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.

    50/406 (page 40)
    [40] to the Incident. Then, beyond thefe two Prifms I placed a third, which might refrad that emergent Light, and by that Refradion caS the ufual Colours of the Prifm upon the oppofite Wall, or upon a flieet of white Paper held at a convenient diftance behind the Prifm for that refraded Light to fall upon it. After this I turned the Parallelopiped about its Axis, and found that when the contiguous Sides of the two Prifms beeame fo oblique to the incident Rays that thofe Rays began all of them to be refleded, thofe Rays which in the third Prifm had fuffered the greateft Re- fradion and painted the Paper with violet and blew, were firft of all by a total Reflexion taken out of the tranfmitted Light, the reft remaining and on the Paper painting their Colours of Green, Yellow, Orange, and Red as before 5 and afterwards by continuing the motion of the two Prifms, the reft of the Rays alfo by a total Reflexion vanifhed in order, according to their degrees of Refrangibility. The Light therefore which emerged out of the two Prifms is compounded of Rays differently Refrangible , feeing the more Refrangible Rays may be taken out of it while the lefs Refrangible remain. But this Light being trajeded only through the Parallel Superficies of the two Prifms, if it fuffered any change by the Refradion of one Superficies it loft that impreffion by the contrary Refradion of the other Superficies, and fo being reftored to its priftine con- ftitution became of the fame nature and condition as at firft before its Incidence on thofe Prifms 5 and therefore, before its Incidence, was as much compounded of Rays differently Refrangible as afterwards. Fig. 12. lllujlratwn. In the 22th Figure ABC and B C D are the the tv/o Prifms tied together in the form of a Parallelo¬ piped, their Sides BC and CB being contiguous, and their Sides A B and C D Parallel. And H J K is the third Prifm,