The citizen. (Frederick City, Md.) 1895-1923, 1895-12-27
Written for the CITIZEN. }

and 1t frequently happens that severa
dams must be built In series one be
hind another. A portable pneumatic
safety dam, intended TO shut off the
fire quickly and effectually, was exhib
tied recently at German Miuing Con
gress 1t is the invention of R. Wag.
ner, of Michalkowitz, Upper Silesia
and three men eau quickly put it in
place, completely closing any level of 8
sectional area of not more than nine.
tenths Of that of its own. A more sub.
stautial dam of brick or wood can al
once be erected before it. The apparo
tus consists essentially of bag of air
tight material supported on frame OF
four legs, with double-acting hand bel
lows for Initiating. The whole folds
into small space when not in use.
Many difficulties have been encOun-
tered in the production of peat coke at
the works at Elenhult, Sweden, but it
is believed that satisfactory results will
be reached. With experience, the
method of working has been improved.
The air-dried peat is carried by rail to
the works, where the more fbrous
matter is removed for textile purposes,
and the remainder is crushed and car
ried automatically downward through,
six pairs of cylinders heated by peat
powder. The temperature increases
downward to white heat in the bottom
cylinders. The peat is only partially
cooked, but thoroughly freed from wa
ter, and is finally ground to dust. The
cost of this fuel is now little less than
$500 per ton.
The study of earth-worms is of re-
cent date, yet at least rs genera are
now known, some containing 100 spe-
cies. They range in length from an
inch to four feet. Their colors are mo-. T.
~ unattraciive, but one species is a fine
peacock blue, and one is green and
pink.
Tallow soon becomes acid and unfit
for purposes of fabrication. Neutral
grease is In great demand in all the in
dustries, and NJ. Nlllon, the French
Chemist, remarks that this is readily
produced by distilling different fats
with lime, as was first recommended
by him in lSSS, the Americans having
pro1ted already 10y the suggestion.
This distilation OF oleic acid gives a
body called olene or is alone of Marga-
ric acid, a margarone: of stearic acid,
stearone. These bodies are neutral, do
not become rancid, do not saponify
and behave like mineral oils without
the same Inconvenience. The disiil-
lation of 200 pounds of oleic acid with
% pounds of lime gives $50 pounds OF
OF neutral oil. With tallow and other
fats are obtained neutral oils of differ.
ent consistencies, and rendering OF
20 per cent. can be relied upon. These
neutral greases resist all chemical
agents except chlorine gas, which
does not exist in free state in the in.
dustries for which these lubricants are
designed.
Tha growth of trees at different times
of the day has been a subject of expert.
ment by Mr.. E. H. Thompson, the
Government entomologist of Tasmania,
who has contributed his results Ia
hnOWtedge. Measurements were taken
as far as possible every three hours.
Of the total growth, 81 per cent. was
attained between the hours of and 8
a. M; l. per cent. betwesn a. III. and
noon; none between noon and 8 D. III.
none between and p. M; II PEI
cent. between q aud D. M; 81 Der
cent. betwe cen 8 and II p. NJ; and So
per cent. between midnight and a.
IN. The greatest growths in twenty
four hours were banksia rose, 6! inches;
geranlum, 81 inches; waffle, 4! inches;
apple, q inches; pear, IL inches.
A novel method of silverlng mirrors,
which has been patented in Germany,
is based on the fact that when one of
the heavy metals forms the cathode of
vacuum tube, containing a trace of
hydrogen, this metal is volatilized py
the current, and is deposited as firmly
adherent and highly polished layer on
the walls of the tube. The mirror pro-
duced is OF much greater brlliancy
than any formed in the usual way.
Twenty years ago, states Mr.. J..
HERSHEY Fowler, it took 124 tons of beet
root to produce ton of sugar; but by
careful selection of the best roots for
seed, only s! tons are required to do
the same now.
The lighting of ordinary railway cars
by electricity has been for some years
practicable on trains that are never di-
vlded, but il is claimed that the new
system OF Mr.. Arthur b. Gill, now be-
ing introduced by London firm, is
the first 10 solve the difficult problem
OF giving each car its own Independent
electric light plant. The electric gen.
orator and a storage battery are placed
under the floor of the car, taking up
40 useful space. The dynamo is driven
by belt from pulley on the car axle,
and Is SO arranged that train speed
OF 10 or 20 miles an hour gives sufficient
current TO light the car, while any in
crease beyond this current ana the
small surplus necessary TO charge the
storage battery is prevented by the
slipping of the belt. AS the train speed
falls below that required to enable the
dynamo to feed the lamps, an auto.
matte switch turns on the current OF
the storage battery. The variation in
the intensity of the light supplied is
said to be surprisingly small, the dy.
namo aud switch are SO carefully pro.
tected from dust as to suffer little weal
and to need little attention, and
the extra load all the locomotive does
not exceed ! horsepower per car. The
cost is estimated at about $3.50 for each
car. A considerable number of Eng.
lish railways are already lighting 81 n.