The Stark County Democrat. [volume] (Canton, Ohio) 1833-1912, 1900-06-15
SCIENTIFIC
MISCELLANY.
Something About a Slow Burn
ing Floor.
ARTIFICIAL LITHoGRAPH STONE
A New Attack Upon the Aurora Borealis-
A Modern Experiment-sprea
Plague Among Rats Nutmeg
Manufacture.

"a SV-Cdiltu hIt ItSlStlh6 hooIs Noh-
structed as required by the London
county council, was lately tested by
British fire engineers. The floor was of
* inch straight joint planks, laid upon
fir joists by inches in section and 121s
inches between centers, with ceiling
beneath of Is inch match boarding.
Wood fillets nailed along the joists two
inches above the lower edge supported
layer of concrete between the joists
inches deep. The floor had an area of
1000 square feet and was loaded with
bricks to 100 pounds per square foot.
In fifteen minutes after fire was star
ted under the floor the wooden ceiling
was entirely consumed. The flame did
not penetrate the floor until the end Of
54 minutes, causing the floor to crack
at the end Of 60 minutes, and the COL
lapse completely in So minutes. The
joists were found to be burnt and
charred for 2 or ga inches up from the
bottom, but otherwise sound.
A new Belgian gun, adopted by the
state of Congo, and expected to come
into extensive use, weighs 515 pounds
with the carriage, and throws a shell
weighing 3.3 pounds, using charge of
~ pounds of black powder or SA TBS
of cordite. It's essential popularity is
that it can be taken apart for ready
carrying by men or animals to places
inaccessible for ordinary artillery. 1t
forms load for nine men, the dismoun-
ted 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 a
load.
A tree census just completed in the
province of Saxony, Prussia, shows a
total of 1893, 461 fruit trees. OF these
52.7 per cent are plum trees, 1876 per
cent apple trees, 1858 sweet cherry trees,
and 1913 pear trees.
Some Photographic dry plates have
been tried after keeping Is years. The
was considerably lessened,
but the plates were still useful except
those that had been packed in contract
with paper. The latter were hopelessly
logged.
An imitation photographic stone lately
patented in England consists of plate
of zinc coated with stony compound.
The zinc is first prepared by cleaning
and placing in a solution of potassium
bicarbonate, which causes a layer of
zinc carbonate to form upon the sur
face. To this layer the stony material
firmly adheres. The material is mix
t,,,- 90 nj ho 70 pf lima q lnit1fn phln-
ride, and aluminium oxide, produced by
the action of hydrochloric and sui
phuric acids upon limestone
and aluminium, and given the yellowish
tint of photographic stone by little fer
ric chloride. The mixture, with the ad-
dition 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 instruments being
at the same time affected, and the auro-
raj activity has been found to coincide
with the sunspot cycle of a little more
than eleven years. These facts indicate
that the electrical condition of our at
mosphere is in some way dependent
upon the sun. Though the problem has
received much attention 1t is still one OF
the great unsolved mysteries Of our
planet, and DR.. Paulsen, Of Copenha-
gen, hopes to throw some light upon II
by an exhaustive study of the aurora In
it's home in Iceland. Systematic obser-
vations with modern instruments are
to be made at the village Of Akureyri
and on a neighboring mountain, the two
stations being connected by telephone.
The problem Of high speed railways is
being energetically attacked in Germa-
ny. A review Of traction systems makes
it appear that the speed limits with
steam must be lower than with electric
ity that the Heilmann steam-electric
locomotive has proven unsatisfactor
that the acumulator system has yet
many faults, and that the present most
promising system is the ordinary one OF
supplying current from central stations
to motors on the cars. A German soci-
ETY., now building an experimental line
of nine miles, is to devote its entire cap
ital of $375,000 to study Of the ques-
tion.
Galvanism is used by DR.. Friendlan'
der, of Wiesbaden. to reduce pain and
swelling from insect bites, the negative
pole being placed over the wound.
The destruction Of rats by bacteria
has been a subject of experiment by
M. J. Danysz, Of the Pasteur institute
Of Paris. An epidemic disease having
been noticed in field mice, its germ wa,
sought, and was found in bacillus o.