The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1880-09-23
SCIENTIFIC.


extra prices. The tanning material prefer
red is the bark of the black willow, and.
where this cannot be obtained, birch bark IS
next resorted to. Their dyed leather is
usually red or black; for the former, the
hide is first soaked in alum water, and then
dyed with Brazil wood; the black is given
with an iron color liquor. The leather is
thsc smirched with birch tar, which Gives
the pecun6c' smell SO much prized-and
which, when used for book binding, goes
far toward protecting the book from worms
and is finished by various other manipula-
tons. The safian or dyed maroquin leather
is another famous product, made only from
the skins of bucks and goats, and the favorite
colors are red and yellow. The general
method of preparing the pelt is by the use
OF lime, dogs excrement, and bran, and
honey is also used after branning -some of
1t. dissolved in warm water, being first
poured on each skin, three days allowed for
fermentation, the skin being then sailed in
strong brine and hung up to dry; after this
the dye is applied -cochineal for red-the
color is finished with alum, and the skins are
tanned with sumac ~ h..
ARTICLES made of imitation amber aro
now produced in immense quantities and of
beautiful appearance, and sold for the nat
ural material. The resembling substance
thus employed is principally colophony-a
resin obtained by the decomposition of tur-
pent1ne-though many other ingredients are
also made use of to give it the requisite
Qualities So perfect is the imitation said
to be, that the false substance has the cleo
11cal properties of the true, and some in
gen1ous tabrlcators have even managed to
introduce into the substance foreign bodies.
insects, &C., to render the SIMILARITY
more striking The means of detection are
simple. Genuine amber requires a heat of
from 545 to $50 degrees Fab to melt it.
While the spurious substance becomes Gouid
at much lower temperature Again, while
the true article is only slightly attacked,
after very long time by ether and alcohol,
the imitation rapidly loses it's polish in con-
tact with such liquids, and soon becomes
soft. True amber pieces of small size NAV
be formed into lump of much greater
value, by mcistening the surfaces to be
united with caustic potash, and pressing
them together while warm 'se
A GERMAN philosopher, having directed
his attention to phosphorescence, in order to
discover, if possible, the real cause of that
remarkable phenomenon, concludes that the
simplest method of bringing about phos-
phorescence is to. place marine fish in three
per cent. solution of salt-the phenomenon
being observable the second evening. The
luminosity, it seems, begins in the eyes, and
thence spreads all over the fish, Increasing
IN intensity from day to day, it's duration de-
pending upon the temperature. 1t is also of
such nature that the fish appears, after a
time, to be luminous oil through which.
however, is not the case, for on scraping off
the surface, it is quite black underneath.
This luminous matter is, indeed, kind of
slime; which is quite apparent IN daylight,
when it is of dirty white color it is only
in the dark that it shines. .a ..s
Some unusual results are reported by Prof.
Roberts, obtained by him from an examina-
ton of certain alloys by means of the induc-
ton balance. He has been able to detect o
difference of one part in 1000 in the amount
OF silver in two English shillings of equal
weight. Referring to Mathiessen's division
OF alloys into three classes, VIZ, soldied
solutions of one metal in another, solidifed
solutions of one metal in an allotropic modi-
tcation of another metal, and soidifed SO,
lutions of allotropic notifications of both
metals, he remarks that, for the first class,
the curve of electric conductivity is straight
llne, for the second a paraboic curve, and
for the third bent line. It was found that
the balance gave the characteristic curve for
the first class with an alloy of lead and tin,
and for the second with an alloy of gold and
silver. ..--...-...... .. srs..
In memoir on cyclones and waterspouts,
NJ. Monchez presents some interesting OBJ
servahons made by him while upon the
ocean, and the meteorological bearing of
which is Of no slight Importance. Accord
ing to his account, at or near the surface of
the ground the current of air in the cyclone
is always from below upward, while in
whi1]winds the movement is, on the con-
trary from above downward In the for
mer case, the winds are winds of aspiration
in the latter case, the winds descend from
the cloud in the form of bag or tube
which terminates in a point. From the
character of these observations, it would ap-
pear that waterspouts have in fact no rela-
ton whatever to cyclones having, in
reality, opposite appearance and cause to tho
latter
I The best quality of olive oil, according to
the Bulletin de IaadustrTe, is refined by pre-
pairing large, shallow tin boxes, with holes
pierced in the bottom, and which is then
covered with thin sheet of wadding. Four
five or more of these boxes are placed on
frames one above the other; and the oil,
being poured in at the top box, soaks
through the wadding and drops to the next
box, and thus on to the last, when it is al
!