Opticks: or, a treatise of the reflexions, refractions, inflexions and colours of light / Also two treatises of the species and magnitude of curvilinear figures.

  • Newton, Isaac, 1642-1727.
Date:
1704
Catalogue details

Licence: Public Domain Mark

Credit: Opticks: or, a treatise of the reflexions, refractions, inflexions and colours of light / Also two treatises of the species and magnitude of curvilinear figures. Source: Wellcome Collection.

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    round hole about a fifth or fixth part of an Inch in Dia¬ meter. Upon this Paper I caufed the Spedirum of Homo- geneal Light defcribed in the former Propofition , fo to fall, that fome part of the Light might pafs through the hole of the Paper. This tranfmitted part of the Light I refracted with a Prifm placed behind the Paper, and let¬ ting this refracted Light fall perpendicularly upon a white Paper two or three Feet diflant from the Prifm, I found that the Spedlrum formed on the Paper by this Light was not oblong, as when 'tis made (in the third Experiment) by Refradting the Sun’s compound Light, but was (fo far as I could judge by my Eye) perfe6tly circular, the length being no greater than the breadth. Which fliews that this Light is refracted regularly without any Dilatation of the Rays. Exper, i In the Homogeneal Light I placed a Circle of - of an Inch in Diameter, and in the Sun’s unrefradted Heterogeneal white Light I placed another Paper Circle of the fame bignefs. And goingfrom the Papers to thediftance of fome Feet, I viewed both Circles through a Prifm. The Circle illuminated by the Sun’s Ideterogeneal Light appear¬ ed very oblong as in the fourth Experiment, the length being many times greater than the breadth : but the other Circle illuminated with Homogeneal Light appeared Cir¬ cular and diftindily defined as when ’tis viewed with the naked Eye. Which proves the whole Propofition. Exper. 14. In the Homogeneal Light I placed Flies and fuch like Minute Objects, and viewing them through a Prifm , I faw their Parts as diftindlly defined as if I had viewed them with the naked Eye. The fame Objects pla¬ ced in the Sun’s unrefradled Heterogeneal Light which was white I viewed alfo through a Prifm, and faw them moft confufedly