NASHVILLE., Tenn, Tuesday, Dec. 13, 1864. The theatre of war has again been transferred to Middle Tennessee, and naturally, all eyes are turned in this direction. Military matters and events it seems, are uncertain, like changes in the weather, and the like. That man who, three months ago, would have dared to announce the fact that HOOD’s army would have been encamped within gunshot of Nashville, in December, 1864, would have been declared insane. Any person who would have cogitated upon such an event, would have involuntarily esteemed himself an ass. But such is the state of affairs. The rebel Army of Tennessee and the Army of the Cumberland confront each other precisely upon the ground they did just two years ago. ROSECRANS left this city on Christmas Day, 1862, and fought, and won a victory on the banks of stone River, near Murfreesboro, thirty miles from Nashville, a week after. Three hundred miles nearly, were the obstinate enemy pushed into the very bowels of Georgia, in the space of nineteen months, while tens of thousands of brave men upon each side were hurried to untimely graves. Three short months elapse, and we find the rebel army back where it was two years ago, numerically stronger, and more defiant, and better soldiers than Europe ever saw. But, ah! is there any one so unwise as to compare the interior of the situation of to-day with that of two years ago? I suppose not; I trust not. It cannot be possible that men of sense are impressed with the idea that the bloody battles of “Stone River,” “Chickamauga,” “Mission Ridge,” “Lookout Mountain,” “Resaca,” “New-Hope Church,” “Kenesaw,” “Peach-tree Creek,” and other sanguinary contests were fought in vain — that the blood of SILL KIRK, LYTTLE, HARKER, the great MCPHERSON, and fifty thousand other noble fellows has been spilled for nothing. God forbid that such an impression should become rife. No: the Federal situation, as I have many times informed you, is perfectly satisfactory. The rebels present a bold front, indeed; but they have no rear. Their army is like a snake with his guts snapped out. Gen. GEORGE H. THOMAS is pretty well known. I will merely add that he says everything is all right. It is known here and in Washington that he can whip and drive off HOOD’s army to-day. He aims to annihilate Hood and his army. Time will tell. Since my last, no material change in the movements of national or rebel troops, can be chronicled. While I write, the brightest moon, if you please, shines upon the coldest night I ever saw in Tennessee. Three days ago a violent storm of sleet ceased, and gave birth to a spell of cold weather, which makes even the sturdy Michiganders squeal. This sort of weather is still on hand, and absolutely nothing has transpired for nearly a week. Saturday and Sunday not a gun was fired, the soldiers’ time being chiefly occupied in feeding the roaring fires which blazed for miles around. Our troops, with plenty to eat and drink, with warm clothes, heavy blankets, good fires and sheltertents, have suffered with the cold. Must not the suffering on the rebel side, among the private soldiers, be intense? They are thinly clad, poorly shod, badly fed, with no tents and few blankets, and with thinner blood in their systems than that which courses through the veins of our own soldiers. This state of affairs can be relied upon. Rebel correspondents, more than two months ago stated, grandiloquently, that the “boys, blanketless and shoeless, started off upon their march for Tennessee, rending the air with their vociferations of joy.” Gen. HARDING, Mrs. A.V. BUREN and ladies and gentlemen of reliability within the rebel lines, send in the intelligence that the whole neighborhood has been stripped of carpets, which are cut up and made into blankets. Other statements, of a reliable character, are to the effect that the rebels are suffering for substantial food and clothing. Statements which I made in my last letter, regarding HOOD’s sweeping process of conscription, are corroborated by many who have escaped within our lines. His conscription, however, cannot injure us in the least. He gathers to his ranks a worthless crowd, who are traitors at heart, but unwilling to fight — a set of men who have invited this thing all along, and who have devoted their leisure in abusing the Government and slandering the patriots who are acting in its defence. As the war goes on brave men get braver. For instance; LYTTLE was killed at the head of his column, MCPHERSON was shot through the heart while rallying his troops. Gen. DODGE had a piece of his head chopped off while inspecting his lines. The rebel Gen. GRACLE’s life has just been cut off while personally examining his position. Hundreds and thousands of other brave men have perished in like manner. During the siege of Atlanta, which may be considered to have lasted from the date of MCPHERSON’s death to the capture of the city, I was impressed with the conduct of the general officers assisting in that campaign. The rebel strength, in the way of fortifications, lie in front of Atlanta, upon