RECENT ADVANCES IN SCIENCE 191 



W. von Dyck (Abh. der k. b. Akad. der Wiss. zu Munchen, 

 1914, 28) communicates some lately recovered correspondence 

 of Kepler with Edmund Bruce. 



In 1 91 6 was the two-hundredth anniversary of the death of 

 Gottfried Wilhelm Leibniz (1646-17 16), and the number of the 

 Monist for October, 191 6, was almost entirely devoted to 

 articles on various aspects of Leibniz's life and work. From 

 the point of view of mathematics the most interesting are those 

 on Leibniz's logical work (Philip E. B. Jourdain, Monist, 26, 

 504-23), on Leibniz's dyadic system of numeration (Florian 

 Cajori, ibid. 557-65), and a translation by J. M. Child {ibid. 

 577-629) of Leibniz's Historia et Origo and the cancelled part 

 of a letter to Jacob Bernoulli of April, 1703. Child continues 

 his translations of Leibniz's manuscripts written between 1673 

 and 1675 in the number of the Monist for April, 191 7 (27, 238- 

 94), from the well-known publications of Gerhardt of 1848 and 

 1855. It is to be noticed that the manuscripts are arranged 

 with great care and some very useful notes are added. 



The Address of Cajori on discussions of fluxions from 

 Berkeley to Woodhouse, which was read before the Mathe- 

 matical Association of America at the end of 1916, is printed 

 in the Amer. Math. Monthly for April, 191 7 (24, 145-54). This 

 exceedingly important period of critical work on the foundations 

 of the calculus has been hitherto not very well known, and yet 

 the Analyst of Berkeley and the Discourse of Robins, as well as 

 Newton's tract on the quadrature of curves and Maclaurin 's 

 Fluxions, are landmarks in the logical treatment of mathe- 

 matics. It may be mentioned that Cajori 's full researches on 

 this subject are to be published after the war in the " Open 

 Court Classics of Science and Philosophy." 



Hk. de Vries (Nieuw Tijdschrift voor Wiskunde, 191 5-6, 3, 

 255-69) has a study of Gaspard Monge and the discovery of 

 descriptive geometry. 



L. Mongardon {U Intermediate des Mathematiciens, 191 6, 23, 

 113) has a note relating to a bibliography of Wronski's works. 



E. Lampe and R. Rothe, whose papers on Weierstrass and 

 Weierstrass's Werke have been already noticed in Science 

 Progress (191 7, 11, 617), have published papers which are 

 presumably identical with those previously mentioned in the 

 Archiv der Math, und Phys. (191 6, 25, 36-58 and 59-62). 



The first volume of the (Euvres de G. H. Halphen was 



