ROR eee Wes cee a ee aT IE ee ee ee ees See eS fa ee a eee ee ee eR Se Oe ee eS ee Pte 
Te SON SR ME te Ee Pa, oe Pe 
ee pn ee a ae Eee ne tee enter a 
N. 8. Maskelyne on the fail of Butsura. 75 
The pag of the interior see only gradually be overcom: 
and, long before it would be so, the expansion of the external 
core, the sonditions under which jon would ensue (indeed, 
whether it would ensue at all, as it would not if the mass were 
absolutely homogeneous), would depend on the structure of the 
mass, its directions or planes of weaker aggregation, or perhaps 
the unequal distribution in it of matter of various degrees of 
conductibility. But when the disruption comes, it must come 
with Sp cen 
e process may be repeated, or it may fone place at pgpees 
intervals on the different sides of the meteorite. The earlier 
explosions may take place at points in = path where A is 
still velocity enough to produce a fresh enameling,—sometim 
in a copious flow, at others only enough to barely glaze the ex- 
posed surface of the stone again; the later ones may occur when 
the velocity is more nearly spent, and the friction is no longer 
competent to generate the glaze. 
The cloud in the air, out of which the meteorite bes been seen 
to come in so many authenticated instances, would be satis- 
factorily explained by the dust of the enamel after its separation 
from the aerolite in its course, and the combustion of its iron, 
eter &e.; perhaps, also, small fragments are splintered and 
fly off by the same principle as the larger ones, and, partially 
burning, becomes dust too. 
‘Following in the track of the body, this dust would soon, 
however, linger behind it and hang in the air like a vapor-cloud 
as is often seen to be the case in the wake alike of a meteor and 
of a meteorite. ae 
Finally, if the reports represent the successive concussions of 
the air produced by the disruption of the aerolite (and reaching 
the ear generally in the inverse order of their occurrence in time), 
we must attribute the “thunder” that is so often described as 
succeeding the reports, to the echo of the reports themselves. 
hat a noise, the true extent of which is likely to be exagge- 
rated, should be heard over so large a range of country as sixty 
linear miles, is perhaps not so surprising when we consider the 
distance to which a small cannon may be heard, even over a 
surface of country teeming with obstacles and air-currents cal- 
culated to impede the passage of the sound; whereas from a 
height of two or three miles in a still, eae air, the spread of 
even a comparatively small sound over an area with a radius of 
thirty or forty miles seems nothing astonishing. To me, at least, 
who have heard the roar of a train between Shrivenham and 
indon, as I stood, on a still night, in the station at Cirencester, 
4 ‘a distance of of certainly nearly twenty miles, such a wide promul- 
