Mat 21, 1909] 



SCIENCE 



821 



marked by some peculiarity of spectrum. If 

 sucli were the case the stars so marked should 

 be found only in or near the milky way and 

 they should be especially numerous and com- 

 pactly clustered astern of the solar group, they 

 should be more sparsely distributed ahead of it 

 and should be almost completely lacking on 

 either side of the procession. The so-called 

 Orion stars constitute just such a set of ob- 

 jects, marked and distributed as above and 

 presenting the further peculiarities that .their 

 apparent motion across the sky is abnormally 

 small and that their number shows no tendency 

 to increase as we pass from the brighter to 

 the fainter magnitudes. All of these char- 

 acteristics are such as would be possessed by 

 stars formed as above suggested. 



In a somewhat similar class are the new or 

 temporary stars believed to result from col- 

 lisions of some kind and found only in or 

 near the milky way. Why they are limited to 

 the milky way is now apparent, since that is 

 the region, according to the present hypoth- 

 esis, in which large relative motions are to be 

 expected. 



We may look upon double stars as pro- 

 duced by the close approach of a solar to a 

 sirian star under circumstances such that the 

 gravitational bond between them becomes too 

 strong to be broken and the two bodies abide 

 thenceforth in enforced partnership. The size 

 and shape of the orbits in which they shall 

 move about their common center of gravity 

 are determined by the circumstances of their 

 meeting and an elementary analysis sufSces to 

 show that the circumstances that tend to pro- 

 duce a small orbit will equally tend to make 

 that orbit nearly round, while those which 

 make a large orbit will equally tend to make it 

 more pronouncedly oval. A statistical exami- 

 nation of double stars shows that they do in 

 fact show this relation among themselves, a 

 small major axis being predominantly asso- 

 ciated with a small eccentricity, an agreement 

 between fact and theory that can hardly be 

 accidental. 



The test of a valid theory is- its power to 

 coordinate apparently unrelated facts without 

 coming into conflict with any of them and, 

 in view of the illustrations of such coordina- 



tion given above and of others for which space 

 does not here suffice, there is here presented 

 the concept of a definite group of stars moving 

 through a much more widely extended chaos 

 as the best working hypothesis at present at- 

 tainable with reference to the stellar system. 



BOTANWAL NOTES 

 OUT OF DOOE BOTANICAL STUDY 



Within a few weeks students who are 

 planning out of door study in the summer 

 vacation will decide where they will go. In 

 the hope of being able to help such students 

 to decide wisely we here bring together in 

 summary form abstracts from the announce- 

 ments made by the directors of half a dozen 

 laboratories. 



The oldest laboratory of this kind is the 

 Marine Biological Laboratory at Woods Hole, 

 Mass., whose twenty-second session extends 

 from June 1 to October 1. In addition to in- 

 struction in botany, zoology, embryology and 

 physiology, opportunities are afforded for in- 

 vestigation in these departments of biology. 

 For botanical students instruction is offered 

 (1) in the morphology and taxonomy of the 

 algae, and (2) the morphology and taxonomy 

 of the fungi. Five buildings with fifty-five 

 private rooms for investigations, and seven 

 general laboratories, constitute the plant, and 

 are supplied with aquaria, collecting appa- 

 ratus, reagents and glassware. The labora- 

 tory has a steam launch, boats, dredges and 

 the apparatus necessary for collecting and 

 keeping alive material for class use or re- 

 search. Dr. George T. Moore, of Water MiU, 

 N. T., is in general charge of the botanical 

 work. 



The twentieth session of the Biological Lab- 

 oratory at Cold Spring Harbor, Long Island, 

 begins July 7 and closes August 21. Op- 

 portunities for instruction and investigation 

 in botany and zoology are offered. In botany 

 the instruction includes courses in: (1) 

 Cryptogamic botany — especially algae and 

 fungi, and (2) ecology. The laboratory pos- 

 sesses three buildings for study purposes, 

 supplied with needed appliances, and five 

 dormatories, accommodating seventy-five per- 

 sons. A 28-foot motor boat, with small boats. 



