The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1907-08-10
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.

Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
An Indication for Steel Tempering-An
Engineering Department-Unsafe Sig
nAls-Early Geological Gardens-Light
for the Diver-An Improved FLEA
Scientific Aquarium-Wired Glass
Count of the Stars.
The idea that the critical temperature for
tempering steel is the temperature at whichthe
metal loses its magnetic properties has suggest
90 TO William Taylor, British metallurgist, a
curious indicator for guiding tempering work.
.oVang his theory by experiments with an cleo
sslcal balance, he made for factory work an in
.nument consisting of permanent horseshoe
net having extended soft-iron poles, one
pole being arranged to rock back under normal
conditions. A piece of cold steel holds both
soft iron poles but when the sample is heated
until its magnetic properties are lost, the rock
ing pole is released, and its flying back gives the
signal for quenching the steel. The device has
proven of great value in avoiding overheating,
with the resulting brittleness, cracking and
varying.
sFs
Building engineering structures on solid
foundation of water is the rather startling plan
By which W. e. Murray, California engineer,
cApCCbo W COUI6E great DtuCub upOu buC WOIAus
The floating structures would have a large
weighted base, with broad projecting flange,
and would be immersed in the sea until the low
er portion would rest in the stable waters below
the disturbed surface. With this form of con-
structon, it is believed that the action of waves
would be slight. 1t is claimed that this form of
building should have wide range of usefulness
and 1t is specially adapted for breakwaters,
lighthouses forts and bridges.
s%s
When bell signals are sent under water to
vessel Lord Rayleigh has found that the micro
phone receiver will indicate whether the sound
is from the right or the left, but that it cannot
be determined with certainty whether the sig
!, nal is from point ahead or one behind.
-
An attempt to trace the origin of geological
gardens and natural history museums has been
made By J. Won Pleyel, German. He concludes
that menageries originated partly in the wor-
ship of sacred animals and partly in the ambi-
ton of rulers to collect specimens of rare
valuable and savage creatures. The simplest
form of geological gardens was known to
the Chinese, Indians, Greeks, Romans and
pre-Spanish Bexicans in very ancient times,
Chinese menaeerie dating from 1850 b. G. being
the Oldest on record. The den of lions kept by
Dariu, of which we are told in the Book of
Daniels, is an illustration of the primitive men,
ageries, and the sacred white horses of Greece
and Rome and the so-called white elephants of
Burma and Siam represent another type. The
menagerie founded in 1927 in Regents Park,
~zondon, seems to have suggested the establish
ment In Paris that is regarded as the earliest
modern geological garden.
sss
Cropping in darkness or dim light. the diver
has been able hitherto to make only the sim
plest makeshift repairs, but with the Yale sub
marine lamp and recently invented pneumatic
tools 1t is possible for him to do almost any re-
pairing and cleaning of vessels without docking
The lamp comprises water-tight metallic cas-
ing enclosing a special regulator. double
glass chamber beneath the casing is protected
by rigid metal guard, and holds the carbons.
A storage battery or small generator supplies
electric current through suitable cable. The
submerged lamp weighing but few pounds,
may be easily carried about, and brilliantly
lights space equal to large room.
-
novel file made by London firm has semi
circular teeth. which have the convex side to-
ward the point of the file, and are cut very deep.
The file is adapted for hard and soft metals.
wood and marble. and is claimed to do three
Times the work of the ordinary file, while keep
ing its edge longer, being self-clearing and cut
ting without slipping.
A new aquarium at Brussels is to be made an
institution of scientific Importance, and, in
place of the usual few tanks of more or less I'M
healthy looking fishes, it is expected eventual
ly to display the complete river. lake and pond
fauna of Belgium. More than this, as much of
the fora will be shown as may be found practi-
cable. The central salon will resemble winter
garden, with a central basin and tanks let into
the walls, and some tanks will show specimens
of all indigenous freshwater fishes, while others
will contain crustaceans, molluses, batrachians,
reptiles, worms, insects and plankton. To aid
in restocking the depleted Belgian rivers with
natfxe- and foreign fishes will be a purpose Of
ctors. Especial attention will be given
to acclimatizing foreign species. and one tank
Is to be reserved for the American catfish,
which is to be introduced into the rivers of the
country.
Glass reinforced with wire has been shown by
the tests of the British Fire Prevention Com
mittee to be really of great advantage in resist
ing fire. Three openings were closed with wired
glass, and fire was applied for forty-flve min
utes, the temperature reaching 1902 f. but not
exceeding 1880. The new material is valuable
not only for the obstruction it offers to fire, but
for its reduced liability to do damage by break
ing and falling when used in such places as the
glass roofs of railway stations.
-
The 100 million stars usually supposed to be
shown by telescopes and photographs may be
taken as a maximum estimate. From counts on
photographs, Mr.. Gore gets an average of 4,137
stars per square degree in the Milky Way, 1,7s2
near the Milky Way, and 4Os in the nom galactic
regions. Combining these results with Prof.
chickering's, the grand total of stars is found to
be 64,lS4,757. Stars too faint to photograph
would increase the number, as would also clus-
ters, one of which has 25, 900 stars per degree.
f(H x1uU H.