A Mr. Bunch, British Consul, has written an impudent letter to the department, alleging that an Irishman, unnaturalized, is forcibly detained in one of our camps. He says his letters have not been answered, which was great discourtesy, and he means to inform Lord John Russell of it. This letter was replied to in rather scathing terms, as the Irishman had enlisted and then deserted. Besides, we are out of humor with England now, and court a French alliance.

The President was at Chattanooga on the 15th instant; and writes the Secretary that he has made some eight appointments of brigadiers, and promotions to major-generals. Major-Gen. Buckner is assigned to command at Mobile.

We are straightened for envelopes, and have taken to turning those we receive. This is economy; something new in the South. My family dines four or five times a week on liver and rice. We cannot afford anything better; others do not live so well.

Custis and I were vaccinated to-day, with the rest of the officers of the department.

The Northern papers now want the Federal army to go into winter quarters. This was, confessedly, to be the final effort to take Richmond. It failed. Many of the people regard the disaster of Burnside as the harbinger of peace.

An officer from the field informs me that all our generals were sadly disappointed, when it was discovered that Burnside had fled. They wanted one more blow at him, and he would have been completely destroyed.

December 20th.—Last accounts from Fredericksburg state that the enemy are retiring toward the Potomac and Washington. We have got some of their pontoon bridges, and other things left behind. It is now very cold, with a fair prospect of the Potomac freezing over. Let them beware!

But we were in a bad way: our army, instead of numbering 200,000 as the Federal journals report, did not exceed 50,000 men; and not half that number went into action. The Secretary of War had ordered several regiments from Gen. S. Jones, in Western Virginia; now sent to North Carolina.

There is no mail yet from beyond Goldsborough, and the news from North Carolina seems vague and unsatisfactory. They say we beat the enemy at Kinston; yet they have destroyed a portion of the railroad between Goldsborough and Wilmington. They say the Federals are retreating on Newbern; yet we know they made 500 of our men prisoners after they crossed the Neuse. It is reported that our loss is small, and the enemy’s large; and that our 3000 men fought successfully their 18,000. However, we have sent some 15,000 reinforcements.

It is reported that the Federals are evacuating Nashville; but reports from the West are not always reliable.