612 PROCEEDINGS OP THE AMERICAN ACADEMY. 



The following paper was read by Dr. W. E. Castle : " Men- 

 del's Law of Heredity, illustrated by Breeding Experiments with 

 Guinea Pigs." 



The following papers were presented b}^ title : 



Contributions from the Chemical Laboratory of Harvard 

 College: "The Significance of Changing Atomic Volume. 

 IV. The Effects of Chemical and Cohesive Internal Pressure." 

 By Theodore William Richards. 



Contributions from the Jefferson Physical Laboratory ; 

 " Spectra Produced by the Wehnelt Interrupter." By H. W. 

 Morse. Presented by J. Trowbridge. 



" The Green Schists and Porphyries of Rhode Island." By 

 B. K. Emerson. 



Contributions frOm the Gray Herbarium of Harvard Univer- 

 sity. New Series. —No. XXVIII. 



I. " Revision of the Genus Sabazia." By B. L. Robinson and 

 J. M. Greenman. 



II. " Revision of the Mexican and Central American Species 

 of Trixis." By B. L. Robinson and J. M. Greenman. 



III. " Revision of the Mexican and Central American Species 

 of Hieracium." By B. L. Robinson and J. M. Greenman. 



IV. " Synopsis of the Mexican and Central American Species 

 of Alnus." By M. L. Fernald. 



V. " Diagnosis and Synonymy of Mexican and Central Ameri- 

 can Spermatophytes." By J. M. Greenman. 



VI. " Some Mexican and Nicaraguan Dicotyledons." By 

 M. L. Fernald. 



Presented by B. L. Robinson. 



Nine hundred and forty-seventh Meeting. 



March 9, 1904. — Stated Meeting. 



Vice-President Trowbridge in the chair. 



The Corresponding Secretary read a circular from the Or- 

 ganizing Committee of the International Congress of Ameri- 

 canists, announcing that the fourteenth session of the Congress 

 would be held at Stuttgart, in August, 1904. 



