... the gleams of day that leaked/leaked up round the edges ...

[constantinusphilo]

And the night that encircled them, absolute as it seemed, was itself only a spurious unity, being modified by the gleams of day that leaked up round the edges of the earth, and by the stars.
A Passage to India by E. M. Forster
Any difference if I said just 'leaked'? Or is 'up' added to mark the completion of the action?

 

[emsr2d2]

"And the night that encircled them, absolute as it seemed, was itself only a spurious unity, being modified by the gleams of day that leaked up round the edges of the earth, and by the stars."
A Passage to India by E. M. Forster

Would there be any difference in meaning if I said just 'leaked' no question mark here or is 'up' added to mark the completion of the action?

Note my changes above. "Up" gives us the direction of the leaking.

 

[Skrej]

'Up' is also reference to the sun rising, as if the light is coming up from below the horizon.

Omitting 'up' invokes far less imagery.