On the invention of stereoscopic glasses for single pictures : with preliminary observations on the stereoscope, and on the physiology of stereoscopic vision / by T. Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891.
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: On the invention of stereoscopic glasses for single pictures : with preliminary observations on the stereoscope, and on the physiology of stereoscopic vision / by T. Wharton Jones. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    perception of the sensation excited by the impression of tlie light on that nervous expansion, the lyaychical part of vision begins. In the act of seeing, we refer our perceptions to without, and to some distance from the eye,—to the place where the object is, whence the rays of light making the impression emanated. In this respect, sight differs from touch; for we refer our tactile sensations to the part of the skin impressed. In tills peculiarity of sight we may perceive an adap- tation to the means by which the retina is impressed —viz., not directly by the object, as the skin is in touch, but only tlmough tlie medium of the rays of light proceeding from the object. In thus referring our visual perceptions to without, and to some dis- tance from the eye, we take no cognizance of the fact that the impression exciting the sensation is actually made on the retina, nor of the nature of the intervention of the impressing agent, light. This faculty of outness of visual perception is owing to an original inborn law of our muids, and not, as has often been maintained, on experience and association acquired through the sense of touch. In support of what is here advanced, the sense of touch itself affords an illustration — viz., the well-known fact that persons who have had the mis- fortune to lose a limb sometimes feel as if the lost organ were stffl in connection with the body, and that some part of it, perhaps, is the seat of pain. Thus, to quote from the ‘ Spectator,’ “ The poor fellow, who lost his arm last siege, will teU you he feels the fingers that were buried in Flanders ache every cold morning at Chelsea.” This is an example of a tactile sensation referred by the inmd, under abnormal conditions, not to any part of the existing body, but to without and to some distance there- from, just as a visual sensation is, under normal con- ditions, referred. The direction outwards in wliich the mind refers 1