Fbbeuaky 13, 1903.] 



SCIENCE. 



273 



H. B. Newson, of the University of Kansas. 

 The following papers were read: 



Db. Saul Epsteen, University of Chicago: 

 ' Determination of the group of rationality of a 

 differential equation.' 



Professor E. W. Davis : ' A group in logic' 



Professor H. B. Newson: 'On the generation 

 of finite from infinitesimal transformations; a 

 correction.' 



Professor L. E. Dickson, University of Chi- 

 cago : ' The ternary orthogonal group in a gen- 

 eral field.' 



Professor L. E. Dickson, University of Chi- 

 cago : ' The group defined for a general field by 

 the rotation groups.' 



Professor A. S. Hathaway, Rose Polytechnic 

 Institute : ' Vector Analysis.' 



Professor James Btbnie Shaw, Kenyon Col- 

 lege : ' On nilpotent algebras ' ( preliminary com- 

 municati.on). 



Professor D. P. Campbell, Armour Institute 

 of Technology: 'On homogeneous quadratic rela- 

 tions in the solution of a linear difi'erential equa- 

 tion of the fourth order.' 



Db. S. E. Slocum, University of Cincinnati: 

 ' Relation between real and complex groups with 

 respect to their structure and continuity.' 



Pbofessob Arnold Emch, University of Colo- 

 rado : ' On the involution of stresses in a plane.' 



Mb. R. E. Wilson, Northwestern University: 

 ' Polar triangles of a conic and certain circixm- 

 scribed quartic curves ' ( preliminary communi- 

 cation) . 



Pbofessob H. S. White, Northwestern Univer- 

 sity : ' Orthogonal linear transformations and cer- 

 tain invariant systems of cones' (preliminary 

 communication) . 



Pbofessob R. E. Allabdice, Leland Stanford 

 University: 'On the envelopes of the axes of 

 similar conies through three fixed points.' 



The report of the committee appointed at 

 the last Christmas meeting to devise a scheme 

 of uniform requirements for the Master's de- 

 gree for candidates making mathematics their 

 major subject, was discussed, and portions of 

 it adopted, the remainder being held over for 

 consideration at the next meeting of the sec- 

 tion. The report deals with the undergradu- 

 ate program and suggests a basis for graduate 

 study on the assumption that one year of such 

 study will be required for the Master's degree. 

 Copies of the report may be had from the 

 secretary of the section. 



The following officers were elected for the 

 ensuing year: 



Secretary — Professor Thomas F. Holgate. 



Additional Members of the Program Committee 

 — Professor Ernest B. Skinner and Dr. S. E. 

 Slocum. 



The next meeting of the section will be 

 held in April. 



Thomas F. Holgate, 

 Secretary of the Section. 

 EvANSTON, Illinois. 



geological society of WASHINGTON. 



At the 136th meeting of the society, held in 

 assembly hall of the Cosmos Club, Wednesday 

 evening, January 14, 1903, the following pro- 

 gram was presented: 



Dr. Arthur C. Spencer exhibited some speci- 

 mens of metallic copper taken from the 

 crevices of an old wall which had been cov- 

 ered for perhaps thirty years by sulphide-bear- 

 ing debris from the mines at Cobra, near 

 Santiago, Cuba. A calcareous mortar was 

 locally replaced by copper, which now occurs 

 without admixture of any foreign material. 



The chemical reactions involved were dis- 

 cussed by Dr. H. N. Stokes, who has recently 

 been engaged in an extensive study of the 

 conditions under which metallic sulphides are 

 deposited. 



In a brief review of the history of the work 

 on ore deposits, in America particularly, Mr. 

 S. F. Emmons introduced Mr. W. H. Weed, 

 who proposed a genetic classification of ore 

 deposits, whose major subdivisions are as 

 follows : 



I. Igneous (Magmatic segregations). 



A. Silicious. 



B. Basic. 



n. Igneous emanation deposits (deposited by 

 highly heated vapors and gases in 

 large part above the critical point, 

 e. g., 365° and 200 atm. for H,0). 



A. Contact metamorphic deposits. 



B. Veins (closely allied to magmatic 



veins and to division IV.). 

 1 1 1. Fumarolic deposits (metallic oxides, etc., 

 in clefts in lavas; no commercial im- 

 portance). 



