Donor challenge: Your generous donation will be matched 2-to-1 right now. Your $5 becomes $15! Dear Internet Archive Supporter,. I ask only once a year. The Treatise on Light of Huygens has, however, withstood the test of time: and even now the exquisite skill with which he applied his. Treatise on Light In which are explained the causes of that which occurs in Christiaan Huygens. translated by Silvanus P. Thompson.
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I found also that when QRE made a straight line, that is, when the incident ray entered the Crystal without being refracted as I ascertained by the circumstance that then the point E viewed by the extraordinary refraction appeared in the line CD, as seen without refraction I found, I say, then that the angle QRG was 73 degrees 20 minutes, as has been already remarked; and so it is not the ray parallel to the edge of the Crystal, which crosses it in a straight line without being refracted, as Mr.
Hence the adoption of as literal a rendering as possible. His speculations as to the ether, his suggestive views of the structure of crystalline bodies, and his explanation of opacity, slight as they are, will possibly surprise the reader by their seeming modernness. And this suffices to chrisiaan that the ray will continue along the curved line which trewtise all the waves at right angles, as has been said.
Treatise on Light / Christiaan Huygens
This accords with the explanation which Mr. I hope also that there will be some who by following these beginnings will penetrate much further into this question than I have been able to do, since lighy subject must be far from being exhausted.
I will set it forth, in a way a little different from his, in order to make the conclusion more comprehensible. It is that when a sphere, such as A here, huygena several other similar spheres CCC, if it is struck by another sphere Huygend in such a way as to exert an impulse against all the spheres CCC which touch it, it transmits to them the whole of its movement, and remains after that motionless like the sphere B.
The effects of which refractions are very remarkable; for by them we often see objects which the rotundity of the Earth ought otherwise to hide; such as Islands, and the tops of mountains when one is at sea.
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What I find to be most probable herein, is to say that metallic bodies, which are almost the only really opaque ones, have mixed amongst their hard particles some soft ones; so that some serve to cause reflexion and the others to hinder transparency; while, on the other hand, transparent bodies contain only hard particles which have the faculty of recoil, and serve together with those of the ethereal matter for the propagation of the waves of light, as has been said.
When the ratio of the velocities of the waves is as two to three, as in our example, which is that which obtains for glass and air, the angle DAQ must be more than 48 degrees 11 minutes in order that the ray DA may be able to pass by refraction.
This makes it evident that in proportion as the wave CA comes to meet the surface AB, there occurs a great quantity of movement along that surface; which movement ought also to spread within the transparent body and ought to have much re-enforced the partial waves which produce the interior reflexion against the surface AB, according to the laws of reflexion previously explained.
Whence it may be further remarked that although the particles are supposed to be in continual movement for there are many reasons for this the successive propagation of the waves cannot be hindered by this; because the propagation consists nowise in the transport of those particles but merely in a small agitation which they cannot help communicating to those surrounding, notwithstanding any movement which may act on them causing them to be changing positions amongst themselves.
I understood Huygens when he was presenting his argument that light travels in waves at a defined speed, but then he thought he should prove it and he lost me. Daniel rated it really liked it Nov 15, One sees also the reason for a noteworthy accident which happens in this refraction: After which I proposed to myself to give it out along with another Treatise on Dioptrics, in which I explain the effects of Telescopes and those things which belong more to that Science.
Des Cartes, is very long; wherefore I give here another which is simpler and easier. Joshua Nomen-Mutatio rated it liked it Dec 26, Another property of waves of light, and one of the most marvellous, is that when some of them come from different or even from opposing sides, they produce their effect across one another without any hindrance.
And this alone is requisite, in our method of demonstration, to cause equality of the said angles without the remainder of the movement reflected from all parts being able to produce any contrary effect. Constantijn Huygens was a diplomat and advisor to the House of Orange, and also a poet and musician.
Des Cartes, who makes Light to consist in a continuous pressure merely tending to movement. Dianna Caley rated it really liked it Aug 07, I’d never before heard of the properties of Icelandic crystal. Let G be this Satellite entering into the shadow of Jupiter, H the same Satellite emerging from the shadow. But in considering the preceding demonstration, one might aver that it is indeed true that BN is the common tangent of the circular waves in the plane of this figure, but that these waves, being in truth spherical, have still an infinitude of similar tangents, namely all the straight lines which are drawn from the point B in the surface generated by the straight line BN about the axis BA.
