Chemistry and Physios. 423 



be greater than that of any other known substance excepting 

 phosphorus. The atomic refraction of nickel in this substance is 

 nearly two and a half times as large as in any other nickel com- 

 pound. In accordance with the view that the valence of an ele- 

 ment is higher in proportion as its compounds have a higher 

 refractive power, the valence 8 has been assigned to the nickel 

 in nickel-carbonyl. Ferro-carbonyl is prepared in a similar way. 

 It is an amber-colored liquid, solidifying below —21° to a mass 

 of needle-shaped crystals, and decomposing at 180°. Its formula 

 is Fe(CO) 5 . It is permanent in the dark but on exposure to sun- 

 light is decomposed, yielding a fine gold-colored solid. Experi- 

 ments on a somewhat large scale to test the practicability of 

 utilizing nickel carbonyl in the extraction of nickel from its ores, 

 proved entirely successful. — Nature, xlvi, 230, July, 1892. 



G. F. B. 



7. Rapid Electrical Oscillations. — In the experiments by 

 Hertz on electrical oscillations and also in the experiments of 

 subsequent investigators, Ruhmkorf coils have been used to prop- 

 agate the electrical oscillations. It is well known, however, 

 that the oscillation in the sparks from a Holtz machine or a Ley- 

 den jar are far more rapid than those produced by the aid of a 

 Ruhmkorf coil. Toepler, therefore, has endeavored to study 

 electrical oscillations by the aid of a Toepler-Holtz machine. 

 His attempt has met with success and he describes his experi- 

 ments at length in the paper we cite. His conclusions state the 

 ratio between the primary and secondary circuits which he 

 employed in order to produce the phenomena of resonance. He 

 also studied the electric spark between a conductor and a surface 

 of water, and discovered that this spark did not oscillate and he 

 therefore concludes that it is probable that the ordinary light- 

 ning discharge does not oscillate. A loud noise and strong 

 development of light in an electric spark is not in general a crite- 

 rion of oscillatory character of the spark. — Ann. der Physik und 

 Chemie, No. 7, 1892, pp. 464-484; No. 8, 1892, pp. 642-665. J. T. 



8. Electricity of 'Waterfalls. — Ph. Lejstard refers to the opin- 

 ion formerly held upon this subject, and after an exhaustive 

 examination conducted in the Alps and also in the laboratory, 

 concludes that drops of water which fall upon water or wet bodies 

 develop electricity. The water is positively electrified. The air 

 moves away from the place of the fall of the drops charged neg- 

 atively. The charge of the water can become so great as to 

 produce small sparks. The air potential in a room can become 

 strongly negative. Slight impurities in the water have very great 

 effect upon its electrification. A simple explanation is afforded 

 by the hypothesis that contact electricity is developed between 

 fluid and gaseous bodies. — Ann. der Physik und Chemie, No. 8, 

 1892, pp. 584-636. J. T. 



9. Photograjyhy of Color. — At a meeting of the Physical 

 Society in Berlin, June 17, 1892, H. W. Vogel read a paper 

 on the various attempts which have been made to reproduce 



