senting a direct demon- 
stration of the fact first 
found mathematically, 
that the ring system is 
composed of disjoined 
particles. In the spec- 
trum of the planet Ve- 
nus the absence of in- 
clination of the lines 
shows its diurnal rota- 
tion to be exceedingly 
slow, which confirms 
the early observations 
of Schiaparelli and Dr. 
Lowell who found its 
day and year to be 
Jupiter, September 23, 1914. To the left of the planet is seen a Bs , 
small round bright spot against the sky. This is Satellite Ill. It has equal. This causes Ve- 
just crossed the face of the planet. On the extreme right of this face nus to present always 
(the left of the photograph) is its shadow just entering on the disk. h 
It denotes an eclipse of the sun taking place for Jupiter at that point. the same face to the 
Some distance to the right of the planet is shown another round bright sun. The d ay ot 
spot. This is Satellite I, soon to transit the disk and cause another if : 
solar eclipse. This plate, securing both planet and satellites on such a Uranus was unknown, 
scale and definition, is, as far as known, unique 
photographs where exposures of as 
much as thirty seconds were required, 
attest to the exceptional atmospheric 
conditions existing at Flagstaff. 
Although less picturesque than the 
direct photographs, the spectrographic 
observations are just. as replete with 
revelations. After the light from a 
celestial object has passed through 
the prism of a spectrograph, many 
important facts are disclosed concern- 
ing it which would be impossible to 
learn by other means. It is from 
spectrum analysis that we obtain 
much of our knowledge of the density 
and constitution of planetary atmos- 
pheres; of the motions, constituents 
and the states of stars, comets and 
nebule. The spectrogram of the 
Saturnian system shows the lines in 
the ball spectrum and those of the 
rings to be oppositely inclined show- 
ing that the rate of revolution differs 
for each part of the rings, thus pre- 
212 
due to the absence of 
any marked _ surface 
Saturn, December 23, 1912. It is as seen in a tele- 
scope magnifying about 1400 times, thus covering an 
area approximately 200 times that of the moon to the 
naked eye. Cassini’s division is the dark gap separat- 
ing the two bright rings. The inner or crépe-ring is 
visible where seen against the ball of the planet. 
Saturn’s belts are a counterpart of Jupiter’s; both 
planets are in a ‘‘youthful chaotic state, swathed in 
cloud”’ : ar ? 
