HEADQUARTERS ARMY OF THE POTOMAC,
Sharpsburg, September 19, 1862--1.15 p. m.

Brigadier-General PLEASONTON:

GENERAL: Your two dispatches just received. General McClellan directs me to say that he does not propose to cross the river, and that he does not desire you to do so, unless you see a splendid opportunity to inflict great damage upon the enemy without loss to yourself.

I am, general, very respectfully, your obedient servant,

R. B. MARCY,

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC,
September 19, 1862--10 p. m.

Brigadier-General PLEASONTON:

GENERAL: Colonel Hunt opened nineteen guns on the enemy just before dark and kept up his fire until night set in. The enemy scattered in all directions. An infantry force of about 400 men was crossed immediately, and it is believed that five or six guns have fallen, or will fall, into our possession. Colonel Hunt thinks that you should be at the river by daylight without fail, and that you should take your artillery with you. General McClellan concurs fully in this, and directs that you push your command forward after the enemy as rapidly as possible, using your artillery upon them wherever an opportunity presents, doing them all the damage in your power without incurring too much risk to your command. If great results can be obtained, do not spare your men or horses.

I am, general, very respectfully, your obedient servant,

R. B. MARCY,

Chief of Staff.

P. S.--Our troops will hold the heights on the opposite side of the river during the night.

[19.]

R. B. M.

HEADQUARTERS ARMY OF THE POTOMAC,
September 19, 1862--11 p. m.

Brigadier-General PLEASONTON:

GENERAL: The rebel General Stuart is reported to have moved to Williamsport with 4,000 cavalry and six pieces of artillery. It is also reported that 10,000 infantry of the enemy are approaching Williamsport from Winchester. Couch has been ordered to move to Williamsport so as to be there at daylight, picking up Colonel Voss' regiment of cavalry at Jones' Cross-Roads. General McClellan, therefore, directs that you send out immediately sufficient cavalry to scout all the roads on our right, to give timely notice of the approach to this point of any mounted force of the enemy. You will send two batteries with half of your entire cavalry force to report at daylight in the morning to Major-General Porter at Shepherdstown. With the remainder of your cavalry and two batteries of artillery you will proceed at once to Jones' Cross-Roads, and there await the arrival of General Couch's command. From this point you will move on Williamsport with General Couch, and co-operate with him in capturing, if possible, or elese in driving off, such force of the enemy as may be found there.

I am, general, very respectfully, your obedient servant,

R. B. MARCY,

Chief of Staff.

[19.]