f political economy in Amherst
College. He was appointed professor of political economy at Columbia
University in 1895. Among his works are: _The Philosophy of Wealth_
(1885); _Wages_ (1889); _Capital and its Earnings_ (1898); _The Control
of Trusts_ (1901); _The Problem of Monopoly_ (1904); and _Essentials of
Economic Theory_ (1907).

CLARK, JOSIAH LATIMER (1822-1898), English engineer and electrician, was
born on the 10th of March 1822 at Great Marlow, Bucks. His first
interest was in chemical manufacturing, but in 1848 he became assistant
engineer at the Menai Straits bridge under his elder brother Edwin
(1814-1894), the inventor of the Clark hydraulic lift graving dock. Two
years later, when his brother was appointed engineer to the Electric
Telegraph Company, he again acted as his assistant, and subsequently
succeeded him as chief engineer. In 1854 he took out a patent "for
conveying letters or parcels between places by the pressure of air and
vacuum," and later was concerned in the construction of a large
pneumatic despatch tube between the general post office and Euston
station, London. About the same period he was engaged in experimental
researches on the propagation of the electric current in submarine
cables, on which he published a pamphlet in 1855, and in 1859 he was a
member of the committee which was appointed by the government to
consider the numerous failures of submarine cable enterprises. Latimer
Clark paid much attention to the subject of electrical measurement, and
besides designing various improvements in method and apparatus and
inventing the Clark standard cell, he took a leading part in the
movement for the systematization of electrical standards, which was
inaugurated by the paper which he and Sir C.T. Bright read on the
question before the British Association in 1861. With Bright also he
devised improvements in the insulation of submarine cables. In the later
part of his life he was a member of several firms engaged in laying
submarine cables, in manufacturing electrical appliances, and in
hydraulic engineering. He died in London on the 30th of October 1898.
Besides professional papers, he published an _Elementary Treatise on
Electrical Measurement_ (1868), together with two books on astronomical
subjects, and a memoir of Sir W.F. Cooke.

CLARK, THOMAS (1801-1867), Scottish chemist, was born at Ayr on the 31st
of March 1801. In 1826 he was appointed lecturer on chemistry at the
Gl