The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-09-18
SCIENTIFIC.

Gum euphorbium has been found in Natal
to be an effective rust preventive, iron OBJ
Jects being free from rust even after two
years immersion in sea water.
The curious fact that corn, potatoes and
other plants thrive better when placed in
rows running north and south has been
proven by DR.. Wollny, of Munich. This re-
duces the shading by each other to mini
num- more uniform and regular light, heat
and moisture resulting.
The high price of ivory and the great
waste of its dust have induced an English
manufacturer to offer $500 for process of
so consolidating the dust that it can be
used for making handles. The belief is ex-
pressed, however, that, although fortune
doubtless would be realized, no process will
be found.
A German metallurgst, Herr Haedicke,
has devised a process for the direct tenn
pering of steel under pressure, only saws
and steel ribbons being treated thus far.
The tempering is accomplished by first
hardening the steel by plunging it red-hot
INTO cold water. or by plunging it into GER
tain chemical baths and then drawing the
temper. In saw-making the steel is first
hardened in oil or fat, and then, while still
hot, It is placed in press between hot dies,
and the temper is thus drawn while under
pressure, A special press is used, the Gle
being hollow and arranged to allow of the
circulation of steam or oil.
In recent address to pharmacists, at
toned about fifty products of synthetic
chemistry having medical Importance that
have appeared since 1880. Great progress in
similar line has been made with synthetic
esters and odorous substances Artificial
musk and vanillin have long been known 10
have the anyl, butyl and ethyl COMPOUNDS
resembling fruit fiavors, but more recent
are heliotropine (heiiotrope), ionone and
iraldine iviolet), cumarine (neW-mown hay)
terplneol (1lac), bergamiol (bergamoD. jas
I 1anl OH. gerahol roSe geranum), carvol
low not only used for toilet soaps but also
for the essences named after the flowers.
While the gold fields of the world cover
an area of more than 100000 square miles,
Mr.. B. J. Skertchley. an Australian geolo-
gist, finds that the fields of tin, which metal
is the most sparingly distributed of any OF
those in general use, occupy less than II 800
square miles. The area of the gold-bearing
ground is, therefore, 1872 times that yielding
tin Europe has seven tin districts, pro-
ducing about $500 tons yearly, OF which the
Cornish mines furnish about 5000 tons.
Asias two districts supply the bulk of the
worlds tin. One of them-the Straits Set
Elements and adjacent palities-turns
out $500 tons yearly, but the other-Hu-
nan, in China-is shown by official figures
to have an annual production of less than
$500 TONS although credited by some of the
best authorities with 10000 to 5000 tons. No
tin mine is known in Africa; no payable
one exists in North America. The only tin
region in South America-Bolivia and
Peru-yields less than 4,Oo0 tons a year. and
Australia furnishes about 5000 tons.
A new magician's slate, for exhibiting
spirit writing" consists of a grating of
tiEned iron wire, which is covered on each
side with an insulating sheet of mica, over
which is placed sheet of Russia iron, which
may be given a more slate-like appearance
by coat of mineral paint. In the usual
frame this cannot readily be told from the
ordinary school slate. Hidden conductors
pass from the iron wire to screw eyes in
the frame, and the cord by which the slate
is suspended on an easel is a wire connect
irg with other concealed conductors rum
ming. from a source of electricity. If a pow
erful current, like one for lighting, is used,
d safety fuse is placed in curcuit. The ma
g.cian lays a sheet Of paper on the slate,
places pen and ink on a little shelf directly
beneath, closes his cabinet about the easel,
and in a few moments his question of the
spirit is found to be answered by q writing
on the paper: The paper is prepared before
hand by writing the word or sentence re-
CURED with dilute sulphuric acid, the writ
ing being invisible until heated AS the