The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1894-03-08

ening by more sfan one method admits
Of no question. The advocates OF the
quick heating system at one time claim
cd much for this mode, and there are
still some old-ti,ne smiths who win not
heat to. harden in any other way.
A veteran in steel practice reminds
Us, however, that the quick heating
plan was in vogue at a time when ev-
erything was faced with steel, that is.
4 piece of steel, say three-e:ghts of an
inch thick or more was Welded OF pla-
ed on iron, and this was heated up
quickly for hardening. s..5s.. ~.
The smiths who followed this prac-
tice were skilled in the art and could
sometimes harden steel of high tenn
nerir qualities suitable for purposes
such as roll-turning tools and plugs
The considerable loss of rolls in hard
ening With the best appliances for hand
ling indicates that where a man can
bring these out sound by following the
quick-beating method, he had better
continue in the old way; he would be
extremely unWise to change.
The veteran to whom allusion is made
has himself hardened in a single day
as many as six large rolls weighing
500 pounds each, or 5000 pounds alto
gether, and he heated them all thor
oughly in a furnace and did not break
one. They were mint rolls for Uncle
Sam,'' and the steel was Crescent spec
ial, made with full knowledge Of the
mode Of hardening.
One person may heat certain shape
| in an alright box with bone aud char
| coal, while another may prefer the
| Quick-heating method, and both may
be alike successful. This is not always
the case, and where it is, it would be
unwise for either to change the mode
which as proved itself success in prac-
tice, especially as the steel maker
could be coaXed to try his hand at fur
nishing steel Of tempering qualities to
suit either method.-The Crescent An.
vii.
| Light of Years as n Measurement.
Astronomers have had to invent a
new measure for talking of the dis
tances of the heavenly bodies since find
ing miles too small, they talk Of light"
which means the distance that a ray
of light, travelling some hundred and
eighty-six thousand miles a second,
would traverse in a year, it may be
We'll to get lotion what a light year
really is.
1t means a journey that would take
an express train move than eleven mil
lion years.
It means velocity that the periphery
Of a gigantic flywheel one hundred
miles in diameter could not keep up
with, though it made five hundred
revolutions in a second.
1t means distance traversed in one
second that sound will not pass over in
ten days. And this is the unity for the
quantities that modern astronomy deals
with when treating of the distribution
cubic light year spoken of-that is,
an imaginary cube with each side q
light year long. 1t was long after men
saw how to measure the distance Of
the stars before they succeeded SO as to
feel much confidence in the results OBJ
tanned; but now the distances Of a few
stars are known with comparative ac-
curacy and certainty, many measures
having been made that probably come
within twenty or thirty per cent of the
truth.
Aluminium Boat.
A boat constructed Of aluminium and
> intended for the forthcoming expedi-
ton Of Commander Monteil into Gen.
trail Africa, has just been launched
from the Quay dOrsay in Paris. It
is fat-bottomed fe'.ryboat, capable
Of load Of Is tons. is So Aeet long and
8 IL feet wide, and the total weight Of
the boat is 2034 cwt.. Of which 10
cwt is of metal and the remainder of
wood.
This lightness of construction has
only been obtained by the use Of alum
mum, and the difficulty had to be over
come of rolling sheets of this metal
feet long, 2 feet inches in width,
and OLE inch thick. The boat is made
in tWenty-four parts, each Of which can
be carried by one man, snd which are
adjusted by means of bolts; India rub
Der being provided at the joints Of the
sections so as to render the boat water
tight. With two exceptions all the
parts are intel changeable, and the boat,
which ic fitted with tho tOO1S nocoSSarv