The citizen. (Frederick City, Md.) 1895-1923, 1897-01-15
Written for the Citizen.

the island of the black and brown rats
that were destroying the sugar cane
and other crops, the mongo0se was
brought from India in 1872. The re-
suit was disastrous. The mongoose
multiplied with fearful rapidity, de-
stroyiug the rats, then preying upon
poultry and even pigs, lambs and pup.
pies, and APP arently discriminating
the birds, with the harmless lizards
and snakes that had kept down the
ticks and other troublesome insects.
1t devOured the crops of fruit and vege-
tables and even rivalled the former
ravages OF the rat in its destruction of
sugar-cane. With the disappearance
of the reptiles, the ticks increased
alarningly, not only swarming on cat
tie, but becoming plague TO the hui
man race, and these with the mon
goose has long held the field in the
strange battle for supremacy A new
phase in the strug gle is now reported
y
the Museums Of Jamaica. In recent
months the mongoose has been notice.
ably fewer i'll numbers, and those
caught have been found to he suffer
lug from attacks of the ticks. Species
of birds and reptiles supposed to have
been eXierminated have reappeared.
The most striking change seems to he
the abundance of the ground lizard,
recently supposed extinct, hut snakes
are more numerous, game is incIeas
ing, poultry aud domestic ANIMALS are
molested less often, rats are increasing
in the cane, and ticks are diminishing
The dynasty of the mongoose is wan
ing, the Cause, however being un-
known.
A report of the Forest Conservator
of Weet Australia shows that timber
is abundant. Nearly all Australian
woods, however, are more remarkable
for durability than ease of orklng,
the kauri pine of New Zealand being
the only wood of Australia compare
bile wi h the pine aud fir timners of
Europe aud North America. The
principal South Australian timber
is the jarrah, of which the colony has
S,000O00.
Waste gases from blast furnaces at
Horde, Germany, are TO lie used in gas
engines, which will drive dynamos for
light and power.
The idea of electric signalling with
out wires is said to have been first sug-
gested III letter III the Mechanics
Magazine of December 30, 1887. Steln-
hlll, regarded in Germany as the in
vcntor Of the telegraph, directly after
ward recognized the p ,ssibllIty of tue
plan, but only in recent years have ex-
perinlents met with any degree of sue
cess, and even these have thus far Of
ie ed little Of practical value. The
new system OF Signor Marconi, a
young Italian electrician, now gives
promise of better results. At least it
has met with favor from Mr. Preece,
the expert of the British telegraph de
partment, who declares that it will
be July tested without regard to ex-
pense. The system, it is stated, de-
ponds on electrostatlc effects on electric
waves of so high rate as 250 UOU, 600
be projected in the same way as those
of light, and can be refracted and re-
fi-ctei, aud, indeed. made to exhibit
all the phenomenon OF light. In this
system no wire on each side is neces.
sary as in system already tried. vi
brations are set up by one apparatus
and received by the otber-he secret
being that the receiver must respond
to the humber of vibrations of the
transnitter. Both sets of apparatus
are carried in ordinary -looking boxes.
Marconi's invention includes nov ell
and beautiful devices not yet made
public, and by means of these, making
practical use of the waves first gener-
ated hy Hertz, vibrations set in motion
in one box ring bell,in the other, ex-
p,riments thus far having proven sa Is
factory up to two miles. 1t was Lord
Kelvin who dubbed The invention "the
electric eye" Concerning which Mr..
Preece says, a great deal of noi sens
has been written. Mr.. Preece believes
the apparatus will prove successful,
and give to navigators new friend, rs
warnings OF dangerous rocks Can be
given by day or night in any state of
weather.
A magnified phonograph record was
exhibited by Prof. M'Keudiick during
a recent address to the Edinburgh
Royal Society. The vibrations occur
ring in half a second were spread over
a length of 20 feet, aud showed that
any word is collection of musical or
other sounds running rapidly INTO each
other, the musical sounds of the novels |
predomiuating. "Consta u tinoplen
shows 700 to 800 vibrations. No word |
can be read from the curves, and two
if ever be alike.
By thermo-electric methods, Hol- |
man, Lawrence and Barr have found |
that copper melts at 109ho Cent; silver,
at 300; platinum, at 1852, and alumni
mum, at $500.
Whether memory is purely me-
chanical process or not, it has curious
analogy III the "hysteresis" that causes
a magnet to retain an impression of a
previous different magnetlzanon, and
In other phenomena of similar kind,
Through this principle it is even pos
sible-theoretically at least-to make ad
doll that would remember that its I
hand had been burned! Suppose, says
Prof. Reginald A. Fessenden, a mana- {
kin TO be so constructed that on being
held to candle wire spring in its
head would cause its hand To be thrust
into the flame, aud, after heating, 10 be
withdrawn. Such a toy is simply an