1852.] OF THE ROYAL INSTITUTION. 109 
Stereoscopes (on Brewster’s principle) illustrating the Phoenomena of 
Binocular Vision, as explained by Professor Wheatstone. [Exhi- 
bited by Mr. Claudet.] 
Talbotypes from the Great Exhibition, by Mr. Henneman. 
A Telescopic Camera Lucida and a Microscope with improved 
Mechanism, by Mr. C. Varley. 
Specimens illustrating Claussen’s Processes of Preparing Flax, Hemp, 
&e. [Exhibited by Dr. Ryan.] 
Minerals. [Exhibited by Mr. Highley, jun.] 
Model (in similar materials) of the Lion, Bull, and Column from 
Nineveh in British Museum. [Exhibited with permission of Dr. 
Layard. ] 
Carving on wood by Mr. W. G. Rogers. 
WEEKLY EVENING MEETING, 
Friday, January 30. 
W. R. Hamitrton, Esq., ERS. &c. Vice-President, in the Chair. 
Proressor BRANDE, 
On Electro-Magnetic Clocks. 
Mr. Branpe began by adverting to the various opinions which 
had been entertained in reference to the mutual relations of elec- 
tricity and magnetism, previous to the grand discovery of Oersted 
in 1819. As soon as the influence of an electrical current upon a 
magnetic needle had been developed by the researches of that 
eminent philosopher, many most important applications of the fact 
almost of necessity suggested themselves, amongst which the 
wonders of the electric telegraph were to be included. Another 
result of Oersted’s discovery was the electro-magnet ; the power 
namely, of conferring by proper adjustments of an electric current 
any degree of magnetism upon a bar of soft iron: and inasmuch 
as these magnetic energies cease the moment that the electric 
current ceases, so we have it in our power to render any conve- 
nient form of soft iron, such as bars, or horse-shoes, powerful 
magnets at one moment, and at the next, entirely withdrawing 
all their powers; and this, simply by making and breaking the 
contacts upon which the flow of electricity from voltaic arrange- 
ment depends. In this way a horse-shoe magnet was made 
alternately to lift and drop a weight, to raise and depress a loaded 
lever, and to bend and release a spring. These effects were merely 
due to the attractive force of the electro-1fiagnet upon holders and 
