Geology and Natural History. 489 



11. Catalogue of the Collection of Palmar ctic Butterflies formed 

 by the late John Henry Leech y by Richard South. British 

 Museum, 229 pp., 2 colored pis. — The collection made by Mr. 

 Leech comprises 18,000 specimens representing 1100 species. 



12. The Determination of the Parallax of the Ten First Mag- 

 nitude Stars in the Northern Hemisphere ; by Wm. L. Elkin. 

 Trans. Astronomical Observatory of Yale University, vol. i, pt. 

 6, pp. 259-330. — This publication gives the details of the results 

 of one part of a plan entered into some years ago by the author 

 and Sir David Gill, Her Majesty's astronomer at the Cape of 

 Good Hope, by which the latter was to make a similar determi- 

 nation for the brightest southern stars. 



The work was begun in 1885 and the original plan of securing 

 some fifty helioraeter measurements of each star was completed 

 in 1891. A discussion of the results showed that the hoped-for 

 degree of accuracy had not in every case been attained, and 

 accordinglv further series were made extending through the year 

 1894. 



The author in his characteristic, painstaking manner, has dis- 

 cussed every possible source of error and has deduced the best 

 results possible from his accumulated material. His final results 

 are as follows : — 



aTauri... *■ = .+ 0"-109 ± 0*-014 



a Auriga __ =+ /7 '079 ± 0"-021 



a Ononis = + 0"'024 + //> 024 



a Canis minoris . _ . = + 0"'334 ± 0"-015 



/3Geminorum ._ = + 0"-056 ± /7 -023 



aLeonis _ = + 0"-024 ± // -020 



aBootis =+ // -026 ± O'-OIT 



aLyusis = + 0"*082 ± 0"'016 



aAquilse . == + 0"-232 ± 0-"019 



aCygni =— 0"'012 ± /7 '023 



In the probable errors here given is included an estimated 

 systematic error, which has increased the magnitude of the prob- 

 able errors about fifty per cent. 



The small result found for Arcturus (a Bootis) was somewhat 

 surprising in view of the well known large proper motion pos- 

 sessed by this star, which would naturally lead us to think it one 

 of the nearest. It was at first thought the anomalous result 

 might possibly be due to the star's color, but investigations upon 

 other red stars made at the Yale Observatory and by several 

 other heliometer observers, as well as a special analysis by the 

 author of his own measures of this star, indicate that this can 

 hardly be the explanation. It is understood that a further series 

 of observations of this star, to be carried out on somewhat differ- 

 ent lines, is now in progress at the Yale Observatory. c. 



