Line 4 - For in the arc of the Staff of Time’s Scythe even the form of the thrice great Hermes falls in its wake.

I believe that the subject of this line has also been covered by the late monthly clues:

"December 2nd 2010
Draw a circle around hermes using his feet as the edge"

"January 3rd 2011
Draw a square around time using his back as the edge"

So now the book is referring us to the first image in the book, with "Time" and Hermes.

Historically speaking, "Time" is often equated with Saturn, and Hermes with Mercury.
Alchemically speaking, Saturn is the last of the planets out from the Sun (understood in the classical manner of 5 planets: Mercury, Venus, Mars, Jupiter, and Saturn) and Mercury is one of the 3 philosophical principles of Alchemy. Saturn is known as the keeper of Time, as his passage through the heavens was the slowest, as well the figure was often depicted as an old man. But also, in this sense, as a keeper of time and a figure of old age, Saturn was also considered by some degrees the ruler of Death, thus he wields a scythe.

Mercury is the principle that brings "3 worlds together", in that he is a figure that can "travel" through them all. Mercury is a metal, therefore a material substance, therefore to Earth. Yet, as a fluidic metal, it is also related to the transitory liquid state of Water. And yet finally, as a conductive substance, it has the ability to transmit electrical energy thus associative to Fire.

Yet philosophically speaking, Mercury is symbolically tied with mental attributes, such as reason and applied logic. However, he is also, as a ruler of mind also connected with the ability to realize the other aspect of it; the subconscious.

The original drawings of this image usually always show Saturn threatening to cut off the feet of Mercury. If Mercury is thus the substance which can connect the lower worlds with the higher worlds, perhaps it is thus the figure of Saturn, of Time, which is the influence that stops his flight to the other realms.