Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1875-07-08
MECHANICAL AND SCIENTIFIC.

MECHANICAL AND SCIENTIFIC.
Awnings can be rendered waterproof
by plunging the fabric into solution con.
tanning 20 per cent. Of soap and afterward
into another solution containing the same
percentage of sulphate of copper. Wash,
and the operation is finished
To make cheap galvanic battery
take cylindrical vessel, and put another
OF porous porcelain inside of it, fill the
vessel with diluted sulphuric acid, and
the space between the two with sulphate
of copper tif you require to plate the ar
ticle with copper) if not solution with
the salt of gold, silver, ETC., according to
that which you wish it to be; put Slip
of zinc in the sulphuric acid and attach
copper wire to it, and the other end to
the medal or article you wish to plate, and
immerse that in the other solution. Your
battery is now complete. you want the
copper to be very thick you must put
few solid crystals of copper in the solu-
ton; where you do not want it to come
in contact you must touch it with little
grease; if you want to take the copper off
the article you must do it over with
slight varnish
OF late years one of the most impor-
tant and useful operations in surgery has
been that OF grating new and healthy skin
upon wound or sore and thus establish
ing the healing process and obtaining
clcatrlzatlon. Hitherto the particles of
skin have been taken from some sound
part of the patients body and applied to
the diseased or injured point, but NJ
Anger has recently demonstrated that
pieces of skin may be taken from ampu-
tated limbs and used successfully in
heteroplasty. In one case Nj. Anger took
strips OF skin from the palmer surface of
an amputated finger and applied them 10
the liberated leg Of another person. In
three days the bandages were removed
and the grated parts found firmly united
to the surface and evidently vascularized
To insure success it is necessary that the
graft be made Immediately upon amputa
ton.
An ingenious apparatus for saving
wood has been introduced in England
with very satisfactory results. In order
to secure the log from rising with the drag
Of the saw on its bed while being cut it is
kept down by means of pressing rollers
or bowles, carried by vertical water
cylinders, III which stationary pistons are
inserted, their rods being pendant from
transverse beam of the saw frame. The
upper and lower ends of each cylinder
are brought into communication by an
outside pipe which allows the water which
fills the cylinder to pass from one to the
other side OF the fixed piston. The water
forms an elastic packing between the PTS
ton and the lower ends of the cylinder
and serves to retain the bowles of the
cylinders in contact with the timber when
once lowered in contact Herewith. In
order that the machine may operate
upon balks or logs of varying thickness
the cylinders are fitted with vertical
rack in gear with pinions for raising and
lowering the cylinders.
1t is stated that previous to its being
made known that Mr.. Lick, of San Fran
cisco, intended to found an observatory
with the grandest telescope in the world a
similar instrument had been projected in
France by M. Foucault, in 1865, but was
suspended in consequence of the latter's
death. 1t has since, however, been re-
sumed under the direction of NJ Wolf,
and the work Is being pushed forward rs
rapidly as possible. The tube of this
gigantic instrument is nearly fifty feet
long and six feet eight inches in diameter.
The reflector is to be produced at the St.
Goblin glass works, and the production OF
the mold alone, which is already com
pleted, occupied six months. The mirror
will be produced spherical and will after
ward be worked up to a parabolic form,
and will finally be covered with silver or
gold. The power of this telescope will be
far greater than that of any other hitherto
constructed-to be greatly exceeded, how
ever, by the Lick instrument