1868.] 



President's Address. 



145 



outline of a large and apparently well-considered scheme, with estimates 

 and other essential details ; it contemplates an expedition to last three or 

 four years, starting from the eastern shores of Queensland, and termi- 

 nating in an exploration of the western portion of the Australian conti- 

 nent ; and he offers his own services for the conduct of such an underta- 

 king. Should the plan find favour with the different Australian Colonies 

 who would bear its expense and reap the chief material advantage of its 

 results, there can be no doubt of its producing a rich harvest in physical 

 geography and natural history, and as little doubt of the warm interest it 

 would command in the Scientific Societies of the mother country, espe- 

 cially in the Eoyal Society, and of the pleasure with which they would 

 give to it every assistance in their power. 



I proceed to the award of the Medals. 



The Copley Medal has been awarded to Sir Charles Wheatstone, F.R.S., 

 for his researches in Acoustics, Optics, Electricity, and Magnetism. 



The researches of Sir Charles "Wheatstone in acoustics, optics, elec- 

 tricity, and magnetism, numerous and important as they are, have already 

 taken their place as integral parts of science, and have become so com- 

 pletely incorporated into its teaching that it will be hardly necessary on 

 the present occasion to do more than enumerate the leading ones, in 

 recognition of which the Copley Medal has this year been awarded. 



The earliest of these researches in point of time were those connected 

 with acoustics ; and among these we may mention a paper on the trans- 

 mission of sound through solid conductors, which (in 1828) describes the 

 means discovered by the author of transmitting musical performances to 

 distant places, where they are made audible by sounding-boards through 

 the intervention of wires or wooden rods. 



His paper on the acoustic figures of vibrating surfaces was published in 

 the ' Philosophical Transactions ' for 1832. In this the laws of the for- 

 mation of the varied and beautiful figures discovered by Chladni were 

 first traced. 



His subsequent invention of the Kaleidophone furnished him with an 

 elegant means of showing optically the coexistence of different forms of 

 vibrations in sounding bodies. 



His wave-machine furnished a still more complete method of demon- 

 strating the composition of undulations by mechanical means. 



In optics his contrivance of the Stereoscope and the Pseudoscope, and 

 his discussion of the modes in which binocular vision is effected, described 

 in the ' Philosophical Transactions ' for 1838 and 1852, were even more 

 ingenious and important, as showing us how we obtain a perception of 

 solidity or relief, or of its reverse, by the simultaneous observation of two 

 plane images. 



Another ingenious optical invention was the Polar Clock, described to 

 the British Association at their Meeting in 1849. This is an instrument 



