FORT SUMTER, S. C., March 11, 1861.

General JOS. G. TOTTEN,

Chief Engineer U. S. Army, Washington, D. C.

GENERAL: The sudden change of temperature from the warmth of yesterday to the cold of last night and this morning seems to have checked the ardor of the laborers on the field work on Cummings Point, as but little activity is observed this morning. The work on the extension of the line of parapet on the channel side towards the Star of the West battery still continues. Very little else appears to be doing. We are still steadily at work, and will try the second 10-inch columbiad again to-day.

Very respectfully, your obedient servant,

J. G. FOSTER,

Captain, Engineers.

No. 70.] FORT SUMTER, S. C., March 12, 1861.

Colonel S. COOPER,

Adjutant-General U. S. Army:

COLONEL: I have the pleasure of reporting that Lieutenant Snyder has succeeded in raising another 10-inch columbiad, which I shall place in barbette on the left flank, upon the 8-inch columbiad platform nearest to the gorge. We do not see that they are at work this morning, except a small party, which is getting up some heavy timbers at the Cummings Point wharf.

The weather is delightful now, but a few of the men are suffering from colds.

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

ROBERT ANDERSON,

Major, First Artillery, Commanding.

FORT SUMTER, S. C., March 12, 1861.

General JOS. G. TOTTEN,

Chief Engineer U. S. Army, Washington, D. C.:

GENERAL: The line of entrenchments on the channel side of Cummings Point, or rather of Morris Island, is now extended down to the rear of the Star of the West battery. This line is composed of redoubts, connected by lines of parapet serving for curtains. The rear of the redoubts, or the parts towards us, are raised so high as to secure them from our reverse fire. There is one in rear of the Star of the West battery, situated on the top of the sand hill, which conceals that battery from our view, and two more between this and the works on Cummings Point. Both of these are situated on sand hills, and well protected in their rear, as described above.

The weather being unusually pleasant, their operations are actively carried on this morning. Other work is being done farther down the beach, say six hundred yards below the Star of the West battery. I cannot make it out at present. It is probable that it is to be another small battery to fire on the channel, and to be closed in the rear.

I am inclined to think, from the materials that have been carried in that direction, that the defenses at the mouth of the Stono have been much strengthened. This river was an avenue by which and Wappoo Creek the city could be approached by vessels drawing less than eight feet of water. The defense of this point has, therefore, not been neg-