The Portland daily press., 1896-03-13
DISCOVERY BY LIGHT
Solar Corona Photographed in
Broad Daylight.
CATHODE RAYS FROM sun SPOTS.
Bearing on the knowledge of Meterologi.
cal Conditions.

cal Conditions.
| Close upon Prof. Roentgen's sensation
al discovery D. &. Packer Of South Bir-
| mingham, England, annonoes another
that has much similarity to it, though
| the cathode rays of which it treats pro-
| coed from that great res ervoir of electric
energy-the sun. Mr.. Packer has since
July last been photographing the SUMS
corona in broad daylight. The results of
this photography are said to be SO re,
markable that Mr.. Packer has withheld
them from the public till this late date
that he might test them thoroughly; and
it is not until now, when he is con-
WINGED that his discovery is real one,
that he makes announcement of it to
his brother astrcon omers.
The suns corona as IL we'll known.
can be seen only during total solar eclip-
ses, when it shines out in soft, silyery
beams all around the dark body of the
moon as she crosses the SUMS disk. It
has been the hope of astronomers that
some way Of effectively blocking out the
SUMS glare might be discovered. 30 that it
| might be seen or photographed in ordi-
nary times; but till recently all such
efforts have met with little success. Now,
apparently Mr.. Packer has succeeded.
| The method is simple enough. 1t has
long been known that thin metal foil,
or metal films deposited on glass, will
let strong light through, though in ordi-
nary thioknesses the metals are extreme
ly Opaque. Packer has now discovered
that the rays that do succeed in getting
through are the Photographic rays, in
which the corona is very rich, while the
solar disk, with all its glare, has rela-
lively few of them. He, therefore, sim
ply photographs the sun through one of
these films, and gets a picture of what
in broad daylight.
VALUE OF THE DISCOVERY.
The Importance of this to astronomers
may be imagined when it is known that
they have not yet decided what the coro-
ma is. Probably most of them agree that
it is an envelope of very thin matter sur
rounding the sun, and shining either by
reflected light or electrically. But it
is hard to find out anything about q
thing that can be seen clearly only once
in two or three years, and then for but a
| few seconds. Now, however, the corona
| and its changes can be observed from day
to day, and probably Mr.. Packer has
seen more of it in the past few months
than have all the other astronomers of
the world since the dawn of time.
Packers first photographs were tax en-
| with a camera of four-inch aperture,
| through screens of tin and lead foil and
| sheet copper. Later he substituted pin
| hole for the camera lens, with great adj
| vantage. He made three or four pictures
| at time, some with the lens, and some
ment of detail showed that the pictures
| were real, not the result of some reflection
Or refraotion in his instrument. This
was an important point to prove. since
his brother astron omers would be sure to
suggest that such remarkable results
were probably unreliable.
The photographs thus taken show that
the streamers of the corona are very
closely connected with sun spots. Every
| sun spot has its own ray; wherever a
prominent ray shoots out in the corona,
a big sun spot is sure to be found at the
bottom of it. The corona changes, too,
with the number of sun spots. This ac-
| counts for the conflicting accounts Of
observers at eclipses no two of whom
ever saw the coorna of the same shape
and size. The reason is now seen to be
| that its shape and size depend on the sun
| spot from which its rays spring. Many
of the most prominent rays are twisted
| OF spiral-a surprising fact never before
| noted. and at present inexplioable.
ELE CRITICAL IN IT'S NATUR RE.
hut the most interesting gpart of the
new discovery is the announcement that
| it definitely proves the corona to be cleo
trical in its nature. II this is so, every
sun spot must be vast center of cleo
| trical disturbance, sending out visible
rays into space. The similarity of these
| to the much-talked-of cathode rays will
| at once attract attention, and the an
"a ouO 0ioOOtCEy, COluluR DIS
| it does close upon Prof. Roentgen's, is
something of coincidence.
Many astronomers have long believed
the ooronal steamers to be electric, and
have compared them to those of the
aurora; but while the aurora is more
like the glow of a partially exhausted
tube, the corona is like the cathode rays
of highly exhausted Crookes tube
Prof. Bigelow, of the Weather Bureau,
has often pointed out the likeness be
tween the curves of the ooronal rays and
those of electric or magnetic lines of force,
such as those in which filings arrange
themselves when sprinkled over mag
net. He thinks that they ultimately
reach the earth, here they profoundly
affect the weather, originating cyolonic
storms, cold and warm waves. etc. The
discovery of Mr.. Packer may thus put
at our disposal the machinery for study
ing the causes that lie at the root of all
our changes of weather. We can already
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