A Compleat System of Opticks in Four Books, Viz. A Popular, a Mathematical, a Mechanical, and a Philosophical Treatise. To which are Added Remarks Upon the Whole. By Robert Smith, Volumen1
author, and sold there, 1738 - 171 páginas
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aberrations alſo angle aperture apparent diſtance apparent magnitude appear arch axis becauſe become bodies breadth brightneſs caſe cauſe cauſtick circle colours concave conſequently conſidered continually contrary convex Corol corona curve cylinders decreaſe denſity deſcribed determined diameter directly draw drawn emergent equal experience fall farther figure firſt focal diſtance focus focuſes follows formed former given glaſs glaſſes globules greater Hence horizon incident rays inclined increaſe inverſely laſt lens leſs light manner mediums middle moon moſt muſt object obſerved parallel parhelia paſſing pencil perpendicular picture placed plane poſition produced proportion propoſition ratio reaſon reflected refracted rays refraction ſame ſeen ſeveral ſhall ſide ſince ſmall ſome ſphere ſuch ſun ſuppoſing ſurface tangent teleſcope theſe thing thoſe triangles vertical whole whoſe
Página 43 - He knew not the shape of any thing, nor any one thing from another, however different in shape, or magnitude, but upon being told what things were, whose form he before knew from feeling, he would carefully observe, that he might know them again; but having too many objects to learn at once, he forgot many of them : and (as he said) at first he learned to know, and again forgot a thousand things in a day.
Página 43 - One particular only (though it may appear trifling) I will relate. Having often forgot which was the cat, and which the dog, he was ashamed to ask ; but catching the cat (which he knew by feeling) he was observed to look at her steadfastly, and then setting her down, said, so puss ! I shall know you another time.
Página 74 - I speak of Light and Rays as coloured or endued with Colours, I would be understood to speak not philosophically and properly, but grossly, and accordingly to such Conceptions as vulgar People in seeing all these experiments would be apt to frame. For the Rays to speak properly are not coloured.
Página 43 - ... a glass of broken jelly, where a great variety of surfaces so differently refract the light, that the several distinct pencils of rays cannot be collected by the eye into their proper foci ; wherefore, the shape of an object in...
Página 89 - Body by the vibrating Motion of the Parts of the Body, and gets beyond the reach of Attraction, being driven away with exceeding great Velocity.
Página 43 - ... (by which the rays cannot be brought into a focus upon the retina) they can discern in no other manner, than a sound eye can through a glass of broken jelly...
Página 44 - Before he was couched, he expected little advantage from seeing, worth undergoing an operation for, except reading and writing; for he said, he thought he could have no more pleasure in walking abroad than he had in the garden, which he could do safely and readily.
Página 44 - ... it; but his gratitude to his operator he could not conceal, never seeing him for some time without tears of joy in his eyes, and other marks of affection ; and if he did not happen to come at any time when he was expected, he would be so grieved, that he could not forbear crying at his disappointment.