Second. There were no observatories of the enemy's at the time of the capture of the Isaac P. Smith as he has at present on Folly and Black Islands, and possibly on Long Island, whereby he may not only discover the removal of the rifled siege-guns from east lines (Major Manigualt's command), but the movements or location of guns on the Stono on the former plan.

Third. That from the above, heavy supports of infantry would be requisite in proportion to the weight of the guns sent to Battery Island and to John's Island.

Fourth. That these supports would be the more necessary that the enemy can now operate on the Stono with the assistance of iron-clads; whereby, even with such supports, the enterprise might fail under former plan.

Fifth. That even under the most favorable circumstances, what has to be done now must be done in one tide, for on the next a monitor might be in the Stono to recapture the gunboats, or, perhaps, attempt the destruction of our own steamboats.

Sixth. That in order to secure a captured vessel the torpedoes now, and not then, existing would have to be removed before hand, which would endanger our defense, if detected, and that the only means advisable in that contingency would be to haul her over the line of torpedoes from this side, taking the risk of her blowing up.

Under all these circumstances, the matter of the destruction, and still more of the capture of the gunboat in question, is exceedingly doubtful, and far more dependent than that of the Isaac P. Smith on the contingency of a happy shot, and other favorable circumstance. The gunboat, however, might be seriously damaged or, by good fortune, destroyed, with no reasonable anticipation of disaster, by the following plan: Unmask sufficiently Battery Pringle to use upon the bunboat her long-range guns. Put the following four siege-masked by the trees thereat, &c., a banded 24-pounder, one 30-pounder Parrott, and two 4.62's. Send a light battery of Napoleons to this side of Battery Island, where Lieutenant-Colonel Brown masked formerly his 24-pounder, if, on reconnaissance, it be found now practicable and advisable, to act in the rear of the gunboat, when the other guns open, with spherical case on her deck. Send to John's Island the Palmetto Guard, with their light battery of steel rifled Blakelys, and the section of the Georgia Siege Train, with their 20 and 10 pounder Parrotts, all easily moved or withdrawn; to be located by Major Jenkins, commanding advanced forces on John's Island, and thoroughly acquainted with the ground. Place reliable torpedoes below the position taken lately by the gunboat; if possible, under the personal superintendence of the chief officers of that department. Have a steamer concealed up the Stono below Fort Pemberton, ready for any emergency, and some row-boats, for which purpose construct a draw on the foot-bridge of Elliott's Cut, a desirable improvement for this and other cases. When the gunboat reaches the highest point she advances to, at the signal given by the whole broadsides of Battery Pringle, the other guns will open, and, with previous preparation for range, &c., her crippling, if not destruction, may be compassed. As yesterday was, as stated, the fifth Tuesday that the Pawnee, or her consort, has been running up the Stono on a reconnaissance, it might be preferable, so as not to keep the guns and supports too long inactive, to order them to their positions by Monday night next.