Micrographia - Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon by Robert Hooke
page 155 of 465 (33%)
page 155 of 465 (33%)
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_secundary_ and weak pulse that shall follow the Ray, namely PP which will
be the weaker: first, because it has suffer'd many refractions in the impeding body; next, for that the Rays will be a little dispers'd or confus'd by reason of the refraction in each of the particles, whether _round_ or _angular_; and this will be more evident, if we a little more closely examine any one particular tinging _Globule_. Suppose we therefore AB in the eighth _Figure_ of the sixth _Scheme_, to represent a tinging _Globule_ or particle which has a greater refraction than the liquor in which it is contain'd: Let CD be a part of the pulse of light which is _propagated_ through the containing _medium_; this pulse will be a little stopt or impeded by the _Globule_, and so by that time the pulse is past to EF that part of it which has been impeded by passing through the _Globule_, will get but to LM, and so that pulse which has been _propagated_ through the _Globule_, to wit, LM, NO, PQ, will always come behind the pulses EF, GH, IK, &c. Next, by reason of the greater impediment in AB, and its _Globular_ Figure, the Rays that pass through it will be dispers'd, and very much scatter'd. Whence CA and DB which before went _direct_ and _parallel_, will after the refraction in AB, _diverge_ and spread by AP, and BQ; so that as the Rays do meet with more and more of these tinging particles in their way, by so much the more will the pulse of light further lagg behind the clearer pulse, or that which has fewer refractions, and thence the deeper will the colour be, and the fainter the light that is trajected through it; for not onely many Rays are reflected from the surfaces of AB, but those Rays that get through it are very much disordered. By this _Hypothesis_ there is no one experiment of colour that I have yet met with, but may be, I conceive, very rationably solv'd, and perhaps, had |
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