The Wheeling daily intelligencer. [volume] (Wheeling, W. Va.) 1865-1903, 1900-08-04
SCIENTIFIC MISCELLANY.

y.
Water orrosion of Glass-Motion of
Dissolving Crystals = Protective
acknowledgements on Uncoated
Metals-The Greatest Polar Prob
lem = Automatic Train Saving.
Electric Waterproofing = Spinning
Machines of Ants.
Workers in glass, especially opticians.
are warned that certain kinds Of glass
appear to be so soluble in water that
moisture quickly etches the surface,
and destroys the transparency. Mr.. E.
Mordy, Of Decca College. East Bengal.
reports having noticed the dull appear
ance Of "a cut .wine-glass and of finger
bowls in which water had been allow
ed to stand, also the spotting of two
decanters which had been dried after
partial draining. These effects were
all due to water-etching. This explains
the rapid deterioration of optical APP
paratus In the moist climate of India,
and proof that the fault Is In the kind
of glass used Is furnished by the object
glass of n 31ls-inch telescope. the inner
surface of the convex lens being badly
corroded, while the adjacent face Of the
concave lens was quite clear.
The motion of camphor In water Is
well known. A German chemist. X.
Schaum, has taken surn readily solu-
bic substances as potassium, cyanide,
potassium. nitrate, silver nitrate, cal
clum chloride, potassium permangan-
ate and sugar. and has studied their
their travels In dissolvinS by dropping
single crystals upon mercury covered
by water or dilute acid. The move
ments-greater in dilute acid than In
water-are very characteristic. The
crystal first takes n zlgzaG course, then
changes to circular path and finally
turns rapidly on Its axis. The rate OF
motion varies with the rate OF solution
and the surface tension of the mercury.
The new method of packing used for
shipments OF butter from Melbourne to
Kimberley Is recommended for delicate
articles In general. The box Is made
from six panes of window glass. closed
ut the edges with gummed paper. and
this Is given q Notwithstanding covering
Of plaster Of paris. the whole being
wrapped If waterproof paper
The curious fact Is noted by French
observer that nlghtlnsales devour the
drones of a hive, without harmlng the
workers.
An interesting discovery that has
been forgotten for more than half 4
century was lately brought to notice
by Major General j. Waterhousc. In
1872 Moser found that silver, like itS
compounds, is sensitive to light, and
that 4 distinct image could be formed
on 4 clean silver plate by exposing to
sunlight for two or three hours behind
a blalt tablet, with cut-ouf characters,
and then developing over mercury va
por. He obtained similar results with
copper. concluding that all substances
ARE changed by light. Taking up the
investigation General Waterhouse has
proven that the Photographic image
may be visible after exposure. but lhat
whether visible or Invisible. IL Is
clearly brought out on metallic silver
| by mercury yapor or developing So
buttons acting on the silver. The pho
tographic. action on other metals, except
lead, appears to be very slight. al
though not yet fully tested. Expert
ments thus far made Indicate that the
cause of the action cannot be heat or
pressure. but that the effect Is due to
the blue and violet rays OF light.
Whether It Is n result Of oxidation Is
yet to be learned. apparently, pure sill
yer. 1t Is known, often containing oc-
cluded oxygen.
The Importance of magnetic survey
In the vicinity OF the magnetic poles
seems TO have been overlooked by cx-
piorers. DR.. Cook, of the Belgian Ant
arctic cxncdltlon. points out that geo.
graphical survey Is of far less consc-
Qucncc. though VASTLY more difficult
In the region OF thu poles. Even tho
position iof the magnetic poles Is yct
10 be fixed. Many years ago tho
4 eco .