ACADEMY OF SCIENCES. 127 



The President transmitted to the Academy a short paper, 

 dated October 12th, upon the recent search for Vulcan. LeVer- 

 rier's telegraphic dispatch asked observers upon the Pacific Coast 

 to make search for Vulcan on the 9th and 10th of October. 

 Professor Davidson was then stationed at the U. S. Coast Sur- 

 vey trigonometrical station, Mt. Helena, at an elevation of 4343 

 feet above the sea, and had been systematically observing the 

 sun for sun spots and planet from the 6th of October. On the 

 9th and 10th the disc of the sun was very carefully and fre- 

 quently examined with a good telescope of three inches aperture 

 and a magnifying power of 85, adjusted for the determination 

 of position of any object on the Sun's surface. Especial care 

 was given to the afternoon hours when the sun was below the 

 horizon to the eastern observatories. Late in the afternoon of 

 the 10th two small spots were discovered, and from their size 

 and want of definiteness it is safe to say that any well defined 

 dark object having a diameter of ten seconds of arc would have 

 been readily detected. 



Professor Davidson states that his examination of the sun's 

 disc before the request of LeVerrier was made known, arose 

 from tentative studies which he had been making upon the action 

 of Mercury, Venus, Earth and Jupiter, (together with a probable 

 intra-mercurial planet, ) upon the fluid surface of the sun in not 

 only changing its form and causing solar spots, but in the 

 almost infinitesimal reactionary effect of the very slightly dis- 

 torted form upon the planets, and especially upon the yet unex- 

 plained variation of the earth's rotational velocity, which he sur- 

 mises may have a period of about forty years. 



A description of a fish caught at Port Madison, W. T., was 

 submitted by Ferdinand Westdahl, through Prof. Geo. David- 

 son. 



Pboc. Cal. Acad. Sci., Vol. VIII- 9. 