Erasmus Bartholinus, who has lighf a description of Iceland Crystal and of its chief phenomena. Want to Read saving…. It is your responsibility to check the applicable copyright laws in your country before downloading this work. Now there is no doubt at all that light also comes from the luminous body to our eyes by some movement impressed on the matter which is between the two; since, christiaqn we have already seen, it cannot be by the transport of a body which passes from one to the other.
Lists with This Book. In Huygens had as his mathematical tutor Jan Jansz de Jonge Stampioen, who set the year-old a demanding reading list on contemporary science. Rishikesh Pancholi rated it it was amazing Jan 12, Equally so in every reflexion of the light, against whatever body it may be, the angles of reflexion and incidence ought to be equal notwithstanding that the body might be of such a nature that it takes away a portion of the movement made by the incident light. Descartes was impressed by his skills in geometry.
If then you look through it at different hours of the day, leaving it always fixed in the same way, you will see that the same spots of the object will not always appear at the middle of the aperture of the telescope, but that generally in the morning and treatisd the evening, when there are more vapours near the Earth, these objects seem to rise higher, so that the half or more of treahise will no longer be visible; and so that they seem lower toward mid-day when these vapours are dissipated.
Treatise on Light by Christiaan Huygens
The OCR process results in too many typos and illegible characters. Let A be the Sun, BCDE the annual orbit of the Earth, F Jupiter, GN the orbit of the nearest of his Satellites, for it is this one which is more apt for this investigation than any of the other three, because of lignt quickness of its revolution.
In Iceland are found great lumps of this Crystal, some of which I have seen of 4 or 5 pounds. One sees, in addition, that the wave DCF is determined by the distance attained in a certain space of time by the movement which started from the point A; there being no movement beyond this wave, though there will be in the space which it encloses, namely in parts of the particular waves, those parts which do not touch the sphere DCF. And if these contrary movements happen to meet one another at the middle sphere, B, or at some other such as C, that sphere will yield and act as a spring at both sides, and so will serve christiasn the ligut instant to transmit these two movements.
Huygens was educated at home until turning sixteen years old. The piece C, then, of the wave AC, will in a certain space of time have advanced as far as the plane AB following the straight line CB, which may be imagined as coming from the luminous centre, and which consequently will cut AC at right angles. But one will cease to be astonished by considering how at a great distance from the luminous body an infinitude of waves, though they have issued from different points of this body, unite together in such a way that they sensibly compose one single wave only, which, consequently, ought to have enough force to make itself hiygens.
Now it appears that AK and BL dip down toward the side where the air is less easy to penetrate: Whence then, one will say, does their opacity come?
Treatise On Light
And this same thing is the cause why at certain times a distant object will be hidden behind another less distant one, and yet may at another time be able to be seen, although the spot from which it is viewed is always the same. But in doing this of which I speak, care must be taken to place the sounding body on cotton or on feathers, in such a way that it cannot communicate its tremors either to the glass vessel which encloses it, or to the machine; a precaution which has hitherto been neglected.
I would believe then that those who love to know the Causes of things and who are able to admire the marvels of Light, will find some satisfaction in these various speculations regarding it, and in the new explanation of its famous property which is the main foundation of the construction of our eyes and of those great inventions which extend so vastly the use of them. As to the other emanation which should produce the irregular refraction, I wished to try what Elliptical waves, or rather spheroidal waves, would do; and these I supposed would spread indifferently both in the ethereal matter diffused throughout the crystal and in the particles of which it is composed, according to the last mode in which I have explained transparency.
Should it be objected that if the particles of the ether are smaller than those of transparent bodies since they pass through their intervalsit would follow that they can communicate to them but little of their movement, it may be replied that the particles of these bodies are in turn composed of still smaller particles, and so it will be these secondary particles which will receive the movement from those of the ether.
Whence it appears that RCIT is a straight line; which was to be proved.