A Mrs. —— from Maryland, whose only son is in a Federal prison, writes the President (she is in this city) that she desires to go to Canada on some secret enterprise. The President favors her purpose in an indorsement. On this the Secretary indorses a purpose to facilitate her design, and suggests that she be paid $1000 in gold from the secret service fund. She is a Roman Catholic, and intimates that the bishops, priests, and nuns will aid her.

March 23d.—Snow fell all night, and was eight or ten inches deep this morning; but it was a bright morning, and glorious sunshine all day,—the anniversary of the birth of Shakspeare, 300 years ago,—and the snow is melting rapidly.

The Secretary of War had a large amount of plate taken from the department to-day to his lodgings at the Spottswood Hotel. It was captured from the enemy with Dahlgren, who had pillaged it from our opulent families in the country.

March 24th.—A bright pleasant day—snow nearly gone.

Next week the clerks in the departments, between the ages of eighteen and forty-five, are to be enrolled, and perhaps the greater number will be detailed to their present employments.

Gov. Vance is here, and the President is about to appoint some of his friends brigadiers, which is conciliatory.

Gen. Longstreet has written a letter to the President, which I have not seen. The President sent it to the Secretary to-day, marked “confidential.” It must relate either to subsistence or to important movements in meditation. If the latter, we shall soon know it.

March 25th.—Raining moderately.

Yesterday Mr. Miles, member of Congress from South Carolina, received a dispatch from Charleston, signed by many of the leading citizens, protesting against the removal of 52 companies of cavalry from that department to Virginia. They say so few will be left that the railroads, plantations, and even the City of Charleston will be exposed to the easy capture of the enemy; and this is “approved” and signed by T. Jordan, Chief of Staff. It was given to the Secretary of War, who sent it to Gen. Bragg, assuring him that the citizens signing it were the most influential in the State, etc.

Gen. Bragg sent it back with an indignant note. He says the President gave the order, and it was a proper one. These companies of cavalry have not shared the hardships of the war, and have done no fighting; more cavalry has been held by Gen. Beauregard, in proportion to the number of his army, than by any other general; that skeleton regiments, which have gone through fire and blood, ought to be allowed to relieve them; and when recruited, would be ample for the defense of the coast, etc. Gen. Bragg concluded by saying that the offense of having the military orders of the commander-in-chief, etc. exposed to civilians, to be criticised and protested against—and “approved” by the Chief of Staff—at such a time as this, and in a matter of such grave importance—ought not to be suffered to pass without a merited rebuke. And I am sure poor Beauregard will get the rebuke; for all the military and civil functionaries near the government partake of something of a dislike of him.