ultaneously reverse the motion of the crank shafts. On the crank
shafts are also formed two other crank arms pivotally connected by
opposite pitmen with a slide mounted in vertical guideways, supported
on a frame erected on the base, the motion of the crank shafts causing
the vertical sliding motion of the slide traveling loosely in the
guideways, and thus serving as a governor, as, in case one of the
propellers becomes disabled, the power of the shaft carrying the
disabled propeller is directly transferred to the other shaft through
the crank arms, pitmen, and slide, and the other propeller is caused
to do all the work. All the parts of the engine are within easy reach
of the engineer, and there are so few working parts in motion that the
friction is reduced to a minimum.

It is said that the plan of construction and the operation of this
engine have been carefully observed by practical engineers, and that,
considering the dimensions of the boat, her speed, the smallness of
the power, the ease with which she passes the centers, the absence of
vibration while running, and the very few working parts in motion, the
engine is a notable success. She can be run at a very high velocity
without injury or risk, and is designed to be very economical in cost
and in weight and space. This engine has been recently patented in the
United States and foreign countries by Mr. James A. Clarke, of New
Westminster.

* * * * *

IMPROVEMENTS IN THE CONSTRUCTION OF RIVER AND CANAL BARGES.

By M. RITTER (KNIGHT) VON SZABEL, late Austrian Naval Officer, of
Vienna.

This innovation consists essentially in an arrangement by which two
distinct vessels, on being revolved round their longitudinal axis to
an angle of 90 deg., can be combined into one single duplex vessel, or, to
put it in different words, a larger vessel is arranged so that it can
be parted into two halves (called "semi-barges"), which can be used
and navigated with equal facility as two distinct vessels, as if
combined into one. By the combination of the two semi-barges into one
duplex barge the draught of the vessel is nearly doubled, the ratio
existing between the draught of a loaded semi-vessel and the equally
loaded duplex vessels being 5:8 (up to 8.5)

The advantage of the invention consists:

1. In this difference of draught.

2. In the smaller width of the semi-vessel as compared with
the duplex vessel.

3. I