Montgomery County sentinel. [volume] (Rockville, Md.) 1855-1974, 1926-12-17
MOONS OF JUPITER
BEHAVE LIKE OURS
u. of w. Astronomer Makes
Interesting Discovery.

Mount Hamilton, Calif-At least
three Of the moons Of Jupiter, like the
moon of the earth, rotate once on
their axis in the same time that It
takes them to make one revolution
around their parent planet, declares
DR.. Joel Stebbins, professor Of astron-
omy at the University Of Wisconsin,
nov working at the Lick observatory
here.
Doctor Stebbins is making use Of
the twelve-inch refract1hg telescope o.
the observatory, and q photo electric
photometer by means Of which the
light from a star, planet or moon IL
focused on film Of metallic potas-
stun. This results in q minute cleo
trio current which can be measured
with a delicate galvanometer, and 80
the brightness Of the object can be
accurately deterpiined
Cut OH Juplter's Light.
The chief difficulty IS In keeping the
brilliant light from Jupiter itself of
the cell, but Doctor stebbina has over
come this by the use Of a small dia-
phragm with hole through which
the light from the satellite can shine,
but not the planet. However, satellite
I, the nearest to Jupiter, Is too close
to be measured even with this
method.
Measurements have been made Of
II, III and ". All Of these satellites
were discovered by Calico 10 1910,
and can be seen with a small tete-
scope. In addition there are dYe
others, but these require a large IN
strument to make them visible.
Moons II, III and ~ take three
days. thirteen hours seven days, tour
hours and sixteen days, eighteen hours
respectively, to reyolve around Jupi-
ter and Doctor Stebbins finds that The
variation Of the light Of the frst two
at least also follow these periods,
This, he explains, is probably due 10
their being bodies like our moon, and
unequally bright over their surface,
so that as a greater or less area OF
the bright surface is exposed to the
earth their light is greater or less,
because this Is largely reflected sun
light
Compares Light With stare.
In order to check the photo-electric
cell, Doctor Stebblns compares the
light Of the satellites with nearby
stars. whose light is constant, and he
suggests that this may be used as
possible check on the variation Of
sunlight. Direct measurements Of sun
light vary greatly because of varia-
lions in atmospheric conditions, but
since these would affect alike the bril-
liancy Of the satellites and Of the
comparison stars, a variation In the
difference between satellites and stars
would indicate an actua! variation OF
sunifS$=
Duchess of Fontdnses
Marie Angelique, duchess Of Fon-
tanges, was the successor to Nine
Montespan In the favor of Louis XIV.
"She was beautiful as an angel, but
silly as a goose" said Able Cholsi Of
her. She, nevertheless, captivated the
affections of Louis XIV, who was tired
Of Nine. de Montespan.
As soon as she had discovered the
passion she had inspired In the king,
she became naughty and extravagant,
spending at times as much as 100000
crowns a month. She became the gen
eral dispenser of the kings favors and
the model of fashion. She was made
a duchess BY the king, but did not long
enjoy the rank, since she died at the
age of twenty, In the abbey of Port
Royal, at Paris.-Chlcago Journal.