239 



Chester Furnace, Huntingdon County, Pa., containing a small 

 quantity of Oxide of Cobalt, — the surface of the ore is in 

 some places covered with a thin fihn of oxide of cobalt. It 

 also contains a moderate proportion of manganese. 



The ore was dissolved in chlorohydric acid, the solution neutral- 

 ized by ammonia, and then the iron precipitated by boiling, after 

 previous dilution with water. The oxide of cobalt which remained 

 in the solution with the manganese, was discovered both by its reac- 

 tion in the moist way, and by the blue bead it yielded with salt of 

 phosphorus. 



Dr. B. also stated that by a visit to Colemanville Iron Works, Lan- 

 caster County, Pa., he had found on the outer surface of the coal- 

 pits for charring wood, a yellowish white deposition. 



On examining this deposition it was found to consist of acetate of 

 lime. By dissolving it in water and treating it with animal charcoal, 

 the acetate of lime was obtained perfectly colourless. Dr. Boye re- 

 marked, that the lime was probably derived from the soil, but as ace- 

 tate of lime was not volatile, it must be carried up mechanically by 

 the vapours of pyroligneous acid and other volatile substances, given 

 oft" by the process of charring. 



Mr. Haldeman called the attention of the Society to the ap- 

 parent projection of a planet on the disk of the moon, while 

 observing occultations. This appearance he ascribed to a state 

 of tension of the retina, which preserved the impression of the 

 object after the eye was removed from it. Further remarks 

 were made on the subject by Prof. Frazer, Drs. Dunglison,, 

 Patterson, Coates, Bache, and Mr. G. W. Smith. 



Dr. Coates observed, that though he had not been able to verify 

 all the laws of ocular spectra described by Charles Darwin, a cir- 

 cumstance which inclined him to the opinion that these phenomena 

 were materially modified in different individuals, he had observed the 

 sudden disappearance of spectra. Spectra did not decline indefi- 

 nitely, or till the death of the individual experiencing them, by the 

 law of an infinite series ; they terminated abruptly. Our eyes were 

 not constructed with mathematical exactness, nor capable of indefi- 

 nite minuteness ; resembling, in this respect, those of many insects 

 in which a great number of facets replaced the surface of a sphere. 

 Various irregular, nervous sounds, produced in the ear, also termi- 



