Six Lectures On Light Delivered In America In 1872-1873 - nuovo libro

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: LECTUEE II. ORIGIN OF PHYSICAL THEORIES?SCOPE OP THB IMAGINATION?NEWTON AND THB EMISSION THEORY?VERIFICATION OF PHYSICAL THEORIES? THE LUMINIFEROUS BTHER?WAVB-THEORY OF LIGHT?THOMAS YOUNG ?FRESNGL AND ARAOO CONCEPTION OF WAVE-MOTION?INTERFERENCE OF WAVES?CONSTITUTION OF SOUND-WAVES?ANALOGIES OF SOUND AND LIGHT ILLUSTRATIONS OF WAVE-MOTION?INTERFERENCE OF SOUND WAVES?OPTICAL ILLUSTRATIONS PITCH AND COLOUR?LENGTHS OF THB WAVES OF LIGHT AND RATES OF VIBRATION OF THB ETHER- PARTICLES ? INTERFERENCE OF LIGHT ? PHENOMENA WHICH FIRST SUGGESTED THB TJNDULATORY THEORY?BOYLB AND HOOKS THE COLOURS OF THIN PLATES?THB SOAP-BUBBLE?NEWTON'S KINGS? THEORY OF 'FITS'?ITS EXPLANATION OF THH RINGS?OVERTHROW OF THB THBORY?DIFFRACTION OF LIGHT?COLOURS PRODUCED BY DIFFRACTION COLOURS OF MOTHBE-OF-PEARL. 1. Origin and Scope of Physical Theories. WE might vary and extend our experiments on Light indefinitely, and they certainly would prove us to possess a wonderful mastery over the phenomena. But the vesture of the agent only would thus be revealed, not the agent itself. The human mind, however, is so constituted and so educated, as regards natural things, that it can never rest satisfied with this outward view of them. Brightness and freshness take possession of the mind when it is crossed by the light of principles, shewing the facts of Nature to be organically connected. Let us, then, inquire what this thing is that we n. CONCEPTION OF PHYSICAL THEORY. 43 have been generating, reflecting, refracting and analyzing. In doing this, we shall learn that the life of the experimental philosopher is twofold. He lives, in his vocation, a life of the senses, using his hands, eyes, and ears in his experiments: but such a question as that now before us carries him beyond...