, 1869-08-14

These quantities are Complementary 70 each
other: that Il, the lepgth OF each wave, multiplied
into the number 0! vibrations IN each cnsc, gives
constant quantity, SO that the actuhl velocity OF
light Ia the samo whether 1t pfotccd " q
Unit Of wh,to light, or ~ separated
intO the prisWnuc cOlors. hut IT. H
easy to understand that tho individual wares
sirskc the rcsrac,tng medium tthc prism, with dit.
Ierrnt lntcns!tfes thus tho red xavc Ii the long
est, and tho most 1nnahtrc, and therefore may ra
t!onnlly ho s4pposed to be the icaRt l1ntlc to TO
turned out Of !t8 rrnTtons path. We mad this TO
: be the case, md VIC also nnt that the violet or
shortest ray, !s tho very one Of tho series whl;h
Is most bent In its passage through tho prlsm ana
thrown tho spectrum !urthest nom tho place It
would have occupied II not twisted out Of IT.
course by thu Intervening Elass,
Whrn the different clements arc burned on tho
carih1 surface, they combine with different qusn-
titles Of oxygen Tar, and, therefore, burn With dt
fen III tntca.ltlca Of light In other wos11r. she
viblntory movements ef their constituent atoms
arc s;lCeErns IN each ca.r. They arc, undoubtedly,
different nl.o, II sat In motion Iy any other aEcbcy
than that which Effects their conversion Into
o1ydc1, or ac!da, iu The act Of hnrnlnE.
Win differing intepsitiea Of atomic motion. The
vibration OF the rays which arc Ihns set In motion
will 1.so vary 10 each case, and hence those Fays
atnkc the prism with force which Is the samc nj
nl Zines for the s2nc body hut not the ZANE for
dircrent GotlIcs and the lines produced by them
In the spectrum will occupy definite positions.
Where several lines are produced by one body. VIC
have hut parallel to the plurality Of colors IN
white light
Mcst Of the lines on the solar spectrum are
dark, whence II has been thought that the SUBJ
stances Indicated BY thelz presence present an cI-
oeption to tho highly heated condition Of The solar
atmosphere. The probability Is, however. that
they are simply dark hy comparison. being really
luminous, Just Ike the sun epots, which afe CON-
posed ol aEErccauons Of gaseous matter; the LAT.
ter Are dark wheu seen on the sun & facc. but Ted
when viewed at the edges Of the lDmtnalJ, during
tot1l ecllpse-
We hare spoken Of these substances As "burn-
tp2.H but ths process teRily involves the yoatzs-
tlon Of the elements examined. In making eI-
ptr1aents on elementary bodies Within our reach,
for the purpose o! establishing the positions OF the
tines In the spectrum, It Is necessary 10 reduce
them TO state Of yspor. which can be done In
the Of the least Volatile metals By the use OF
the electric battery. We conclude that the sub
stances shown 10 exist IN the Eun1 atmosphere,
afc there in similar STATE Of lncaDdesccnt y3por.
We ndrnls 1has this thepTg Ia opeuito the ohjec-
tlou that We Judge only hy an RoRJ II the spectral
analyst, and that 1t Is impossible to tell how fat
conditions Of which We have no knowledge, may
vitlAte the deduction. But II Mugt be rcnem-
bercd that we Judge qualsiy tn most cases BY
fnalogy. We say that ceza!n substance On the
Garth IS piece Of Iron, E1mpls because tis Quad-
ttet, 80 far as We arc able TO tuoge1 arc
the same az those Of fonc other piece OF matter
which ne have agreed to call irln. Ii With. this
We remember that the phcnone1a Of combns-
tIor. when vieM cd with scientific eye, Are the
least ltaote to be mistaken OF any OF the
phenomena by which We judge the Identity Of OBJ
jects va shall see that there Is but little anget Of
beIag mistaken Ia our deductions from the spec