Philosophical observations on the senses of vision and hearing ; to which are added, a treatise on harmonic sounds, and an essay on conbustion and animal heat / by J. Elliott, apothecary.

  • Sir John Eliot, 1st Baronet
Date:
1780
Catalogue details

Licence: Public Domain Mark

Credit: Philosophical observations on the senses of vision and hearing ; to which are added, a treatise on harmonic sounds, and an essay on conbustion and animal heat / by J. Elliott, apothecary. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    excited, anfwerable to the times of vibration of the feveral forts of rays. That any one fort of rays, falling on the eye, excite thofe vibra- tions, and thofe only which are in unifon with them, not at all affecting the others, and there- fore caufe only their proper colour. And that in a mixture of feveral forts of rays, falling on the eye, each fort excites only its unifon vibrations, whence the proper compound co- lour refults from a mixture of the whole. N. B. As the following remark relates to vi- fion, it may be here funjoined. Ma r riot t e has publifiied a curious expe- riment which mews that there is an infenfible fpot in the retina, at the entrance of the optic nerve. If an object, be looked at whofe image occupies the whole furface of the retina, one would imagine from thence that an hole or dark fpot mould be perceived in the part of the object anfwerable to the infenfible fpot in the retina; but no fuch fpot or hole is feen. I have obferved that images which fall near that