144 [January, 1842. 



with the white chalk of Europe, as maintained by Dr. Morton. 

 He announced the discovery at that locality, of a Planularia, a 

 multilocular shell characteristic of the European chalk. Mr. Con- 

 rad has also detected in the medial cretaceous beds at Wilming- 

 ton, North Carolina, the Cirrus perspectivus, a Nautilus which he 

 believes to be the N. Danicus, and the Cyprsca bullaria ; the last 

 two being characteristic of the Faxoe limestone. 



Mr. Conrad's paper being designed for publication, was 

 referred to a committee. 



Verbal Communications. Professor Johnson stated the 

 results of some experiments on the magnetism of bars of 

 wrought iron broke by tensile force. 



He referred to a former communication, in which he had given 

 an account of trials on cast iron in a state of fusion, and to the 

 influence of terrestrial magnetism, inducing the magnetic state in 

 bars of iron, according to the position in which they are placed 

 with reference to the magnetic axis. He had found that when a 

 bar of soft iron is drawn asunder at ordinary temperatures, and 

 in the direction of the magnetic meridian, there was also manifes- 

 ted at the point of fracture a decided evidence of magnetic polar- 

 ity; and that the kind of magnetism was that belonging to the 

 region towards which the broken extremity of each fragment 

 pointed. This magnetic condition was indicated by the adhesion 

 of any particle of iron or of hammer cinder, which chanced to be 

 near the fracture at the moment, as well as by the action of a 

 small needle when held near the point. 



If the two extremities separated from each other by a short 

 distance, be at the moment of fracture in contact with a mass of 

 iron filings, the latter will adhere to the two ends, and extending 

 across, form a continuous line or bridge, which appears to serve 

 as a keeper, for they continue for a considerable time with little 

 diminution of their force. 



When the fracture is made at a red heat, little or no magnetic 

 effect appears to result from the action of breaking. But when 



