Letter from G R M Garratt to Basil Binyon

A letter from G.R.M. Garratt, Deputy Keeper, Science Museum, South Kensington, London SW7, to Major Basil Binyon, Hawthornedene, Hayes, Bromley, Kent, asking for assistance in writing a description of the Number 1 Spark Radio Set in the Museum's collection. He is particularly interested in knowing when the type was introduced, what its relation to the Type 52 is and the history of the War Department Wireless Factory. Attached is a hand drawn sketch of the set.