irresistible force * * * other logs in all directions
up-ended. * * *

Then all at once down by the face something crashed, the
entire stream became alive. It hissed and roared, it shrieked,
groaned, and grumbled. At first slowly, then more rapidly, the
very fore-front of the center melted inward and forward and
downward, until it caught the fierce rush of the freshet and
shot out from under the jam. Far up-stream, bristling and
formidable, the tons of logs, grinding savagely together,
swept forward. * * *

Then in a manner wonderful to behold, thru the smother of foam
and spray, thru the crash and yell of timbers, protesting the
flood's hurrying, thru the leap of destruction, the drivers
zigzagged calmly and surely to the shore.

Sometimes cables have to be stretched across the chasm, and special
rigging devised to let the men down to their dangerous task and more
especially to save them from danger when the crash comes.

[Illustration: Fig. 20. Splash-Dam.]

[Illustration: Fig. 21. Logs in Boom. Glens Falls, New York.]

In case such efforts are unavailing, it is necessary to "shoot" the
jam with dynamite. Another device resorted to where the supply of
water is insufficient is the _splash-dam_, Fig. 20. The object is to
make the operator independent of freshets, by accumulating a head of
water and then, by lifting the gates, creating an artificial freshet,
sufficient to float the timber down stream.

[Illustration: Fig. 22. A Sorting Jack.]

Thus by one means and another, the logs are driven along until caught
by a boom, Fig. 21, which consists of a chain of logs stretched across
the river, usually at a mill. Since the river is a common carrier, the
drives of a number of logging companies may float into the mill pond
together. But each log is stamped on both ends, so that it can be
sorted out, Fig. 22, and sent into the boom of its owner.

MECHANICAL METHODS IN LUMBERING.

The operations described above are those common in the lumber regions
of the northeast and the Lake States. But special conditions produce
special methods. A very effective device where streams are small is
the flume, Fig. 23. This is a long wooden trough thru which water is
led, and the logs floated end on. It is sometimes many miles long; in
one case in California twenty-five miles.

In the South where there is no snow, logs are largely brought out to
the railway or river by being