The Knife Quicksilver

(Title from this, which I neither understand nor truly wish to. Post is otherwise unrelated.

Well, except insofar that I have been making another attempt to re-read Hitherby, a thing which always inspires into me a mad and fervent desire to write.)

It occurred that the sun set, and did not rise; the night continued without end. Elsewhere, on the other side of the world, the sun rose, and thereafter remained stationary; a natural transition applied between these area. It became, nonetheless, a matter of some concern for all and sundry.

"What shall we do?" the people cried out. "In the regions of eternal day, it grows terribly warm, moreso by the moment; in the lands of night, the chill is ever-increasing. (Furthermore, it is difficult to see.) Shall we move to the lands of twilight, there to gain some modicum of respite?"

The scientists considered, and met, and studied the matter; and their spokesperson gave her judgement on the matter. "There must be constructed an instrument," she declared to the assembled journalists of Earth; "a long thing, a sharp thing, a knife to sever night from day. And there will be a terrible price - " but the price was paid, and the knife was made, and they named it Quicksilver. And the knife rose skyward, and descended, and in its passing there was a change; and once more the sun moved, and day turned to night turned to day again; though those who had lived through those times claimed that it was never again so steady, so reliable in its passing, as it had been before those events here described.

But -

- what then became of the knife?