188 TRANSACTIONS OF THE CANADIAN INSTITUTE. [ Vo. TAL 
electrified and put in connection with another not electrified, by a wire—when the wire 
fulfils certain conditions, the electricity, instead of distributing itself over the two 
bodies, and suddenly readjusting the equilibrium, rapidly oscillates from one to the 
other body, and does not equilibrate till after a great many such oscillations. By in- 
genious experimental arrangements, Hertz succeeded in shewing that electrical 
impulses, to which these oscillations give rise in surrounding space, propagate them- 
selves with a definite velocity, and this was the first direct confirmation of the ideas of 
Faraday and Maxwell, that electrical activity could be transmitted between two bodies 
without interposing a third. He showed that the propagation of these impulses on 
wires and through air took place in the same way as that of light and sound. He 
measured the velocity of that transmission, and found in air an equal velocity to that 
of light. He studied the reflection of electrical vibrations on metallic reflectors, and 
found in this respect again, complete analogy with that of light. He showed that in 
wires and in the air we could have continuous waves formed by electrical vibration, as 
in the case of sound. He made a great prism of insulating material, and demonstrated 
that a ray of electrical vibration made to fall upon one of its sides, was refracted like 
a ray of light. He found that the index of refraction of that substance was about the 
same for light and electrical vibrations. All these experiments came in wonderfully to 
confirm the electro-magnetic theory of light, and every one perceived the great impor- 
tance of the labors of Hertz, in correlating and referring to the same cause two such 
important parts of physics—two such large classes of phenomena. Besides this 
principal consequence of the experiments mentioned, Hertz has arrived at other con- 
clusions, among which may be mentioned the proof that electrical movements, occurring 
within insulating bodies, produce on external bodies electro-dynamic effects, and that 
the ultra-violet radiations determine the discharge from two bodies of different 
potential, when the difference of potential without the influence of these radiations 
is insufficient therefor. 
“The theory of transformation groups, by Prof. Sophus Lie, of the University of 
Leipzig, is a work of capital importance, in which are gathered together the original 
researches which science owes to Ze, into the internal structure of groups of transfor- 
mation in general, and especially those of contact. The results of such researches 
apply to analysis and differential equations in mechanics, as well as to various 
geometrical problems. The richness and value of the theories of Zze have been widely 
recognised. Illustrious French mathematicians, such as Darboux, Poincaré, Picard, 
Goursat, have published works based upon them, and refer to him with the greatest 
admiration. 
“In preceding competitions, the committee entrusted with the final investigations, 
have placed the names of the authors in order of merit, yet, without having wished to 
dictate thereby how the Academy might be pleased to vote. In the present case the 
committee does not feel enabled to act in that manner—they have examined three 
eminent works, relating to different sciences, and present the three without any 
distinction of their merits. Your vote will determine which best answers the desires 
of the founder of the prize.” ' 
