New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1905-09-01
ECLIPSE DISSERTATIONS.

At nearly all points where the astronomers
were prepared to observe the eclipse Of the sun
last Wednesday the weather was favorable 10
their plans. Until the photographs OF the corona
which were secured have been developed and
compared both with each other and with trust
worthy records obtained on previous occasions,
their significance cannot be fully learned. Many
minor facts must be supplied, too. for the inter
probation Of the new pictures, Without knowl-
edge of certain details 1t will be impossible to
explain the discrepancies which are already be-
ginning to appear.
1t is reported from SPAIN for instance, that
the corona appeared to be almost circular, es II
has been two or three times before at maxi
mum Of spot abundance, On the other
hand dispatches from Tunis and Egypt say that
streamers were seen, and these have been re-
garded as characteristic Of the minimum stage
of solar activity. OF course, II the dlscordant
announcements are based mainly on visual OBJ
servations, little Importance need be attached
to them; for in the days when drawings were
the only pictures of the great solar envelope
which were procurable there was mystifying
and astonishing lack of harmony between
sketches made by experts simultaneously. More
over, even photography will sometimes tell more
than one story. Plates differ in sensitiveness-
Astronomers use lenses that are greatly unlike
in focal length and other properties Again,
the length of the exposure may vary from TWO
or three seconds to nearly a minute. The inner
portion Of the corona being much more brilliant
than the outer, it Is customary to choose in ad-
vance which Is to be depicted; for it is almost
impossible to represent both in q satisfactory
fashion on the same plate, and one part must
therefore be sacrificed to the other. Until the
photographs obtained on Wednesday are studied
In the light of half dozen incidental facts no
safe differences can be drawn from them.
The camera is not the only instrument which
the astronomer is using to solve the problems
presented by the corona Good pictures may help
him discover the forces which arrange Its ma
terial in the form Of tufts and steamers and
project some Of 1t to distance Of several mill
ions of miles But he wants to know something
about the composition Of that material as we'll
The spectroscope is primarily chemical detec-
tive and it has already proved Of service to the
student of solar physics. Still, its testimony is
tantalizingly imperfect third piece Of appa-
ratus which has only recently been employed
during an eclipse is an exceedingly delicate Their
mometer perfected by Professor Langley. Five
wears ago an attempt was made with this device
to measure the heat emitted by the corona near
its base. Inasmuch as the temperature indi-
Gated by the test was only little higher than
that Of the shaded side of the moon (where
water is supposed to freeze a repetition Of the
experiment has been deemed necessary before
drawing conclusions. For the kind Of research
in question however this apparatus had prob
ably never before been tried. If. therefore,
fresh use Of it has been made this year. an an
of the result should prove excep-
tionally interesting.