Intended as the west curtain of the never-completed Fort Constitution, "the . . . battery is a straight line constructed by Mr. Romans, at very great expense; it has fifteen embrasures, which face the river at a right angle, and can only annoy a ship in going past; the embrasures are within twelve feet of each other; the merlons on the outside are but about two feet in the face, and about seven feet deep, made of square timber covered with plank, and look very neat . . . . Upon the whole, Mr. Romans has displayed his genius at a very great expense and to very little publick advantage."
The powder magazine, located in the northwest corner of the battery, was destroyed with the battery in October 1777. Covered by a vaulted roof of brick and stone, the magazine was constructed to ensure safety. An exterior brick screen at the doorway protected the powder from flying sparks. Inside magazines, nails and barrel hoops were normally copper, a metal less likely than iron to produce sparks accidentally from friction.