228 Scientific Intelligence. 



At 19 c- 5 under pressure of 210 atmospheres. 

 " 0- " " " 620 " 



" 10- " " " 900 " 



M. Amagat suggests that there may be for each liquid a tempera- 

 ture above which solidification cannot take place under any pres- 

 sure : that is to say, a critical point of solidification. — Comities 

 JRendus, July 18, 1887, p. 165. j. t. 



1 0. The Conduct ibility for heat of Bismuth in the magnetic 

 field. — -M. A. Right announces that the heat conductibility of bis- 

 muth varies in a magnetic field. In other words, that a rotation 

 of the isothermals analogous to the Hall phenomenon takes place. 

 — Comptes Rendus, July 18, 1887, p. 168. j. t. 



11. Size of the Silver Molecule. — In an exhaustive paper upon 

 methods of measuring thin films, Otto Wiener makes certain 

 measures of the thickness of a film of silver which can just be 

 perceived by the eye, and arrives at the conclusion that 0'2 mil- 

 lionths of a millimeter is an upper limit of the diameter of a 

 silver molecule. — Annalen der Physik tend Chemie, No. 8 a , 1887, 

 pp. 629-672. j. t. 



1 2. Changes in the Ohm. — Himstedt has repeatedly re-measured 

 certain standards constructed of german silver and has discovered 

 that, independent apparently of changes of temperature, the re- 

 sistance of german silver undergoes a slight change. He calls 

 attention to the custom of Messrs. Siemen and Halske of keeping 

 their german silver wire six months after it is covered and wound 

 before it is used for electrical standards of resistance. The ex- 

 periments of Himstedt supports this procedure of the manufact- 

 urers, although no reason is assigned for it. It is better, there- 

 fore, to compare with a mercury standard, although the extent 

 of the change of the german silver standards is too small to affect 

 their use in the arts. — Ann. der Physih und Chemie, No. 8 a , 

 1887, p. 617. J. t. 



13. The Chemistry of the Sun; by J. Norman Lockter. 8°, 

 pp. xix and 457. Macmillan & Co., London, 1887. — The prime 

 object of this volume is to set forth the theory of dissociation which 

 Mr. Lockyer propounded many years ago, together with the 

 various researches which he has himself carried on to test the 

 theory, and also to show what bearing the investigations and 

 observations of other scientists have upon the same. The earlier 

 chapters of the book are preliminary and are devoted to a history 

 of the work done upon the solar spectrum previous to the last 

 twenty years ; the rest of the work is a rehearsal of later work, 

 and a comparison of the theory with facts. 



Mr. Lockyer's theory is thus stated (p. 260) : " chemists regard 

 matter as composed of atoms and molecules. The view now 

 brought forward simply expands the series into a larger number 

 of terms, and suggests that the molecular grouping of a chem- 

 ical substance may be simplified almost without limit if the tem- 

 perature be increased." The earlier hypothesis of the structure 

 of the solar atmosphere and that propounded by Mr. Lockyer he 

 thus contrasts (p. 303). On the old hypothesis : 



