346 Filter and Prepared Charcoal of M. Duraont. 



found in the calcareous rocks of the West Indies, and the entrance 

 to the cavities in which they reside is far less than the" shells them- 

 selves, a proof that they have the power of perforating limestone, 

 for they must have entered the rocks when very young and gradual- 

 ly enlarged their habitations as they increased in size. For this fact 

 I am indebted to General Parker who presented me a specimen 

 which he himself had procured by breaking the rock in which it was 

 concealed. 



Pholas costata. Lin. The same gentleman bought in the Ha- 

 vanna market fine living specimens of this Pholas, far larger than are 

 generally met with on our coast. Dead shells are common on all 

 the coasts of the Middle and Southern States, but I believe a living 

 specimen has never been obtained here. They must certainly how- 

 ever, burrow in the sand at or near low water mark. 



Cardium Mortoni. This shell, described and figured by me in the 

 6th. vol. Jour. Acad, of Natural Sciences, was at that time supposed to 

 be peculiar to the Eastern States, and especially the shores of Long 

 Island Sound. Specimens however have lately been sent from the 

 extreme Southern States ; Dr. Blanding obtained it in East Florida, 

 and Dr. Hutchins in the vicinity of Pensacola. 



Art. XVIII. — Report on the Filter and Prepared Charcoal of M. 

 Dumonf,* by MM. Serullas, Bussy, and Derosne. Translated 

 from the Journal de Pharmacie, by Franklin R. Smith, of Phi- 

 ladelphia. 



To the Societie*de Pharmacie de Paris. 



Gentlemen, — M. Dumont, an experienced manufacturer of beet 

 sugar, called your attention to a filter of his invention, and to a pre- 

 pared charcoal, which he employs in the bleaching of syrups, and 

 you charged MM. SeruUas, Bussy, and myself, (Derosne,) to give 

 you an account thereof. 



The discovery of the decolorizing property of charcoal, is due to 

 Lowitz of St. Petersburg, who however did not remark the difference 

 in activity between vegetable and animal charcoal. Therefore the 

 former only was employed in the sugar refineries for the decolora- 

 tion of syrup. In 1811, M. Figuier of Montpellier ascertained that 



* This paper would long since have appeared, but for the accidental circumstance 

 of its having heen mislaid and forgotten. In searching for another document, we 

 were glad to recover this. 



