This event might have three causes: 

The first and the most natural was that it might be an ambuscade of the Rochellais, who might not be sorry to kill one of his Majesty’s Guards, because it would be an enemy the less, and this enemy might have a well-furnished purse in his pocket.

D’Artagnan took his hat, examined the hole made by the ball, and shook his head.  The ball was not a musket ball—­it was an arquebus ball.  The accuracy of the aim had first given him the idea that a special weapon had been employed.  This could not, then, be a military ambuscade, as the ball was not of the regular caliber.

This might be a kind remembrance of Monsieur the Cardinal.  It may be observed that at the very moment when, thanks to the ray of the sun, he perceived the gun barrel, he was thinking with astonishment on the forbearance of his Eminence with respect to him.

But d’Artagnan again shook his head.  For people toward whom he had but to put forth his hand, his Eminence had rarely recourse to such means.

It might be a vengeance of Milady; that was most probable.

He tried in vain to remember the faces or dress of the assassins; he had escaped so rapidly that he had not had leisure to notice anything.

“Ah, my poor friends!” murmured d’Artagnan; “where are you?  And that you should fail me!”

D’Artagnan passed a very bad night.  Three or four times he started up, imagining that a man was approaching his bed for the purpose of stabbing him.  Nevertheless, day dawned without darkness having brought any accident.

But d’Artagnan well suspected that that which was deferred was not relinquished.

D’Artagnan remained all day in his quarters, assigning as a reason to himself that the weather was bad.

At nine o’clock the next morning, the drums beat to arms.  The Duc d’Orleans visited the posts.  The guards were under arms, and d’Artagnan took his place in the midst of his comrades.

Monsieur passed along the front of the line; then all the superior officers approached him to pay their compliments, M. Dessessart, captain of the Guards, as well as the others.

At the expiration of a minute or two, it appeared to d’Artagnan that M. Dessessart made him a sign to approach.  He waited for a fresh gesture on the part of his superior, for fear he might be mistaken; but this gesture being repeated, he left the ranks, and advanced to receive orders.

“Monsieur is about to ask for some men of good will for a dangerous mission, but one which will do honor to those who shall accomplish it; and I made you a sign in order that you might hold yourself in readiness.”

“Thanks, my captain!” replied d’Artagnan, who wished for nothing better than an opportunity to distinguish himself under the eye of the lieutenant general.

In fact the Rochellais had made a sortie during the night, and had retaken a bastion of which the royal army had gained possession two days before.  The matter was to ascertain, by reconnoitering, how the enemy guarded this bastion.