New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1877-04-16
SCIENCE FOR THE PEOPLE.

test-naner is now sold in Paris, by which
the artificial eoloring of wines can be readily oe'ec
pipped in unauthorized wines the paper becomes he'
blue and dries OF lead cOlor If anne color Is III INC
wine, the paper becomes red; II eochiheai' Vioie.'
a,derbcrry Juice. green If ogwood or the hke dark
brown and so ON with variety Of nctures and results
huUdre9thousaadth part OF magenta can be detected:
The inventors of the teStpaper are sad 10 nav ma
devised for extracting the fraudulent coio's "
leaving the wine pure
A new cement for glassware has been dis
covered by Prof. Schwarz. which is said to nave the
quality of being unaffected by boiling water III iS "o
free from an other Objectionable feature of china ana
glass cemcnts rs il does not dsure by adark line along
the junction The method of making this cement twicn
must be used when frosh) is to add 10 hVe parts VI
solution OF gelatin part of solution OF ac ehfo
mate OF lime The articles, after the broken surfaces
have been emitted with this cement, must be exposed 70
strong sunlight for few hours; and mean Nhlc slou ne
Sram n NIrc or a string 4 fracture thus repaired in
glassware is said to be hardly rerccpibie'
Prof. A. X. Eaton of Brooklyn, widely known
rs the inventor OF an improved pccroscope' describes
I'm The Aaaeroan Chemist curious fact about Iceland
SPAR Hitherto the statement has been currently mace
and accepted that the axis of the crystal is inc only
direction along which there is no dpay OF the curious
property Of the sparOube refraction Wishing 10 Cd
tain the widest possible divergence OF the two rays rom
the SPAR Prof Eaton cut it in planes perpendicular 10
The axis of the crystal and To his great surprise instead
of getting separation OF the rays ne Iouo ho
doube rcfraction perceptble Finally he cut crystal
In the form of sphere and, by experiment upon 10 as
certained that the tw images OF the ray are superpoed
OIL each other so as to make no double reiracon not
only when he passes through the axis Dnl al,o ~
plane direction pcTlchdlcutf
the From Prof Eatons diagram It anpeals 'tao
the greatest divergence is 10 be attained ny pssIs
raN through angle Of 40 to the axis OF the cI!
The fact decidedly important III the use OF the poal-
scope.
Few events in the history of chemistry have
produced more profound sensation than did the pro-
duction of azarn, in 1850, from artificial sources
Some readers will doubtless rccocct that there was at
one time supeIstitiouS belief that the chemist WOi
never be able to pass the barrier which separated the
live from the dead world in respect 10 the products OF
each. 1t was laid down law IN chemical textbooks
in the early part of this century that science could not
construct organic products out OF inorganic materials
That barrier had been already broken down i'll several
places when Gr;ibe and Lebermann described their
method OF making ahzarin-the colorng principle OF
madder-by treating anthracenc, substance obtained
from gas tar with acids and akaes which transform IT.
But artificial alizarn more than chemical cum
osity; it was a matter of commerce; 1t changed
the course Of trade and industry. Great dis
tricts in France, Asia Minor, and Holland
had been for centuries gwen mp the production OF
madder The vegetable product was now found unable
TO compete in price with products OF the chemists
art But after running the madder-rowers tie makers
of artificial azarn have themselves suceumbed TO mis-
fortune One chemical company III Germany engaged III
this business reports the exhaustion Of almost all its cap
ital about S7O00OO; two others have lost every
q private firm engaged in the manufactue mas ,lc;i
after heavy reduction Of assets. Dr FREDERICK Ncis-
man reviewing these results ascfibcs tue mis- oihh
to tl,c bo nrc of coal tan and the inferior quality Of
the anthrac,Ic furnished by the tar diStleis Abroad
well as here, the gas companies nave 2Ge ihh'
Orbitant profits; la TINS case thcy nave h40d SUM- u "
geese that laid golden eggs.