Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1875-10-07
MECHANICAL AND SCIENTIFIC.

"A cement impermeable by air and
steam, and especially well adapted to use
for steam or gas pipes, is made of pow
dered graphite six parts, slaked lime
three parts, sulphate of lime eight parts
and boiled oil seven parts, we'll kneaded,
1t is thought that M. Jamin's research
es point to an important modification in
the construction of magnets. Thus, sup
posing that great number of PLATES,
which. after being separately magnetized
to saturation, are placed together, the
magnetism of the combination is seen to
increase up to limit which cannot be
passed, and which is reached when the
polar surfaces are filled. Surprising that
ten plates are required--if the same eX-
pertinent be recommended, applying the
same plates against two iron armatureS Of
large surface-the intensties increase
much more slowly, because the sum of
the magnetism is ditfused over a more
considerable extent, the limit not being
reached till this extent is full. For this it
may be needful to superpose twenty,
thirty or forty plates, and, generally
speaking, a number so much greater as
the armatures are larger. The total power
of the magnet increases, therefore, with
its armatlnes.
The London Nelrs, speaking of the
superior elasticity of steel as compared
with iron, gives an illustration of the fact
as presented in the course of some recent
Investigations, as follows: A bar of hard
ened steel, one inch square, being laid on
two supports, fitty-four inches apart,
load was applied at the center, beginning
at fifty pounds and increasing gradually
by that amount until it reached 1,400
pounds. Now, under 800 pounds the de-
Election was one inch; with 1000 pounds
it was one auG onefourth inches, and
with 1900 pounds little over one and
one-half inches, showing the increase of
detection to be nearly as the strain. With
a load of 1900 pounds slight "set' was
Observed amounting to 016 inch, which
was quadrupled by the addition ofanother
fifty pounds. From this point the deflec-
ton and set increased more rapidly, being
14.5 inches and 1873 inch respectively, un-
der strain of 1900 pounds, and with
1850 the set was .429 inch-the fact thus
appearing that the elasticity remained
perfect until the load exceeded 1900
pounds.
An interesting geological theory has
lately been the subject of discussion in the
foreign journals. An eminent scientist,
it seems, has made the curious calculation
that every year ninety-two horse power of
work-heat meaning works. got rid of
from every PAT acres of the surface of the
globe and that the dissipation of energy
and the contraction of rocks not being
uniform, the effect of these disturbing
causes is to produce horizontal thrusts,
which form mountain ranges by crump-
ling up the earth, mountains being formed
by this crump action rather than by direct
volcanic or other upheaval. This theory
also assumes that the changes produced 10y
such contraction are slow, and that there
is every reason for believing that the sea
floors and continents now existing are eX-
tremely old, geographically speaking, so
far as their present forms or configuration
are concerned. An illustration of this is
cited in the case of Snowdon, the loftiest
mountain in Wales and South Britain.
The upper part consists of sea sand, fossil
sea fishes and volcanic ashes, all mixed
together, and, IN fact, appears to have
been at one time in the same condition
that the Bay of Biscay is in at present
that is, volcanic ashes fell into it and
sometimes buried fish. The lower part
consists of vast streams of old lava-show-
ing that at some geological period the
crumpling action took place below the
bay Of Snowdon; consequently the bottom
of the bay was elevated, and became the
very ton of the highest mountain in Wales