chark

Gimblet folded the letter carefully, replaced it in the envelope, and handed it back to Mr. Chark.

Sir Gregory and I, Mr. Chark, were on our way to see if she had been heard of at the hospitals, at the moment of your arrival.

Or perhaps your friend Chark would rather think that I was given to poisoning my relations?

But with the "chark" the result was nearly as certain as when flint, steel, and tinder were employed for this purpose.

Another suggestion is that it is connected with “chirk” or “chark,” an old word meaning “to make a grating noise.”