egoing, we would remind our correspondent, that in
his former communication, he proposed a limited weight of apparatus,
and in our answer, it was far from our intention to allow an
additional weight on account of the requisite extent of surface. With
regard to the philosophy of the flight of the eagle, it must be borne
in mind that atmospheric resistance is as the square of the velocity
_downward_ and the only way in which the phenomenon of the flight
of the eagle can be reconciled with the laws of mechanical science as
established by experiment, is by supposing the velocity of the wing
downward to be equal to 70 feet per second, whereby a resistance would
be encountered equal to 12 pounds per square foot of surface to the
wings. It is a fact, however, that kites, and hawks are often seen to
continue suspended in the air several minutes without any apparent
motion of the wings; but by what law or theory the feat is
accomplished, natural philosophy has ventured no other conjecture than
that the bird is endowed with the faculty of suspending occasionally
its ordinary subjection to the laws of gravity. If any observing
theorist will give any more rational conjecture on the subject, we
should be glad to have him examine it.

* * * * *

It is proposed and urged by the papers in several States, to have a
thanksgiving day throughout the Union, on the 26th of November.

* * * * *

"As dull as a hoe," is a very common phrase, and implies that hoes are
necessarily or ordinarily dull. But it is advisible for farmers to
keep their hoes sharp, as they regard a saving of labor.

* * * * *

[Illustration: the conical windlass]

THE CONICAL WINDLASS.

Various methods have been heretofore described, for raising heavy
bodies, or producing for other purposes, a great force,--usually
miscalled power--by the application of a comparatively small force:
but no method is known, more unlimited in its effect, or more simple
in construction; than the conical windlass. It consists of a simple
horizontal windlass, with a crank at one end, as shown in the
engraving. The windlass is made in a conical form, being a little
larger at one end, than at the other; and if the friction of its
bearings be relieved by the ordinary friction rollers, it will so far
multiply the force applied, as to break a double inch-rope, by the
power of one man