The labor world., 1904-08-06

('fTO1n -Cae rCNeWaY oTks1I1ouue:$ $E4ME ai
Tas earshs stmosPhss,s enXsloRs ! Is
like .2a storage battery or zLeyden. Jar:
In different localities, however the
character. and intensity of the charge
is not always the same. Besides, even
In q single place the conditions are not
uniform, but undergo variation Though
the study of this phenomenon has not
yet had any important practical result,
meteroloeists have hoped that event
ually they might thereby obtain a
number Of useful clews. -. ;
Several forms of instrument have
been devised for the purpose Of meas
ur1ng the intensity of atmospheric
electricity. What is known as the wat
er dropper, an invention OF Lord KEEL
vim, has given more satisfaction than
any other, perhaps, but it does not
meet all the necessities of the work.
For this reason experiments recently re-
ported from France possess special in
terest. They were conducted at an OBJ
servatory in Pare st. Maur, under the
auspices of Director Moureaux, and
with the cooperation Of Professor and
Nine. Curie, the attempc was made to
see if a small quantity Of radium,
suitably inclosed and placed in the
usual elevated position above buildings
would not give the desired results.
In the center OF thin copper disk,
slightly over an inch ard half in
The radium was put in the cavity, and
a bit of aluminium soldered over it.,
so that the radfum was hermetically
sealed. From this device copper wire
extended downward, like that from a
water collector. and the usual electro
meter was attached to the lower end.
to indicate by it's movements the
strength Of the current. For purposes
of comparison the old type Of instru-
ment was placed beside the new, each
having it's own wire and electrometer.
The experiments were made with
three different specimens in succession.
The first had been made in 1899, and its
activity was not known. It did not ap-
pear to be sufficiently sensitive though
and hence was replaced with a second
one. This had an activity of 5000 times
that Of uranium. It worked no better
than the other. Strong fluctuations in
the electricity would affect it percepti-
bly,, but feeble ones did not. Finally,
bit OF rad1um was used whose actfv-
ity was 10000 times as great as that OF
uranium. The third specimen rivalled
the water dropper in sensit1veness. The
two instruments kept close together in
all their Indications.
After eight months the last mentioned
specimen seems to be as powerful as
ever, though the combined action of
the rad1ations from it and the weather
hurt the cover plate of aluminium. At
the suggestion Of Professor Curie, the
cell has been covered with several
coats Of the best coach varnish, in
place of metal, and the new method
Of protection is effective. In the hope
that some cheaper material than ra-
dium may be found to work equally
well, further experiments are in prog
ress.
Radium possesses several advantages
which make 1t superior to the agencies
formerly employed for measuring at
nospheric electricity. The most i'm
portant is that it will not freeze. Hence
it can be employed on mountain tops
and in the Arctic regions, where in
tense cold prevails. The record obtain
ed thereby is not interrupted, as is that
Of the water dropper, where dust gets
into the fluid and checks its flow. The
new apparatus can be more easily
raie than the old to high levels above
tree and buildings-a considera ton
which will be better appreciated when
it is remembered that, elevation is es-
senttals7to the proper working of any
apparatus # q. test atInosphe hericS electric
fty: The new device requires much less
personal attention to keep its III order,
and practically no expense. for main
tenance