Stanza 3 Summary

Get out the microscope, because we’re going through this poem line-by-line.

I think of cinemas, panoramic sleights
With multitudes bent toward some flashing scene

OK, so where were we? Oh, right: transience, things passing out of view, things like ghosts.
These ideas lead the speaker to an imaginative "leap" – he thinks of the movies, a relatively new technology at the time this was written.
Images from movies are also like "ghosts," lacking in substance, passing quickly.
Crane gives a very suspicious, almost paranoid description of the act of watching movies.
The movies are like a trick, or "sleight." You probably know the expression "sleight of hand."
Movies are shown on wide, "panoramic" screens.
A "panorama" is also a relic of the 19th century – a circular space that shows some scene (like a battle) as it progresses. The "trick" of a panorama is that, by moving in a circle, you think you are moving forward in time.
Crane describes anonymous "multitudes" of people bent towards the screen like mindless drones.
The movies promise a "flashing scene" – Redemption? Paradise? Escape? But the viewers never arrive at the expected scene.

Never disclosed, but hastened to again,
Foretold to other eyes on the same screen;

The movies are not a complete experience. Like the elevator from line 8, a movie "drops" the viewer before revealing or "disclosing" its secret.
New viewers enter the theater and are "hastened" to the same dead end.
Something is "foretold" to the viewers, like a prophecy. What is the prophecy, and how does it relate to the cryptic "flashing scene"?
The prophecy is not fulfilled, it is just told again and again to other eyes or, thinking in puns, to other "I's".