servation
that the whole island was electrified by the battery at the telegraph
station.

Jenkin's position at Edinburgh led to a partnership in cable work with
Sir William Thomson, for whom he always had a love and admiration.
Jenkin's clear, practical, and business-like abilities were doubtless
an advantage to Sir William, relieving him of routine, and sparing
his great abilities for higher work. In 1870 the siphon recorder, for
tracing a cablegram in ink, instead of merely flashing it by the moving
ray of the mirror galvanometer, was introduced on long cables, and
became a source of profit to Jenkin and Varley as well as to Sir
William, its inventor.

In 1873 Thomson and Jenkin were engineers for the Western and Brazilian
cable. It was manufactured by Messrs. Hooper & Co., of Millwall, and the
wire was coated with india-rubber, then a new insulator. The Hooper left
Plymouth in June, and after touching at Madeira, where Sir William was
up 'sounding with his special toy' (the pianoforte wire) 'at half-past
three in the morning,' they reached Pernambuco by the beginning of
August, and laid a cable to Para.

During the next two years the Brazilian system was connected to the
West Indies and the River Plate; but Jenkin was not present on the
expeditions. While engaged in this work, the ill-fated La Plata, bound
with cable from Messrs. Siemens Brothers to Monte Video, perished in
a cyclone off Cape Ushant, with the loss of nearly all her crew. The
Mackay-Bennett Atlantic cables were also laid under their charge.

As a professor Jenkin's appearance was against him; but he was a clear,
fluent speaker, and a successful teacher. Of medium height, and very
plain, his manner was youthful, and alert, but unimposing. Nevertheless,
his class was always in good order, for his eye instantly lighted on any
unruly member, and his reproof was keen.

His experimental work was not strikingly original. At Birkenhead he made
some accurate measurements of the electrical properties of materials
used in submarine cables. Sir William Thomson says he was the first to
apply the absolute methods of measurement introduced by Gauss and Weber.
He also investigated there the laws of electric signals in submarine
cables. As Secretary to the British Association Committee on Electrical
Standards he played a leading part in providing electricians with
practical standards of measurement. His Cantor lectures on submarine
cables, and his treatise on EL