Phenomena of Falling Meteorites. — Farrington. 87 
sudden generation of heat and the consequent expansion oi 
the outer shell account not only for the breaking up of the 
meteorite into fragments, but partly also for the crash like 
that of thunder, which is a usual accompaniment of the fall. 
Profs. Maskelyne and Dewar have expressed similar views. 
In the view of the writer, the sound ordinarily to be ex- 
pected from the passage of a meteorite will be like that of 
thunder, such as follows a stroke of lightning. The phenom- 
ena are similar, as pointed out by Mr. Hirn,* in that a sudden 
heating and expansion of the air takes place, followed by a 
violent contraction ; and thus are caused vibrations which are 
transmitted to the ear. Inasmuch, however, as this column 
of heated air is many miles in length, the sound will not all 
reach the observer at once but will be prolonged into a long 
roll as the vibrations from more distant parts of the column 
come to him. 
But this view does not preclude the possibility that addi- 
tional sharp, explosive sounds should arise from a bursting of 
the mass when fragments of a great size are hurled outward 
suddenly and with great force. These should produce still 
more distinct vibrations whose character would be recognized 
as differing from that of the general sound. 
Since most meteorites are marked upon their surface by pit- 
tings which have been shown by Daubree to be similar to 
those found on masses of steel upon which dynamite has been 
exploded, it is reasonable to suppose that the masses have been 
acted upon by similar forces, and that if a detonation accom- 
panied the action of the one it did that of the other. While 
such reasoning from analogy can rarely lie accepted as con- 
clusive, the writer is inclined to believe that detonations may 
accompany the fall of a meteorite without any bursting of its 
mass. It is also his belief, however, that when such bursting 
does occur it will produce a sound like that of an explosion. 
S. "Would it he possible to produce the detonations heard 
at the time of fall, by the separation of t he meteoric mass into 
parts and at the same time not reduce it to powder?" There 
seems to be irrefutable evidence that meteoric masses have 
separated into parts at tin- time of fall without being reduced 
to powder, and that such falls have been accompanied by de 
tonations. 
♦Nature, vol. xxxv, p. 303. 
