COXTENTS TO VOLUME IV. 



Number 19. 



Page 



Art. I. — The Melting of Potash Feldspar; by G. W. Moeey 



and N. L. Boavex, 1 



Art. II. — Triasssic Reptilian Order Thecodontia, by F. 



vox Huene, 22 



Art. III. — A Discussion of Triple Salts; by H. L. Wells, 27 

 Art. IV. — Horned Eocene Ungulates; by E. L. Troxell, . . 31 

 Art. V. — The Genus Hyrachyus and its Subgroups; by E. 



L. Troxell (with Plate I), 38 



Art. VI. — A New Occurrence of Ilsemannite; by C. W. Cook, 50 

 Art. VII. — On the Zonal Division and Correlation of the 

 Silurian of Bohemia ; by J. Perner, with the collaboration 

 of O. Kodtm, 53 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — A New Process for the Industrial Production of Barium 

 Hydroxide for Treatment of Molasses in Sugar Kenning, Deguide and Bode: 

 Advanced Course of Instruction in Chemical Principles, A. A. Notes and 

 M. S. Sherrill, 73. — Determination of Sulphur in Iron and Steel, H. B. 

 Pulsifer: Organic Chemistry, V. v. Richter, 74. — Friction and Lubri- 

 cation. Hardy and Doubleday, 75. — Power Alcohol, G. W. Monier- 

 Williams, 76. — The Journal of Scientific Instruments: La Theorie Ein- 

 steinienne de la Gravitation, 77. 



Geology and Mineralogy. — Gravity Anomalies and their Geological Interpre- 

 tation, 78. — Publications of the United States Geological Survey, G. O. 

 Smith, 79. — Die Eruptivgesteine des Kristianiagebietes IV; Das Fengebiet 

 in Telemark. Norwegen, W. C. Brogger, 80.— Mineral Resources of the 

 Philippine Islands for 1919 and 1920. 82. -A List of new Crystal Forms 

 of Minerals: Handbook and Descriptive Catalogue of Gems and Precious 

 Stones in the U. S. National Museum, G. P. Merrill, etc.: Virginia Geo- 

 logical Survey, T. L. Watson: The Topographic and Geological Survey 

 of Pennsylvania, G. A. Ashley: Geology of Drumheller Coal Field, Alberta, 

 J. A. Allan, 83. — Potash in a new area of Texas, 84. 



Natural History. — Arctic Alcyonaria and Actinaria, A. E. Verrill: Genetics, 

 An Introduction to the Study of Heredity, H. E. Walter, 84. — A Natur- 

 alist in the Great Lakes Region, E. R. Downing: La Constitution des 

 plantes vasculaires revelee par leur Ontogenie, G. Chatjveaud, 85. — The 

 Vegetation of New Zealand, L. Cocayxe: Les Mouvements des Vegetaux, 

 R. Dutrochet: Die Pflanzenwelt Afrikas, insbesondere seiner tropischen 

 Gebiete, A. Engler, 86 — Precis de Physiologie Vegetale, L. Maquenne: 

 The North American Slime-moulds, T. H. Macbride, 87. — Soil Conditions 

 and Plant Growth, E. J. Russell: A Handbook of the British Lichens, 

 A. L. Smith. 88. 



Miscellaneous Scientific Intelligence. — The Outline of Science, J. A. Thompson, 

 88. — Publications of the Smithsonian Institution, G. D. Walcott, 89. — 

 Banking, Principles and Practice, R. B. Westerfield: Civic Science in 

 the Home. G. W. Hunter and W. G. Whitman, 90. — Memoirs of the 

 Queensland Museum: United States Life Tables. J. W. Glover, 91. — Public 

 Opinion, W. Lippmann, 92. — Publications of the Carnegie Foundation for 

 the Advancement of Teaching, 93. — American Association for the Advance- 

 ment of Science: Observatory Publications, 94. 



Obituary.— G. Simonds: A. Bacot: L. A. Ranvier: H. M. Howe, 94. 



