JANUARY 25, 1884.] 
from the summit, and the snow had disap- 
peared from the island. After the first dis- 
turbances were over, it was found that the 
northern slope of the summit had fallen to 
the level of the cliffs which form the shore, and 
the mountain appeared as if split in two. Two 
previously quiet volcanoes on the peninsula of 
Aliaska began simultaneously to emit smoke 
and dust; and in the ten-fathom passage be- 
tween Augutin Island and the mainland a 
new island, seventy-five feet high and a mile 
and a half in extent, has made its appearance. 
It is stated that subterranean noises had pre- 
viously been heard by a party of hunters, some 
of whom are reported missing. 
The volcano has not been approached nearer 
than ten miles since the eruption, at which dis- 
tance the new island was distinctly seen north- 
west from Augustin Island. Its dimensions, 
therefore, are merely approximate. The morn- 
ing of the eruption was perfectly clear, with a 
light south-west wind, and the tide extremely 
low. ‘Three days before, all the fish are said 
to have disappeared from Port Graham. At 
last accounts smoke was arising from a point 
on Augustin Island, south from the cleft above 
mentioned, which crosses the island from east 
to west. 
It would seem as if these events were local 
manifestations of an awakening of volcanic 
energy nearly world-wide. Wwm. H. Datt. 
WHIRLWINDS, CYCLONES, AND TOR- 
NADOES.1—IX. 
Tornaposs differ from the storms thus far 
mentioned in their excessive violence over a 
very restricted area, and their visibly rapid ad- 
vance. After a great deal of theorizing, it is 
now possible to explain them very satisfacto- 
rily and simply as whirls in the air, a little 
above the ground, into the vortex of which the 
surface-winds are drawn up with great velocity. 
Electricity has no essential share in their ac- 
tion. 
Recent studies, especially the reports by Mr. 
Finley of the signal-service, have done much 
to show us the regions of, and general condi- 
tions preceding, tornadoes. They are most 
numerous in Kansas, Missouri, and Illinois, 
although they have been recorded throughout 
the states east of the Mississippi, except in 
the far north-east and on the central Allegha- 
nies. So they have occurred in all the months, 
and at nearly all hours of the day; but their 
time of greatest frequency is in the afternoons 
of June and the months adjoining. Where 
1 Concluded from No. 50. 
SCIENCE. 93 
most fully studied, they seem to occur along 
the contact-line of warm southerly winds and 
cooler north-westerly or westerly winds. Local 
quiet and rather excessive warmth commonly 
precede them, and chilly winds come after 
their passage. Main and hail fall in their 
neighborhood, but usually at a moderate dis- 
tance away from the destructive wind-centre. 
Their advance is nearly always to the north- 
east, at about thirty miles an hour. 
When first perceived, the tornado is gener- 
ally described as a dark, funnel-shaped mass, 
hanging from heavy, dark, agitated clouds (fig. 
23). Its roaring sound is heard as it comes 
nearer; and the whirling funnel is often seen 
to swing from side to side, and to rise and fall. 
Withinits dark column, various objects snatched 
from the ground may be seen rising and turn- 
ing round and round in the eddying winds: 
pine-trees appear like bushes, and barn-doors 
are mistaken for shingles. At a certain height 
these fragments are thrown laterally out of the 
power of the ascending current, and then fall 
to the ground, often with violence, from their 
lofty flight. If such a cloud appear in the 
west or south-west, one should make all possi- 
ble haste to the north or south of its probable 
track; but there is seldom time to escape. 
The rapidity of the storm’s approach, the 
noise of its roaring, the fear that its darkness 
and destruction naturally inspire, too often 
serve to take away one’s presence of mind; 
and, before there is time for reflection, the 
whirl has come and passed, and the danger is 
over for those who survive. The force of the 
wind is terrific. Heavy carts have been car- 
ried, free from the ground, at such a velocity, 
that, when they strike, the tires are bent and 
twisted, and the spokes are broken from the 
hubs. Iron chains are blown through the air. 
Large beams are thrown with such strength that 
they penetrate the firm earth a foot or more. 
Children, and even men, have often been 
carried many feet above the ground, and some- 
times dropped unhurt. A velocity of wind ex- 
ceeding one hundred miles an hour is required 
to produce such effects. Strange examples of 
the wind’s strength are found in the treatment 
of small objects: nails are found driven head 
first firmly into planks; a cornstalk is shot 
partly through a door, recalling the firing of a 
candle through a board. More than this, the 
wind shows signs of very unequal motions in 
a small space : bedding and clothing are torn to 
rags; harness is stripped from horses. Noth- 
ing can withstand the awful violence of the tor- 
nado’s centre; and yet, at a little distance one 
side or the other, there is not only no harm 
