is, as will be clearly understood from the illustration, cut away to
allow of the descent of the rods. To the cross head E is attached the
piston F, which may be made of wood or of a hollow metal tube closed
at the end, or other suitable material. It will be easily understood
that when a weight is hung upon the hook B, the piston F is caused to
descend into the mercury which rises in the annular space between the
piston and the tube. The weight of the volume of displaced mercury is
proportional to the weight of the body hung upon the hook, and the
buoyancy of the piston in the mercury forms the upward force which
balances the downward pull of gravity. When the apparatus is at rest
the piston F descends into the mercury to such a distance as will
balance the weight of the rods, hook, and piston itself. If, now, the
cross bar G, provided with a pointer H, be fixed to the rods, it
should at that time register zero, upon the scale J fixed to the
outside of the tube, and as the descent of the piston into the mercury
is directly proportional to the weight of the body attached to the
hook B, the divisions of the scale will all be equal. It will thus be
seen that the apparatus is extremely simple in theory, and it only
remains to construct it in such a form that the mercury may not easily
be spilt in moving the instrument from place to place. This is
effected by causing the cross head E to fill the tube while working
freely therein, and a small valve is arranged to allow for the passage
of air. The cross bar G can be regulated upon the rods by means of set
screws.--_Industries._

* * * * *

REEFING SAILS FROM THE DECK.

While this method may be applied to topsails and top-gallant-sails, I
especially apply it to courses, which, being so difficult to reef the
old way, may by this method be reefed from the deck in a few minutes.

After several years of trial by myself and others, on voyages around
Cape Horn under all circumstances of weather, of sleet and snow, this
method has always given the utmost satisfaction.

[Illustration: REEFING SAILS FROM THE DECK. Front View. Rear View.]

The average time required for reefing and setting was noted for five
years, being seven and one-half minutes.

This trial was made on a mainsail, the yard being seventy-one feet
long, and reefyard sixty-six feet long, eleven inches diameter at
center and nine at yard-arms.

By reference to the drawing it