1 86 
THE GUIDE TO NATURE 
was given to it because only a lynx-eyed 
person could see it. It is full of fine 
double stars. Twelve Lyncis is a fine 
triple star. 
On another side of Ursa Major we find 
Camelopardalis, with thirty-six naked 
eye stars. This is not now in good po- 
sition. Other constellations surround- 
ing Ursa Major are Draco, Bootes and 
Leo. These are better known. Draco 
is faint. Leo and Bootes have only 
small parts of them joining Ursa Major 
and their brighter stars are distant. 
Thus LTsa Major is surrounded by 
constellations which are decidedly 
faint. This no doubt makes it more 
conspicuous than it would be otherwise. 
Venus, which has been conspicuous 
as an evening star, is now equally con- 
spicuous as a morning star. It is bright- 
est May 28. It is visible in the east 
before sunrise. 
ifi 
Jupiter Satellites. 
The telescope is believed to have 
been invented first by Lippershey in 
1608. In 1609 Galileo learned that such 
an instrument had been made, but no 
more. He then tried to reason out the 
means by which it would be possible to 
see distant objects, and soon solved the 
problem and made a telescope. His first 
telescope magnified only three times, 
but in a short time he made one which 
magnified thirty-two times. He made 
many telescopes with his own hands. 
Galileo did more than make telescopes ; 
he used his telescopes to study the 
heavenly bodies. He was the first to use 
the telescope as an astronomical instru- 
ment. Naturally he turned his tele- 
scope on the moon and planets first. 
The power of three showed little. At 
one o’clock in the morning of January 
7, 1610, he turned his higher power 
telescope on Jupiter. He saw the disc 
of the planet and three stars near it, as 
shown in Figure 2. The stars were near- 
ly in a straight line and rather striking 
in appearance, but Galileo thought of 
them merely as stars which happened 
to be so arranged. For no particular 
reason he turned his telescope on Jupi- 
ter again the next night. What he saw 
is shown in Figure 2. The three stars 
were now all on the same side of Jupi- 
ter and closer to each other than on the 
previous night. As Jupiter moves 
among the stars, he might move and 
leave the three stars on the same side. 
However, at this time Jupiter should 
have been moving in the opposite direc- 
tion from that in -which it seemed to 
move from the positions of the stars. 
Now thoroughly interested he waited 
anxiously for the next night. He was 
disappointed to find it cloudy. On Jan- 
uary 10 he found two stars again on 
the east and the third he supposed was 
behind the planet. Evidently the mo- 
tion of the planet would not account 
for these changes. The changes must 
be primarily due to motions of the stars. 
On January 11 he saw two stars in 
about the same positions, but one much 
brighter than on the previous night. 
Taking the facts together he conclude^ 1 
that there were three stars revolving 
about Jupiter. On January 12 he saw 
a star on each side of Jupiter and about 
three o’clock another appeared faintly 
on the eastern side. What wonder that 
he was observing at three o’clock in 
the morning! Who that had the slight- 
est spark of enthusiasm would not 
under these conditions? On January 13 
he saw for the first time the four satel 
lites, and his discovery ended. He con- 
tinued to observe the positions until the 
end of March. 
To those familiar with these bodies it 
seems strange that he should not have 
seen the four at the same time earlier. 
They may be seen about three-fourths 
