The principal object of the next campaign was, for the king of Prussia,
the recapture of Schweidnitz. Frederick had not one man more than was
requisite for the execution of this important enterprise. Seventy
thousand Austrians composed the army of Marshal Daun and the corps of
Laudon, Hadduck, Brentano, De Beck, and Ellershausen. The Prussian
army was not inferior, but troops must be detached from it for the
siege, of which M. de Tauziern had the direction. He invested the
place on the 4th of August, and opened the trenches on the 7th; they
commenced at Briqueterie, and turned towards Warben, to embrace the
polygon of Jauernick, upon which the principal attack was directed.
M. de Guasco made a sortie, but it did not answer his expectations;
the Prussian dragoons beating the Austrians back into the place. The
king of Prussia thought that Laudon, in order to succour the place,
would take the route of Sibelberg, Warther, and Langen-Brelau; he
went, therefore, to place himself at Pfaffendorff, whilst he caused
the post of Peila to be taken by the prince of Bevern. Everything
happened as the king of Prussia had foreseen. Marshal Daun took the
route of Langen-Brelau, attacked the Prussians at Peila, was beaten and
retreated. The check experienced by Marshal Daun gave M. de Guasco a
bad augury of the fate of the place, and he made an attempt to obtain
an advantageous capitulation, with a free departure for his garrison.
The king of Prussia refused to comply, because it would have been a
capital error to allow ten thousand men to march out of a city, of
which, with a little patience, he should render himself master; the
Prussian army would be weakened at least by four thousand men necessary
to garrison Schweidnitz, and the Prussian strength would be lessened
to the amount of fourteen thousand men. The king of Prussia repaired
in person, on the 20th of September, before Schweidnitz, in order to
push on the works with more vigour. Lefebvre, the chief engineer, was
opposed to Gribeauvel, esteemed one of the first men of the age for
the defence of places. Lefebvre was soon outwitted by the activity of
the French engineer, who countermined his mines and thwarted all his
plans. Frederick was obliged to take the details of the siege upon
himself; the third parallel was lengthened; a battery in breach was
placed there; ricochets were there established against Briqueterie,
with another battery upon Kuhberg; and the works of the Austrians
were taken in rear. Some branches of the mines of the besieged were
likewise sprung. The garrison made two sorties, and dislodged the
Prussians from a crowned tunnel, from which they wished to debouch by
fresh branches. These manœuvres prolonged the duration of the siege,
because they rendered a subterranean war necessary. All the cannon of
the place were, however, either _évasés_[17] or dismounted; provisions
were beginning to be scarce, and the enemy would have been compelled
to surrender on that account, if a bomb, falling in front of the
powder-magazine of Jauernick, had not set fire to it, knocked down a
part of that fort, and killed three hundred Austrian grenadiers. This
accident, which laid the place open, obliged M. de Guasco to beat a
parley; he surrendered himself and his garrison prisoners of war, on
the 9th of October, and they were marched away into Prussia.
The palpable lessons in these two sieges are--in the first, the
imprudence of the governor in granting opportunities for treachery in
prisoners; and in the second, the consummate prudence of the king of
Prussia in not allowing the garrison to march out free, for the sake of
quickly terminating the siege.