Gloucester County Democrat. (Woodbury, N.J.) 1878-1932, 1886-06-17
POPULAR SCIENCE.


A German Investigator, Semmola, has
succeeded in producing musical tones
from metal plate by electrifying it in
termiftently from an induction machine,
the wires being attached to opposite
sides Of the plate and the path Of the
current interrupted SO that sparks strike
across.
Explorations made last summer prove
that the ancient mound-buiIding inhab-
itants Of America extended their works
northward beyond the Red River of the
North. Along this river and Lake Win
nipeg were found mounds identical in
structure with the famous ones of the
Ohio and Mississippi valleys.
AS an example Of the strength Of enc
kind of fibre, recent work on the sub
ject states that the best fbres Of New
Zealand fax are equal in strength to a
piece Of the best wrought iron of tfe
same diameter. These strengthening
fbres are placed in the plant just where
they can be of the best service in sustain
ing weights and resisting strain.
A Chinese block is engraved on a hard
native wood with close grain, cut in
different direction to the lockwood pre-
pared for English engravers The Chi
nese printer inks the block with brush
the ink being suitable compound
largely composed Of India ink. To secure
an impression soft paper is laid on the
block, and dry brush is passed over the
back Of the paper, which is printed on
one side only.
The heat of the earth is caused by
light impinging upon the earth's sub
stances and its friction through the at
mosphere, that is, if we accept the
''Newtonian" theory of light. If, how
ever, the theory Of ''undulation" is be-
lieved, then heat is caused in substan-
italy the same way by the action of these
rapid waves or unduIations, for in no case
will heat be found till within the bounds
Of. the atmosphere.
A ''black snow" which fell in 1875,
over an area Of about fifteen by twenty
miles in the vicinity ofHolland, Mich,
was found TO contain a considerable pro
portion Of dark, earthly matter. This
was subjected to elaborate scientific ex-
animation, and pronounced volcanic dust
from some far distant crater. A dissenter
from this view has sought a simpler ex-
planation, and has since proven that the
dust came from the prairie soil hundred
miles to the southward.
Three years after date the floating is
lands Of pumice thrown up and into the
sea by the stupendous volcanic eruption
at Krakatoa, in the Java seas, are found
to have drifted along the Indian Ocean in
the last twelve months 97O miles in
direction west by south from where they
were one year ago, or about five miles
day. This accidental help to hydro
graphers, and all who study ocean cur
rents and drift, is probably the best they
have ever had, because the origin Of the
pumice is well known, the floating ex-
panse Of it is SO large that it cannot es-
cape notice. and the dates and other par
ticulars about it are all matters of rec
ord.
There has been introduced at the Paris
observatory an apparatus specially de-
signed for photographing the heavenly
bodies and M. Mouchez, director Of the
observatory, has presented to the French
Academy of Sciences a chart obtained
by this wonderful method. This map
contains small section of the Milky
Way, and presents to view five thousand
stars, ranging from the sixth to the if
teenth magnitude Inview Of the fact that
there are forty-one thousand superficial
degrees in the armament, it is estimated
that representation of the whole surface,
completed in the same way, would re-
quire six thousand similar sections,
forming one thousand five hundred eclip-
teal charts. 1t is further estimated
gigantic as such work appears-that,
if it were undertaken by six or eight
observatories, favorably situated in both
hemispheres, the work might be con
cluded in five or six years, and would
contain photographs CT 20, 900, 900 stars,
down to the fifteenth magnitude.