142 



concluded expedition of the " Challenger,'' and presented to the Town 

 Museum by Lieut. Carpenter, son of Mr. Charles Carpenter, of 

 Brunswick-square, who, Mr. Wonfor explained, in introducing the 

 specimens to the members' notice, had for some time the charge of 

 the dredger. 



The nodules of manganese dredged up at various depths in 

 the Pacific were also exhibited. These were of small size,— smaller 

 than a chestnut, which they resembled in colour ; but he had been 

 informed by Lieut. Carpenter that they varied in size from that of a 

 pea to that of a man's fist, or even larger. When broken up, they 

 were, in almost every case, found to contain either a portion of bone 

 or a shark's tooth. This fact was important, as it indicated that there 

 were formations going on at the bottom of the ocean about which 

 geologists were but slightly informed. One tooth, found encrusted in 

 manganese in this way, measured 4i- inches in length ; and he was 

 given to understand that no sharks having teeth of such size had been 

 met with in recent times, 



In reply to Mr, Dennet, Mr. WoxiOR said that, having had the 

 nodules in his possession but a few hours, he was unable to say what 

 relation the manganese bore to the manganese of commerce. 



These nodules might help in explaining how iron nodules 

 (commonly called thunder-bolts) and flints were formed in the chalk. 



The meeting then became a Conversazione. 



September 14th. 



ORDINARY MEETING.— MR. E. A. PANKHURST ON 

 "SOME OF THE PROBLEMS CONNECTED WITH 

 THE DEPOSITION AND CRYSTALLIZATION OF 

 SILICA." 



The substance, silica, which formed so large a part of the crust of 

 the earth, was the oxide of a seini-metallic body, which was called 

 silicon or silicium. On account of the difficulty of isolating it from its 

 compounds silicon was one of the curiosities of chemistr)-. It might be 



