of Edinburgh, Session 1875 - 76 . 
11 
or otherwise. He stuck closely to the work he had undertaken, 
and continued at it till the year 1869, when failing health led him 
to resign. 
He, however, continued to take an interest in geological pursuits, 
and gave, from his private funds, a donation of L.5000, for the 
endowment of a chair of' geology in the M‘Gill College, Montreal. 
Charles Wheatstone was born at Gloucester in 1802, and died 
in Paris 19th October 1875. He was on the list of our British 
Honorary Fellows. 
The rudiments of education were obtained by him at a private 
school. Whether he afterwards went to a university, I have not 
discovered. 
His youth and early manhood were devoted to the construction 
of musical instruments, and to experiments with the view of dis- 
covering more exactly the laws of sound. He paid special attention 
to the instruments depending on vibrating springs. The present 
improved Concertina is due to his invention. 
His first scientific memoir was in the year 1823, when he pub- 
lished in the “ Philosophical Annals” an account of some “ New 
Experiments on Sound.” It excited considerable attention among 
physicists, and was translated into several foreign periodicals. In 
1827, in the “ Quarterly Journal of Science,” he published farther 
“ Experiments on Audition,” accompanied by a description of the 
Kaleidophone, an instrument to illustrate both acoustical and optical 
phenomena. 
During the next eleven years, he continued to produce papers and 
to invent instruments for illustrating the properties of sound. 
In 1838 he seems to have entered on a different subject of inves- 
tigation altogether, viz., light. He had discovered relations be- 
tween waves of sound and waves of light. He communicated to 
the Royal Society of London, and also to the British Association^ 
an account of some hitherto unobserved phenomena of binocular 
vision, illustrating them by means of the instrument vhich he 
invented, called the “ Stereoscope.' 1 To Wheatstone is due the 
discovery, that the conception of solidity is due entirely to the 
mental union of two dissimilar perspectives. 
In 1852 he invented an instrument called the u Pseudoscope ,” 
