946 



SCIENCE 



[N. S. Vol. XLI. No. 1069 



of mass occurs mostly in the formation of 

 the heliiim atom and scarcely at all in the 

 combination of helium and hydrogen atoms 

 into the atoms of higher atomic weight. 



7. Huntington's Chorea in Relation to Hered- 

 ity and Eugenics: C. B. Davenport, Station 

 for Experimental Evolution, Carnegie In- 

 stitution of Washington. 



Nearly 1,000 cases of Huntington's chorea 

 are traced back to some half dozen individuals. 

 The choreic movements never skip a genera- 

 tion and in other respects show themselves 

 clearly to be a dominant trait; nevertheless, 

 there is no clear evidence that persons belong- 

 ing to the choreic lines voluntarily abstain 

 from marriage, or are selected against in 

 marriage. 



8. The Alcyonaria as a Factor in Reef Lime- 

 stone Formation: L. R. Cary, Department 

 of Biology, Princeton University. 



To determine the amount of material con- 

 tributed to reef formation by the gorgonians 

 three factors are taken into consideration: 

 first, the amount of lime held as spicules in the 

 tissues of these colonies; second, the bulli of 

 the gorgonians present on any reef area ; and 

 third, the number of colonies which will set 

 free their spicules through the death and sub- 

 sequent disintegration of their coenenchyma. 



9. Transformations of Conjugate Systems with 

 Equal Invariants: L. P. Eisenhaet, De- 

 partment of Mathematics, Princeton Uni- 

 versity. 



The author has previously described what he 

 has called "transformation E" and "trans- 

 formations n " ; and in this note he shows that 

 there is a fundamental relation connecting 

 those transformations. 



10. On the Pole Effect in the Iron Arc: C. E. 

 St. John and H. D. Babcock, Mount Wilson 

 Solar Observatory, Carnegie Institution of 

 Washington. 



In a continuation of their communication 

 in the March number of the Proceedings, the 

 authors find that it is necessary to consider the 

 pole effect in the determination of wave- 

 lengths in international units. The wave- 

 lengths are not afl^ected by wide variations of 



density of the radiating vapor and appear to 

 be independent of changes in temperature. 

 The pole effect does not occur in vacuo and 

 appears independent of electrical conditions. 



11. Inheritance in the Asexual Reproduction 

 of Hydra Viridis : K. S. Lashley, Zoological 

 Laboratory, Johns Hopkins University. 

 This investigation aims to contribute to the^ 



answer of the questions : Do heritable varia- 

 tions commonly occur among the offspring of 

 a single individual multiplying asexually? and 

 may selection among such offspring produce 

 strains differing in hereditary characters ? He 

 finds that the only effect of selection is a 

 temporary change in the vigor of the selected 

 polyps and that there is no cumulative inher- 

 itance of variations in the number of tentacles 

 within the clone. There is some evidence that 

 the same conclusions apply to the inheritance 

 of size. 



12. On the Monticellite-lihe Mineral in Meteor- 

 ites and on Oldhamite as a Meteoric Consti- 

 tuent: G. P. Merrill, Department of Geol- 

 ogy, United States National Museum, Wash- 

 ington. 



The author has subjected to microchemieal 

 analysis and to optical study the colorless 

 mineral whose presence in chondritic meteor- 

 ites has been observed by several previous in- 

 vestigators. He presents sectional drawings 

 showing the appearance and optical properties 

 of the mineral, which appears to be a form of 

 calcium phosphate. He also calls attention to 

 the presence of oldhamite (calcium sulphide) 

 in meteorites from various sources. 



13. Absolute Scales of Photographic and 

 Photovisual Magnitude: F. H. Seares,, 

 Mount Wilson Solar Observatory, Carnegie' 

 Institution of Washington. 



Mr. Seares describes the arrangement at the 

 Mount Wilson Observatory for determinating 

 absolute scales of photographic and photo- 

 visual magnitudes extending over about 17J 

 magnitudes for the photographic scale and 

 about 15J for the photovisual scale. The vari- 

 ous difiiculties which are met in comparing 

 stars so different in brightness as is implied 

 in these ranges of magnitudes are discussed, 



