the locality. It is about 80 feet above the basin, overlooks it throughout its whole extent, and is about 800 yards from the wharves and the railroad running through Pratt street. About a fortnight ago I requested Major Brewerton to survey it, and ascertain its capacities for defense by a strong entrenchment-one which could be held against a large force on the land side and covered on the water side with a heavy battery, overawing the city, and capable, from its proximity, to single out and assail particular localities in case of an outbreak. When i requested Major Brewerton to make the examination the place was occupied by the Eighteenth Regiment of Pennsylvania Militia. It is now occupied by Colonel Duryea's Fifth Regiment of New York Volunteers, or the National Zouaves. They have a rifled cannon, three howitzers, and some field pieces, belonging to Fort McHenry. They are becoming well drilled as artillerists, but have no breastworks. I propose, then-

1. That Federal Hill should be strongly entrenched. The Zouaves will do the greater part of the work.

2. That the height before referred to should also be strongly entrenched. it not only commands Fort McHenry, which should be rendered secure from bombardment, but it commands every other eminence from which the fort can be assailed and overlooks a part of the city which is rank with secession. This work should be at least as extensive as Fort Corcoran, and should be furnished with a battery of heavy cannon and mortars. This work can be chiefly done by the volunteer regiments, if I can have the force, which in my letter of the 24th of July I considered necessary for the security of the city and State.

I am not quiet satisfied with Fort McHenry. It is very strong on the water side, but, like most of our harbor fortifications, was constructed with no special reference to attack by land. The approach from Baltimore is faced by a curtain, which was only designed for infantry. Major Morris, who has done all for the work it is capable of, has placed some mortars behind it, but there is no room for cannon. I suggested to Major Brewerton the construction of an outwork between the two bastions which this curtains connects. It should be a permanent work, and, with the prevailing indications, it would be wise to make preparations for a long-continued contest. If the suggestions I have made are carried our, I think the city of Baltimore can be controlled under any circumstances. I have thought proper to make them before asking the engineer for plans, for the reason that a gentlemen for whose judgment I have a great respect thought such indications of a determination to not agree with him. I do not think the secessionists could be more intemperate than they are now, and the Union men would be encouraged and strengthened by such a demonstration.

I am, respectfully, yours,

JOHN A. DIX,

Major-General, Commanding.

GENERAL ORDERS, HDQRS. CORPS OF OBSERVATION,

Numbers 1.
Rockville, August 12, 1861.

By virtue of orders from Headquarters Division of Potomac, dated August 10, 1861, the undersigned assumes command of the forces of the United States along the line of the Potomac between Point of Rocks and Seneca Falls, including the forces at both places.

CHAS. P. STONE,

Brigadier-General.