You will demand of him that he evacuate the town, with his forces, within one hour from the delivery of this communication. This demand is made in order to avoid the effusion of innocent blood and the destruction of private property. You will inform him that we have force sufficient to take and occupy tho town, and intend to do so.

Respectfully, your obedient servants.

D. B. MORRIS,

Colonel 101st Regiment Pennsylvania Volunteers.

C. W. FLUSSER,

Lieutenant-Commander, and Senior Naval Officer of Expedition.

JULY 9, 1863. - Explosion at Fort Lyon, Va.

REPORTS.

Numbers 1. - Brigadier General John P. Slough, U. S. Army.

Numbers 2. - Brigadier General Gustavus A. De Russy, U. S. Army.

Numbers 1. Report of Brigadier General John P. Slough, U. S. Army.

ALEXANDRIA, VA., June 9, 1863.

SIR: Having just returned from the scene of the accident (Fort Lyon), I report that at 2 o`clock this afternoon men were engaged in examining artillery ammunition, at the open door of the north magazine, when, from some cause, one shell exploded; immediately a few others, and then the magazine. Everything in the vicinity is a wreck. No serious damage was done, however, to the guns or guncarriages. Between 20 and 30 men were killed, and quite as many were severely wounded. In addition, quite a number were slightly wounded. The severely wounded have, been removed to the hospital in Alexandria. Men are engaged in clearing up the wreck and putting the fort in condition for defense.

JNO. P. SLOUGH,

Brigadier-General of Volunteers, and Military Governor.

ASSISTANT ADJUTANT-GENERAL, Hdqrs. Dept. of Washington.

Numbers 2. Report of Brigadier General Gustavus A. De Russy, U. S. Army.

ALEXANDRIA, VA., June 9, 1863-8 p. m.

SIR: I visited Fort Lyon. Found the magazine in west bastion of fort exploded to-day at 2 o`clock. Cause unknown. No men at the time inside of the magazine. Those outside engaged filling shells. Casualties, 20 deaths, 14 wounded. The guns of the batteries are now m firing order, and the rubbish will be cleared from the work by 2 o`clock to-morrow. Destruction complete. Written report will be made you in the morning.

G. A. DE RUSSY,

Brigadier-General. Lieutenant

Colonel J. H. TAYLOR, Chief of Staff, and Asst. Adjt. General