The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1900-12-01
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.

SCIENTIFIC MISCELLANY.
A Slow-Burning Floor-Portable Cannon
Artificial photographic Stone-A New
Attack Upon the Aurora Borealis-A
Modern Experiment Plague
Among Rats-Nutmeg Manufacture
The Greatest Earthquake Country.
A so-called fire resisting floor, constructed as
required by the London County Council, was
lately tested by British fire engineers. The floor
was of X-inch straight joint planks, laid upon
FIR joists by 2 inches in section and 12K inches
between centres, with ceiling beneath of 4
inch understanding. Wood illets nailed along
the joists inches above the lower edge sup
ported layer of concrete between the joists
inches deep. The floor had an area of 100 square
feet, and was loaded with bricks to 100 pounds
per square foot. In Is minutes after a fire was
lighted under the floor, the wooden ceiling was
entirely consumed. The flame did not penetrate
the floor until the end of 81 minutes, causing the
floor to crack at the end of 60 minutes, and to
collapse completely in SO minutes. The joists
were found to be burnt and charred for 2 or TX
inches up from the bottom, but otherwise sound.
s~s
A new Belgian gun, adopted by the State of
Congo and expected to come into extensive use,
a shell weighing 3.3 pounds, using charge of
TX pounds of black powder or 3X pounds of
cordite Its essential popularity is that it can
be taken apart for ready carrying by men or an
finals to places inaccessible for ordinary artil-
lery. 1t forms a load for nine men, the dis
mounted gun being assigned to three, the wheels
to two, the cheeks to two, the pointing screw
and duplicate pieces to one, and the equipments
to one. Other men carry ammunition, box of
ten cartridges weighing 81 pounds, being load.
-
A tree census just completed in the province
of Saxony, Prussia, shows total of H. ,46l
fruit trees. Of these, 52.7 per cent. are plum
ts0os 1870 apple trees 100, sweet cherry trees,
and 1913. pear trees.
Some Photographic dry plates have been tried
after keeping Is years. The constituencies was
considerably lessened, but the plates were still
useful except those that had been packed in con-
tact with paper. The latter were hopelessly
logged.
An imitation photographic stone lately paten-
ted in England consists of plate of zinc coated
with stony compound. The zinc is first pre-
pared by cleaning and placing in a solution of
potassium bicarbonate, which causes layer of
zinc carbonate to form upon the surface. To
this layer the stony material firmly adheres.
The material is a mixture of sulphate of lime,
calcium chloride and aluminium oxide, produced
by the action of hydrochloric and sulphuric
acids upon limestone and aluminium, and given
the yellowish tint of photographic stone by little
ferric chloride. The mixture, with the addition
of solution of soda, is sprayed by an injector
upon the prepared zinc.
-.
The appearance of great spots on the sun has
been attended bY remarkable auroral displays
on earth, telegraphic and other magnetic instru-
ments being at the same time affected; and the
auroral activity has been found to coincide with
the sunspot cycle of little more than eleven
years. These facts indicate that the electrical
condition of our atmosphere is in some way de-
pendent upon the sun. Though the problem
has received much attention. it is still one OF
the great unsolved mysteries of our planet, and
DR.. Paulsen, of Copenhagen. hopes to throw
some light upon it by an exhaustive study of the
aurora in its home in Iceland. Systematic OBJ
servations with modern instruments are to be
made at the village of Akureyri and on neigh
boring mountain, the two stations being connec-
ted by telephone.
The problem of high-speed railways is being
theoretically attacked in Germany. A review
Of traction systems makes it appear that the
speed limits with steam must be lower than
with electricity. that the Heilman steam-elec.
trio locomotive has proven unsatisfactory, that
the accumulation system has yet many faults
and that the present most promising system il
the ordinary one of supplying current from cen
trail stations to motors on the cars. A German
society, now building an experimental line Of
nine miles, is to devote its entire capital of $685.
600 to a study of the question.
~.
Galvanism is used by DIR. Friedlander of Wies
baden, to reduce pain and swelling from insect
bites. the negative pole being placed over the
wound.
The de struction of rats by bacteria has beer
a subjectNof experiment by NJ. J. Danysz, of the
Pasteur Institute of Paris An epidemic dis
ease having been noticed in field-mice, its germ
was sought and was found in a bacillus of glob
ular shape. This micro-organism has been care
fully passed through long series OF repeated
cultures in mice and rats. The result hss beer
an increase of virulence until the fnaLcultur,
proved to be sure death to rats~i6 laboratory
trials, and this has been followed by attempts tt
and other places. Reports from several hun
bred localities have now shown a complete dis
appearance of rats in SO per cent. of the case
and greatly reduced numbers in 30 per cent
while in 20 per cent. the method has failed.
sFs
Connecticut, as 1.-THE wooden nutmeg State,
must look to its laurels. Belgium counts
among its industries the manufacture of arti
fetal nutmeGs, which are found to consist o.
Underground extracted or injured nutmeg
mixed with about 20 per cent. of mineral sub
stances and are said to be so cleverly made al
almost to defy detection, especially when mixet
with genuine kernels. The imitation can be de
tected by various tests. On being cut the ker
nels lack the well-known plant-like structure
of the genuine, they become soft when soaked
in boiling water, on being burned they leave
about IS per cent of ashes instead of the usua
or 8 per cent, and they are heavier than thu
genuine.
1t appears that earthquakes are about twice
as frequent in Greece as in Japan when area ii
considered. A catalogue of the National Obser
vatory at Athens shows that 3,l87 earthquakes
were felt in Greece in the years 1898 1898, and o.
these 2,0lS were recorded in Zante alone. The
shocks were more numerous in April and May
than in any other months.
A"s
The new incandescent lamp flament of S. B
Husselman consists of a thread of asbestos
upon which is fused a compound of aluminium
and iodine. Tho process of manufacture II
claimed to be simple and inexpensive, and II