1891. ] NEW YORK ACADEMY OF SCIENCES. 105 
To-night I wish to show you the most intense light known to 
science, and its adaptation for purposes of projection, which is 
only awaiting a general adoption for use in the optical lantern. 
There is no obstacle to prevent its use, and it recommends itself 
upon its merits to all workers in this direction. .. . 
(A brief history of the electric light follows.) The electric 
light is the outgrowth of the experiments of Sir Humphry 
Davy, made at the Royal Institution, London, in 1801, when 
he made use of 2,000 cells with which he decomposed sodic 
and potassic hydrates and separated their metallic bases. 
These experiments were repeated and extended, and by using 
charcoal points as terminals an intense and dazzling light was 
produced, to which the name voltaic arc was given. 
The are light, then produced from a battery, brilliant as it is, 
was confined to the lecture-room or an occasional outdoor dis- 
play. The fatal difficulty was the labor and cost of the elec- 
trical energy, and it was not until the discovery of induced cur- 
rents by Faraday that this obstacle was removed. The light 
produced by the voltaic are received no practical application 
until 1844, at which time it was regarded as an interesting 
lecture experiment, requiring the use of large and powerful 
batteries, together with suffocating fumes, and labor for a 
possible use of one or two hours. In 1844 Leon Foucault made 
use of the Bunsen battery, and replaced the charcoal points used 
by Davy with pieces of compact gascarbon. He also constructed 
a lamp worked by hand, and the first use made of it was in tak- 
eee oust teolypes and lighting La Place de la Concorde at 
aris. 
It required the combined labors of Nollet, Van Maldern, 
Holmes, Wilde, Ladd, and Siemens to produce by mechanical 
means, direct from motion, a supply of electrical energy that 
would equal that produced from the battery. Even as late as 
1870 this did not seem possible, for the best dynamos at that 
time yielded only a small amount of electrical energy. 
In 1871 Gramme presented to the Academy of Science the 
description of a form of magneto-electric machine possessing 
new features, which were so remarkable as to astonish the world. 
Gramme conceived the idea of using a ring, and rotating this 
between the poles of a magnet in such a way as to prevent re- 
versals in the armature. Many ridiculed this idea. Neverthe- 
less it produced in practicea machine that yielded large currents 
at much less cost, and laid the foundation of our present system 
of electric lighting. 
From whatever source the electricity is supplied, it is neces- 
sary that it meet with some resistance to produce light, and this 
