SIK CHARLES WHEATSTONE. 373 



electricity. The application of the irvolviug mirror to the nieasiire- 

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

 mination of th(^ velocity of li^ht l)y Kizeaii and Foucanlt. In 1837, 

 "VVheatstone associated himself with Cooke in a new attempt to solve 

 the often mooted problem of an electric telegraph. The history of 

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

 not the tirst inventor of an electric telegraph, lie was not even the 

 first who atteni[)ted to carry into execution a clearly delined scien- 

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

 problem great mechanical resources, with extraordinary energy and 

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

 Morse triumphed iu 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 develoi^meut 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 neai-ly for- 

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

 AVheatstoue's papers iu the catalogue of the Royal Society includes 

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

 vision, and during the same year he gave to the world the eai'liest 

 form of tlie stereoscope. lie seems to have considered the subject 

 from a purely scieutific point of view, and the form which lie gave to 

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

 lenticular stereosco^De by Sir David Brewster was the next step; but 

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

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

 bitter controversy which followed Brewster's improvemeut, 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 way 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 physiological 

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

 form, and full of fruits of usefulness and beauty. In 1843, Wheatstone 

 rendered another great service to science by the publication 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 ai)plicatious 



