400 Scientific Intelligence. 



Paris Congress." The committee also recommend the adoption 

 of the Watt as the unit of power. " The Watt is defined as the 

 work done per second by the Ampere passing between two points 

 between which the difference of electric potential is one Volt." — 

 Nature, Sept. 22, 1887, p. 498. j. t. 



12. Absolute wave lengths. — From a careful comparison of the 

 observations of Pierre, of Kurlbaum and his own, Mr. L. Bell 

 concludes that the wave length of D is very near to 5896, and 

 consequently all wave lengths based upon Angstrom's value are 

 incorrect by at least one part in 8000. Angstrom's relative wave 

 lengths are also inexact. — Nature, Sept. 29, 1887, p. 524. j. t. 



13. Annalen der Fhysik unci Ohemie, No. 9, for 1887, contains 

 the following articles : 



An investigation on a jet of steam, by R. v. Helmholtz. The 

 author shows the influence of certain substances in forming clouds 

 of vapor by means of the steam. He also discusses the behavior 

 of the jet under electrical influences. The action of finely 

 divided particles in forming clouds is commented upon. 



On electrical residual charges and induction in dialectrics, by 



A. WtJLLNER. 



The Contact Theory, by Franz Exner. The author tries an 

 experiment to disprove the theory. 



Upon the theory of an experiment by F. Exner on the Contact 

 Theory, by Wilhelm Hallwachs. The author exposes an error 

 made by F. Exner. 



On the development of Electricity by the friction of drops of 

 liquid, by Julius Elster and Hans Geitel. This is a careful 

 repetition of Faraday's experiment, with certain amplifications. 



Electrical polarity of Hock crystal, by W. Hankel. 



Resistance of Selenium when exposed to light, by S. Kali- 

 scher. This paper contains various measurements of specimens 

 of selenium. 



Electrolytic separation of metals at the free surface of a solu- 

 tion of a salt, by Dr. J. Gubkin. 



Galvanic Polarization, by Franz Streintz. This is a careful 

 study of the relation of the oxygen and hydrogen polarization to 

 the polarizing current. 



Electrical conveyance of heat, by H. Haga. This is an answer 

 to objections raised by Budde against the author's work. 



Magnetization formula, by A. von Waltenhofen. 



Electromagnetic rotation phenomena in fluid conductors, byF. 

 Schumann. 



Separation of white light into complementary colors, by W. 

 von Bezold. This is a lecture-room experiment, the main feature 

 of which is the employment of a prism and a cylindrical lens. 



Optical peculiarities of certain chemical compounds. This is a 

 study of the absorption spectra of certain organic compounds, 

 with reference to the constitution of the compounds. 



Experimental investigation upon rotating fluids, by W. von 

 Bezold. This investigation bears upon the theory of cyclones 

 and tornadoes. 



