Air Ministry

The American Electric Speciality Co.

Andrew Rapid

Armaments Research Dept.

A. W. Gamage

B. Davies

Becker

Bellingham and Stanley

Benjamin Martin

The British L. M Ericsson Mfg. Co.

British Telegraph Manufactory

British Thompson

Brownie Wireless Co.

BTH

Cambridge Instrument Co.

Cambridge Scientific Co.

Clarke

Crompton

Cryselco

Cuttriss and Co.

C. Zeiss

Easton Anderson and Goolden

E. M. Job

Elliot Bros.

EWC

F .E. Becker

F. R. Butt

Gambrell Bros.

Gebr Ruhstrat

Gerhardt of Bonn.

George Blythe

G .Leitz Wetzla

The Gramophone Company

Griffen and George.

Hartmann and Braun

Harvey and Peak

I. C. Jones

John Browning

J. White

Kelvin and White Ltd.

Kew Observatory

L. Oerting

Machlett

Muirhead and Co.

Mullard

Nalder Bros.

Nernst.

Newton and Co.

Osglim G. E. C.

Osram G. E. C.

Philips

R. M. Co.

Robertson

Robt. W. Paul

Royal Ediswan

Siemens

Siemens Bros. Co.

Spencer

Sunbeam

T. Carpertier

Tisley and Spiller

Thomas A. Edison

U. C. W. Workshop

Vulcan Works

Wates Bros.

W. Groves

W. G. Pye

William and Samuel Jones

Willats

W & J. George and Becker

W. Shapland

W. T. Goolden and Co.

W. Thompson

Zimmerman

Ben Davies

F. W. Rudler

Maentwog Hydroelectric Station

Miss Gwen Davies

Prof. H .P. Lewis

The Shirley Institute

St. David’s College, Lampeter