The moral effect of combat is literally terrible, Colonel Ardant Du Picq reminds us:
A body advances to meet another. The defender has only to remain calm, ready to aim, each man pitted against a man before him. The attacking body comes within deadly range. Whether or not it halts to fire, it will be a target for the other body which awaits it, calm, ready, sure of its effect. The whole first rank of the assailant falls, smashed. The remainder, little encouraged by their reception, disperse automatically or before the least indication of an advance on them. Is this what happens? Not at all! The moral effect of the assault worries the defenders. They fire in the air if at all. They disperse immediately before the assailants who are even encouraged by this fire now that it is over. It quickens them in order to avoid a second salvo.
Lest you forget that this was written by a Frenchman:
It is said by those who fought them in Spain and at Waterloo that the British are capable of the necessary coolness. I doubt it nevertheless. After firing, they made swift attacks. If they had not, they might have fled. Anyhow the English are stolid folks, with little imagination, who try to be logical in all things. The French with their nervous irritability, their lively imagination, are incapable of such a defense.
“Anybody who thinks that he could stand under a second fire is a man without any idea of battle.”
— Prince de Ligne
“Modern history furnishes us with no examples of stonewall troops who can neither be shaken nor driven back, who stand patiently the heaviest fire, yet who retire precipitately when the general orders the retreat.”