When it had vanished from sight, Evelyn turned to Captain Raymond, exclaiming, "O sir, will you not point out Forts Mercer and Mifflin to us when we come in sight of them?"

"With pleasure," he replied. "They are at Red Bank. Port Mercer on the New Jersey shore of the Delaware River, a few miles below Philadelphia, Fort Mifflin on the other side of the river on Great and Little Mud Islands. It was, in Revolutionary days, a strong redoubt with quite extensive outworks."

"Did our men fight the British there in the Revolutionary war, papa?" asked Grace.

"Yes; it was in the fall of 1777, soon after the battle of the Brandywine, in which, as you may remember, the Americans were defeated. They retreated to Chester that night, marched the next day toward Philadelphia, and encamped near Germantown. Howe followed and took possession of the city of Philadelphia.

"The Americans, fearing such an event, had put obstructions in the Delaware River to prevent the British ships from ascending it, and also had built these two forts with which to protect the chevaux de frise.

"The battle of the Brandywine, as you may remember, was fought on the 11th of September, and, as I have said, the British pushed on to Philadelphia and entered it in triumph on the 26th."

"Papa, what are chevaux de frise?" asked Grace.

"They are ranges of strong frames with iron-pointed wooden spikes," he answered; then went on:

"In addition to these, the Americans had erected batteries on the shores, among which was the strong redoubt called Fort Mercer, which, and also Port Mifflin on the Mud Islands, I have already mentioned. Besides all these, there were several floating batteries and armed galleys stationed in the river.

"All this troubled the British general, because he foresaw that their presence there would make it very difficult, if not impossible, to keep his army supplied with provisions; also they would be in more danger from the American forces if unsupported by their fleet.