The Londonderry sifter. (South Londonderry, Vt.) 1883-19??, 1886-12-02
- SCIENTIFIC &

closing the grain, This can he done oy
lightly hammering its surface with
round pene.hammer.
The amount of force exerted by heat
and cold In expansion and contraction
of metal is equal to that which would
be required to stretch or compress it TO
the same extent by mechanical means,
experiments with cast gears it was
found that when dry the loss by fric-
ton was about thirty-llye per cent. of
the total power but when thoroughly
fabricated this loss was reduced 20
thirteen per cent,
At late meeting of the MICROSCOPE
cal Society of London, ProfF.J.Bell gave
an account of what he regarded as the
most extraordinary biological discoy-
cry of the last twenty-five years-that
of third eye at the top Of the head of
certain lizards,
NJ. Palmeri of the Vesuvian Obserya-
tory has made some interesting expert
ments showing that when steam is
condensed by cold negative electricity
is developed, but that positive electric
i.y is manifested when evaporation
takes place.
To produce red stain on wood, first
plunge it in solution of one ounce of
curd soap in thirty-iive fluid ounces Of
water, or ruby with the solution and then
apply magenta sufficiently diluted to
bring out the tone required. All the
aniline colors act very well on wood.
A fabric has been patented which is
made insect proof by stepping in a solu-
ton of tobacco and cascarilla bark
macerated in bcnzine, then drying and
STEPPING in tobacco, cascarilla bark and
hot water. the fabric to be used in
trunk Innings, etc, as protection from
moths or other insects.
In some experiments conducted by
the German Government on steel and
iron gir(erS. the soft-steel girder proved
twenty-five per cent. stronger, and the
hard-steel girders sixty-six per cent
stronger than the iron girder. The
strength of steel girders appeared to be
about the same for the tive flanges, if
made alike in sections.
German photographers have sue
ceCded in photograpGng aprojectile in
the course of its flight, and some of
these photographs show the head of
condensed ar which pr2cedes every
SHOT. 1t is said to be this "head "
which prevents even s,iilful rifemen
from hitting an empty egg shell when
hang on long thread. The air blows
the shell ont of IA way of the bullet.
The Ottawa iunbcrmen are building
furnaces to burn IL II sawdust, as fol-
lows: The structure is of fire brick. in
cased in plate iron. is circular tower,
and when finished viii t,a 40 feet high,
and is thirty-six or forty feet in diane
ter This has become necessary because
this refuse was choking the river.
The composition of metallic mirrors
of the present day differs very little
from that used by Sir Isaac Newton
Many and different ALLOYS have beer
suggested, some including silver Or
nickel or arsenic; but there is little
doubt that the best alloy, taking all
things into account, is made with fouI
atoms of copper and one of tin, which
gives the following proportions by
weight copper, 252; tin, ll7.8.
A Manchester England) firm has
completed anew rope-making machine
which, whilst enabling any lengths OF
ropes to be manufactured dispense en-
tirely with any necessity for rope
walk. The complete machinery does
not occupy floor space of more than
three yards square. and is very simple
both in construction and working
The yarn is wound on series of bob
bins, and the whole process Of manufac-
ture is finished on the maehine, the
rope being transferred direct to q
drum, on which it is wound in coils
ready for delivery. The machine can
be readily regulated to give any twist
or hardness to the rope that may be
required.
If it were possible to rise above the
atmosphere which surrounds the earth
we should see nothing but an intense
and sharply defined bail Of fire, while
everything else would be wrapped in
total darkness. There could be 10 diff
fusion of light without an atmosphere
Or some similar medium for it to act
upon; but if the air about us extended
to height of 100 miles. the rays of the
sun could not penetrate it, and We
would be left in darlneSs, \ the depth
Of 100 feet in the ocean the'light ceases
altogether, one-half of the light being
described in passing through only seven
feet of the purest water
The discovery that heat influences
one set of nerve points in the skin
while sensations Of cold are received by
another set, has been followed by an
interesting Investigation by two italian
psychologists, whose apartments seem
to indicate that the various tastes re.
suit from the exciting of distinct sets
Of nerye-iibres in the tongue The pro-
ionged application Of ice removed the
sensibility for all tasteS sweet. sonr
salt and bitter. Cocaine DESTROYED :
temporarily, Of course sensib!hty for
FOR bitter only. Other substances, such
as caffeine and moriliia reduced the
power Of discriminating between differ
ent degrees of bitter. Dilute sulphilric
acid had peculiar effect, causing dis
titled water and even quiIline to taste
sweet at the tipo the tongue, although
the bitter of the quinine was elsewhere
tasted as usual
--s.~%S..-----
SOmetiiihg You neca-Shorthand.
4.