A familiar introduction to the study of polarized light; with a description of, and instructions for using the table and hydro-oxygen polariscope and microscope / [Charles Woodward].

  • Woodward, Charles
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: A familiar introduction to the study of polarized light; with a description of, and instructions for using the table and hydro-oxygen polariscope and microscope / [Charles Woodward]. Source: Wellcome Collection.

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    more luminous; and as they are quicker or slower, the body is of a different color. (5.) Huyghens supposed that an exceedingly thin and highly elastic medium called ether fills all space, and occupies the intervals between the particles of all substances; that luminous bodies excite vibrations in this ether, which spread like waves formed by dropping a stone into still water; and that the ethereal vibrations impinging on the retina of the eye produce the sensation of light in the same way as the undulations called sonorous, affecting the auditory nerve, produce the sensation of sound. (6.) Newton objected, that if light, like sound, be propagated by undulations, like sound, it would pass through bent tubes, which he considered contrary to fact; hence he supposed light to consist of material particles emitted by luminous bodies, and moving through space with an immense velocity. (7.) To this it was objected, that as light is ascertained, by repeated observations on the eclipses of Jupiter’s satellites, and the aberrations of the fixed stars, to be propagated at the rate of 192,000 miles in a second, its particles if material ought to acquire a momentum; but that no indication of such an effect had ever been experienced even by that delicate organ the eye. Newton’s objections, however, prevailed ; his views were generally adopted under the name of the corpus- cular theory, and the question as to the propagation of light was supposed to be decided. (8.) But the attention of philosophers had been for some time directed to the dark bands seen when light passes through very narrow apertures. If, for instance, we hold the hand between the eye and a bright cloud, or the ground glass of alighted lamp, and open the fingers so as to admit the smallest portion of light, we shall perceive dark bands inter- secting the luminous space at regular intervals. (9.) Little progress was, however, made towards the ex- planation of this phenomenon until Dr. Young pointed out a principle upon which it could be accounted for, and which he termed the interference of the waves of ether.