iqS reviews 



following propositions concerning the propagation of the seismic energy 

 of the earthquake: 



1. The propagation is most rapid in the direction of the strike of the 

 rock layers, and slowest perpendicular thereto. 



2. Breaks {Briiche) in the earth's shell oppose to the propagation a 

 very considerable obstacle. 



It appears that the great rift of the fossa magna, first made known by 

 Naumann, has played an important role in the seismic history of Japan. 



F, Omori. "Report of the Observation of Pulsatory Oscillations 

 in Japan" (ist paper), Bull. Imp. Earthq. Invest. Comm., Vol. 

 Ill, No. I, 1909, pp. 1-35; pis. 1-6. 



This study, though carried out in Japan, was made in consequence of 



the resolution adopted at the 1907 conference of the International Seismo- 



logical Association, and had for its object the observation of pulsatory 



movements on isolated islands and the comparison of the motions observed 



at several stations within a small area. Dr. Omori has found that these 



pulsatory motions of seismographs, as regards their periods of vibration, 



are practically the same all over the earth, and that they are probably 



due to the translatory movements and not to the inclination of the ground. 



There are found to be two mean periods of vibration: a short one, Qi =4 . 4 



seconds, and a longer one, Q2=8.o seconds. The movements occur very 



frequently, in fact almost constantly, on broad alluvial plains, though but 



rarely in places situated on granite or Paleozoic rocks. Though up to 



the present, they have generally been registered on instruments which record 



horizontal components only, they are found to have a vertical component 



as well. Marked pulsatory oscillations are connected with the approach 



of an area of low barometer, these movements being especially those of the 



shorter period. 



W. H. H. 



The Metallurgy of the Common Metals, Gold, Silver, Iron, Copper, 

 Lead, and Zinc. By Leonard S. Austin. Pp. 494, $4.00. 

 In the second edition of this work much of the material has been recast 

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