The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1892-08-04
SCIENCE AND INDUsIRY 7.
USEFUL. INFORMATION 4 ABOUT
RECENT INVENTIONS
Diamond Mining In South AfrIca--
Machinery In Shoemaking--O
Hundred Miles an Hour--An
Atlantic Telephone.

Hundred Miles an Hour--An
Atlantic Telephone.
Diamond Mining In South Africa,
The De Beers and the Kimberley
mines are probably the two biggest
holes which greedy man has ever dug
into the earth, the area OF the former
at the surface being thirteen acres,
with depth OF $50 feet, the area and
depth OF the latter being even greater.
These mines are no longer worked
from the surface, but from shafts sunk
at some distance flom the original
holes, and penetrating to the blue
ground by transverse drivings at
depths varying from 500 to 1900
feet. The blue ground, when extract
ed, is carried in small iron trucks to
the FLOORS" These are made by re-
moving the bush and grass from affair
~ level piece Of ground; the land is
then rolled and made as hard and as
smooth as possible. These floors
are about 600 acres in extent. They
are covered to the depth of about a.
foot with the blue ground, which for
time remains on them without much
manipulation. The heat OF the sun and
moisture soon have a wonderful effect
upon it. Large pieces which were as
hard as ordinary, sandstone when
taken from the mine, soon commence
to crumble. At this stage Of the work,
the winning OF the diamonds assumes
more. the nature of farming than Of
mining; the ground is continually har-
roWed to assist pulverization by ex-.
posing the larger pieces to the action
OF the sun and rain. The blue ground
from Kimberley mine becomes quite
well pulverized in three months, while
that from De Beers requires double
that time. The longer the ground re-
mains exposed, the better it is for
washing" The process OF exposure
being completed, the blue ground is
then carried to very large elaborate,
and costly washing machines, in
winch, 6y means OF the
action Of running water, the
diamonds are separated from the
ordinary earth. 1t may be mention
ed that in this process one hundred
loads OF blue ground are concentrated
into one load OF diamondiferous stuff.
Another machine, the 'tpulsator,",
then separates this latter stuff, which
appears to be mass OF blue and ark
pebbles Of all shapes, into four differ
ent sizes, which then pass on to the
assorters. '"The asserting is done on
tables, first while wet by white men,
and then dry by natives" The as
sorters work with kind oil trowel,
and their accuracy in detecting and
separating the diamond from the
eight different kinds of mineral forma-
tions which reach them is almost UNI
erring. Lord Randolph. Churchill, in
The Popular Science Monthly.
One Hundred Miles an Hour,
There is not much probability OF
attaining regular and continuous
speeds OF 100 miles per hour with our
present locomotives. Their fire boxes
which perform the same functions
Tor the machines that their stomachs
do for animals-are with the present
system OF construction, necessarily
contracted in size. The weight of the
whole locomotive being fixcd, the
dimensions OF the different parts are
also limited.
1t is proverbially dangerous to
prophesy when you are not quite
sure, and it representations are
based upon calculations the mend
acity Of figures may rise up hereafter
to deprive the prophet Of ali honor.
From what has been said, however,
it will be seen that fast running is
largely question of steam production.
Given q boiler which will generate
Enough steam, and other problems
Of comparatively easy solution. The
difficulty is,to get the boiler sufficient
" large within the limits OF size and
weight to which it must be confined.
1t will be safe to say that to be able
to travel continuously at LOO miles an
hour we must have either boilers or
fuel which will generate more steam in
@ given time than those we are using
now do, or our engines must use less
steam to do the same work, or, what
is more prot able still, we must have
all three OF these features combined.
A writer in Scribner's Magazine thinks
that in the locomotive 81 the future
the reclprocating parts will probably
be more perfectly balanced than itnow
IS; coupling-rods will either be dispen-
sed with altogether or their risk Of
b re will be lessened by placing