Published online by Cambridge University Press: 14 March 2018
At the suggestion of Professor H. H. Read the optic axial angle and the refractive index y were measured in four hypersthenes from Aberdeenshire norites. As the values obtained suggested that the minerals were iron-rich, it was decided to have chemical analyses made. These and the optical data are set out in table I below. At the same time the literature has been searched for analyses and optical data of enstatites and hypersthenes, in order to supplement those used by A. N. Winchell in his diagram of variation of the properties of the series. The references given by Winchell have been examined, and it is found that some of the data is not reliable.
Page 165 Note 1 Winchell, A. N., Amer. Journ. Sci., 1923, set. 5, vol. 6, p. 504 CrossRefGoogle Scholar [M.A. 2-219] ; and Optical mineralogy, 3rd edit., 1933, pt. 2, p. 218.
Page 165 Note 2 Read, H. H., Quart. Journ. Geol. Soc. London, 1923, vol. 79, p. 454.CrossRefGoogle Scholar
Page 165 Note 3 H. H. Read, Quart. Journ. Geol. Soc. London (in the press).
Page 166 Note 1 Read, H. H., Mem. Geol. Surv. Scotland, Explanation of Sheets 86 & 96, 1923, p. 135;Google Scholar and Geol. Mag., 1921, vol. 58, pp. 177-183.
Page 168 Note 1 e.g. Berek, M., Universaldrehtischmethoden. Berlin, 1924, pp. 31-36,Google Scholar 50-64.