Apbil 16, 1915] 



SCIENCE 



569 



fact the evidence is now strong that it consists of 

 exactly two. This twentieth century has then dis- 

 covered for the first time a new subatomic world 

 of electrons, the constituents of atoms. 



All this is definite and probably permanent. 

 But atomic conceptions in more or less vague form 

 have also begun to invade the one remaining field 

 of physical investigation, namely, the field of 

 ethereal radiations. The most significant of re- 

 cently discovered facts in the domain of radiant 

 energy are these: 



(1) Ethereal radiations when absorbed by mat- 

 ter, if they are of high enough frequency, will de- 

 tach one and only one electron from a single atom. 

 (2) The energy transferred to this electron from 

 the ether wave is independent of the intensity of 

 the incident radiation. (3) It is also independent 

 of the kind of matter from which the electron is 

 taken, but (4) it is exactly proportional to the 

 frequency of the ether wave which detaches it. 



These facts are stated in an equation set up 

 tentatively by Einstein in 1905, and arrived at by 

 him from the standpoint of a modified corpuscular 

 theory of radiation. New proofs of the exactness 

 of Einstein's equation will be presented and the 

 evidence for and against Einstein's conception 

 will be discussed. Whether the conception ulti- 

 mately stands or falls, it appears probable, at any 

 rate, that an equation has been obtained which is 

 to be of no less importance in future physics than 

 Maxwell's equation of the electro -magnetic field, 

 and which seems destined to unlock for the phys- 

 icists of the future the doors to the understanding 

 of the relations existing between matter and radi- 

 ant energy. 



W. M. Davis : Problems Associated with the Origin 

 of Coral Beefs suggested by a Shaler Memorial 

 Study of the Meefs of the Fiji, New Caledonia, 

 Loyalty Islands, New Hebrides, Queensland and 

 the Society Islands. (Illustrated.) 

 The sea-level coral reefs of the Pacific are sing- 

 ularly non-committal as to their origin. The visible 

 reefs accommodate themselves indifferently to any 

 one of the eight or nine theories invented for their 

 explanation. Hence a choice among the theories 

 must be guided not so much by a study of the 

 reefs themselves as by a study of associated phe- 

 nomena, which thus gain an unexpected importance 

 in coral reef investigation. It is because the as- 

 sociated phenomena have been insufficiently studied 

 that so many contradictory theories have found 

 favor. Of all associated phenomena, those pro- 

 vided by the central islands within barrier reefs 

 are the most accessible and the least equivocal; 



next in importance are those offered by uplifted 

 and dissected reefs. It will be shown by means of 

 landscape views and theoretical diagrams that no 

 theory accounts for all the facts — those of the as- 

 sociated phenomena as well as those of sea-level 

 reefs — so well as Darwin's original theory of sub- 

 sidence; and that the strongest confirmation of 

 Darwin's theory is given by the embayments of 

 the central islands within barrier reefs, as was long 

 ago pointed out by Dana. Thus the results now 

 reached regarding the reefs of the Pacific agree 

 with the conclusions announced in recent years by 

 several Australasian observers. It is believed 

 that the several alternative theories advocated by 

 various investigators during the last thirty-five 

 years will be given up, and that Darwin's theory 

 of subsidence will regain the general acceptance 

 that it formerly enjoyed (1840-80). 



Geokge E. Hale: Some Vortex Experiments on 



the Motion of Sun-spots. 



A closely wound helix of brass wire, with cir- 

 cular disks threaded on it, is hung vertically in 

 water and spun at high velocity. The columnar 

 vortex thus formed gradually changes into a semi- 

 circular vortex ring, by the rise of the lower end 

 of the helix until it meets the surface. Thus the 

 second sun-spot in a typical bipolar group might 

 be formed by the turning up of the columnar vor- 

 tex assumed to constitute a single spot. Prelimi- 

 nary rotation of the whole mass of liquid retards 

 or prevents the turning up process if in the same 

 direction as that of the helix, and hastens it if in 

 the opposite direction. Hence, a persistent single 

 spot may represent a rotating gaseous column whose 

 diameter is large in comparison with its length. 



Circular or semicircular vortices have a proper 

 motion at right angles to their planes, in the di- 

 rection of motion of the inner edge of the whirling 

 ring. As high and low latitude bipolar spots ro- 

 tate in opposite directions, they should, therefore, 

 move toward the pole and the equator, respectively. 

 Carrington's observations show this to be the case. 

 The velocity to be expected is being determined 

 by measuring the velocity of vortex rings in liq- 

 uids and compressed gases. Observations of the 

 stream-lines of ionized smoke particles, above 

 single and double magnetic vortices representing 

 sun-spots, are also in progress. 



P. W. Claeke : The Inorganic Constituents of Ma- 



ri/ne Invertebrates. 



Essentially a report of progress. The object of 

 the investigation is to determine, more systematic- 

 ally than has been done hitherto, just what each 



