The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1881-04-07
POPULAR SCIENCE.
CASTING STEEL.

AOOu1 Gno cuu Ol ldSC mOnCQ the
largest crucible steel casting hitherto
made was effected in the works of a
firm in Sheffield. England. 1t was "a
spur rim % feet in diameter and cast
whole. To cast, 27O pots, each holding
80 pounds of molten steel, were used,
Steel wheels are likely to supersede
the cast-iron wheels now in general
use in the Lancashire mills.
FOREST AND PLANT LIFE.
Some observations made at Giessen
last winter by Herr Hoffman, throw
light on the way in which plants are.
injured in time of hard frost. The
great advantage of a hilly position
was then apparent; the plants so
situated took little or no harm, while
in the valley there was extensive in
jury. The injury, too, decreased in
proportion to elevation above the
valley. Still more instructive was
the fact that one and the same bush
was killed in it's foliage on the south
side, while on the north side, it re-
manned green. The author infers that
it is not a particular degree of cold
that kills plant, but the amount of
quick thawing. T
A MILK LABORATORY.
A dairying company of London has
lately established a laboratory at
which samples of milk received from
farmers are subjected to chemical
analysis. Prizes have been offered
by the company, which are to be
given to those farmers whose milk
SUPPLY stands highest in quality dur
ing a stated period of time. The SAM
plies are carefully examined by the
company analyst, whose analysis and
reports will decide the competition
for the prizes. 1t is expected that
much valuable information respecting
methods for producing the richest
possible milk will be secured in this
way. s.
TOUGHENING GLASS. r..
A Leipsic journal, which makes a
speciality of matters relating to glass,
gives a method which il asserts will
prevent lamp chimneys from cracking.
The treatment will not only render
lamp chimneys, tumblers, and like
articles more durable, but may be
applied with advantage to crockery,
stoneware, porcelain, etc. The Chin
neys, tumblers, ETC., are put into a
pot filled with cold water, to which
some common table salt has been
added. The water is we'll boiled over
a fire, and then allowed to cool slowly.
When the articles are taken out and
washed they will be found to resist
afterward any sudden changes of tenn
perature. The process is simply one
of annealing, and the slower the COOL
ing part of it is conducted the more
effective will be the work.
PERFoRATING GLASS.
An ingenious method of perforating
glass with the electric spark is
described by M. Fagee. The appa.
ratus in this case consists of
rectangular plate of ebonite, it's size,
for a coil giving IL cum. sparks, about
Is ctm. about Is ctm, by IL; also a
brass wire passing under the plate,
and having it's pointed end bent up and
penetrating through the plate, not
fu1ther-this wire being connected
with one of the poles of the coil. A
few drops of olive oil are placed on
the ebonite plate about the point and
the piece of glass to be superposed,
care being taken that no bubble of
air be imprisoned. The olive oil per-
fectly accomplishes the object of in
sulating the wire, and it is then only
necessary to bring down wire from
the outer pole of the coil, upon the
piece of glass, above the point of the
lower wire, and pass the sparks, it is
easy to make a cross series of holes in
few seconds.
A NEW NAUTICAL PRINCIPAL.
Referring to the fact that, even yet,
the great majority of ship builders
tenaciOusly hold to the idea that a
vessel should be made to ride over the
water and waves rather than through
them, a recent writer remarks that it
is easier to propel deep vesselof any
given tonnage through the waters than
shallow vessel Of equal capacity
along the surface. The reason alleged
for this is, that the deeper the wake in
the water. the quicker it is filled to
support the after part of the vessel,
and that it is the sinking of a ship in
her wake at the stern that compels her
to raise hill Of water-so that. even
if the propelling power be doubled
after reaching the practical maximum
of ships speed, only two or three
knots more Of speed can be gained.
According to the writer iu question,
the Scotch and English iron ship
builders are just beginning to operate
on these principles, and are bnilding,
in accordance with them, vessels 600
to 700 feet long.
A NOVELTY IN FIsH-HATCHING.
Mr.. E. Z. Sachs writes to Nutatre
from Batavia: ss Within the past
month I have been so lucky as to
make what / hope is very interesting
if not remarkable discovery. On the
island of Billion, 200 miles from here,
| found a fresh water fish which pro-
duces its young living from it's mouth.
am quite prepared for the cry of
incredulity that will be raised, but /
conducted my observations with
living fish and closed doors, and what
assert is urdeniable; the eggs are
Matched in the lower portion Of the