* * *

POWER STRAIGHTENING MACHINE.

The machine is provided with a pair of rolls at each end of the bed, which
are adjustable for different lengths of shaft, and are made to revolve by
power applied through suitable gearing and a splined rod inside the bed;
the bar of iron being placed on the periphery of the rolls receives a
rotary motion by friction, and shows the crooked places in the same way
and with the same ease as though rotating on centers in the usual manner;
vertically adjustable blocks are arranged in the base of the press to
support the iron; power is applied by means of gearing to a splined rod at
the back of the machine, on which is a sliding clutch connecting, at the
will of the operator, with an eccentric; the eccentric conveys motion and
power through a link to the elbow joint at the front of the press, which
forces a plunger down against the iron.

[Illustration: POWER STRAIGHTENING MACHINE.]

Sufficient adjustment is provided for different sizes of iron by turning a
nut at the top of the press.

Any point in the length of the bar can be reached by moving the press on
the bed. Any length of iron can be straightened, and the most laborious
and disagreeable work in the process of making shafting is rendered easy
and rapid. Made by Wood, Jennison & Co., Worcester, Mass.

* * * * *

HYDRAULIC MINING IN CALIFORNIA.

By GEORGE O'BRIEN.

Our knowledge of the primitive operations of the aboriginal inhabitants of
the globe in pursuit of gold is barely traditional, as we are only aware
that from very early times the precious metal was collected and highly
prized by them, and that they chiefly extracted the visible gold, which
existed in prodigious quantities on or closely beneath the surface of the
earth, and of its being particularly abundant in Asia and Africa. But we
can draw more positive conclusions as we survey remains of the rude but
effective contrivances used by them in later, but still remote, periods,
with full evidence as to the extent of their operations, in the numerous
perpendicular shafts located at short distances from each other, over
large areas of auriferous gravel in India, as well as from precisely
similar memorials of ancient workings which remain also further
demonstrations, in the abandoned "hill diggings," and shifted beds, and
beds of rivers, in Peru South America, flowing between the sea and coast
ranges of th