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Dr. Winslow had recently spent a short time in investigating 

 the geology of Acapuico, Mexico, and the earthquake pheno- 

 mena, of which that place is peculiarly the focus. He states 

 that he found, in accordance with his previous theory, that the 

 shocks were more numerous there as winter approaches, and 

 during December and January. The earth passes its perihelion 

 about the last day of December. His theory is, that an increas- 

 ing condensation of the matter of the globe, and its contraction 

 as it approaches the sun, augments necessarily the tension of the 

 fluid mass embraced within its crystalline or consolidated crust. 

 A repulsive action necessarily ensues between the molecules of 

 the molten mass, and the mobility of this mass so acts, here and 

 there, as to rupture the crust and allow the melted earth to insin- 

 uate itself between strata, or vertically through the entire crust, 

 in the form of dykes, or to be forced out of volcanic openings. 

 Dr. Winslow bases his hypothesis upon the following data: The 

 increasing weight of the atmosphere, from September to January ; 

 the increasing rapidity of the pendulum during the same time; 

 the autumnal increase of water in springs, wells, and rivers, 

 independently of rain ; the increasing frequency and violence 

 of earthquake and volcanic phenomena during autumn and 

 winter. 



The President remarked, that at the last meeting of the So- 

 ciety, in connection with the subject of a supernumerary tooth 

 of the Mastodon, he had stated, that it was the commonly received 

 opinion that supernumerary teeth are not rare in man. Since 

 that time he had examined the subject further, but had not been 

 able to find on record, any well-authenticated cases of human 

 supernumerary teeth. Hunter says, very distinctly, that no such 

 teeth exist, and nothing satisfactory is to be found in Owen or 

 Bell upon the subject. A French author of a work on odontology, 

 says he saw a woman, after her first and second set of teeth had 

 fallen, cut four new incisors; but the author says these were not 

 supernumerary teeth, but belonged to the second set, having 

 never previously been cut. Boyer says there are no instances 

 of human supernumerary teeth. Corse, who wrote on the teeth 

 of elephants, and who had great opportunities of study in India, 



