The Wave Theory Of Licht And Spectra PDF Download

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 edition. Excerpt: ... more effectual remedy by changing the magnifying power; and then, if the appearance remain constant in kind and in degree, we may be assured that it truly represents the nature of the substance to be examined. It is natural to inquire whether or not the figures of the globules of blood delineated by Mr. Hews0n in the Phil. Trans, vol. lxiii., for 1773, might not in some measure have been influenced by a deception of this kind; but, as far as I have hitherto been able to examine the globules with a lens of one-fiftieth of an inch focus, I have found them nearly such as Mr. Hewson has described them. V. Remarks on the Colors of Natural Bodies, 0mz'tted. VI. EXPERIMENT ON THE DARK RAYS OF BITTER Experiment 6. The existence of solar rays accompanying light, more refrangible than the violet rays and cognizable by their chemical effects, was first ascertained by Mr. Ritter; but Dr. Wollaston made the same experiments a very short time afterwards without having been informed of what had been done on the Continent. These rays appear to extend beyond the violet rays of the prismatic spectrum, through a space nearly equal to that which is occupied by the violet. In order to complete the comparison of their properties with those of visible light, I was desirous of examining the effect of their reflection from a thin plate of air, capable of producing the wellknown rings of colors. For this purpose I formed an image of the rings, by means of the solar microscope, with the apparatus which I have described in the Journals of the Royal Institution, and I threw this image on paper dipped in a solution of nitrate of silver, placed at the distance of about nine inches from the microscope. In the course of an hour portions of three dark rings were very...