Slide-rule, 10-inch, comprehensive model (P221) mark 2
Slide-rule, 10-inch, comprehensive model (P221) mark 2, made by A.G. Thornton Ltd.
Slide-rule, 10-inch, comprehensive model (P221) mark 2, made by A.G. Thornton Ltd.
Slide-rule, 10-inch, comprehensive model (P221) mark 2, made by A.G. Thornton Ltd.
Case for slide-rule, black, marked 'Thornton' in gold lettering.