258 Scientific Intelligence. 



and importance of recent spectroscopic work in Astrophysics 

 ensured for the able and comprehensive survey of the subject, by 

 so competent a writer as Dr. Scheiner, an immediate and cordial 

 reception in astronomical circles, and gave it at once a recognized 

 position as a standard treatise. The very rapid development of 

 this branch of science since 1890, when this work was issued, has 

 resulted in the accumulation of a great number of interesting 

 discoveries, and thrown new light upon many important prob- 

 lems. This fact, as well as the desirability of making the work 

 accessible to a wider circle of students and readers, afforded ex- 

 cellent reasons for a revision. 



Professor Frost's translation follows the original text, in the 

 main, very closely, especially in those portions where there has 

 been comparatively little occasion for change. Additions have 

 been liberally made, however, where necessary, and in some 

 instances the newer material is of such a character as to super- 

 sede the older results and require a substantial recasting of the 

 topics. Thus, in the chapter upon the motion of the stars in the 

 line of sight, the remarkable application of photographic methods 

 made by Vogel in 1892, giving values with a degree of precision 

 hitherto unapproached, has necessitated the omission of the long 

 list of star velocities determined at Greenwich, and the substitu- 

 tion therefor of Vogel's list of fifty-one stars made by the new 

 method, while the excellent determinations made by other ob- 

 servers in a few cases have not been overlooked. Among other 

 additions may be mentioned Rowland's determination of solar 

 lines, his catalogue of standard lines, and his table of elements 

 occurring in the sun ; Young's table of chromospheric lines, cor- 

 rected and extended by his recent observations; the extension of 

 this catalogue into the ultra-violet region by Hale and Deslandres, 

 and Hale's work upon the spectra of sun-spots and faculas ; recent 

 discoveries of Huggins, Vogel, Keeler, and Campbell in respect to 

 spectra of the nebulae ; Keeler's determinations of the motion of 

 nebulas in the line of sight; Langley's remarkable work upon the 

 ultra-red region of the solar spectrum, and Abney's table of wave- 

 lengths of solar lines in the ultra-red. Very great changes have 

 been made also in the part relating to the spectra of stars of the 

 different types, the amount of new matter added being very con- 

 siderable, and well representing the work in this department to 

 the date of publication. A very judicious change is the adoption 

 of Rowland's scale of wave-lengths, unquestionably the most 

 accurate now extant, and, in connection with his photographic 

 charts, the most convenient for practical use. 



The volume, as thus expanded, has but few pages more than 

 the original work, owing not only to the slightly larger and more 

 compactly printed page employed, but also, as explained by the 

 author, to the fact that the English saves in space nearly one page 

 for every ten of the German in translation. Professor Frost 

 has executed his task very skillfully, and has shown excellent 

 judgment in the selection and co-ordination of the new material. 

 The style is clear and flowing, and remarkably free from the 

 stiffness and awkwardness so difficult of avoidance in a translation. 



