The two together made a complete position, while singly each was a very bad neighbour to the other.

On the aide-de-camp riding up, however, to inquire from General Buller whether the time had come for this advance, he replied, 'We have done enough for the day,' and left out this essential portion of his original scheme, with the result that all miscarried.
Speed was the most essential quality for carrying out his plan successfully.

So it must always be with the attack.

The defence does not know where the blow is coming, and has to distribute men and guns to cover miles of ground.

The attacker knows where he will hit, and behind a screen of outposts he can mass his force and throw his whole strength against a mere fraction of that of his enemy.