A WEEKLY JOURNAL DEVOTED TO THE ADVANCEMENT OF SCIENCE, PUBLISHING THE 



OFFICIAL NOTICES AND PROCEEDINGS OF THE AMERICAN ASSOCIATION 



FOR THE ADVANCEMENT OF SCIENCE. 



Editoeial Committee : S. Newcomb, Mathematics ; E. S. Woodward, Mechanics ; E. C. Pickering, 

 Astronomy ; T. C Mendenhall, Physics ; R. H. Thurston, Engineering ; Ira Remsen, Chemistry ; 

 Charles D. Walcott, Geology ; W. M. Davis, Physiography ; Henry F. Osborn, Paleon- 

 tology ; W. K. Brooks, C. Hart Merriam, Zoology ; S. H. Scudder, Entomology ; C. E. 

 Bessey, N. I.. Britton, Botany ; C. S. MiNOT, Embryology, Histology ; H. P. Bow- 

 DiTCH, Physiology; J. S. Billings, Hygiene; William H. Welch, Pathol- 

 ogy ; J. McKeen Cattell, Psychology ; J. W. Powell, Anthropology. . 



Friday, November 22, 1901. 



CONTENTS : 

 The American Association for the Advancement of 

 Science: — 

 The Geology of Ore Deposits, II. : Professor C. 



R. Van Hise 785 



Section E, Geology and Geography : H . B. Pat- 



TON 794 



Membership of the Association 800 



The American Microscopical Society : Professor 



Henry B. Ward 801 



Total Eclipse of the Sun: Dr. S. A. MITCHELL... 802 



Scientific Books : — 



Alaska: W J M. Calkins on the Protozoa: 

 Professor W. M. Wheeler. Annual Report 

 of the Chief of the Bureau of Steam Engineering : 

 Professor R. H. Thurston. Boscoe-Schor- 

 lemmer's Lehrbuch der organischen Chemie : PRO- 

 FESSOR W. A. NOYES 807 



Scientific Journals and Articles 812 



Societies and Academies 813 



Discussion and Correspondence : — 



Effect of Diminished Air Pressure : PROFESSOR 

 R. DeC. Ward. Practical Ameliorations of 

 English Grammer : Professor Alexander 



F. Chamberlain 814 



Shorter Articles: — 



Catalase, a. New Enzym of General Occurrence : 

 D. W. May. Toads killed by Squash-bugs : 



Albert F. Conradi 815 



Current Notes on Meteorology : — 



The Weather Bureau ; MontJily Weather Review ; 

 Geological Changes of Climate in the Eastern 

 Cordilleras ; Tree Planting on the Prairies : PRO- 

 FESSOR R. DeC. Ward 817 



Proposed American Electro-chemical Society 818 



The United States Naval Observatory 819 



Scientific Notes and News 820 



University and Educational News 824 



MSS. intended for publication and books, etc., intended 

 I for review should be sent to the responsible editor, Pro- 

 ■ fessor J. McKeen Cattell, Garrison-on-Hudson, N. Y. 



THE GEOLOGY OF ORE DEPOSITS. 



11. 



We have now traced the metals of many 

 ores to their first positions in the veins. In 

 order to understand other cases, we must 

 recall the facts as to the relations of ' rich- 

 ness with depth.' At this point I take my 

 illustrations from regions outside of Col- 

 orado. James Douglass says that in the 

 Appalachian region every copper mine has 

 diminished in richness with depth, Near 

 the surface rich oxidized products were 

 found. Near the level of ground-water 

 rich belts of sulphides occurred — in some 

 instances extraordinarily rich. Below the 

 level of rich sulphides every old mine has 

 passed into cupriferous pyrrhotite, a sul- 

 phide of iron bearing a very small per- 

 centage of copper. In the Sierra Nevadas, 

 of California, Mr. Lindgren states that 

 near the surface the values range from $80 

 to $300 per ton ; but a little way below the 

 level of ground- water these values fall to 

 $20 or $30 per ton, and no exceedingly rich 

 deposits are found. You all know the his- 

 tory of the Comstock lode ; and of the great 

 bonanzas found above or about the 2,000- 

 foot level, and which did not extend deeper. 

 In the Lake Superior region the greatest 

 iron-ore mines in the world occur; four- 

 fifths or more of the entire product of iron 

 of the United States comes from that re- 

 gion ; but at the present time vastly more 



