New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1857-06-06

,,,a;,s Of .yrlcsve mixture No box attached 10 the
gun and 80 connected with the hammer thatthe cock
irg of /; made grain come out oil the oo1 10 the
prorer place to be struck by the hammer on coming
Jorp. We find that Dr.. Gallagher of Charleston, has
imuroved the idea by making the box waterproof aud
by 30 simplifying the parts as TO make adaptable 70
v'usk,,s Colts reviewers, and fowHng-pieces, very
easily and al trihng cost. patent has been
secured and the Doctor il his way to bpg the M
ventjon To- the notice of the Superintendent Of the
United States Army.
RorAscorr or GYRoscoPE is that ingenious modih-
cation Of the common top which year ago was inc
subject Of popular interest. Thousands OF these '-
strumens have been made for the public, and hundreds
of theories have been devised for explaining motion
as yet considered in general "mechaniea! pazz1e'
The explanation is old Newton, and has been
annually given by Professor Smell to the pupils OF Am
herst College for upward Of twenty years. gyro-
scope and a more con picated instrument of winch
the gyroscope is only part, have been exhibited by
Professor :. in q lecture Planetary Disturbances
a, the Smithsonian Institution. We extract tie eI-
Narration of the phenomena from the last Report Of
this Institution
The instrument consists Of solid disk Of any shape
fastened on SHAFT set up in metal ring where 1t IS
free to revolve A small hook with a swivel is at
tached to the ring at Of the places where the shan
enters Il and bv means of the hook the instrument '
su.perdcd q, the end Of string. When so suspended
il clear that the effect Of gravity will keep the SHAFT
hanging vertically under the string, the ing standing
vertically ard the disk horizontally. To exhibit the
singular effects Of compound rotations unlock the IN
struert wind gut around the shaft, and holding rmly
the ring. pull rapidly OF the gut the consequence VIII
be fast otaory motion of the disk in the rng heep
ing the shaft and ring horizontal, hook the instrument
to the string before and let 60. The apparatus VIII
Immediately begin to revolve slowly around the END
attached the string the other end OF the instrument
remaining suspended in the air instead OF falling down
in line with he sting it does when the disk Is not
rotating. BY means of sPrng-baance 1t may De
ascertained that the whole weight of the machine
bears on the string. Let the suspendng string be
in front Of any observer. facing the NORTH the appa
ratus be- bis right and suppose that the top OF the
rotating disk is coming toward him. The tendency OF
gravity is make the apparatus 90 down IN describing
a ouarter of circle about the hook as a CENTER IN
that motion the particles of the top urged TO the
east, along the are of circle they have already
rapid motion toward the south; they consequently take
an intermediate erection The tendencyis therefore
70 turn the plank of the disk outward which, on &C.
count of the fixed position of the end of the shaft at
tached to the spring. must cary the other end back
ward or north. The same reasoning applies
to the lower particles of the disk: tsey move
rapidly from the observer toward the north;
the tendency of gravity is to carry them west tnce
they are below the horizontal diameter of the circle
they describe; they take an intermediate direction
west northwest which be done only by the sy:-
TEN moving not downward, but horizontally from the
observer. This composition Of forces is momentariy
repeated, in exactly the same circumstances, and
hence the rotation is continued uniformly long as
the disk maintains its speed When this speed
gradually decreases, the constant effect OF gravity
becomes more and more important, aud the direction
Of the component force DIVORCES and more from
the plane of the disk; the effect is an increased
velocity of motion around the hook. The same
theory explains. why ball from rife-bore cannon
deviaes always in the direction. This is an in
terestiDg application of compound rotation, which our
readers may easily understand after carefully reading
the above description and making the appropriate
sketches,