January 1, 1904.] 



SCIENCE. 



23 



are few and the book furnislies an excellent 

 idea of the structure of the cat, free from a 

 superfluity of detail which too often serves 

 merely to conceal from the young student the 

 fundamental principles which they may be 

 intended to elucidate. Profusion of detail 

 does not always make for accuracy in the stu- 

 dent and it is principles rather than facts that 

 he should acquire from his laboratory training. 

 Throughout the book are frequent remarks 

 of a comparative nature and at the close of 

 each chapter is a list of questions or sugges- 

 tions, for the most part of a general nature, 

 which will serve as excellent topics for com- 

 ment by the teacher or for collateral investiga- 

 tion under his direction by the student. An 

 introductory chapter is devoted to an account 

 of useful methods by which the dissection of 

 a mammal may be facilitated, and the text is 

 illustrated by numerous figures and diagrams 

 for the most part admirably executed. 



J. P. McM. 



SOCIETIES AND ACADEMIES. 

 PHILOSOPHICAL SOCIETY OP WASHINGTON. 



The 5Y3d meeting was held November 7. 



Dr. A. L. Day spoke on ' The Black Body 

 and the Measurement of Extreme Tempera- 

 tures.' He outlined the history of the 

 theoretical study of the problem, and showed 

 how such a body had been constructed arti- 

 ficially; he then discussed at length the results 

 of experiments made with it, pointing out the 

 relation between the temperature and the 

 total radiation, and between the temperature 

 and the wave-length of radiation of maximum 

 intensity, and expressing these relations by 

 equations ; from these equations temperatures 

 outside the range of measurement can be cal- 

 culated by extrapolation. 



Mr. 0. E. Van Orstrand followed with 

 ' Notes on the Emission Function,' discussing 

 mathematically the second of the equations 

 presented by the preceding speaker. 



At the 574th meeting, held November 21, 

 the subject of ' Synchronous Actions in the 

 Atmospheres of the Sun and the Earth ' was 

 discussed by Professor F. H. Bigelow, of the 

 Weather Bureau. The curves first published 



in 1894, showing simultaneous variations in 

 the sunspot areas, the magnetic field, the pres- 

 sures and temperatures of the northwestern 

 states, the movements in latitude and longi- 

 tudes of the storm centers, were compared 

 with the prominence secular variations and 

 found to agree. The meteorological data have 

 been extended to all parts of the earth and 

 they give similar variations, supplemented by 

 inversion of the type. Thus the direct type 

 of temperature prevails throughout the tropics, 

 and the inverse tjrpe in the temperate zones; 

 the direct type of pressures holds around the 

 Indian Ocean and the inverse type in North 

 and South America. The distribution of the 

 prominences in latitude and their movements 

 in the eleven-year cycle were explained, also 

 their distribution in longitude. From the 

 latter were derived the periods of rotation of 

 the sun in different zones, and the variations 

 of the several periods in the eleven-year 

 cycle, which gave the same curve as holds for 

 the prominence frequency. This important 

 phenomenon was referred back to the internal 

 circulation of the sun, and it confirms the 

 second case of von Helmholtz's equations, as 

 applied to a rotating mass heated at the center. 

 The fundamental period of the sun's rotation 

 is that of the equator, 26.68 days, and as this 

 is the shortest possible period in the sun it 

 follows that numerous determinations of the 

 solar rotation from terrestrial phenomena, 

 such as aurora, thunderstorms, must be ex- 

 cluded as misleading. The observed syn- 

 chronism at the earth has its basis in the 

 sun's circulation, and this is of a kind to pro- 

 duce vertical polarization, and an internal 

 magnetic field. Hence all stars should be 

 magnetized while the process of cooling under 

 their own gravitation is going on. 



Mr. L. A. Bauer then presented several brief 

 ' Contributions to the Theory of the Earth's 

 Permanent Magnetism.' He showed that the 

 energy of the earth's magnetization had di- 

 minished by one thirty-sixth part in forty-six 

 years. He stated as a result of his analysis 

 that the principal cause of secular variation 

 resides outside the earth's crust. He also 

 attempted a calculation of the magnetic en- 



