352 
W. F. STANLEY & CO. LTD. 
Quote Stanley's *A’ Catalogue 
SLIDE RULES 
“P.I.C.” “ DIFFERENTIAL ” SLIDE RULES 
Advantages of Differentialism 
Slide Rules incorporating both the Trigonometrical and Log-Log Differential Scales 
enable the user to carry out a wider and more comprehensive range of Trigonometrical 
and Log-Log computations with only 9 units of Scale length, compared with at least 
13 units of Scale length of equivalent orthodox pattern slide rules (where some of the 
Scales are inconveniently located on reverse of slide). 
Slide Rules incorporating Trigonometrical Differential Scales enable the user to carry 
out a wider and more comprehensive range of computations with an economy of at least 
2 units of Scale length compared with the equivalent orthodox pattern slide rule. 
A8821-A8822 
STANDARD 
(Improved) Basic Scales with Sine and Tangent Range to 0° 
A882I 10 in. Mahogany (Pattern 101). 
A8822 20 in. ditto. (Pattern 102). 
REITZ 
(Improved) Basic Scales, Cube Scale, Sine and Tangent Range to 0° 
A8825 10 in. Mahogany (Pattern III). 
A8826 20 in. ditto. (Pattern 112). 
COMPREHENSIVE LOG-LOG 
Log-Log Values I0 5 to l ] 0, Vector Scale, Sine and Tangent Range to 0° 
A8828 10 in. Mahogany (Pattern 121). 
A8829 20 in. ditto. (Pattern 122).