Unpublished letter, 'On Nobili's plate of colours' from J P [John Peter] Gassiot to Sir J F W [John Frederick William] Herschel

Description

Gassiot describes an experiment inspired by late Signor Nobili, which involves inducing colours on a steel plate. He explains how two of Professor Daniell’s large constant cells are excited with the usual solutions of copper sulphate and sulphuric acid. A polished steel plate is placed in a porcelain soup plate, and a filtered solution of acetate of lead is poured onto it. A piece of cardboard, out of which the required figures had been previously cut with a sharp knife, is then placed upon a steel plate. Over the card, and resting on it, is a ring of wood a quarter of an inch thick the inner circumference of which is of the same size as the figure. A convex copper plate is placed so that its outer edge rests on the inner part of the wooden ring, and its centre placed near to the cardboard. Connecion is made by the positive electrode of the battery with the steel plate; the negative being placed in the centre of the copper convex plate. Gassiot notes that if a concave plate is used instead of a convex plate, the same colours are obtained as in the former experiment, but in an inverse order.

Annotations in pencil throughout.

Subject: Chemistry

Received 15 January 1840. Read 16 January 1840. Communicated by John William Lubbock.

Written by Gassiot at Clapham Common [London].

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 4 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'On Nobili’s plate of colours; in a letter from J. P. Gassiot, Esq., addressed to J. W. Lubbock, Esq., V. P. and Treasurer R. S. Communicated by J. W. Lubbock, Esq'.

Reference number

AP/23/27

Earliest possible date

13 January 1840

Physical description

Ink and graphite pencil on paper

Page extent

8 pages

Format

Manuscript