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, Volume 2
author, and sold there, 1738 - 171 pagina's
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Pagina 39 - ... may be looked upon as so much the stronger, by how much the induction is more general. And if no exception occur from phaenomena, the conclusion may be pronounced generally. But if at any time afterwards any exception shall occur from experiments ; it may then begin to be pronounced, with such exceptions as occur.
Pagina 39 - And although the arguing from Experiments and Observations by Induction be no Demonstration of general Conclusions; yet it is the best way of arguing which the Nature of Things admits of, and may be looked upon as so much the stronger, by how much the Induction is more general. And if no Exception occur from Phaenomena, the Conclusion may be pronounced generally.
Pagina 451 - For I perceived that, if light was propagated in time, the apparent place of a fixed object would not be the same when the eye is at rest, as when it is moving in any other direction than that of the line passing through the eye and object; and that when the eye is moving in different directions, the apparent place of the object would be different.
Pagina 39 - ... and from motions to the forces producing them ; and, in general, from effects to their causes ; and from particular causes to more general ones, till the argument end in the most general. This is the method of analysis. And the synthesis consists in assuming the causes discovered, and established as principles, and by them explaining the phenomena proceeding from them, and proving the explanations...
Pagina 295 - Copper wetted to make it fpread eavenly all over the convex. Thus by Working it well I made it as thin as a Groat, and after the convex was cold I ground it again to give it as true a Figure as I could. Then I took Putty which I had made very fine by...
Pagina 296 - Putty upon the Pitch, and ground it again till it had done making a noife, and afterwards ground the Object-Metal upon it as before. And this Work I repeated till the Metal was polifhed, grinding it the laft time with all my ftrength for a good while together , and frequently breathing upon the Pitch, to keep it moift without laying on any more frefh Putty.
Pagina 451 - Object would not be the same when the Eye is at Rest, as when it is moving in any other Direction, than that of the Line passing through the Eye and Object; and that, when the Eye is moving in different Directions, the apparent Place of the Object would be different.
Pagina 404 - ... or excessively thin-blown glass, which he afterwards glewed to the needle, in the same manner as his other objects. . . . The glasses are all exceedingly clear, and shew the object very bright and distinct, which must be owing to the great care this Gentleman took in the choice of his glass, his exactness in giving it the true figure; and afterwards, amongst many, reserving such only for his use, as he, upon trial, 47 found to be the most excellent.
Pagina 39 - This analyfis confifts in making experiments and obfervations, and in drawing general conclufions from them by induction, and admitting of no objections againft the conclufions, but fuch as are taken from experiments, or other certain truths. For hypothefes are not to be regarded in experimental philofophy.