C 318 ] 

 XL. Intelligence and Miscellaneous Articles. 



NOTICE OF A METEOR. BY J. WALLIS, ESQ. 



To the Editors of the Philosophical Magazine and Journal. 



338 Albany Road, Camberwell, 

 Gentlemen, Marcli 4, 1850. 



ON Friday the 22nd of February, at thirteen minutes before mid- 

 night, I saw in the S.S.E. by S., at about the altitude of 15°, a 

 large bright meteor, whose apparent diameter was equal to that of the 

 moon. It was visible during three or four seconds, while describing 

 about seven or eight degrees, nearly perpendicularly downward. 

 Its globular form was well-defined, and the anterior portion remained 

 permanently so, while the hinder portion separated into numerous 

 fragments, leaving evanescent streaks of a dull red colour for several 

 degrees on the sky. My eye was fortunately directed to the place 

 where it originated, so that I traced the whole of its course. But 

 for the presence of the moon, which was shining brilliantly at the 

 time, its illuminating power would have been very considerable. It 

 was intensely bright, of the electric blue colour. The form under- 

 went some change in the vertical direction, being somewhat sud- 

 denly elongated into an egg-shaped figure, the more obtuse end 

 foremost. The atmosphere being at the time free from cloud or 

 vapour, would account for the light being very local and circum- 

 scribed. I presume that in physical constitution it must have been 

 very much like the meteor recently described in the Pictorial Times 

 by the Astronomer Royal. The moon in the gibbous form aflForded 

 me a ready object of comparison ; its lustre was more vivid than the 

 serene countenance of our ever-beai:j|iful and admired satellite. 



I can easily imagine all the changes assumed in its track as re- 

 sulting from the rapid passage of a coherent liquid or gaseous body 

 through a resisting medium. In perfect quiet I listened for more 

 than a minute after its extinction, but heard no explosion. Indeed, 

 from the manner in which it finally broke up, might be inferred 

 rather the idea that the luminous fragments were left detached from 

 the general mass by the diminution of atmospheric pressure immedi- 

 ately behind it, than from an inherent force of explosion ; for by 

 the composition of such force with that common to the whole body, 

 the fragments would have diverged in a direction more laterally, or 

 across its path. As we know not the distance of the meteor, we 

 have no data from which to determine its velocity ; but little doubt 

 can exist that the compression of the air before it must have been 

 very great. Mere spontaneous ignition of any aggregate of com- 

 bustible materials would produce only a radial divergency of its ele- 

 ments ; hence a progressive motion of the whole points to some ex- 

 traneous source of attraction or impulse ; and the velocity conse- 

 quent to or resulting from this may, by condensation of the air 

 before it, elicit the heat in which its ignition originates. And this 

 elevation of temperature may eflfect decompositions among its ele- 

 ments, which are attended with the observed evolution of their 

 usually brilliant light. I remain, &c., 



John Wallis. 



