July 24, 1908] 



SCIENCE 



125 



of the April meeting of the society, by F. N. 

 Cole; report of the April meeting of the 

 Chicago Section, by H. E. Slaught; In 

 Memoriam Heinrich Maschke ; " Criteria for 

 the Irreducibility of a Reciprocal Equation," 

 by L. E. Dickson; " A New Graphical Method 

 for Quaternions," by J. B. Shaw ; " Logic and 

 the Continuum," by E. B. Wilson; Shorter 

 Notices (Picard's " Developpement de 1' An- 

 alyse and La Science moderne," by E. B, 

 Wilson ; Mathew's " Algebraic Equations," by 

 F. Cajori ; Bertini's " Geometria Proiettiva 

 degli Iperspazi," by C. H. Sisam; Staude's 

 " Analytische Geometria des Punktes, der 

 geraden Linie und der Ebene," by G. N. 

 Bauer ; Shepard's " Strength of Materials," by 

 E. W. Ponzer; Hering's " 200-jahriges 

 Jubilaum der Dampfmaschine," by F. Ca- 

 jori) ; Notes ; New Publications. 



The July number of the Bulletin (conclu- 

 ding volume 14) contains : " The Inverse of 

 Meusnier's Theorem," by Edward Kasner; 

 " On the Distance from a Point to a Sur- 

 face," by Paul Saurel ; " On the Solution of 

 Algebraic Equations in Infinite Series," by P. 

 A. Lambert ; " The Deduction of the Electro- 

 static Equations by the Calculus of Varia- 

 tions," by A. C. Lunn ; " The Fourth Inter- 

 national Congress of Mathematicians," by C. 

 L. E. Moore ; Shorter Notices (" Encyklopadie 

 der Elementar-Mathematik," Bande 2-3, by 

 H. S. White ; Lebesgue's " Lemons sur I'ln- 

 tegration et la Eecherche des Fonctions Prim- 

 itives," by D. E. Curtiss) ; Notes ; New Pub- 

 lications ; Seventeenth Annual List of Papers 

 read before the Society and subsequently pub- 

 lished; Index of Volume. 



At the sitting of the Paris Academy of 

 Sciences on June 22, according to a report, 

 M. Poincare read a note from M. Jean 

 Becquerel on the nature of positive electricity 

 and the existence of positive electrons which 

 have been found in a Crookes tube. Dr. 

 Salmon, of the Pasteur Institute, announced 

 that sleeping sickness had been cured in 

 monkeys by means of a form of atoxyl. MM. 

 Beorges and Gustave Laudet gave particulars 

 of their success in photographing sounds. 

 Those photographs are so clear that they 



permit of a study of sound far more precise 

 than any hitherto known. The most delicate 

 peculiarities of the voice, such as lisping, and 

 even breathing, are produced with the greatest 

 distinctness. The MM. Laudet, who have been 

 pursuing those inquiries since 1905, when they 

 first communicated their ideas to the Academy 

 of Sciences, have been induced to give the 

 present account of their success owing to the 

 recent communication on the same subject by 

 M. Devaux Charbonnel. The MM. Laudet, 

 instead of having recourse to electricity, like 

 M. Devaux Charbonnel, have employed a 

 purely mechanical and direct means for secur- 

 ing the desired record. 



SPECIAL ARTICLES 



OBSERVATIONS ON CHANGE OF SEX IN CARICA 

 PAPAYA 



While change of sex among the phanero- 

 gams is not unknown yet it is of such rare 

 occurrence that any well-demonstrated in- 

 stances as those shown by the Caricas under 

 observation are worthy of careful study. This 

 is especially true when that change can be 

 brought about by cultural methods as seems 

 to be clearly proved in the present instance. 



Carica papaya is a tropical, rapidly growing 

 tree-like form belonging to the Passiflorese 

 family. As found in Porto Eico it is dis- 

 tinctively dioecious, the monoecious form being 

 very rare except when produced as were the 

 ones under observation. The tree is non- 

 branching, but will readily develop lateral 

 buds if the terminal bud is destroyed. 



The staminate trees bear the flowers 

 in dense, dichotomously branched head-like 

 groups on a very long helicoid dichotomous 

 branched peduncle. The flowers in each group 

 on the peduncle develop successively, continu- 

 ing over a long period of time, so that there 

 is no time during the year when flowers are 

 not shedding pollen. The pistillate tree bears 

 axillary flowers of a very different form from 

 the staminate. " The pistillate flowers are bom 

 in an unbranched peduncle and vary in num- 

 ber from one to five or even more; usually 

 three. Of these only one, with rare excep- 

 tions, sets fruit. It is said that the flowers 



