Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1867-06-20
PROFESSOR TYNDALL ON THE SUN.

PROFESSOR TYNDALL ON THE SUN.
Professor TyndaIl recently delivered the last of
the series of Christmas juvenile lectures at the
Royal Institution, London, choosing for his subject
the phenomena of Spectrum Analysis" The
object of the lecture and experiments was to
explain the principles which Of late years have en-
abled men to ascertain the metals and other sub
stances contained in the sun. There was q crowd
ed attendance. Professor Tyndal began by ex,
planning that light travels in waves. l. he Obtained
slice Of white light, by means of slit in front OF
the electric lamp, and decomposed, or ''unrolled,"
this ray of light by passing it through prism. He
further took small glass wheel, painted with all
the colors of the spectrum and threw magnifed
image of it upon the screen. When the wheel
was made to revolve rapidly, all the colors disap:
peared, because they were thrown into the eye all
at once, and white circle Of light apparently oc-
cupied their place.
The lecturer then explained that the only differ
ence between the colors is the rapidity Of their
waves, the red being the. slowest, yellow, green,
and blue coming next, and the violet the quickest.
Colors of objects depend therefore, not so much
upon the substaces as upon the light which tails
upon them.
Professor Tyndal then showed how different ig-
nited vapors threw off different rays. Silver was
placed. between the carbon points Of the electric
lamp, and the rays of the ignited metal, when de.
composed by o prism, threw brilliant bands Of
green light upon the screen. Zinc produced red
and blue bands, and it was proved that each met
al, when ignited always throws out its own rays,
and none other. These facts having been clearly
proved, Professor Tyndal threw the spec trum Of
the electric light upon the SCREEN and interposed
the fame of burning sodium in the path OF the
rays. The fame cut black band out Of the yellow
part of the spectrum on the SCREEN leaving all the
othercolors untouched This simple experiment
gives the clue to the method by which the
substances In the sun are ascertained. The sun,
vast molten mass, represents the electric light In
the experiment. The photosphere, or burning
luminous atmosphere of the sun, represents the
ignited vapors placed in the path Of the rays. As
the sodium experiment proves that ignited Vapors
''tend to absorb the rays which they themselves
emit" the vapors in the photosphere of the sun
absorb certain rays. Consequently, by the aid Of
good prisms and screen upon the the surface Of
the earth, numerous black bands are seen in the
solar spectrum, and those black bands correspond
exactly with the spectra of many known metals.
Hence it is known with certainty, as Prof Tyndall
stated "by us DOOR crawling insects upon the sur
face of the earth, that iron and seven or eight
other metals exist inthe sun. In spectrum analy,
sis proper, a screen is not employed, bpt slice OF
light is thrown upon a prism, and decomposed
rays are examined by the aid Of telescope point
ed at the prism; by good instruments made In this
way, several thousand dark lines in the spectrum
of the rays of the SUN have been seen and mapped.
The sodium experiment closed the lecture, which
was listened to with attention, and warmly applau
ded throughout.