Notices respecting New Boohs. 147 



The translation is an admirable one, and our thanks are due to 

 Mr. Pattison Muir for introducing the work to English readers. 

 One alteration might be suggested for a future edition, to suit 

 fastidious mathematical readers, namely the notation used for 

 logarithms throughout the book. It would be more in accordance 

 with English custom to write for the natural logarithm of x, log e x 

 instead of Ix, the latter being a too faithful translation of the 

 original G-erman formula. James L. Howaed. 



Index of Spectra. Appendix B. By W. Marshall Watts, D.Sc, 

 F.I.O., Senior Physical Science Master at the Oiggleswick Grammar 

 School. Manchester : Abel Hey wood and Son, 1891. 

 This pamphlet of forty pages appears as an appendix to the 

 author's previous volume which we have already noticed in this 

 magazine. It contains four tables which have been compiled since 

 that work was issued, and also a list of such errata as have been 

 observed in it. The first table is an extremely useful one, being a 

 table of corrections for reducing the numbers of Angstrom and 

 Cornu to the standard of Rowland's latest map. By means of these 

 corrections all the lines tabulated in the previous volume can be 

 reduced to absolute wave-lengths with great ease and accuracy. 



Then follow two tables giving Liveing and Dewar's results for 

 the spectra of cobalt and nickel. In each table there are two sets 

 of numbers ; one set, in italics, includes those lines whose wave- 

 lengths have been directly measured by means of a grating, the 

 other set, printed in ordinary type, gives the remaining lines. The 

 author states on the first page that the scale used was that of 

 Angstrom ; presumably, however, the remark applies only to the 

 latter set of observations, the numbers in italics being already 

 corrected and reduced to absolute wave-lengths. 



Several lines in the cobalt spectrum are marked as being coincident 

 with nickel lines and vice versa. The lines of wave-lengths 3452 9 

 and 3445*7 belonging to cobalt are marked as nickel lines ; in the 

 nickel spectrum they are not marked as cobalt lines, whereas an 

 intermediate one, 3452-3, is so designated, although not to be found 

 in the cobalt spectrum. 



The greater portion of the book is taken up with the table giving 

 Hasselberg's measurements of the lines found in the absorption- 

 spectrum of iodine. The list includes over 3000 lines, 83 of which 

 coincide with solar lines, and thus lead us to infer that iodine 

 exists in the sun's atmosphere. The spectrum is interesting 

 inasmuch as it contains a large number of double lines, and no 

 fewer than 19 triple lines. James L. Howaed. 



Star Groups. By J. Ellaed Goee, F.R.A.S. 



(Crosby Lockwood and Son.) 



Those who are acquainted with Mr. Gore's previous writings in 



the attractive realm of Sidereal Astronomy will gladly welcome 



this new contribution to the subject. The book consists of a series 



