National Republican. (Washington City (D.C.)) 1872-1888, 1872-12-04


science. Some simply oontented themselves with
what had been found out and others were busy
with the problems Of smother world, and looked
win lofty scOTn upon all that concerned this one.
Seneca spoke Of the bending Of a stick when
thrust In water but the reason for II he never
presumed TO know. In 100 Al Hasan, Roger
Bacon and the Polish philosopher NltelllA made
great advahcesNn science, while TyCho Brake
became aware that certain things were found out
only by precise measurement. Kcplor came
after him DesCartes explained how the rainbow
was produced, and always In particular angle.
Before proceeding to his experiments he spoke
Of the rlstlnR Of iron rs simply the combustion
Of Iron, and II was his impression that the FIRST
Atlantic cable was destroyed by Tustlng, as there
was no way for the escape Of It's heat. Iron could
lie then executed his frst experiment with
small battery Of ten cells the poles Of which were
put In circuit by q thick wire. The wire was cut,
ann when the ends were brought near each other
very powerful and luminous light was the
result. They were then connected by small
platinum wire, which, rs the electrical current
passed through became white hot" and as the
brighter and brighter until Il fused and fell apart.
Two pieces OF carbon were then rendered lncan-
descent by attachments the ten cells, and the re-
SUIT was brilliant and hOty-burning star
lie created similar star hut q thOusand-fOd
brighter one by the attachment Of the two pieces
q carbon TO the full battery Of sixty cells. The
htth experiment was that Of the Image Of the
lncandescent carbon points themselves.
Points about quarter Of an inch square were
attached TO the wires aud brought In contact,
producing light so fierce and brilliant that II
could not be looked upon. A short tube, possibly
three Inches In diameter, one end Of which was
covered with tln-fOll, with small hole prcked
In u, was placed over the OTinCe Of the lantern,
and then the points were LUMINOSITY shown on
the screen, and then by pricklng several holes In
the tn-foll the screen was covered with the
bright points, which shot up and down IKE ne
scntlllatiOns Of ar aurora; then by taking the
on the screen.
The Professor now nterposed lens in the
lantern, and single bright and beautiful photo
graph or image Of the carbon points was revealed,
surrounded by magnificent halo. As the lens
was gradually contracted the halo disappeared
and the points remained. lie very ucldly and
Interestingly explained how the halo was caused
by the lmperfeCtiOn Of the lens, the cause being
technically known as spherical alteration. He
next proceeded 10 Illustrate the law OF perfect
equality between the angles OF incidents and re-
Election. This was done by setting a beam Of
light On mirror, TO which lath or rather index
the mirror. II was very beautifully executed.
The angular velocity Of the beam as reflected
was proved TO be twice that Of the mirror itself,
ddy shown byihe 1se Of prisms Of water Siass and
sulphlde OF carbon, A beautiful colOred spectrum
was revealed on the screen. Newtons expert
ment Of sending beam OF light through circu-
lar aperture and decomposlng It by means OF a
prism was repeated and then II was reCompOsed.
A long spectrum was thrown upon the screen by
the use Of two bl-sulphate carbon prisms. Differ
ent-cOlOred batOns were held In the spectrum,
giving Interesting proofs Of the TefraCtiOn OF
light on different cOOr. A clear synthesis was
made by wheel made up Of seven GOlors; when
II was rapidly reyOlved II seemed entirely white.
A fine purple color was next shown, produced
by passing white light through a solution Of pO-
tasslc permanganate. Upon analysis this gave a
spectrum containing red and blue rays, showing
that It's color was mixture Of these, and due to
Its power OF transmitting such rays and absorb
ing Others. Thus the color OF q body Ia deter
mined by the light which escapes absorption.
TWO nFiamg unltpl 10 obtain n lnTup
spectrum, and the lecturer brought forward two
sticks, one red, the other green. Now, why Ii
red red7 The color Is sometimes ascribed IN
popular works to Its supposed reelection Of red;
but as commonly understood this statement Is
wholly erroneous, since the light reflected from
the outer surface Of colored body Is precisely
That which falls upon II.
The truth is, that part OF the light which
falls upon surface punges beneath II and passes
20 and fro. During this stay beneath the sur.
face certain rays are distracted from II and
quenched; those which are finally rejected by
the substance determining It's color. This Is
what happens with white light. But suppose
green light falls upon the red stick. This light
being qucnchcd by red the stick appears black,
This was proved by experiment The red stick
retained its color In red or white light, hut lost
II In green. SO the green stick was black In red
light, but recovered Its hue In white or green.
This property which bodies have OF sitting light
explains an erroneous idea, which still holds II.
ground that blue and yellow make green. This
y true Of pigments, but not Of COlOred lights
When blue and yellow pigments are mixed, be-
tween them they absorb ali the rays OF the spec,
trum save green, and that color appears. But
blue and yellow light produced, when thrown to-
gctheT on the screen, clear white.
They are then Complementary COOrs; thai
name being applied 10 any two cOlOrs which
when mingled form white. Now solar light Ia q
very complex agent. The bodies upon which II
falls silt Us rays AMI produce various cOlOrs
Finally, we have brain and eye to study them
The light ut starting Is complex, the bodies upon
which Il falls are complex, and to study II botf
brain and eye must he complex. whence thu
cOmpleNlty when simple mechanism might sui
I nce7 There Is prOdlgalty In nature, aud seem
tngy for the purpose Of letting us see Oblech
/ ROBBED In beautiful COlOrs, we are endowed moi
[ only with faculties 10 enjoy the useful, but alsl
I 10 appreciate the beautiful and the true.
The lecture throughout was Of absorbing In
! tercst, aud oil the experiments and teaching
were male so clear and simple that n child cOult
understand them, However, II the old gentle
man, who was hugglng and talking with youni
, girl all the time, will keep away from the mex
lecture, those who were annoyed by him vii
feel thankful.
The next lecture will be delivered Thurs la!
evening at Lincoln hall.