Chemistry and Physics. 465 



of calcium carbide, even after having been filtered through cotton 

 and passed through water, deposited lime in the conducting pipes. 

 This fact seemed to indicate the presence of a volatile compound 

 of calcium in the gas. In order to study the matter further, a 

 large volume of the acetylene was passed through a number of 

 wash-bottles containing acetone, then through ammoniacal cop- 

 per solution to remove the acetylene completely. A colorless gas 

 was thus obtained, which burned in the air to calcium oxide and 

 water, and formed an exceedingly explosive mixture with oxygen, 

 As the gas was not obtained quite free from air, its quantitative 

 composition has not yet been determined. — Zeitschr. anorgan. 

 Chem., xlviii, 137. h. l. w. 



6. The Electrical Nature of Matter and Radioactivity ; by 

 Harry C. Jones. 8vo, pp.' 212. New York, 1906 (D. Van 

 Nostrand Company). — In this book Professor Jones gives a very 

 clear and interesting; account of the recent developments in 

 regard to gaseous ionization, electrons, rays of various kinds and 

 radio-active bodies. The style is semi-popular and non-mathe- 

 matical, so that it is well adapted for the use of the general 

 scientific reader. The work is to be highly recommended to those 

 who desire to obtain an insight into the fascinating fields of work 

 in which J. J. Thomson, Becquerel, the Curies, Rutherford and 

 many others have been laboring. h. l. w. 



7. Energy, Duration, Damping and Resistance of Condenser 

 Sparks. — The art of wireless telegraphy has given a new import- 

 ance to the study of electric sparks. A. Heydweiller con- 

 tributes an interesting paper upon the necessity of adding another 

 term to Lord Kelvin's celebrated differential equation which 

 expresses energy relations in regard to the discharges of a 

 condenser. This new term expresses the spark energy : the 

 resulting differential equation is complicated and its integration 

 in the words of the author "must remain a pious wish"; still 

 several solutions can be obtained by making suitable suppositions 

 in regard to the electrical constants of the circuit. Heydweiller 

 finds that the resistance of the condenser sparks which are usually 

 employed in wireless telegraphy is less than an ohm. — Ann. 

 der Physik, No. 4, 1906, pp. 649-691. j. t. 



8. Magnetic Relations of Powdered Iron of Various Densi- 

 ties. — W. Teknkle finds that, with equal magnetizing forces, the 

 magnetization and susceptibility of clean iron powder is always 

 greater than a mixture of iron powder and a non-magnetic sub- 

 stance : the magnetization of the iron sinks cet. par. with its 

 density. — Ann. der Physik, No. 4, 1906, pp. 692-714. j. t. 



9. Spectrum of the High Tension Flaming Discharge. — This 

 discharge results from the high degree of ionization which is pro- 

 duced from the terminals of a transformer which is excited by a 

 powerful current in the primary of the transformer. It is also 

 the characteristic discharge of a high tension storage batteiy. 

 13. Walter finds that the spectrum of this discharge contains 

 some very characteristic bands in the ultra-violet end of the spec- 



