Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1899-03-10
Notes on Science and Industry.
New York SUM-


The statement has recently been made
by Professor Cleveland Able, before the
American Philosophical Society, that some
observers have seen the aurora DO
reals light in such positions between
themselves and neighboring objects as 10
demonstrate that the aurora, IKE the
lightning may be entirely confined TO the
lowest stratum; others have seen 1t so
located among the clouds that us origin
must be placed at or below their leVei,
and, therefore, within a lew thousdhu
feet Of the earths surface On the olhei
hand. those who have calculated the
attitudes Of specific beams By trlgohohle-
trical or equivalent methods nave de-
duoed heights of twenty TO hundred
miles. Or. Boiler has even quoted an
altitude Of 1913 miles Professor ADpe
remarks that after reviewing the Whole
subject since the time OF Hailey' he mus
thar all methods agree in one fundamental
ss,,mntion-namely, that the observed
heoms and arches have an Individual ex-
istence and a definite locus, an assump-
tion however. which is negatlved by the
eoual frequency of negative and POSITIVE
parallaxes wherever the paraliaN method
is applied. The only conclusion assumed
as possible is. therefore that the oD-
ser,ers do not see tho same object, partly
because
nartlv because Of optical Illusions.
Additional tests have been made by DR..
Russell, the London physicist and photo
grapher. in exhibiting the ability or GER
tain substances TO photograph themselves
in the dark. Experiments by him with
sundry metals woods, especially II char
red. oils. and substances containing them,
have only confirmed their power 70 i'm
press an image OF their form ana lines
upon a Photographic plate. II leit IN con-
tact with Il or at a little distance IN front
Of ii. in a dark room, for a longer or
shorter time. Various salts OF uranium,
that have been kept under such condition $
for two years, have proved as active IN
their effect ct the end Of that time as at
the beginning. Experiments also at dilfe-
rent temperatures with various sub
stances have shown that the higher the
temperature the more rapid is the action
upon the plate, so that at an ordinary
temperature for example, the words upon
a scrap Of newspaper--the ink containing
a drying oil-prirt themselves legibly IN
two weeks; at a temperature or III degrees
L. the Image IS clear IA five hours,
Vegetable oils have proved especially ac-
tive in Photographic themselves
According to German authority-Gluk
Auf.-the fact that the locust tree attains
i'm twenty-five 70 thirty years the same
thickness as the pine In nifty and the cak
I'm 100 years has led TO some valuable in
yestieations as to the Industrial value OF
this variety Of wood; the conviction was
narticularly strong on the part OF /.
Kausch that acacia wood has an impor-
tant future, especially as regards its
employment for mining purposes. The
same timber is also found 10 excel in the
propartles OF firmness and durability, and
is therefore, well suited for many other
mechanical uses, such as wheels, bungs
ladder steps. &c. IL Is well known. of
/ course. that the tree in question thriyes
IN the poorest soil. even in the rubbish
| of stone quarries and slaty declivities.
watch OF remarkable perfection u
| described In the London Times, its dis
| tinction resting OH the fact OF rs having
| inst gained the Kew certificate OF Glass
| A Especially Good" with the extraor-
| binary high marks OF ssh out Of a possi-
bic 100. To win the latter watch would
| have to be absolutely perfect as time
| keeper. result admitted 10 be scarcely
within the range OF practical achieve
ment. This watch. an all English pocket
| chronometer, has a meaa variation OF
| daily rate amounting 10 only one-thrd OF
| a second. and the mean difference be-
| tween the extreme gaining and losing
rates to four seconds. The makers attri