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 follow 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 Ist of March, 1834.—Jdem. 
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. Warrmann. 
M. Wartmann made his observations at Geneva, in accordance 
with the request of M. Bessel of Kénigsberg, 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 parallactiquement, 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 whieh, 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, 
seusibly curved, (convex downwards,) and dividing the disc of Saturn 
into two unequal parts, the superior much smaller than the lower. 
