The rarity of any reference to him in contemporary documents makes further specification conjectural.
111578 of 1898, or British Specification, No.
In the specification of the patent applied for on the list of July 1877 he showed a sketch of an instrument which consisted of a diaphragm, with a small platinum patch in the centre for an electrode, against which a hard point, made of plumbago powder cemented together with india-rubber and vulcanized, was pressed by a long spring, the pressure of the carbon against the platinum disk being adjusted by a straining screw near the base of the spring.
By this agreement the Postmaster-General agreed to purchase all plant, land and buildings of the National Telephone Company in use at the date of the agreement or constructed after that date in accordance with the specification and rules contained in the agreement, subject to the right of the Postmaster-General to object to take over any plant not suited to his requirements.
Some of the proposed enhancements and extensions of the abc specification are described on the third page of this tutorial.