Line 4- Thus it was through the dreams of these damned beasts that the secret prize entrusted to Abraham can be discovered again.

Line 4- "Thus it was through the dreams of these damned beasts that the secret prize entrusted to Abraham can be discovered again."

"Dreams of these damned beasts":
I know others have claimed that the damned beasts represent the 3 figures on the mount in Image #2.  I'm not disputing this.  
But since it comes right after the mention of the Promethean Serpents and the King of Terrors, it would be obvious to consider that it is through their dreams the secret prize can be discovered.  

There is also a connection with "Dreams" when it is mentioned later, through Joseph, as it is stated that he is able to  "...read could he the messages of dreams sent from the topless mount of Olympus."

Dreams are an obvious connection the the idea of the subconscious.  To be able to read the stream of subconsciousness would suggest that Joseph was connected to the type of mind that was intuitive, symbolic, and automatic; perhaps even psychic or clairvoyant to a degree.  

Joseph was the one who placed the silver cup in the sack of Benjamin.  It is said that the cup was used for divination.  Joseph is a descendant of Abraham (Great, Great grandson, it appears) , so as it is later described as an "heirloom" in the text, it would follow that it was something passed on down the line.

The Silver Cup placed the Benjamin's sack:
The heavenly body associated with Silver is the Moon. The moon wold be another connection with the realm of Lunar/Female reason, or the subconscious mind.