ISBN: 9781130599077

RareBooksClub.com. Paperback. New. This item is printed on demand. Paperback. 82 pages. Dimensions: 9.7in. x 7.4in. x 0.2in.This historic book may have numerous typos and missing text. … Plus…

RareBooksClub.com. Paperback. New. This item is printed on demand. Paperback. 82 pages. Dimensions: 9.7in. x 7.4in. x 0.2in.This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1895 Excerpt: . . . by arranging structural units of different kinds side by side. 1 Zeitsch. f. Kryst. vi. 6ia. A full confirmation of the validity of laws of this kind is much to be desired, as they would afford a means of deciding whether isomorphous mixtures or definite chemical compounds are being dealt with in certain cases. It must, however, be remarked that from the present condition of optics, and more especially from our knowledge of the refractive properties of chemical substances, no appreciable deviation from these laws would be expected, even if isomorphous mixtures really are chemical compounds. The refraction equivalents of elements or groups of atoms undergo no appreciable change, so long as the bonds between the atoms are of similar kinds, or the individuality of the groups remains essentially unchanged. Further, the chemical bonds uniting isomorphous substances are certainly so feeble, that in any case their influence on the refractive power would probably be but small even when compared with the discrepancies noticed between chemical compounds of the same type. The correspondence of most of the observations with the above-mentioned laws cannot therefore be considered as constituting a proof, even if contradictory observations be rejected on the ground of non-homogeneity of the crystals. The measurement of the refractive indices of artificial crystals, and more particularly of mixed crystals, is attended with so much difficulty, and the values obtained with the better characterized isomorphous mixtures differ so slightly from the calculated numbers, that a definite solution of the problem by experimental methods is hardly to be expected. Wyrouboff correctly recognized that a better criterion of the truth of these laws is to be found in measurements of the opt. . . This item ships from La Vergne,TN., RareBooksClub.com<