Historical information
http://special.lib.gla.ac.uk/exhibns/Kelvin/miscellany.html
https://www.radiomuseum.org/dsp_hersteller_detail.cfm?company_id=16089
Physical description
Cylindrical metal case with glass front.
Semi-circular dial with kilowatt marking from 0 to 35.
Mounting rods on back
Inscriptions & markings
Manufacturer's Name " Kelvin & James White Ltd
Glasgow and London"