The sun. [volume] (New York [N.Y.]) 1833-1916, 1879-06-29
ProG Raad.. ChrnmntIc.

food.
Pref Rood's ChromatIes.
Among the changes wrought by modern
science there Is none more striking than that In
our exception OF the nature Of light. Where
the student OF hundred years ago saw across
the emptiness OF space. n sun which continual
ly sent toward our earth minute particles OF his
own luminous substance. the scientific mnu OF
to-day recognizes. instead OF intervening va
cancy. an iilimitable expanse of at,enuated
matter which ho christens ether and which,
pervading the whole universe and finely per-
meating our own coarser atmos phere offers a
continuous medium OF communication betweon
our world and other orbs. Hts researches have
| taught him that the enormous globe OF the su n
Is the theatre OF a ceaselcss fierce commotion.
passing our feeble powers 10 conceive and that
tho incessant movement taking place among
It's Infinitely small molecular constituents com
municatss itself 70 the surrounding particles
oil ether. and Is by them dirused with incrrdi-
BILE swiftness through space. The effect Is sim
liar to that by which a moving body in winter
gives rise 10 succession OF waves which
spread far beyond tho original source OF mo-
tion and the very small fraction OF the ETHEREAL
waves which strikes against our earth is known
TO us who dwell upon II rs the light and heat
| which we daily receive from the sun
From this altered view OF light have sprung
theories M to tho nature OF color radically dif-
ferent from those OF former times SO many and
so complicated are the phenomena connected
with this subject that the science OF color forms
adstnct branch OF physics. and Prof OGDEN
N. RooD OF Columbia College has Just published
work on Modern Chrondtics (Appleton A Col.
In which the most recent views In this regard
are elaborated with special reference 10 their
application In WOrka az arf md fpHuatrv
review OF the fundamental principles which
ProL Rood lays down will serve to show the gen.
eral scope OF his work. although for the practl-
caldetails with which IL abounds and which are
OF particular interest for all who are Interested
In art, wc must refer the reader TO tho book
itself.
Three-Quarters OF n century ago Thomas
Young. by many considered also the father OF
the undulatOry theory mentioned above pro-
pounded a theory OF ehromatics which. after ly-
ing comparatively unnoticed for many years. has
now been revived by men OF science. most emi-
nent among whom Is the physicist Helmholtz.
the greatest living expounder OF the modern
philosophy. These views are briefly ~ follows;
We are conscious Of tho ETHEREAL waves or yibra-
tons which we denominate light because in
one special organ. the eye. has been developed
both the mechanical apparatus necessary for
receiving and transmitting with extreme accu-
racy the rays Of light. and nervous tissue
OF such exquisite nneness that 1t is capable
OF appreciating ETHEREAL vibrations OF surpass-
ing influences As waves In water will vary
in character according to the nature OF the force
which originated them. 30 do the vibrations of
the ether vary in size and con parativo rapidty
Each minute elementary portion OF the re:ina
THE delicate nervous tissue which lines the in
terror OF the eyel IL supposed 70 be supplied
with three nerve hbrlls. ono more especially
affected by waves comparatively large aud slow,
which produce upon us the impression OF red
another by waves OF medium size aud qulckness
which to Ms look green. and third by waves OF
great minuteness and rapidity. which we see as
violet. II is demonstrated beyond doubt that
there are waves too slow and waves too quick
for our senses to apprehend. and that red and
violet limit on either hand tho range Of veloci-
ties which our eye is capable of translating
into light As far a. there isNny.nropriety In
calling any colors fundamental. red. green and
violet are the three fundamental colors, since
they alone can be produced by a simple sensa- |
ton OF single nerve 1bril. The belief !
hitherto generally accepted. and in many |
cases, still held by artists. that the three
fundamental colors are red yellow. and
blue. was owing to observation Of the
mechanical effects resulting from the mixture
OF paints, and has been disproved by the use OF |
pure cOlored lght In experimenting, BY the |
latter means the results are not liable to error, |
and often bear no resemblance to those obtained |
from the mingling Of material pigments. For |
instance, employing small, a pigment made Of |
ground gGsS4Aa-RiItLra OF certain shades of !
red and green gives dark green; tho mixture Of |
colored lights Of the same shades gives orange; |
purple and green In pigments give dark green |
in lights they make white; purple and blue |
green in paints make dark violet. while in col |
ored lights they give rise TO pale blue-Rreen.
The perception Of the intermediate colors is
caused by fluctuations of such a length that |
they stimulate two nerves at the same time. II |
waves OF light about 1-30 600 OF an inch long |
reach our eye. the rcd nerve is strongly stimu-
lated, and we see rod but let them become a
little shorter. the red nerve is no longer so vio-
lently excited while the green nerve begins to
feel a slight stimulus. and insensiby the red |
passes into orange II the vibrations continue
to be accelerated, the orange turns into yellow,
the yellow into greensh yellow. until at a GER
tain point the red nerve sinks into almost COM
plete inactivity. and the green nerve is excited
to its highest capacity. Let the acceleration
continue, and the green will change through
blush green, blue. aud violet blue to violet The
equal excitement Of all three nerves at once
produces white and the absence OF all stimula-
ton produces black.
The variety Of colorng which results from
the combination OF those different hues lie prac-
tcally unlimited. Two millions IL an inado-