360 Intelligence and Miscellanies. 



Dr. Van Rensselaer made a communication relative to the 

 action of salt water upon copper. A merchant of this city, 

 a large ship owner, had stated as the result of his experience 

 his entire disbelief in the utility of the galvanic method pro- 

 posed by Sir H. Davy, to preserve copper. He considers 

 that a more efficacious protection of the copper would be to 

 cover it with a coat of green paint. The plan was suggest- 

 gested and adopted of applying paints of various colors and 

 composition to different parts of the bottom of a vessel about 

 to sail to the East Indies, in order to ascertain their relative 

 preservative properties. 



Mr. Barnes announced that bituminous coal of a superior 

 quality is found at Williamsport, on the western branch of 

 the Susquehannah, and can be delivered at a reasonable rate 

 at Philadelphia. 



The President announced that there were two vacancies 

 in the class of Honorary Members occasioned by the decease 

 of Dewitt Clinton and Sir James Edward Smith. 



2. On the blue appearance of the heavens; by Benjamin 

 Hallowell, Alexandria, D. C. — The cause of the blue ap- 

 pearance of the heavens, I have never seen satisfactorily ex- 

 plained. I conceive it to be occasioned by our looking at 

 the dark vacuity beyond our atmosphere through an illumi- 

 nated medium. Were there no atmosphere, it is universally 

 admitted the appearance would be perfectly black, excepting 

 in the particular direction of the sun or some other of the 

 heavenly bodies ; and since the atmosphere is transparent, 

 this blackness (if I may use the expression) must be seen 

 through it, only somewhat modified by the rays of light re- 

 flected by the atmosphere to the eye, from the direction in 

 which we are looking. For this reason, the clearer or more 

 transparent the atmosphere is, the darker is the appearance 

 of the heavens — there is then less light reflected by the at- 

 mosphere to the eye. In the zenith the appearance is always 

 darker than nearer the horizon ; and from the tops of high 

 mountains, the heavens in the zenith appear nearly black. 



3. On the twinkling of the stars, and the deception in the 

 number visible to the naked eye on a clear evening; by Ben- 

 jamin Hallowell. — It is a familiar fact, that if a person take 

 a stick with one end ignited, and cause the ignited end to 



