378 Proceedings of the 



means of a pump held in his hands, the sound increased in intensity 

 the moment his ears were submerged, although his distance from the 

 instrument remained the same, thus proving that the hydraulic vibra- 

 tions were directly transmitted to the auricular organs with more 

 energy than when transmitted through the medium of the atmo- 

 sphere. M. Latour also found, that the intensity of the sound did 

 not vary materially in proportion to the depths to which he sub- 

 merged himself; whence he concludes, that the augmentation of the 

 pressure of the air contained in the ears did not operate on the phe- 

 nomenon, but that it depended mainly on the immediate hydraulic 

 communication. 



Oscillations of the Pendulum in Air. On the 22d of August, 

 M. Poisson read a memoir on the simultaneous movements of a 

 pendulum and the ambient air. The learned academician, after 

 remarking that M. Bessel was right in asserting that some slight 

 modifications must be made in the great law of nature laid down by 

 Newton, that all molecules attract each other in the direct ratio of 

 their mass, and the inverse ratio of the square of their distance, 

 stated that he had repeated several of the experiments of M. BesseK 

 He put pendulums composed of substances of unequal weight into a 

 state of oscillation, and ascertained that the variation in the weight 

 occasioned the variation in the number of oscillations. He then, 

 after a great number of experiments, all of which he verified by cal- 

 culation, satisfied himself that the gradual diminution of the ampli- 

 tude of the oscillations of the pendulum must be attributed to the 

 pressure of the ambient air. 



ZOOLOGY. 



Silkworm. On the 4th of July, M. Dume'ril read a report on a 

 memoir by M. Lamare Picquot, relative to the Bombyx paphia of 

 Asia. M. Lamare Picquot, while in India in 1829, had found, in the 

 forests of Bengal which line the right bank of the Damoudore, to 

 the west of Calcutta, some silkworm cocoons, the silk of which ap- 

 peared to be of so excellent a quality, that he was induced to have 

 the insect sought for, and succeeded in procuring several. This 

 silkworm lives in the forests on a kind of wild Badamier (the Ter- 

 minalia of botanists), which is very common. The Indians, who 

 keep these worms, feed them on the leaves of the ordinary badamier, 

 or with those of the Shamnus jvjuba. The insect undergoes its 

 last change on the return of spring, and comes out of the cocoon by 

 a hole which it makes in the extremity. The female soon afterwards 

 lays her eggs, and both male and female shortly die. The eggs 

 come to maturity in about twenty to twenty-nine days, and ordinarily 

 in the month of March. The worm at its birth is about a quarter of an 

 inch long, yellow, with the head black and large. At its full growth, 

 it is from three to four inches long. M. Lamare Picquot differs in 



