HEADQUARTERS, MANASSAS, August 10, 1861.

To the PRESIDENT:

Mr. PRESIDENT: I have suggested, through the Adjutant and Inspector-General, the importance of increasing our forces of artillery and cavalry - the first by borrowing guns from the States, or by casting, especially at Richmond. If guns are to be made, or if different kinds are to be obtained from States, I urgently recommend 12-pounder howitzers to constitute the addition to our present material. We are now deficient in those pieces, even on the principle which regulated the composition of the United States batteries - four 6-pounders and two howitzers. The effect of the howitzers on a field of battle is, I think, more than double that of 6-pounders. With fifty of them respectably served (in addition to our present artillery) we will not fear the enemy, whatever his numbers, in the open field. I beg you, therefore, to aid us by adding what you can to our strength in this arm. I am confident from observation that the Northern troops, like other raw soldiers, fear artillery unreasonably, and that we shall gain far more by an addition of these guns than by one of a thousand men. We are now, you know, far below even the proportion fixed by military writers for an army of veteran infantry. Without that proportion of artillery and cavalry, without further addition of infantry, we ought to be able to drive back all the Northern hordes that may cross the Potomac. It is certain to my mind that all of Napoleon's successes in 1813 were due to his large proportion of artillery. His infantry was as new and far from being equal to ours.

May I remind you that I have more than once mentioned our deficiency in cavalry? We have not half enough for mere outpost duty. If it had been greater our results on the 21st of July would have been better. For a battle I am sure that 3,000 or 4,000 cavalry in a field would be resisted by no Northern volunteers if they had artillery to open their way. For the last two months I have had one regiment of Virginia cavalry, under Stuart, in the presence of superior forces of regular cavalry, who have never appeared in front of their infantry. Our men, and we can find thousands like them, are good horsemen, well mounted. We can find thousands more like them. Can you not give them to us, and with Stuart to command them? He is a rare man, wonderfully endowed by nature with the qualities necessary for an officer of light cavalry. Calm, firm, acute, active, and enterprising, I know no one more competent than he to estimate the occurrences before him at their true value. If you add to this army a real brigade of cavalry, you can find no better brigadier-general to command it. With our present force we shall be obliged to depend much upon the country people for information of the enemy's movements.

Very truly, your friend and obedient servant,
J. E. JOHNSTON.

WHITE SULPHUR SPRINGS, VA., August 10, 1861.

General R. E. LEE, General, Commanding, & c.:

GENERAL: Yours, dated the 5th at Huntersville, post-marked the 8th at Staunton, is just received. I am pressing every means to advance as far as will meet the enemy on the Gauley turnpike and Summersville road. This morning I re-enforce General Floyd with a detachment of artillery (two 6-pounders, forty rounds), and a corps of cavalry, under Captain Corns, in addition to Colonel Davis' force of about 500.