RECENT ADVANCES IN SCIENCE 3 



volumes whose magnitudes are ordinarily found by the analy- 

 tical processes of the calculus." The real point of Child's 

 work has been appreciated by most mathematicians, including 

 Sir Ronald Ross (Science Progress, 1919, 13, 634-5). 



C. Tweedie (Math. Gaz. 1919, 9, 303-5) gives some notes on 

 the life and works of Colin MacLaurin (cf. Science Progress, 

 1916, 11, 615). 



Cajori (School Science and Math. 191 8, 18, 778-9) points 

 out that Joseph Fenn, in a publication of 1769, antedated both 

 Playfair and Ludlam in giving " Playfair's parallel-postulate." 

 It may be mentioned that, as Cajori has since remarked to the 

 present writer, this form of postulate was already given by 

 Proclus. On Fenn, we may recall a note of W. Stott (Science 

 , Progress, 191 5, 10, 214). 



An interesting letter from Sir William Rowan Hamilton to 

 Humphry Lloyd, written in 1856, which contains, among other 

 things, some remarks on the theory of numbers and quaternions, 

 is given in Math. Gaz. (191 9, 9, 302). 



An account of recent publications on the history of mathe- 

 matics is given in the Boll, di bibl. e storia delle sci. mat. 191 8 

 [2], 1, 62-4). 



There are thorough accounts of the life and work of Adolfo 

 Viterbi ( 1873-19 17) by G. Vivanti, and Eugenio Elia Levi 

 (1 883-191 7) by G. Fubini and G. Loria (ibid. 33-7 and 38-45 

 respectively). M. J. M. Hill (Proc. Lond. Math. Soc. 191 9, 17, 

 xlii-xlix) gives a full account of the work of O. Henrici (cf. 

 Science Progress, 1919, 13, 522). The following are among 

 recent deaths of mathematicians : E. R. Neovius (September 26, 

 191 7 ; age 67) ; J. H. Graf (age 66) ; C. Stephanos (age 60) ; 

 O. Reichel (age 83) ; G. M. Green (January 25, 1919 ; age 28) ; 

 K. O. E. Lampe (September 4, 191 8, age yy) — editor of the 

 Jahrbuch since 1885 ; S. I. Lattes (July 5, 1918, age 45) — Amer. 

 Math. Monthly, 191 9, 26, 86, 89, 90. G. B. Mathews (Nature, 

 1 91 9, 103, 49) gives a short account of the work of Ludvig 

 Sylow, who died at the age of eighty-five on September 7, 



191 8. Sylow's most noteworthy discovery is his well-known 

 theorem (1872) on groups of substitutions ; he also wrote on 

 other parts of pure mathematics and edited with Lie the 

 second issue of Abel's (Euvres (cf. also Amer. Math. Monthly, 



1 919, 26, 119). A short notice of the work of the late A. M. 

 Liapounoff is given in Nature (191 9, 102, 509-10). In a notice 



