eliminate. 
The instrument is intermediate in range between the polar planimeters and the 
continuous chart patterns, and is particularly suitable for use on drum recording charts 
(rectangular) and short sections of continuous recording charts having a uniform or linear 
scale. 
The model illustrated above is the Fixed Index pattern, a Sliding Bar model can also be 
supplied. 
Construction 
The carriage is a gunmetal casting of sufficient weight to maintain contact of the ball 
pivot in the guiding groove of the rule-form base. 
The rule-form base is of steel, chromium plated, with an accurately machined vee 
groove and carries upon its upper face the specially prepared matt surface upon which the 
measuring wheel travels. 
In the case of the Sliding Bar models the tracer arm is divided and the position of the 
carriage can be set by means of vernier and fine adjustment screws. A data slip is provided 
giving the calibration of the instrument for various scales and units of measurement. 
The area per revolution of the measuring wheel is engraved on the tracer arm of the 
Fixed Index models. 
Each instrument is supplied with magnifier and is packed in a polished wood case.