Benjamnin F. Butler, Butler's Book: Autobiography and Personal Reminiscences of Major-General Benjamin Butler

[748] falling where the explosion would be injurious to them. The line which a shell describes on being thrown for the purpose indicated, is a parabola of about two miles. I was familiar with this matter, for I had watched the bombardment of Fort Jackson, on the Mississippi, during the considerable part of a week, and thus made its acquaintance.

The first thing to do was to station a couple of well-instructed men at points from which every shell could be watched during its whole flight. These observers could tell after a little practice almost precisely where the missile would land, that is, whether it would

Bomb-proof quarters at Dutch Gap Canal.

come in our excavation so as to do harm or not. While the men were at work these men were on watch, and a shell being seen coming, if it was likely to fall in our way, the watchmen would call out “Holes!” whereupon the workmen would at once protect themselves by rushing into their adjacent and convenient bomb-proofs, to come out and resume their work again as soon as the shell had struck and exploded without harm.

If the shell was not to strike within the excavation or near to it, the watchers allowed it to take its course and the men were not alarmed.