434 Scientific Intelligence. 
meteor was composed of large and smaller globes, recalling the showers 
of stones at L’Aigle and Stranraer. The mechanical theory of the heat, 
roughly estimated from the light of twenty shooting stars, doubly ob- 
served i in August, she — the ne weight of these to have ee 
accounts for their want of penetrating power. Prof. Newton and Mr. 
Herschel have concluded independently, ot shooting stars commence at 
seventy miles and disappear at fifty miles above the surface of the earth.’ 
At sixty miles above the earth, shooting ee are far more frequent than 
at any other altitude, and they are Sone daerentd more between forty and 
eighty miles above the earth than in all other elevations put together. 
The region from forty to eighty = above the earth is the “stable at- 
mosphere” of Mr. Quetelet, as determined by the heights of shooting 
stars. It = on the received law of decrease of density, comprise 
lested by their presence. It appears necessary on this account to re- 
trench very greatly the weights of unproductive fireballs and shooting 
stars. Examples in the present Catalogue of a collapsing and res 
kindling meteors appear to favor an hypothesis that chemical affinities, 
unknown at ordinary temperatures, produce in sinha meteors a consid- 
erable portion of their unaccountable excess of light and heat. Ten me- 
teors have been estimated in the past year by a their apparent 
courses to the stars. The average heights and velocities ese are :— 
Height at first appearance, we miles ; at oem nt 68 miles ; length 
of path, 79 miles; velocity, 49 tuiles. per second. Frequent t observations 
of the radiant ete of shoetibibeties are recorded in the present Cata- 
logue. These have been observed on the 10th of August, the 30th of 
November, and the 6th of December, 1863, the 2d of January, the 10th 
and the 20th of April, and the 10th of August, 1864, by referring the 
meteors to twelve perspective charts representing the whole circuit of the 
constellations as they appear at akon of two hours above the wapors 
of the horizon in the latitude of Greenwich. The longest paths on these 
maps can be traced correctly with an aontind ary rule; and by their pro- 
corded, slowly accumulating from year to year, al more correctly to 
the eye by this means thai ge st rd oe wer ya without the aid 
i. maps; while shies radiant points observed in the past year, 1 it was 
— Fieved, would ete escaped attention had not maps been specially ya of 
‘: vided i in adva' The observations of meteors on the 9th and 10t of 
ugust, 1864, ded display, ranking very nearly with the 
average of the phenomena, which, in the clear sky and sna the 
noon amounts to between thirty and forty per hour for a single observer 
wton afore wm that he has not & arrived at the conclosion here stated. 
