tion of the electric light brings us to an important act of the
inventor, which, though done on behalf of his brother Werner, was
pregnant with great consequences. This was his announcement before
a meeting of the Royal Society, held on February 14, 1867, of the
discovery of the principle of reinforcing the field magnetism of
magneto-electric generators by part or the whole of the current
generated in the revolving armature--a principle which has been applied
in the dynamo-electric machines, now so much used for producing electric
light and effecting the transmission of power to a distance by means of
the electric current. By a curious coincidence the same principle was
enunciated by Sir Charles Wheatstone at the very same meeting; while a
few months previously Mr. S. A. Varley had lodged an application for
a British patent, in which the same idea was set forth. The claims
of these three inventors to priority in the discovery were, however,
anticipated by at least one other investigator, Herr Soren Hjorth,
believed to be a Dane by birth, and still remembered by a few living
electricians, though forgotten by the scientific world at large, until
his neglected specification was unexpectedly dug out of the musty
archives of the British Patent Office and brought into the light.

The announcement of Siemens and Wheatstone came at an apter time than
Hjorth's, and was more conspicuously made. Above all, in the affluent
and enterprising hands of the brothers Siemens, it was not suffered to
lie sterile, and the Siemens dynamo-electric machine was its offspring.
This dynamo, as is well known, differs from those of Gramme and
Paccinotti chiefly in the longitudinal winding of the armature, and it
is unnecessary to describe it here. It has been adapted by its inventors
to all kinds of electrical work, electrotyping, telegraphy, electric
lighting, and the propulsion of vehicles.

The first electric tramway run at Berlin in 1879 was followed by another
at Dusseldorf in 1880, and a third at Paris in 1881. With all of these
the name of Werner Siemens was chiefly associated; but William Siemens
had also taken up the matter, and established at his country house
of Sherwood, near Tunbridge Wells, an arrangement of dynamos and
water-wheel, by which the power of a neighbouring stream was made to
light the house, cut chaff turn washing-machines, and perform other
household duties. More recently the construction of the electric
railway from Po