OF ARTS AND SCIENCES. 



9 



Professor Wyman exhibited to the Academy some fossil 

 bones from New Zealand, evidently the thigh-bone, tibia, and 

 tarsus of some one of the largest birds, probably either the 

 Dinornis or Palapteryx. The tarsus was especially interest- 

 ing, as exhibiting the rudiments of two bones besides the de- 

 veloped one, bones of which no traces exist in other birds ex- 

 cept in the embryonic state ; a phenomenon analogous to that 

 occurring in the metatarsal bones of Ruminants. 



Professor Peirce communicated some observations of Messrs. 

 Southworth and Hawes, daguerreotypists, in relation to photo- 

 graphic images taken for the stereoscope. They had found in 

 practice, that, when two points of view were in a horizontal 

 line, the image as seen in the stereoscope appeared distorted, 

 in consequence of the horizontal lines not being represented 

 in relief, like the vertical ones. They had, however, observed 

 that the best images were produced when the position of the 

 two points of view was such that the vertical component was 

 equal to the horizontal one. 



Professor Peirce stated that he had seen a number of photo- 

 types taken in each way, and that he was able to confirm the 

 statements of Messrs. Southworth and Hawes, that portraits 

 taken with two points of view on the same level had a pecu- 

 liarly unpleasant effect. 



Professor Lovering reminded the Academy that Leonardo 

 da Vinci had pointed out the impossibility of representing ob- 

 jects correctly in pictures when their distance from the eyes 

 was within a certain limit. 



Dr. B. A. Gould said that the circumstance of objects appear- 

 ing in relief when observed in ordinary binocular vision might 

 be explained like the outness recognized in monocular vision, 

 by means of the imaginative and suggestive faculties acting 

 unconsciously on reflection. It seemed but natural that a dif- 

 ference of level in the points of view should be necessary to 

 make relief manifest in systems of horizontal lines. 



The discussion was continued by Messrs. Peirce, Gould, and 

 C. T. Jackson. 



VOL. III. 2 



