68 PROCEEDINGS OF THE AMERICAN ACADEMY 



ing the latter as properly applicable to the planet ; in which case the 

 explanation suggested would no longer be admissible. 



According to the observations communicated, the light of Jupiter, 

 seen from the Earth at its mean opposition, is to the light of the mean 

 full moon as 1 : 6430. Compared with the light of Venus at its 

 greatest brightness, it is as 1 : 4.864. 



Professor Bond also read a memoir on the relative bright- 

 ness of sunlight and moonlight. 



Of the results given by Bouguer and Wollaston, for the proportion 

 between sunlight and the light of the full Moon, viz. : 



Bouguer s = 300,000 



Wollaston s = 801,072 



the preference has been generally given to the latter. Reasons are 

 adduced in the present communication for considering Bouguer's 

 method of observation to be the best of the two, and his results de- 

 serving of most confidence. Comparisons, by means of Bengola lights, 

 of the images of the Sun and Moon reflected from a silvered globe, 

 give the value, 



s = 471,000. 



Other methods, less reliable, also tend to confirm Bouguer's deter- 

 mination. 



Professor Bond also communicated a Catalogue of Stars 

 near the Zenith of the Observatory of Harvard College, col- 

 lected from the best existing authorities, having for its object 

 to furnish to astronomical surveyors in the region of the 

 Great Lakes and elsewhere, nearly in the same parallel, accu- 

 rate star-positions for the determination of latitude by the 

 zenith telescope. 



Professor Agassiz discoursed upon the application of his 

 principles of classification to the systematic arrangement of 

 Polyps. 



Professor Cooke, announcing the favorable result of his 

 recent personal application, in behalf of the Academy, to the 

 Royal Astronomical Society, the Geological Society, and the 

 Museum of Practical Geology, London, to supply deficiencies 