both sides of the railroad. The headquarter-camps of Generals PALMER, JOHNSON, BAIRD, KING, CURTISS, JEFF, C. DAVIS, MORGAN, and others, were less than a mile from the rebel batteries. Gen. THOMAS’ headquarters was a half mile further in the rear, but really in the worst place of all. His headquarters was immediately in the rear of SNYDERMASTER’s battery — the first one which opened upon Atlanta, which was on Saturday, the 23d of July. For weeks three rebel batteries of 32 and 64-pound guns kept up an incessant fire of shells, by day and night, upon SNYDERMASTER, about half of which, however, having “full???rations,” went thundering into General THOMAS’ camp. Several unexploded shells, shaped like a water-bucket, were on exhibition there at one time. They had been thrown from those 60-pounder guns stolen by FLOYD from the Washington navy-yard. The camps of JOHNSON, BAIRD and KING for weeks were pretty well attended to by the rebel artillerists, who hurled enough shot and shell in that space to start several iron foundries. Gens. SHERMAN and THOMAS rode around their lines daily, often to the dismay of some of those who accompanied them. General officers, now-a-days, seem anxious to make a personal inspection of their lines and of their working parties. One day Gen. SHERMAN was riding close to the skirmish line in GEARY’s front, when one of his staff officers launched off and remarked, “He may go right square up and get shot, if he wants to, but I’ll be — if I do.” Gens. BLAIR, LOGAN and DODGE might be seen at their front line of works almost daily. One afternoon Gen. PALMER sent word to BAIRD to open upon a certain battery which had been annoying some portion of his line. Gen. BAIRD ordered up the guns himself. As soon as they opened, the rebels directed their attention that way. BAIRD stood the whole fire, while portions of his staff, half a mile in the rear, took to trees. When BAIRD returned he laughed at them, and recommended that they improvise some “gophers.” I rode out with Gen. BAIRD one night when he was around upon the right. He sneaks around upon neutral ground like an Indian. He actually hitched his horse upon the inside of his works, and went upon the outside, and occasionally told me to “Go a little quiet along here,” and “There’s their line; stoop down a little,” and the like. BAIRD is very brave. CARLIN is just like him. When he was removed from brigade to division headquarters, last Summer, in front of Atlanta, he grumbled because he was so far off from his lines. I was visiting Gen. KING one day, and it happened that Gen. SCHOFIELD was moving his corps from left to right. This attracted the attention of the rebels in KING’s front, and they shelled SCHOFIELD vigorously all the afternoon; but, unfortunately, more than half of them exploded in or near KING’s camp. I must confess, I got slightly demoralized myself, and indulged in frequent potations of commissary, to renew my departing courage. Gen. KING laughed, as he watched the operations of his orderlies and “strikers,” who were exceedingly overcome with fright. After the shelling had ceased, he called up the crowd, and put them all back in the ranks, adding, that he wouldn’t have such a pack of infernal cowards about him. I could tell you a multiplicity of such stories. The above are from my own observation; and I am free to say that this war has developed one fact: that general officers are not to be found in the rear; and I can bear witness that no Commander, from the Chiefs down to Brigadiers’ escaped danger during the campaign from Chattanooga to Atlanta. They seemed to have courted it, if one may judge by the way they pitched into it. Hardly an engagement occurs, either here or in the East, but what some of our general officers are either killed or wounded. Our loss was slight at Franklin and yet we had two general officers wounded. PERSONAL. Although COUCH ranks WOOD, the latter continues to command the Fourth Corps, in STANLEY’s absence. This is as it should be, Gen. WOOD is an able and gallant officer, and has been in every fight in the southwest. He has twice been wounded on the field of action, and, curious to relate, he was both times wounded in the same place. No officer is more beloved than WOOD. Gen. JAMES STEEDMAN was in town yesterday. His headquarters is on the Murfreesboro’ pike, about one mile from town. Mr. JAMES HOOD, of the Chattanooga Gazette, is acting upon his staff, as Volunteer Aid-de-Camp. Gen. COUCH has been given a command of a division in the Twenty-third Corps. His division is one of the finest in the army. Citizens, who have arrived inside of our lines, report that no rebel general officer was killed, and but two wounded. This is the same as our own. They report that PATRICK CLEBURNE feigned dead to avoid capture, and that CHEATHAM’s legs saved him. They report the rebel loss in killed and wounded three times larger than our own. Gen. HOOD was upon the field during the Franklin fight, and in exceeding danger during its progress. He had been out of a sick bed but a week. BENJAMIN C. TRUMAN.