N. L. Bowen — The Binary System. 573 



General. 



It is encouraging to note the occurrence within the mineral 

 kingdom of one of Roozeboom's theoretically possible types 

 involving both solid solution and enantrotropism. Some little 

 hope of the eventual discovery of genera! laws, applicable even 

 to the complex mixtures known as magmas, is aroused. The 

 accumulation of precise quantitative data is the means to this 

 end. 



In conclusion the writer desires to thank E. S. Shepherd and 

 F. E. Wright of the Geophysical Laboratory for much help 

 and advice throughout the course of the experimental work. 



Geophysical Laboratory, Washington, D. C. 

 Massachusetts Institute of Technology, 

 Boston, Mass. 



References. 



1. W. P. White, this Journal, xxviii, 453, 1909. 



2. Shepherd & Rankin, ibid., xxviii, 293, 1909. 



3. Ostwald's Lehrbuch der Chemie, vol. 2, pt. 2, 38-68. 



4. Die Silikatsckrnelzlosungen, ii, p. 128. 



5. Harker, Science Progress, No. 6. Oct., 1907. 



6. Wright, F. E., this Journal, xxvi, 349, 1908. 



7. Neues Jahrb. B. B., ix, 561, 1894. 



8. This Journal, xxix, 52. 



9. Zs. anorgan. Chemie, lv, 160, 1907. 



10. Ibid., lxiii, 1-48, 1909. 



11. Syn these des inineraux et des roches, p. 156. 



12. Zs. Kryst., ix, 321, 1884. 



13. Arch. sci. phys. et nat. (4), xiii, 352, 1902. 



14. This Journal, xxxi, 341. 



15. Arch. sci. phys. et nat. (4), xviii, 537, 1904. 



16. Q. J. G. S., 1907, p. 145. 



17. Neues Jahrb., i, 20, p. 158, 1884. 



18. Neues Jahrb., ii, p. 1~ 1908. 



19. Sitz. d. k. Akad. Wien, cxvii, 581, 1908. 



20. Morozewicz, Bull. Acad. Sci. Oacovie, p. 958, 1907. 



21. Mem. Rov. Accad. Lincei, xiv, 140, 1905. 



22. Sitzb. Berl. Akad., xviii. 400, 1901. 



23. See Wright and Larsen, this Journal, xxvii, 421, 1909. 



24. Bowen, N. L., ibid., xxxiii, 49, 1912. 



