The ring was a complete puzzle to Galileo, most of all when the planet
reached a position where the plane of the ring was in line with the
earth, and the ring disappeared (December 4th, 1612). It was not until
1656 that Huyghens, in his small pamphlet _De Saturni Luna Observatio
Nova_, was able to suggest in a cypher the ring form; and in 1659, in
his Systema Saturnium, he gave his reasons and translated the cypher:
"The planet is surrounded by a slender flat ring, everywhere distinct
from its surface, and inclined to the ecliptic." This theory explained
all the phases of the ring which had puzzled others. This ring was
then, and has remained ever since, a unique structure. We in this age
have got accustomed to it. But Huyghens's discovery was received with
amazement.

In 1675 Cassini found the ring to be double, the concentric rings
being separated by a black band--a fact which was placed beyond
dispute by Herschel, who also found that the thickness of the ring
subtends an angle less than 0".3. Shroter estimated its thickness at
500 miles.

Many speculations have been advanced to explain the origin and
constitution of the ring. De Sejour said [6] that it was thrown off
from Saturn's equator as a liquid ring, and afterwards solidified. He
noticed that the outside would have a greater velocity, and be less
attracted to the planet, than the inner parts, and that equilibrium
would be impossible; so he supposed it to have solidified into a
number of concentric rings, the exterior ones having the least
velocity.

Clerk Maxwell, in the Adams prize essay, gave a physico-mathematical
demonstration that the rings must be composed of meteoritic matter