her ready to
be "folded up" by means of ropes and specially constructed
windlasses--their lateral water compartments having previously been
filled. Fig. 3 shows the duplex vessel after the "folding up"
operation just described; and Figs. 4 and 5 show the cross section of
two loaded semi-barges as outlined in Figs. 2 and 3.

These Figs. 4 and 5 will also serve to illustrate the manner in which
sacks and loose produce should be loaded. Fig. 4 also shows the filled
water compartments, and the effect of their weight in making the boats
lean toward each other.

The materials most suited for this new style of vessel will be iron
and steel such as generally used in the construction of canal and
river vessels.

The new ship can be moved by any motor or driving implement, nor could
there technically a great difficulty be found for making the boilers
move on a quadrant-like rail base in the shape of a circle segment's
quarter, or for building a double screw steamer by combining two
single screw propellers.

May be a ship owner is willing to submit the innovations to an
attempt, so much the more as there is running no great risk by doing
so; for in case the ships should not answer the expectations, both
separable as well as joinable, they can be used like single ships,
without any further alteration being made, except as to the loading
gaps.

The above invention is covered by United States patent No. 435,107.
Any further information may be had by addressing M. v. Szabel, ix
Bezirk, Beethovengasse 10, Wien, Austria.

* * * * *

WELDON'S RANGE FINDER.

Colonel Weldon has recently considerably modified and improved his
ingenious range finder, and we illustrate herewith from _Engineering_
the form in which it is now manufactured. It consists of a metal box,
the lid of which is shown open in the engraving, and on this lid are
fitted three prisms which are the essential constituents of the
instrument. When the lid is closed, these, with the compass and level,
also attached to the lid, lie inside the metal box, and are thus
thoroughly protected. The upper prism marked 1 is a right-angled one
and is mounted with the right angle outward; looking into the
left-hand corner of this prism one will see in it, by double
reflection, objects lying on one's right hand. Below this is a second
prism with a principal angle of 88 deg. 51 min. 15 sec., and below
this a third with a principal angle of 74