Februaby 7, 1919] 



SCIENCE 



139 



short duration of the phenomena. The hy- 

 pothesis of a collision between a star and a 

 nebula meets these two fundamental objec- 

 tions, and appears capable of accounting quali- 

 tatively for many or most of the phenomena, as 

 was shown some years ago by Seeliger. But 

 the spectroscopic data, and especially the dark- 

 line spectrum on the rise, remain difficult to 

 explain. A collision between a star and a rela- 

 tively small dark body — recently postulated by 

 W. H. Pickering — is also worthy of considera- 

 tion, but presents difficulties of its own. 



After what we now know and believe regard- 

 ing the stores of energy which are locked up in 

 the nuclei of atoms, the hypothesis of an ex- 

 plosive release of some such form of energy 

 within a star can not be neglected. The chief 

 difficulty about it seems to be that we might 

 expect an even greater catastrophe than appears 

 to occur — but this theory will probably prove 

 to be increasingly flexible as our knowledge 

 advances. At present, however, the collision 

 theory appears to the speaker the most promis- 

 ing. The great frequency of novae in the 

 spiral nebuke — ^where we might expect collis- 

 ion to occur, if anywhere in the universe- 

 seems to be favorable to this view. 



In concluding this hasty and imperfect sur- 

 vey of a wide field, two things stand out promi- 

 nently — first, the importance of a study, which 

 was once neglected and even rather despised, in 

 the attack upon some of the most fundamental 

 problems of astrophysics, and, second, the 

 urgent need of extensive and active researches, 

 observational, statistical and theoretical, to ad- 

 vance toward solutions of some of the many un- 

 solved problems which still remain before us. 

 Henry Norris Russell 



Peinceton UNrvEEsirr Obsebvatort, 



CHARLES ROCHESTER EASTMAN' 



On this side of the Atlantic there have 

 been few zoologists who have devoted their 

 lives to the study of ancient fishes^which 

 for the rest concerns not a few of the greatest 

 problems of the vertebrates. Of investigators 



1 Born Cedar Rapids, Iowa, June 5, 1868, died 

 Long Beach, N. Y., September 27, 1918. 



who have passed away we recall the distin- 

 guished names of Agassiz the elder, Qo'pe, 

 Newberry and Leidy, and to this goodly fel- 

 lowship we must now add the name of Charles 

 Rochester Eastman, whose services have con- 

 tributed widely and intensively to a knowledge 

 of fossil fishes. To this work he gave his time 

 devotedly for a quarter of a century, publish- 

 ing over a hundred papers, among them a 

 number of monographs which rank among the 

 most scholarly and accurate in their field. 



Eastman graduated from Harvard in 1891, 

 studied at Johns Hopkins, thereafter in the 

 University of Munich, where he took his 

 doctorate in 1894; he worked with Professor 

 Karl von Zittel, whose laboratory then at- 

 tracted a nimaber of young American paleon- 

 tologists. Here, as Eastman's interests al- 

 ready centered in fossil fishes, he was given 

 the only material for research which the Ger- 

 man university had at hand — a mass of de- 

 tached teeth of a Chalk Measures shark — not 

 attractive material, to say the least, but the 

 young investigator attacked it with energy 

 and soon gathered the data for a successful 

 thesis. He was next given a post at Harvard, 

 where in the Museum of Comparative Zoology, 

 under the mantle of Louis Agassiz, he re- 

 viewed the collections of early fishes and found 

 much material for publication. He now be- 

 came interested in the Devonian fossils of the 

 Agassiz collection, which he found shed light 

 upon the rich finds from the Middle West, 

 then being described by Dr. Newberry. East- 

 man's imagination was especially touched by 

 the range and character of " placoderms " as 

 the dominant group of Devonian times, and 

 like many another worker, he set himself to 

 solve the puzzles of their lines of evolution 

 and of their kinship to modem fishes. Hence 

 he sought actively for more extensive and 

 better preserved material upon which to base 

 his findings. The best collecting ground for 

 these American forms was in Ohio, and 

 throughout this region Eastman soon learned 

 to know the fossil hunters and their collec- 

 tions. His studies upon these forms thereupon 

 spread over wider fields, and became well-nigh 

 encyclopaedic; he brought the entire Devonian 



