Prompting is a participle.

The latter action must certainly be open to the ugly suspicion of treachery, but he had as his excuse that the city was under martial law, and that prompt and vigorous measures might be the means of saving more bloodshed in the end.

The margin of water was just opening, but so prompt had been the movement of the men that it was not yet wide enough to permit the vessel to go any further; and it was found necessary to wait until the passage was sufficiently wide to enable her to move ahead.

If his tongue had been as prompt as hers, he might have said that "temporizing" was doing things by halves; but he let her have the last word.

Now So-and-so is naturally prompt and, having had some experience with you he knew you were not; so when, he having arrived fifteen minutes ahead of time as it is his nature to do, you came tripping in fifteen minutes latesmiling confidingly as you excused yourself (he, having spent the half hour in cultivating a grouch at you for not being as prompt as himself)he, of course, looked sulky and answered shortly.