758 



SCIENCE 



[N. S. Vol. XXXI. No. 802 



might be due to the passage of negative charges 

 around the earth. 



Cathode rays coming from the sun and entering 

 the earth's magnetic field at right angles as they 

 would do for the magnetic equatorial regions, 

 would be deflected and be made to pass around the 

 earth in the form of a ring composed of negatively 

 charged particles (corpuscles). Birkeland looks 

 to such a ring as the cause of the said " equa- 

 torial perturbations." However, unfortunately 

 the deflection of the solar cathode rays is not in 

 the right direction, for they would be made to 

 pass around the earth from east to west and not 

 from west to east as required by the results of 

 the analyses stated above. On the other hand, 

 cathode rays coming from the earth would be 

 deflected so as to pass around the earth from 

 west to east, thus fulfilling one condition. But, 

 if the radius is computed of the ring of moving 

 corpuscles, it is found that the orbit of the latter 

 would have to be distant from the earth's center 

 580 times the earth's radius or 3,700,000 kilo- 

 meters or 2,300,000 miles, and thus the possi- 

 bility of a terrestrial origin of the cathode rays 

 is likewise eliminated. Furthermore, if we cal- 

 culate the intensity of the current which at that 

 distance could produce the observed efl'ects of the 

 disturbances of May 8, 1902, and January 26, 

 1903, it is found to be 5,900,000 amperes. Now 

 Birkeland says on page 311 of his book:^ "In 

 the case of the greater storms, we found current- 

 strengths that varied between 500,000 and 1,000,- 

 000 amperes, or even considerably more." Hence, 

 to produce the comparatively insignificant mag- 

 netic disturbance effects here considered, by sup- 

 posing a band of cathode particles circulating 

 around the earth, would require a current at least 

 six times stronger than that which Birkeland 

 finds sufficient to account for the much larger 

 storm effects! 



The hypothesis was next briefly examined on 

 which the disturbance effects considered might be 

 referred to alterations in the electrical con- 

 ductivity of the atmosphere and of the earth 

 either brought about by the secondary effects 

 from bombarding cathode particles, viz., the for- 



laris Expedition 1902-1903," Vol. I., "On the 

 Cause of Magnetic Storms and the Origin of 

 Terrestrial Magnetism," First Section, Christi- 

 ania, 1909. 



- " The Norwegian Aurora Polaris Expedition, 

 1902-1903," Vol. I., "On the Cause of Magnetic 

 Storms and the Origin of Terrestrial Magnetism," 

 First Section, Christiania, 1900. 



mation of Eiintgen rays or say by the entrance 

 into the earth's field of penetrating radiation 

 ( 7 rays of radium ) . The ionizing effect and 

 resultant alteration of electrical conductivity of 

 the regions involved might either be due to the 

 penetrating radiation from the sun or from the 

 earth, if only qualitative results are considered. 

 It is therefore at present not possible to state 

 definitely whether the initial cause of the dis- 

 turbance of May 8, 1902, was due to a terrestrial 

 eruption or a solar one. First, further examina- 

 tions will have to be made of the disturbances of 

 May 20 and July 9, 1902, which were again closely 

 coincident with Mont Pel6 eruptions. The electric- 

 conduction hypothesis appears to satisfy in gen- 

 eral the observed phenomena and accordingly it 

 is to be subjected to a further rigid examination. 

 It seems also to explain why some of the disturb- 

 ances take a westward path although the majority 

 of them go eastward. 



(The abstracts of the above papers are by their 

 authors. ) 



E. L. Fabis, 

 Secretary 



THE GEOLOGICAL SOCIETY OP WASHINGTON 



At the 230th meeting of the society, held in 

 the George Washington University, Wednesday 

 evening, March 23, 1910, Mr. F. L. Hess presented 

 an informal communication on " Mounds Formed 

 by Crystallization." In a playa known as Salt 

 Lake in the Mohave Desert, at Cane Springs, 

 twenty miles west of Randsburg, California, 

 mounds from 2 to 4 feet high and from 50 to 

 200 feet broad are formed in the moist lake bed 

 through the crystallization of salts, mostly mira- 

 bilite with some epsomite. A few mounds are 

 apparently formed through the crystallization of 

 common salt. About six inches of earth forms 

 the surface of the mounds, below which there is 

 a spongy mass of the salts. Mr. E. S. Bastin 

 spoke informally on the origin of the graphite 

 at Lead Hill near Tieonderoga, N. Y. The 

 graphite probably represents the original carbon- 

 aceous constituent of sediments which have been 

 altered first by dynamic and then by igneous 

 metamorphism due to the intrusion of granite 

 pegmatite. A study of the quartz of the contact 

 zone following the methods of Wright and Larsen 

 shows that it crystallized below 575° C. This is 

 the first test which has been made on contact- 

 metamorphic quartz and gives a key also to the 

 temperature of formation of the graphite, augite. 

 scapolite, calcite, titanite, pyrrhotite and vesuvi- 



