Omaha daily bee., 1896-11-08

! heavens containing the moon and a planet
| and a bright comet, then the moon and
| the planet would instantly disappear from
| view. but the comet might still shine on.
| No doubt 1t would lose some of its bright
ness, and probably the tail would be to a
| great extent shorL of its original proper
lions. There would, however, be GER
| tain amount of cometary light independ-
| ent of the sun still forthcoming so that
extinction would not necessarily overtake
| the comet as It certainly would the moon
| and the planets.
The spectrosccpe not only tells us OF the
| existence of light intrinsic to the comet,
but its evidence goes much further; ii IN
| forms us actually as to what the very ele-
ments must be to whose presence in the
| comet tho light owes its origin. We here
| note the peculiar advantage OF the SPEC
| troscoplc methods of research. They de-
! tect special differences in the rays of light,
| thus often enabling us tc trace each differ
ent type of light to its source.
| DISCOVERY IN COMET RADIATION.
The first notable achievement in the de-
| termination of the peculiar character OF
| the radiation from a comet was made by
DR.. Higgins in 1868 He showed that some
| Of the rays OF a comet which appeared that
| year were indicative of the presence of the
| element carbon in the body of the object.
| In the case Of this particular element the
available information carried us somewhat
was the existence of the element demon
| strated, but the particular chemical com
| bnation In which that element appeared
was disclosed. BY its union with hydrogen
| carbon gives rise to an important series
| of compounds The substances thus produced
| are very familiar 1t need only be mentioned
| that the common petroleum, which we use
| in our lamps, is a combination of carbon
and hydrogen! The spectrum OF a hydro
| carbon, as one of these compounds is
| termed, Is of such a characteristic nature
| that ii can be used as a test to show whether
the hydro-carbon itself is present DR.. Hug
| gins compared the spectrum Of the comet
| now referred to with the spectrum of these
hydrocarbons. The identity between the
! two Spectra WAS noted and thus a splen-
| did addition was at once made to our knowl'
| edge. Subsequent research has confirmed
| the important discovery that hydrocarbons
are characteristic components OF many
| comets.
| For many years no. further important
addition was made, to our knowledge, of
the elementary substances present In
these wandering bodies. The light they
dispensed appeared to be partly the reflected
light from the sun, and partly the light
due to incandcscent hydrocarbons. But
in 1882 a great advance was made.
comet was discovered that year in Albany
by Mr.. Wells. At first this body showed
the bright continuous spectrum due to re-
Elected sunlight. while the Indications OF
the presence OF hydro-CarDOn were NANNY
confined to the neighborhood OF the nu-
cleus. After this interesting object had
adorned the heavens for couple OF months,
Doctor Copeland, now the distinguished
astronomer royal OF Scotland, discovered
bright yellow line In the spectrum indicat-
ing the presence OF sodium. This observa-
ton was of particular Importance inasmuch
as IL afforded at once direct evidence OF
the presence In these celestial wanderers OF
another element specially remarkable In its
terrestrial relations. An emphatic confirma-
zion OF Copelands discovery was presently
forthcoming 1t is well known that the
bright yellow line indicative of the presence
of sodium Is seen to he double when eN-
amined under suitable circumstances. As
the comet approached tho sun the charac-
terlstic sodium light became quite strong.
The nucleus glared with the distinct vel
low hue belonging to this element; and,
indeed, by altering away all other light IN
a process with which the spectroscoplst is
familiar an outline Of the head OF the comet
was obtained which WAS produced by sodium
light alone
SCOTTISH SCIENTISTS WORK,
To DR. Copeland and Or. Lolse at the
earl OF Crawford's observatory at Dunecht
we are also indebted for yet one mere i'm
portant addition TO our knO wledge OF the
composition Of these bodies. In the autumn
OF 1882 we were visited by another comet,
which must rank as one Of the most famous
OF these objects which have appeared during
this century. On the 18th OF September,
1882. the two astronomers l have named