SIE CHAELES WHEATSTONE. 37-3 



electricity. The application of the revolving mirror to the measure- 

 ment of very small intervals of time was the germ of the later deter- 

 mination of the velocity of light by Fizeau and Foucault. In 1837, 

 Wheatstone associated himself with Cooke in a new attempt to solve 

 the often mooted problem of an electric telegraj)!!. The history of 

 Wheatstone's share in the invention has often been written. He was 

 not the first inventor of an electric telegraph. He was not even the 

 first who attempted to carry into execution a clearly defined scien- 

 tific conception. But he brought to the practical solution of the 

 problem great mechanical resources, with extraordinary energy and 

 perseverance, and in the end he triumphed in England exactly as 

 Morse triumphed in this country, — triumphed by the tenacity of his 

 intellectual grasp of the subject, by unflagging perseverance and 

 unwavering faith. In estimating Wheatstone's merit in connection 

 with the develojiment of the electric telegraph, the eminent services 

 rendered by his partner, Cooke, must not be forgotten. The two 

 together did for England what Morse alone did 'for this country; but 

 the special methods of Cooke and Wheatstone are already nearly for- 

 gotten, while those of Morse are in almost universal use. The list of 

 Wheatstone's papers in the catalogue of the Royal Society includes 

 only thirty titles. In 1838, he published his first paper on binocular 

 vision, and dui-ing the same year he gave to the world the earliest 

 form of the stereoscope. He seems to have considered the subject 

 from a purely scientific point of view, and the form which he gave to 

 the instrument was not adapted to popular use. The invention of the 

 lenticular stereoscope by Sir David Brewster was the next step ; but 

 the full beauty and usefulness of the invention did not appear luitil 

 after the discovery of the art of photography. With the somewhat 

 bitter controversy which followed Brewster's improvement, we have 

 nothing to do. To Wheatstone belongs the creation, not merely of a 

 scientific instrument which almost takes rank with the microscope and 

 telescope, not merely of a toy which has found its wa}^ to the house- 

 holds of all civilized races of men, and which is an unfailing source of 

 cultivated and refined pleasure, but of a whole branch of physiologiciJ 

 optics, the science of binocular vision, applicable to color as well as to 

 form, and full of fruits of usefulness and beauty. In 18-43, Wheatstone 

 rendered another great service to science by the pul)lication of a memoir 

 on new instruments and processes for the determination of the con- 

 stants of a voltaic circuit. In this paper he made known to Eng- 

 land, and we believe we may also say to America, the theory of the 

 galvanic circuit first proposed by Ohm. He gave to the applications 



