which may deviate from his general line of operations.  The ulterior events of the campaign may possibly cause him to make these new, or accidental lines, his lines of operations.  The approach of hostile forces may cause him to detach secondary corps on secondary lines; or to divide his army, and pursue double or multiple lines.  The primitive object may also be relinquished, and new ones proposed, with new lines and new plans of operations.  As he advances far from his primitive base, he forms new depots and lines of magazines.  He may encounter natural and artificial obstacles.  To cross large rivers in the face of an enemy is a hazardous operation; and he requires all the art of the engineer in constructing bridges, and securing a safe passage for his army.  If a fortified place is to be taken, he will detach a siege corps, and either continue his march with the main army, or take a strategic position to cover this siege.  Thus Napoleon, in 1796, with an army of only 50,000 combatants, could not venture to penetrate into Austria, with Mantua and its garrison of 25,000 men in his rear, and an Austrian force of 40,000 before him.  But in 1806 the great superiority of his army enabled him to detach forces to besiege the principal fortresses of Silesia, and still to continue his operations with his principal forces.  The chief of the army may meet the enemy under circumstances such as to induce or compel him to give battle.  If he should be victorious, the enemy must be pursued and harassed to the uttermost.  If he should be defeated, he must form the best plan, and provide the best means of retreat.  If possible, he must take shelter in some line of fortifications, and prepare to resume the offensive.  Lines of intrenchment and temporary works may sometimes serve him as a sufficient protection.  Finally, when the unfavorable season compels him to suspend his operations, he will go into winter cantonments, and prepare for a new campaign.

Such are the ordinary operations of war:  its relations to strategy must be evident, even to the most superficial reader.

Not unfrequently the results of a campaign depend more upon the strategic operations of an army, than upon its victories gained in actual combat.  Tactics, or movements within the range of the enemy’s cannon, is therefore subordinate to the choice of positions:  if the field of battle be properly chosen, success will be decisive, and the loss of the battle not disastrous; whereas, if selected without reference to the principles of the science, the victory, if gained, might be barren, and defeat, if suffered, totally fatal:  thus demonstrating the truth of Napoleon’s maxim, that success is oftener due to the genius of the general, and to the nature of the theatre of war, than to the number and bravery of the soldiers. (Maxim 17, 18.)

We have a striking illustration of this in the French army of the Danube, which, from the left wing of General Kray, marched rapidly through Switzerland to the right extremity of the Austrian line, “and by this movement alone conquered all the country between the Rhine and Danube without pulling a trigger.”