CONTENTS 
Genetics —Is the Arrangement or the Genes in the Chromosome Linear? . . 
By W.E. Castle 25 
Genetics. — ^The Linkage System of Eight Sex-Linked Characters of Droso- 
PHiLA ViRiLis (Data of Metz) ByW. E. Castle 32 
Botany. — ^The Cause of Proliferation in Begonia Phyllomaniaca 
By Envin F. Smith 36 
Petrology. — ^The Percentage Number of Meteorite Falls and Finds Con- 
sidered with Reference to Their Varying Basicity. . By George P. Merrill 37 
Physics. — Note on a Contact Lever, Using Achromatic Displacement Fingers 
By Carl Barus 39 
Physics. — Interferential Contact Lever Experiments Relating to the Elastics 
OF Small Bodies By Carl Barus 44 
National Research Council. Minutes of the Meeting of the Executive 
Board 50 
