May 19, 1916] 



SCIENCE 



723 



Cerebral Localisation: Harvey Gushing. (Intro- 

 duced by Dr. Keen.) 



The Inorganic Constituents of Marine Inverte- 

 hrates: Frank Wiqgleswoeth Clakke. 

 It is a commonplace of geology that many lime- 

 stones are formed from the remains of marine 

 animals, such as corals, moUusks, crinoids, etc. 

 Some of these limestones are magnesian, some are 

 phosphatic and others are of the ordinary type, 

 consisting chiefly of calcium carbonate. They 

 ■were originally deposited at the bottom of the 

 sea, and their composition depends upon the com- 

 position of the organisms which formed them. The 

 present investigation has for its purpose to deter- 

 mine what each group of organisms contributes to 

 the sediments; and in order to answer this ques- 

 tion nearly 250 analyses have been made of the 

 shells or skeletons of marine invertebrates, cover- 

 ing a range from the foraminifera up to the Crus- 

 tacea, and including also the corellin algae. It 

 was already well known that corals and moUuscan 

 shells were composed almost entirely of calcium 

 carbonate, and that fact has been verified. The 

 shells of one group of brachiopods, however, con- 

 sist largely of calcium phosphate, and that sub- 

 stance is also abundant in the Crustacea. These 

 animals, and also vertebrate skeletons, contribute 

 phosphates to the sediments. The foraminifera, 

 alcyonaria, sea fans, eehinoderms and calcareous 

 algffi, with some minor groups or organisms, eon- 

 tain much magnesia, and therefore aid in the for- 

 mation of magnesian limestones. Curiously 

 enough, the amount of magnesium carbonate in 

 any series of organisms varies with the tempera- 

 ture of the water in which the creatures lived; 

 being small in cold and large in warm waters. A 

 sea urchin from Greenland, for example, contained 

 6 per cent, of magnesium carbonate, and one from 

 near the equator contained over 13 per cent. In 

 certain algse from the West Indies 25 per cent, was 

 found. Furthermore, some organisms have their 

 calcium carbonate in the form of aragonite, and 

 others consist of oalcite. The aragonitie organ- 

 isms are all non-magnesian ; while the magnesian 

 forms are all calcitic. The data obtained in this 

 investigation have been applied to the study of 

 coral reefs, which owe their composition to all the 

 creatures living upon them, and not to the corals 

 alone. In fact, the corals are often of less im- 

 portance than their associates. 



Some Properties of Vibrating Telephone Dia- 

 phragms: A. E. Kennelly and H. O. Taylor. 



(A) Dimensional Gases and the Law of Be flection 

 of Gas Molecules from Solid Walls. (B) The 

 Metallic Sefleation of Light from a Gas: Egb- 

 ert Williams Wood. 

 Some Relations between Matter and Badiation: 

 William Duane. (Introduced by Professor A. 

 W. Goodspeed.) 



To Benjamin Franklin we owe the fundamental 

 conception that the phenomena of nature are due 

 largely to the interaction of atoms of electricity 

 with atoms of ordinary matter, and the object of 

 this paper is to discuss the emission of radiant 

 energy (light, heat-rays. X-rays, etc.) from the 

 point of view of Franklin's conception. Since 

 the discovery, some years ago, of cathode rays, X- 

 rays and radioactivity scientists have had in their 

 hands the means of producing and studying 

 streams of atoms of both electricity and ordinary 

 matter. They have succeeded even in observing 

 effects due to a single atom of each kind. We 

 now know that the impacts of atoms of electricity 

 against atoms of ordinary matter produce radia- 

 tion. Mr. Hunt, Dr. Webster and the author have 

 been investigating the relations between the 

 energy of the atom of electricity and the fre- 

 quency of the radiation it produces. The most 

 striking facts we discovered are that in the case 

 of the so-called general radiation the energy re- 

 quired is strictly proportional to that frequency, 

 and in the case of the so-called characteristic radi- 

 ation the energy required is larger than in the 

 preceding case and not always proportional to the 

 frequency. The author offered the following ex- 

 planations of these facts. High frequency vibra- 

 tions are associated with the central parts of an 

 atom of matter, in which the electromagnetic field 

 is very strong. In order to reach a point in an 

 atom of matter where a given frequency of vibra- 

 tion is produced the atom of electricity must have 

 at least enough energy to overcome a certain force 

 of repulsion acting between them. If we follow 

 out the line of reasoning and apply Maxwell 's dis- 

 tribution law and what has been called the fourth 

 power law to the case of the atoms of electricity 

 flying about in a hot body owing to its thermal 

 agitation, we arrive at an equation for the distri- 

 bution of energy in the spectrum that represents 

 the facts with considerable precision. The above 

 mentioned laws discovered by experimental in- 

 vestigation have a practical bearing on X-ray phe- 

 nomena also. They indicate what must be done in 

 order to produce those very high frequency radia- 

 tions that hitherto have been obtained from radio- 

 active substances only. 



