Electronic Match Output

Number:15a

Maker:Belcher-Hickman "The Electrician"
PHOTO

Type:Electronic

Length:25 cm

Circular:

Special Scales in Well:N

Special Scales on Stock:Y

Gauge Marks:N

Scales Front:30DI 3.28D D = C 1.11BI BI = A cm

Scales Back:

Info: David Walker Collection.
An example of a card slide rule ca. 1911 for wireless (spark gap) telegraphy.