10" A W Faber Castell 398 Electrical Engineer's Slide Rule with Original Box

Made in Bavaria in May 1931 (see date stamps 31 and 5 in photos) with English text.

Stock and slide manufactured from pearwood with celluloid facings, with aluminium chisel cursors on one end of the slide for use with the scales in the stock well.

Cursor made from aluminium and glass.

Scales are:

·       on the Stock and Slide (from top edge to bottom edge): Inch, LL2, A (KW) [ B (HP), CI, C ] D, LL3, K

• in Stock Well: Dynamo/Motor, Volt
• on bottom face of slide: S(in) L(og), T(an)

Cursor lines: W, HP/S, d.

Rear of stock has various data and conversions.

Length X Width X Height = 304 X 40 X 10 mm