The Wheeling daily intelligencer. [volume] (Wheeling, W. Va.) 1865-1903, 1870-02-14
PROFESSOR TYNDALL ON HAZE
AND DUST.
New and Interesting Experiments.

ANN
New and Interesting Experiments.
One Of the most remarkable and, per.
haps, one Of the most prolific discoveries
of modern science, says the EhR Mall
GdzcttC, was announced and described by
Professor Tynlall in lecture delivered ut
the Royal Institution on Friday, january
2lst. The subject of the lecture, which
WIS illustrated by series Of very Deauti'
iul experiments or demonstrations, was
the very familiar one Of dust and Dis.
raSc,' and It's object was u show the
probability Of M intimate connection be-
tween atmospheric dust anil epidemic dis
c:IScs. Everybody knows that whenever
Il direct ray Of sunshine crosses shaded
room its direction is made manifest by II
line Of apparent vapor. Looking ut this
yapOr, it Is seen to consist Of innumCrablc
particles Of dust which float in the ut
nospllcre and, catching and rejecting the
sunshine, are rendered visible
In the course Of some beautiful expert.
mCnts on the decomposition Of vNPOrs by
light, DR.. Tyndall found II to be essen
tinl that lie should get rid Of this floating
dust. lie strained the air through tube
filled with hits Of glass wGttCd with con.
centrntcd sulphuric acid, and through nm
other tube filled with bits Of marble wet
ted with CaustiC potash; he even made II
bubble through the liquid acid and the
potash solution, but still the dust particles
remained in il. lIO tried various other
ways of straining out this dust, hut none
of them succeeded. At length he passed
the mir on It's way to the tube over the
flame Of Il spirit lamp, and nj once every
particle Of the dust disappeared. 1t was,
therefore, organic matter, and the flame
hud burned il.
Passing the mir Il little moro quickly
over the flame, IL fine blue cloud appeared
in the tube-thc smoke Of the dust par.
tiClcs. The organic and COmbustible M
turC of these particles was discovery, for
they had hitherto been taken to he inOr.
gnniC and incOmbustiblc. Air was then
passed through Il tube which contained Il
roll Of platinum gauzc, and it wasi found
TINT when the platinum WIS cold, the dust
particles all passed through with the air,
hut that when It was made rGd-hOt, the
dust particles were NIL consumed. In this
case, too, when the air was forced quickly
through, u fine blue cloud of smoke up.
pGarCd, Just as in the experiment with the
spirit lamp. An attempt was then made
to burn the dust pasticles by the cOnccn-
trated rays ola cOnvGrgcnt mirror, hut Il
failed; tho PARTICLES iiittrd too quickly
through the focus Of the burning ray to DO
consumed byL
The next experiment was to put tho
flame OF n spirit lump in the rny Of light
which was revealing the floating dust. AZ
once the flame was seen to be surrounded
by wrc,lhs OF darkness, resembling in
tCnscly black smoke. On lowering the
flame beneath the beam OF light the same
dark masses were seen wrCathtng up
wards. "IhGy were at times, said DR..
Tyndall, "blacker than tho blacklist smoke
that ! have ever seen issuing from the
tunnel ota steamer, and their resemblance
to smoke was so perfect us TO lead the
most practiCed observer 10 conclude that
the apparently pure flame Of the alcohol
required but beam Of sufficient intensity
10 reveal its clouds Of liberated carbon"
But when IL rcd'hOt poker was placed UNI
der the beam the same black wrcaths
came floating through. A hydrogen flame
was next put under 1t, and tho whirling
masses Of darkness wrcathed upwards
more copiOusly than ever. The blaCkncsS
was therefore nothing but air from which
all dust particles had been burned out, and
which, consequently, contained nothing to
catch the light and reflect 1t TO the eye rs
the dust particles do.
Here, however, II difficulty came In.
The same effect was produced by u cop
per ball not hot enough 10 burn the dust,
md by flask filled with hot water. In
this case It WIS found that the air was
rarctied with the warmth, and us tho dust
particles were not heated TO the same
extent ii dropped them and tloNtctI up
wards without them. Other g'lscs, even
common coal gus carefully prepared so us
to exclude the dust particles, have tho
same black appearance when they cross n
ray which the dUSt.ladcn air renders
visible, and II coal gas or hydrogen he let
into the top part Of glass shade which
has been placed III u sunbeam or ray Of
the electric light, the line between the
dust.ladcn mir aud the gas Is rendered
visiblc-whcrc tho air Is, tho shade will
seem full OF the Illuminated particles,
where the ElS ia II will 0nUpnF absolutely