ROBERTS — ON THE WYRE FOREST COAL-FIELD. 
421 
a space between 4 and 23 and more miles ; the pressure, at an average 
velocity of seven miles per second, being 22 atmospheres per square- 
foot. Benzenberg has already pointed out the analogy of this process 
with the apparatus for lighting matches by sudden and violent com- 
pression of air ; and indeed the passage of a body through air at such 
a rate cannot be conceived without an enormous compression, and 
consequent development of heat and light. The air is forced on. 
every side out of the meteor's orbit, in directions perpendicular to it, 
and must round itself in a spherical or ovoid manner from behind the 
rapidly progressing meteor. As Professor Smith supposes, the sound 
is not a consequence of explosion, but the clash produced by the air 
suddenly filling up the vacuum left by the meteor behind it, and 
renewed every moment as it continues its career. Dr. Haidinger and 
Professor Smith, with many other naturalists, agree in the supposition 
that meteorites are fragments of larger solids pre-existing in the 
cosmic spaces ; the hypothesis of their existing originally in a state of 
igneous fusion being in open contradiction to the generally accepted 
hypothesis of an extremely low temperature (100° C.) of these spaces. 
The tufaceous aspect of meteorites seems rather to indicate an origi- 
nally pulverulent state, in which crystallogenetic forces were called 
into activity, and modified or counterbalanced by external circum- 
stances, in a mode analogous to the formation of the sphserosideritic 
septaria occurring in argillaceous strata. The first effect of pressure 
from without must have been the formation of a solid, superficial 
crust, during whose complete solidification lateral pressure, and the 
descending movement of heavier particles, would call into action 
thermal, electrical, and chemical influences. A similar process going 
on within the external cinist may possibly occasion real explosions. 
The chapter on meteorites has been most ably and profoundly treated 
by M. E. E. Schmidt ("Lehrbuch der Meteorologie"), G. Karsten 
("Algemeine Encyclopjedie der Physik," Leipzig, 1860), and F. C. 
Naumann (" Lehrbuch der Geognosie.") 
DEEP SINKING FOR COAL IN THE WYRE FOREST 
COAL-FIELD. 
By George E. Roberts. 
Mention is made by Mr. Hull, F.G.S., in the second edition of his 
useful work on the coal-fields of England, of a deep sinking for coal 
on the estate of the Arley Pottery and Fire-brick Company, situated 
at Shatterford, five miles north of Bewdley. This work, though 
unfortunately ending in failure, and leading to the abandonment of 
the enterprise, deserves a prominent position in the annals of coal- 
mining, chiefly because the section obtained may be regarded as an 
index to nearly the whoM of the coal measures of the forest of Wyre. 
Through the courtesy of Mr. John M. Fellows, manager of works to 
the late company, I am enabled to place on record the particulars of 
