DEATH OF SIR JOSEPH SWAN.

A PIONEER OF ELECTROCHEMISTRY.

We regret to record that Sir Joseph Swan, whose name is inseparably associated with the invention and development of the incandescent electric lamp, died yesterday at his residence, Overhill, Warlingham, Surrey.

Joseph Wilson Swan was born on October 31, 1828, at Sunderland, where, after leaving school,, he became apprentice to a firm of druggists in order to gain a practical acquaintance with chemistry. At the end of his apprenticeship, which he found es unsatisfactory a form of technical education in chemistry as many others have found it before him, he went to Newcastleon-Tyne and obtained employment in a chehiical business with Mawson, of whom he subsequently became partner and brother-in-law. Under his guidance the firm greatly extended its operations and began, to pay special-attention to the manufacture of photographic supplies.

Photographic Work.

Swan, himself was responsible for several important advances in practical photography. Turning first to photographic reproduction, he patented in 1864 one of the earliest commercially practicable processes for carbon" printing, depending on the fact that gelatine in presence of chromic acid becomes hard and insoluble under the action of light. This phenomenon he further applied to tanning and other purposes in 1866. Eleven years later he was engaged in investigating the sensitiveness to light of emulsions of gelatine with bromide of silver, and his observations on the part played by the temperature at which the manufacture is conducted enabled his firm in 1877 to turn out dry plates of unsurpassed rapidity and general excellence.

The improvement of the dry plate to which Swan thus contributed enormously increased the convenience of ordinary photography. But, more than that, it brought about a revolution in astronomical photography, and Sir William Huggins declared that the great and notable advances which have been made in

astronomical method and discoveries by means of photography since 1875 are. due almost entirely...