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. 1914 edition. Excerpt: ...lying in one plane and a fourth axis of a different kind which is normal to the plane of these three. Hence it will be necessary in writing general symbols to introduce a fourth letter. For all other systems only three letters are required. The fourth letter required for general symbols of the hexagonal system ...
Read More
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. 1914 edition. Excerpt: ...lying in one plane and a fourth axis of a different kind which is normal to the plane of these three. Hence it will be necessary in writing general symbols to introduce a fourth letter. For all other systems only three letters are required. The fourth letter required for general symbols of the hexagonal system is i and stands in the following relationship: h k i l. It will be particularly noted that this is not the alphabetical order. It would be quite possible to indicate the direction of hexagonal planes by using only two indices for the lateral axes since when the indices of two of the lateral axes is known the third one may be calculated. The general relationship existing between the lengths of the intercepts of the three lateral axes may be expressed as follows: if the shortest intercept be considered unity, the longest intercept n, then the intercept of the third axis is-n ' This may be established by reference to Figure 96 as follows: Let AB be a plane intersecting the three lateral hexagonal axes of reference in the points A, B and C, giving the three intercepts AD, BD and CD. The shortest of these CD = 1; the longest BD = n. From C draw CE parallel to AD. Then the triangles ABD and CBE are simiCE-BD l.n n Fig. 96 lar and AD: CE:: BD: BE.-. AD = BE n-1 n-1 Since the plus and minus signs are arranged alternately on the axes of reference of the hexagonal system it follows that a plane which intersects the lateral axes necessarily intersects both positive and negative ends of these axes. Keeping in mind this alternation of positive and negative signs and of the parameter ratio-----ai: na2: --la3 we con n--1 clude that the algebraical sum of the indices for the three lateral axes must in all hexagonal symbols be zero. This may be established by...
Read Less
Add this copy of Crystallography: an Outline of the Geometrical to cart. $58.41, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2016 by Palala Press.
Add this copy of Crystallography: an Outline of the Geometrical to cart. $92.34, new condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2016 by Palala Press.
