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waters, any theory should point out the source from whence the 

 protoxide of iron is taken, to form the dissolved carbonate ; as 

 protoxide of iron does not naturally exist. If a previous reduc- 

 tion of other oxides of iron, by organic matter, is necessary to 

 insure this solution, it will probably be found that crenic acid, 

 instead of carbonic acid, is the solvent. 



The explanation, as given by Prof. Rogers, becomes, therefore, 

 not only the simpler view, and strictly accordant with known 

 facts, but it seems to be necessary, as a basis for the theory gen- 

 erally received. 



There is a point of geological interest, in connection with the 

 manner in which the proto-carbonate of iron is included in the coal 

 series, and often in contact with beds of coal. This compound, as 

 before stated, is a hydrate compound, and its varieties generally 

 lose their carbonic acid and become peroxide by a moderate 

 elevation of temperature ; its presence, therefore, in contact with 

 alternating beds of coal, may be considered as indicating that 

 such beds have not been subjected to heat above the tempera- 

 ture at which the carbonate is decomposed. 



Prof. Jeffries Wyman stated that a year or two since, in the 

 Ohio River, opposite Cannelton, there was noticed a sudden 

 commotion and explosion, followed by a considerable ebullition of 

 the water for some time, so that boats avoided the spot. Imme- 

 diately afterwards, there was found a peculiar substance, light and 

 porous, somewhat resembling pumice-stone, floating around in 

 the neighborhood. Specimens of this substance were presented 

 by Prof Wyman, and placed in the hands of Dr. Hayes, for 

 examination. 



Dr. C. T. Jackson observed, that the material bore resemblance 

 to slag from iron furnaces. On trial, it was found still to float 

 in water. [Dr. Hayes, having since examined the substance, 

 reports that it contains particles of metallic iron, and is, in com- 

 position, the same as iron slag produced in the blast furnaces. — 

 Secretary.] 



Prof. Jeflfries Wyman exhibited some impressions, in clay, 

 of Hail, caught during a recent storm. 



