OO 
On Meteoric Showers in August. 363 
negative, and no one surely will suppose there is sted cround for 
immediate apprehension. 
On the theory of Shooting Stars. 
In the present very imperfect state of knowledge concerning 
many of the phenomena of shooting stars, there is much hazard in 
proposing any hypothesis on the subject. Without further observa- 
tions, it is indeed impossible to state more than a small part of the 
conditions which a theory ought to fulfil. Besides accounting for 
the meteors of daily occurrence, it should explain the reasons for 
their appearance in unusually large but varying quantities every 
year, (or at least for many years in succession,) certainly at two pe- 
riods in the year, viz, about Aug. 9, and Noy. 12, and probably 
also at a third, viz., about the last of April. The various charac- 
teristics of the November shower have been stated at large by Prof. 
Olmsted and Mr. A. C. Twining, in preceding volumes of this 
Journal ; those of the August shower, (so far as they are known,) 
are contained in the present volume. 
It is not impossible that these meteoric showers are derived from 
nebulous or cometary bodies with which, at stated times, the earth 
falls in. This hypothesis, however, does not satisfactorily account 
for the meteors of daily occurrence. 
M. Arago (Comptes Rendus, 1835, pp. 394, 395. 4to. Paris,) 
proposes the hypothesis of an immense zone or ring, composed of 
millions of small bodies or asteroids, revolving about the sun, whose 
orbits meet the plane of the ecliptic at that part of the path of the 
earth, which it occupies from 11th to 13th November. This hy- 
pothesis, in some shape, will probably be found adequate to account 
for all the phenomena. 
The facts at present known, seem to require that the earth should 
pass through some part of this zone in November and in April; and 
approach in August sufficiently near it, to receive an unusually large 
quantity of meteors. It is also necessary that the earth should con- 
stantly keep very near it, in order to obtain its daily supply. If 
however additional periodic showers should be discovered, it might 
be difficult to account for all by one such zone. 
This zone probably lies partly within and partly without the or- 
bit of the earth. When the earth is in that part of its orbit which 
is exterior to the zone, we might expect by the aid of the tele- 
scope, occasionally to detect these bodies passing across the disc of 
