On the Meteors of 13th November, 1833. 151 
Rare as the medium must be at the height of fifty miles, where 
these bodies are supposed to enter it, yet we conceive that the air of 
the upper regions in the path of the falling body, would be put into 
violent motion, and would of course abstract an equal quantity of mo- 
tion from the meteor; and since the body as it descended, would, 
at every stage of its progress, meet with denser and denser air, that 
the resistance would finally become such as greatly to retard or even 
to stop it, according as it were constituted of heavy or light mat- 
ter; and if it were combustible, that heat would be thus evolved 
sufficient to consume it.. For the sake of keeping the principal 
points distinctly in view we will, however, adhere to the method al- 
ready pursued, of enunciating them in separate propositions. 
6. The meteors consisted of combustible matter, and took fire and 
were consumed in traversing the atmosphere. 
That these bodies undennent combustion, we had the ddieetey evi- 
dence of the senses. We saw them glowing with intense light and 
heat, increasing in size and splendor as they approached the earth; 
we saw them extinguished in a manner in all respects resembling a 
combustible body like a. sky rocket, burnt in the air; and inthe case 
of the larger, we saw, for the product of combustion, a cloud of lu- 
minous vapor, which frequently spread over a great extent, and re- 
mained in sight, in some cases, for half an hour. To establish a 
case of real combustion, I do ‘not know that we can either have or de- 
sire any better evidence than that of the senses. By combustion, 
however, it is not implied that every particle was converted into an 
aériform product: the smoke is supposed to have consisted, as in 
most cases of terrestrial combustion, of vapors condensed in that re- 
gion of cold, and of solid matter in a minute state of division, which 
escaped actual combustion, as is the case in the smoke of a common 
fire. The proportion of this solid matter would be greater, in conse- 
quence of the rarefied state of the air at the place of combustion. 
That these bodies took fire 2m the atmosphere, we infer from the 
fact that they were not luminous in their original situation in space, 
otherwise we should have seen the cloud, or body, or whatever it was, 
from which they emanated; but they were not luminous except for the 
few seconds while they were within the atmosphere, for had they 
been so before, we should have seen them during the whole of their 
progress towards the earth, a period of about twenty and three 
fourths minutes.* 
* 20!, 43.55!!, calculated by formula in Young’s Mech. Art. 116. 
