Battle of Smolensk IV - considerations

It is uncertain why Napoleon ordered an assault at all, for he would have been far better advised to mask the cit and move his men on to cross the Dnieper and create a threat to the important Smolensk-Moscow Highway; this would have been a far surer was of forcing a Russian evacuation of the city followed by a major battle.  Indeed, the threat of such a move filled the minds of both Barclay and Bagration throughout the day, and it accounts for the former's decision to evacuate Smolensk during the night of the 17th-18th.  This order caused a storm of recrimination at Russian headquarters, the Grand Duke Constantine (the Tsar's brother) and General Bennigsen accusing the minister of war of cowardice.  Barclay, however, refused to rescind his order, and accordingly Doctorov's four divisions abandoned their positions and retired to the northern bank, burning the bridge behind them.  At two in the morning, Ney discovered that there were no Russians facing his troops.  The men of the Ist and IIIrd Corps rushed into the blazing town, and one party even succeeded in wading through the river at the broken bridge where the water was only four feet deep because of the rubble, and stormed the Russian position beyond.  It took the entire rear guard of Bagrations's army, namely 10 regiments, to contain the jubilant Wurttembergers and Portuguese who performed this feat.

~ D. Chandler, The Campaigns of Napoleon, p.788