DISTEIBUTION OF EARTHQUAKES IN TIME. 261 



M. J. Delauney, from a study of Perrey's tables of 

 earthquakes from 1750-1842, found two groups of maxima 

 each with a period of about twelve years, one commencing 

 in -1759 and the other in 1756. Two other groups with 

 twenty-eight year periods respectively commence in 1756 

 and 1773. These groups coincide with the times when 

 Jupiter and Saturn reach the mean longitudes of 265° 

 and 135°. From this Delauney concludes that earth- 

 quakes have a maximum when the planets are in the 

 mean longitudes just mentioned. 



The increased number of earthquakes, especially in 

 November, are attributed to the passage of the earth 

 through swarms of meteors, and in like manner supposes 

 the influence of Jupiter and Saturn to be due to their 

 passing through meteor streams situated in mean longi- 

 tudes 135° and 265°. 



As a consequence of this he predicts an increase of 

 earthquakes in the years 1886, 1891, 1898, 1900, &c.i 



Dr. E. Naumann, who critically examined the large 

 earthquakes of Japan, showed that there was an approxi- 

 mate coincidence between many of the disturbances and 

 the thirty-three year period of meteoric showers.^ 



Humboldt states that a great shower of meteors was 

 seen at Quito before the great earthquake of Eiobamba 

 (Feb. 4, 1797). The earthquakes of 1766 and 1799 at 

 Cumana are also said to have been accompanied with 

 meteoric showers. Mallet gives a list of large earth- 

 quakes which occurred at the times when meteors were 

 observed.^ 



The hours at which earthquakes are most frequent. — 

 From the examination of a catalogue of over 2,000 earth- 



^ Am. Jour. Sci. vol. xix. p, 162. 



2 Mitth. d. DentSGh. Ges., Aug. 1878. 



^ Report to British Association, 1850, p. 74. 



