The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-01-30
SCIENTIFIC.

Minerals containing calcium have been
found to be brilliantly phosphorescent after
exposure to X rays, those containing metal
lie ores being, as a rule, nOnphosphores-
cent.
The best color for school exercise boards
is stated. by an authority, to be cream
white. with ordinary crayons of sky-blue.
and extra colors of canary yellow and
clear dark green Black is the worst of all
for the eyes.
The successful plating of aluminium with
copper has been announced by a German
named Wachwitz. Many objections to
aluminium are thus overcome, and the cop
per coating is so thin as not to add ma
terially to the weight, while the union OF
the two metals is so perfect that plates
may be rolled or stretched without peel1ng;
The copper-covered wires may be plated
with silver or gold.
Vaccination has received fresh indorse-
ment from the late severe epidemic of
smallpox at Gloucester England. DR.. Sid
ney COPELAND reports a total of 1873 cases,
with 434 deaths the mortality having been
4O.8 per cent. among the unvacc1nated ana
only 9.S per cent. among the previously vac
clnated. Only three cases, moreover OF the
507 accounted severe were among the Vaccl-
mated. The severity of the epidemic is at
| tributed to the large number of unvacci-
mated children.
Color hearing is found by DR.. w. S. Col
man to be of two kinds. In one a trans
parent colored film seems to appear in front
of the person on hearing certain sounds, as
those of the vowels, musical notes or par
ticular musical instruments. In the second
group each letter or word, when spoken or
thought Of is brought to view in char
acteristic color. DIR. Colman regards the
phenomena associated sensations,
analogous to Shivering at sight or thought
of an accident, or at the squeak of slate
pencil. The colorS are rarely the same IN
two individuals.
Curious results have been obtained by NJ.
Guillaume in experiments with alloys Of
iron and to IS per cent. of nickel, the OBJ
ject of the tests being to determine the
metal most suitable for measuring instru-
ments on account of permanence in length
under varying temperature A rule made of
an alloy OF % per cent of nickel, ana an
nealed, continued to elongate when kept at
q lower temperature. An alloy containing
y per cent. of nickel expanded on heating
with 81 per cent. of nickel the character OF
the metal was entirely changed, the alloy
scarcely expanding at ALL
Much of the danger attending. the use of
acetylene, according to Prof. Vivian b.
Lewes may be due to the making of the
calcium carbide from impure materials. An
appreciable amount of sulphur, phosphorus
or silica compounds in the coke may give
rise in the resulting acetylene to phospho-
retted hydrogen and similar gases liable TO
| spontaneous ignition, and giving off on
combustion products Injurious to health
and to fabrics. The pure acetylene can be
| decomposed abruptly into carbon and n.y.
| drogen by contact with detonator or by
| heat, the danger, however, being slight be-
| low two atmoSphereS of pressure, and
| greater the pressure is increased.
| A novel method of feeding plants grown
| in pots is credited M. Georges Truiffent
| French horticulturist The needs of the liv-
| ing plant are first ascertained by analysis.
| when the salts necessary for a certain num-
| Der of months are weighed out and formed
| into pill by Enclosure in metal COW
| ering, and the pill is planted in the pot
| The salts slowly diffuse through the metal
| without acting on it, such regulation or
| the thickness Of the metal and Solubility
| of the salts being said to be possible as to
! give pill to last either three or six months.
! 1t is not clear what advantages are expect
| ed to justify the expense of periodical anal
! Uses, but it is stated that large, well-cOl-
! ored plants are grown in pots of less than
! half the usual size.
| While alchemy has been revived in the
| United States the divining rod has gained a
| fresh hold in England. The mystery of this
| instrument is explained by Prof NJ. E.
Wadsworth, of the Michigan School of
| Mines, who has often shown his classes
! that If any tough twig fork is graSped
! with the palms upward, the branches en-
| tering the clenched hands from the sides
! farthest apart, the twig will bend down.
| ward whenever the grasp is frightened The
! harder the grip the more it must curve.
| Water or no water, mineral or no mineral,
/ the result must always be the same when
| the conditions are fulfilled; and it can be
| easily understood, Prof. Wadsworth adds,
! how an igonrant operator may deceive him
self and be perfectly honest in surprising
/ that some occult force and not his hands
| forces the fork downward.
The effects of sea water on metals 0Gr-
| ing prolonged immersion have been studied
anew in France, various metallic objects
| dredged from the harbor of Brest having
| been presented for examination. bronze
arquebus, supposed to date from the end
! of the sixteenth century, was found to
contain somewhat more than so per cent
or copper, about per cent. of sulphide of
! "copper" about 95 per cent. of tin and traces
| of lead, and the metal was in an excellent
| state of preservation. Such was the case
| also, it is recalled, with the bronze guns
| of the English vessel Mary Rose, which
| were recovered after being under water 292
| years. Cast iron shot found at BreSt how
| ever, had become so soft that they could
| be cut with a knife; but wrought iron OBJ
| jects were a little better kept, having a
| core of sound metal under the rust The
| same effects on iron were noted in the
| cannon of the Royal George after being
| sunk only sixty-two years.
| Five or six years ago so-called dark
meteors" were observed by M. Du Celliee
| Muller to cross the moons disc. Announce
| ments of this discovery were received with
much skeptcism by astronomers, some of
| whom suggested that the dark bodies were
| birds in flight, others that they were seeds
| floating in the air. and still others that they
| were particles of dust in the eyes of the OBJ
| server. Subsequent observations have prov
en- beyond all doubt. if we may accept as
conclusive q recent paper to the British
| Astronomical Society, by Mr.. Fritz Hop
man, that the objects are really bodies NOV
ing in spAAre outside the earth's atmosphere.
| The size of these bodies varies greatly,
| most of them appearing very small but
| crater, Tycho. and their apparent velocity
| also is very different for different meteors,
| the passage across the lunar disc having
| occupied a fraction of a second to three
| seconds. The dark meteCrs have been seen
! passing before the sun, too, in considerable
number