Port Tobacco times, and Charles County advertiser. (Port Tobacco, Md.) 1845-1898, 1850-05-22
SELECT MIS- CELLANY
From Sharpe's London Journal.
CURIOSlTlES OF SCIENCE.
BY JOHN TIMBS.
ECONOMY OF ELECTRIC LIGHT.


BY JOHN TIMBs.
ECONOMY OF ELECTRIC LIGHT.
The motion Of electricity as source of
illumination was suggested by Davy nearly
half century ago and the application is,
in all respects, practical, save in the matter
ofexpense. Mr.. Brande tells US that mode
Of procuring cheap electricity must preoede
the economical use of such illumination /;
and that, were This obtained, water might
be decomposed, and its hydrogen naptha-
lied. burnt, so as TO produce vivid, bright,
and steady fame in its other element,
oxygen.
ELECTRICITY OF GRAvE-YARDs.
Sir James Murray recommends the advo-
Gates Of in,ramural in,ermen,s to employ &C
cura,e electricians, with delicate instruments.
to measure the terrible galvanic derange-
ments of fermenting churchyards as the bes,
proof Of the fatality Of the practice. Sir
James refers to all effervescing golgo,ha,
long kept in active fermentation in Belfast,
near the quays, and on level with low-wa-
ter mark. During many years, Sir James
had proofs demonstrating that persons re-
siding in tenements opening into this Belfast
grave yard could no. be efficiently elec,ri-
fed, because the best machines could sell
dom produce sparks Of any intensity. He
often noticed tina, magnet capable Of sus-
tanning fifty pounds with ease, in other sit
ua,ions, could not for momen, suspend an
iron Of ten ponpds in the habi,a,ions bull,
close.to this devastating place Of in,ermenl
From these and many other observations,
Sir James proved that negative electricity
pervaded this vast swamp, and drew away
the positive electricity from the living crea-
lures in immediate contact with the damp
earth and air Of that fatal and extended
trough, or galvanic pile.
LAW OF STORMS.
Captain Handley, Of the Su7tany, has re-
Gently most successfully tested the truth of
the law which regards tropical tornadoes as
cyclones, or revolving masses of air travel
ling along certain curved lines. The edge
OF the cyclone referred to was thirty de-
grees, al least, from Bombay. Calcutta, and
Alden, and its effects were felt al the dis
lance Of 1900 miles. The course of the
ship SuHdny was southwest, when. over
taken by the storm, Captain HandIey says.
IN his log, he ''fuIed top sails and fore sails
and round the ship to, with her head to
the eastward, as have every reason to be-
lleve am on the edge Of hurricane D.
The storm passed onward to the south
west; and thus, by laying to, and steering
to the eastward, Captain Hsndley, no
doubt, saved his ship and 5000 coolies on
board. This triumph Of scientific obser-
WALTON cannot be too widely known.-.AlAe-
ngum.
COLOR OF TREEFROGS.
In the newly erected Reptile House in
the Geological Society's gardens in the Re-
gents Park. is a glazed case Of the Tree
Frogs of Europe. Although of brigh,
green when exposed to light, these creatures
become almost black in the dark; and for
some time after their new location, the spe-
cImens IN the gardens presented every pos
sible shade between dark brown and bright
green, owing to their having been recently
KEEP. in dark place.
MOLECULAR ACTION
M. Niepce has discovered that. when a
print is held over the vapor Of iodine, the
Iodine IS attracted almost exclusively by the
ink. BY applying an engraving thus satu-
rated with Iodine PARTICLES to film of starch
spread on glass surface, he thus obtained,
IN iodine of starch perfect transcript of the
original design.-Prof Dumas
MANUFACTURE OF CLASS.
IT is curious fact in the history of dis
covery, that the manufacture of glass was,
few years since, unknown at Sidon, where
IT is reported TO have been first invented
Pellat's Cmriosities Of Glass-making.
TO DETECT IMPOSITION IN GoLD-Dusr.
Place little golddust in glass tube or
earthenware saucer, and pour nitric acid up-
on il; then hold the glass or saucer over
flame, or upon a few embers, until red
flames (nltric vapors) arise: if it be pure
gold, the liquid will not become discolored ::
but if pyri'es, or brass filings should have
been mixed with it., the acid will become
,urbid, green and black, discharging bubbles
Of gas. After the ebuli.ion has ceased, the
residue should be washed with water, and