216 
REYNOLDS: ERUPTION OF KRAKATOA. 
greater part of the island of Krakatoa was literally blown to pieces; 
the shocks continued at least from 9 a.m. to 10 p.m., Greenwich time. 
The connection between the great eruption and these atmospheric 
disturbances is suggested in Mr. Scott's paper, and has been distinctly 
traced by General Strachey. General Strachey's reasoning was as 
follows: — Any shock of sufficient violence might be expected to pro- 
duce an atmospheric wave, advancing from the place where it was 
caused in a circular form round the globe, at first expanding until it 
had got half round the earth, and then again contracting till it was 
again concentrated at the antipodes of the place whence it came, 
from which again it would be thrown back, and so pass backwards and 
forwards till it was obliterated. It might also have been expected 
that such a wave would travel with the velocity of sound, being 
probably of the same nature as that which causes sound, though the 
vibrations had not the peculiar character that affects our organs of 
hearing." 
''It remains to be shown how the phenomena may be explained 
by the passage round the earth of a series of air- waves travelling at 
the rate of about 700 miles an hour in opposite directions from the 
seat of the volcanic eruption. From the known distances of the 
various observatories from Krakatoa, and from the times correspond- 
ing to certain sufficiently well-defined points in the barograms, the 
times at which the successive waves passed the several stations can 
be estimated; and from these times the intervals between the suc- 
cessive passages of the waves from east to west and from west to 
east can be deduced. From the results obtained it followed that the 
wave travelled round the earth from east to west in 36 hours 57 min. 
and from west to east in 35 hours 17 min. From the velocities thus 
determined General Strachey has calculated from the known distance 
of each place from Krakatoa, the time occupied in the passage of the 
air-wave from Krakatoa to the place of observation, and the observed 
time of the passage of the waves. Combining all the observations, 
the rate of the waves moving from east to west gave for the time of 
the origin of the disturbance at Krakatoa 2 ■52h.t Greenwich mean 
time, that is 9 hours 32 min. of the morning of the 27th August, 
local time. Treating the waves moving from west to east in a simi- 
