May 26, 1905.] 



SCIENCE. 



817 



taxonomic importance arc clearly elucidated. 

 Brief directions are then given for the collec- 

 tion of material and the determination of 

 species, and this is followed by the taxonomic 

 section which includes quite detailed descrip- 

 tions of 916 species of mosses, with dichoto- 

 mous keys to the families, genera and species. 

 The system of classification adopted agrees 

 very closely with that of Limpricht in Kaben- 

 horst's ' Kryptogamen Flora von Deutsch- 

 land.' 



The second part of the work deals with the 

 liverworts and in general arrangement follows 

 that for the mosses. Keys and descriptions 

 are given for 228 species. The work is bound 

 in 'halbfranz,' and is embellished with 68 full- 

 page lithographed plates, distributed through- 

 out the text, of which 26 are executed in nat- 

 ural colors. The work is on the whole an 

 admirable one, and it is only to be regretted 

 that the production of such works is appa- 

 rently not possible in our own country. It 

 will form a valuable addition to the library of 

 any student of mosses. F. D. IIeald. 



The Uxiveesity of Nebraska. 



SCIENTIFIC JOURNALS AND ARTICLES. 

 The contents of the March issue of Ter- 

 restrial Magnetism and Atmospheric Elec- 

 tricity is as follows : 



Portrait of Svante August Arrhenius, Frontis- 

 piece. 



S. A. Arrhenius : ' On the Electric Charge of 

 the Sun.' 



C. Chree : ' Review of Maunder's Recent In- 

 vestigations on the Cause of Magnetic Disturb- 

 ances.' 



W. VAN Bemmelen: 'Magnetic Survey of the 

 Dutch East Indies.' (Tliird communication.) 



J. Elstek und H. Geitel: ' Vorschlage fiir die 

 Ausfiihrung electrischer Beobachtungen wiilirend 

 der bevorstehenden Sonnenfinsterniss.' 



L. A. Bauer: ' Proposed Magnetic and Electric 

 Observations during the Total Solar Eclipse of 

 August 30, 190.5' (Preliminary Information). 



J. E. BuRBANK: 'Earth Currents: and a Pro- 

 posed ^lethod for their Investigation.' 



Biographical Sketch of Svante August Arrhe- 

 nius. 



Letters to Editor: Nachtrag zur Abhandhing 

 ' Ueber den Einfluss der Torsion bei den Ablenk- 

 ungen eines hiingenden Magneten,' F. Bidling- 



maier; Tortosa Observatorio del Ebro (Il- 

 lustrated), R. Cirera ; Principal Magnetic 

 Disturbances recorded at Cheltenham ilagnetic- 

 Observatory, December 1, 1904, to March 1, 1905^ 

 W. F. Wallis; Present Russian Magnetic Observa- 

 tories, M. Rykatscheff. 



SOCIETIES AND ACADEMIES. 



THE AMERICAN PHYSICAL SOCIETY. 



The regular spring meeting of the Physical 

 Society was held at the Kyerson Physical 

 Laboratory of the University of Chicago on 

 Friday, April 21, and Saturday, April 22, 1905. 

 President Barus presided. The meeting was 

 well attended, nearly all the colleges and uni- 

 versities within several hundred miles of Chi- 

 cago being well represented. An informal 

 dinner on Friday evening at the Quadrangle 

 Club was a pleasant feature of the meeting. 

 The program, which was the largest in the 

 history of the society, is given below: 



H. N. McCoy, University of Chicago: 'On the 

 Relation between the Radioactivity and Composi- 

 tion of Uranium Compounds.' 



G. G. Becknell, Northwestern University : ' The 

 Residual e.m.f. of the Carbon Arc' 



C. W. Chamberlain, Denison University : ' Tlie 

 Radius of Molecular Attraction.' 



G. M. Hobbs, Univer.sity of Chicago : ' Tlie Re- 

 lation between p. d. and Spark Length for Small 

 Values of the Latter.' 



C^KL Kinsley', University of Chicago: 'Short 

 Spark Discharges.' 



J. E. Almy, University of Nebraska: 'The In- 

 liuence of Electrodes upon Spark Potentials.' 



J. E. Almy, University of Nebraska : ' Note 

 on the Potential Difference Required to Produce 

 very Short Sparks.' 



A. B. Porter, Chicago : ' Some Oddities in 

 Lenses.' 



A. H. Taylor, University of Wisconsin : ' On 

 the Possible Variation of Inductance Standards 

 with Temperature.' 



E. M. Terry, University of Wisconsin: 'On the 

 Variation of Capacity with Temperature.' 



A. H. Taylor, University of Wisconsin: 'On 

 the Comparison of Mutual Inductances.' 



R. T. Herdegen, University of Wisconsin : ' The 

 Comparison of the Mutual Inductance of a Pair of 

 Coils with the Self-induction of One of Them.' 



O. M. Stewart, University of Missouri : ' Tlie 

 Use of the Quadrant Electrometer in Measuring 

 Current.' 



