range of 1¼ miles has been attained with the two inch gun, with a
pressure of 420 lb. to the square inch, and one of three miles is hoped
for with the larger gun and a pressure of 2,000 lb.

* * * * *




ROPE PULLEY FRICTION BRAKE.


A novel device in connection with rope pulley blocks is illustrated in
the annexed engravings, the object of the appliance being to render it
possible to leave a weight suspended from a block without making the
tail of the rope fast to some neighboring object. By this arrangement
the danger of the rope slipping loose is avoided, and absolute security
is attained, without the necessity of lowering the weight to the ground.
The device itself is a friction brake, constructed in the form of a clip
with holes in it for the three ropes to pass through. It is made to span
the block, and is secured partly by the pin or bolt upon which the
sheaves run, and partly by the bottom bolt, which unites the cheeks of
the block. Thus the brake is readily attachable to existing blocks. The
inner half of the clip or brake is fixed solidly to the block, while the
outer half is carried by two screws, geared together by spur-wheels, and
so cut that although rotating in opposite directions, their movements
are equal and similar. One of the screws carries a light rope-wheel, by
which it can be rotated, the motion being communicated to the second
screw by the toothed wheels. When the wheel is rotated in the right
direction the loose half of the clip is forced toward the other half,