372, Propagation of Pulses in Elastic Media. 
above the horizon when on the meridian, and the comet did not 
come upon the meridian until about sunrise. 
Is it possible that when Prof. B. describes the comet as seen 
“without the slightest diameter,’ he refers simply to the para- 
bolic envelope subsequently observed, and does not mean to deny 
the existence of an irregular coma of great extent? If so, then 
his observation appears quite consistent with other established 
facts, although we should regard the language he has employed 
peculiarly unfortunate. On the whole it appears very desirable 
that further observations made during the month of January, 
1836, should be rescued from oblivion; and we are impressed 
with the importance of the observatories recently erected in the 
United States, where observations can frequently be made such 
as are impracticable at the more northern observatories of Europe. 
Art. XLIL—A Determination of the General Law according 
to which. Pulses differing in intensity are propagated in Elas- 
tic Media, with remarks on the received Theory of the Velocity 
of Sound; by Ex1 W. Buaxe. 
one point, (prop. 48, case 1,) appears to recognize the fact that 
an i . . . 
ses vary with their intensities, and to determine, in general form, 
the relation which subsists between the velocity and intensity ©! 
__ltis proposed in this article to show that the velocities of puk 
Se 
