Miscellanies. 191 



In treating of the formation of hailstones, as to their physical con- 

 stitution, and the enormous size which they sometimes attain, as to 

 the seasons of the year, and the parts of the day when they are most 

 commonly observed, it will be indispensable to follaw out the conse- 

 quences of the theory adopted, to numerical applications, — whether 

 the theory employs the known properties of heat and electricity— or 

 be founded upon new properties, resulting from incontestable experi- 

 ments. Memoirs to be sent to the secretary of the Academy, before 

 the 1st of March, 1834. — Idem. 



7. Astronomy. — Observations upon the disappearing and reappear- 

 ing of the ring of Saturn, — and new elements of the comet of Biela ; 

 by M. L.-F. Wartmann. 



M. Wartmann made his observations at Geneva, in accordance 

 with the request of M. Bessel of Konigsberg, addressed to the obser- 

 vers of all countries, so as to be able to fix precisely the time of the 

 disappearing and reappearing of the ring of Saturn. 



" On the 22d April last, at 9 P. M. sky very clear, M. Wartmann 

 observed Saturn with an excellent achromatic telescope, by Dollond, 

 mounted parallactiquernent, of three inches and a half aperture, and 

 of forty-two inches focal distance, and of a magnifying power of one 

 hundred and thirty-five times. The ring was hardly perceivable, 

 and appeared like a small straight line in crossing the disc of Saturn, 

 and projecting on each side. On the 23d, at three-quarters past nine 

 P. M. the sky perfectly serene, with the same telescope, M. W. could 

 not see any trace of the lines which, the evening before, fringed the 

 planet, and could perceive, upon the disc of Saturn, about the equa- 

 tor, only the projection of the shadow of the ring like a straight stripe 

 of a deep color. 



The sky was partially overcast from the 24th to the 28th of April, 

 and no new observations were made till the 29th, at eight, nine, and 

 ten P. M., when in a still time, and clear sky, Dollond's instrument 

 and also another by Fraunhofer, of four inches aperture, and six feet 

 focus, and magnifying two hundred and forty times, were directed to 

 the planet, without discovering any trace of the ring. The projec- 

 tion of the shadow of the ring upon the disc of Saturn was feebly 

 visible with Dollond's telescope, but very distinctly with Fraunhofer's, 

 especially towards ten o'clock. It appeared like a small grey line, 

 sensibly curved, (convex downwards,) and dividing the disc of Saturn 

 into two unequal parts, the superior much smaller than the lower. 



