294 ANNUAL OF SCIENTIFIC DISCOVERY. 



Dijon, " On the Relations which may exist between the Frequency of Earth- 

 quakes and the Age of the Moon," and "On the Frequency of Earthquakes 

 relatively to the times of the Moon's passing the Meridian." 



The Report says : 



" If, as is now generally supposed, the interior of the earth is in a liquid 

 or pasty state, through heat, and if the globe has for its solid part only 

 a crust comparatively very thin, the interior liquid mass must tend to yield, 

 like the surface waters, to the attractive forces exerted by the sun and moon, 

 and there must be a tendency to expansion in the direction of the radius 

 vectors of these two bodies ; but this tendency encounters resistance in the 

 rigidity of the crust, which is the occasion of fractures and shocks. The in- 

 tensity of this crust varies, like that for the tides of the ocean, with the 

 relative position of the sun and moon, and consequently with the age of the 

 moon ; and it should also be noted that as the ocean's tides rise and fall twice 

 in a lunar day, at periods dependent on the moon's passing the meridian, so 

 in the internal fluid of the globe, there should be two changes a day, the 

 time varying with the same cause. Without entering now into more details, 

 it will be easily conceived that if the mobility of the internal mass of the globe 

 plays a part in the production of earthquakes, there must be some dependence, 

 admitting of study, between the occurrence of an earthquake and the circum- 

 stances which influence the action of the moon on the whole globe, or on any 

 place or portion of it ; that is, the angular distance with the sun, its actual 

 distance from the earth, and its distance from the meridian of the place ; or, 

 in other terms, the age of the moon, the time of perihelion, and the hour of 

 the lunar day. These considerations, which have not escaped M. Perrey, 

 have, beyond doubt, inspired the idea of the twofold work which we have 

 been charged to examine, and they have obtained for the views the interested 

 attention of M. Arago and many other men of science. They have involved 

 on the part of the author the determination of the precise date and period of 

 the moon for each earhquake on record, and even for each shock of which 

 earthquakes may consist a work of vast labor. 



" M. Perrey has tabulated all the earthquakes recorded since 1801, and 'by 

 discussing the catalogues which he has formed, shows by three ways, inde- 

 pendent of one another, the influence of the course of the moon on the 

 production of earthquakes,' viz.: 



" 1st. That the frequency augments on the syzygies. 



" 2d. That the frequency augments in the vicinity of the moon's perigee, 

 and diminishes toward the apogee. 



" 3d. That the shocks of earthquakes are more numerous when the moon 

 is near the meridian than when 90 from it. 



" But hi each of these results he finds some ' minor' and some ' large anom- 

 alies.' 



"In a recent discussion on the theory of M. Perrey, before the Boston Society 

 of Natural History, Mr. Stodder proposed the hypothesis that the centrifugal 

 force of the diurnal rotation of the earth, acting on the fluid interior mass (if 

 such is the condition of the interior) of the earth, was the cause of earth- 

 quakes, and that if there has been any change in the position of the poles of 



