Elementary Chemical Microscopy (Paperback)

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. 1921 edition. Excerpt: ... the values in Bolland's tables first set the crystal so that its prism edge lies parallel to a plane passing through the short diagonal of the polarizing nicol. Next determine the index for a 1 Kley, Zeit. anal. Chem., 43 (1904), 160. "Bolland, Monats., 29 (1008), 991; 31 (1910), 387. position at g0 degrees to the first. If a third value can be found, determine it. If the values for a and 7 are wanted, determine the values for a very large number of fragments; the minimum value will be a and the maximum y. Determination of the Refractive Index of a Liquid by the Method of the Displacement of Images.--When an object is viewed through a liquid from a point in a line normal to the plane in which the object lies, the image observed will appear to lie in a plane above that of the object, the amount of displacement being dependent upon the refractive index of the interposed medium.1 If, therefore, we place a liquid in a cell of depth DD' (Fig. 140) and measure the amount of displacement of image 0O' of a mark at 0 upon the upper surface of the glass slide, the index of DD' refraction n will be found from the equation n = jy Method 1. A Cell and Cover Glass of Known Thickness.--Cement upon an object slide of clear glass a cell whose top and bottom are ground true and parallel. After the cement has hardened, determine the depth of the cell by means of calipers, dial gauge or by means of the micrometer screw of the fine 1 This method is very old and is generally known as the Due de Chaulnes Method, having been described by him in 1767-1770. See also Sorby, Chem. N., 37 (1878), 151; Watson, Physics; Johannsen, Manual of Petrographic Methods. adjustment of the microscope. The opening in the cell should be not less than twice its depth. A depth...