July 19, 1895.] 



SCIENCE. 



83 



is one sentence of eighty-five words (p. 23). 

 There is no doubt that the work is in every 

 way one of great value to students. 



A. J. MosES. 



SCIENTIFIC JOURNALS. 

 THE ASTEOPHTSICAL JOURNAL, JUNE. 



The Measurement of Some Standard Wave- 

 Length in the Infra-red Spectra of the Ele- 

 ments: ExuM Percival Lewis. 

 In a review of the previous work in this 

 field, the writer shows that very little has 

 been done toward the identification and ac- 

 curate measurement of lines due to the ele- 

 ments in the infra-red, and that the means 

 employed have been comparatively crude. 

 In the present investigation, a grating of 

 high dispersive power was combined with 

 the radiomicrometer, which was found to be 

 more reliable and of greater sensitiveness 

 than the bolometer. Eesults are given for 

 sodium, lithium, silver and calcium lines. 

 On the Distribution in Latitude of Solar Phe- 

 nomena Observed at the Royal Observatory of 

 the Roman College in 1894.: P. Tacchini. 

 The faculse and spots of 1894, and especi- 

 ally the prominences, have been markedly 

 more frequent in the southern hemisphere, 

 like similar phenomena since the summer 

 of 1892. 



A Review of the Spectroscopic Observations of 

 Mars. W. W. Campbell. 

 The writer replies to some critics of his 

 former paper on the spectrum of Mars, and 

 makes a critical examination of previous 

 work along this line. He concludes that 

 many of the former observations were made 

 under circumstances extremely unfavorable, 

 and that between the different sets of re- 

 sults there is not a satisfactory close agree- 

 ment. 



Preliminary Table of Solar Spectrum Wave- 

 Lengths. VI. H. A. Rowland. 

 The table is continued from I 4674.6-48 to 

 ;, 4903.502. 



On the Electromagnetic Nature of the Solar 

 Radiation and on a Neio Determination of 

 the Temperature of the Sun. H. Ebert. 

 A comparison of the form of the solar 

 energy curve with that of a strongly damped 

 electric oscillator shows that in sunlight we 

 are dealing with electromagnetic vibrations. 

 But with respect to electromagnetic radia- 

 tion the principal mass of the Sun acts like 

 a black body. Hence, applying Rubens' 

 formula for the maximum energy of the 

 radiation of blackened bodies, ^- v^T = 123, 

 and using 0.6 /^ for the value of I as found 

 hy Langley for the maximum energy of the 

 solar spectrum, a temperature of 40,000° 

 C. is found for the more interior regions of 

 the Sun. This is in good agreement with 

 values previously determined by other 

 methods. 



Phbtograp)hs of the Milhj-Way near 15 Mono- 

 ceros and near s Cygni: E. E. Baenaed. 



On the Limit of Visibility of Fine Lines in a 

 Telescope : Albert A. Michelson. 

 A theoretical discussion proves that a 

 line subtending an angle of one-fiftieth of 

 the limit of resolution may be distinctly 

 seen. This is verified by experiment and 

 applied to the ' canals ' on Mars. Suppos- 

 ing them to be quite dark, and distinguish- 

 able by an objective of not less than eighteen 

 inches aperture, their width is calculated 

 to be about one mile. 



Conditions affecting the Form of Lilies hi the 

 Spectrum of Saturn : James E. Keelee. 

 The effects of instrumental displacements 

 are considered, limiting the question to the 

 case where the slit is parallel to the major 

 axis of the ring. 



A displacement of the image at right 

 angles to the slit gives a disproportionate 

 exposure to the middle parts of the lines, 

 but unless the displacement exceeds one- 

 fourth the semi-axis minor, there is scarcely 

 anjf change in direction produced. A drift 

 in the direction of the slit broadens the 



