This was an unexpected development: ‘any other but a modern French Army would now leave the province (Andalusia), as they have absolutely no communication of any kind with France, or with any other French army, and are pressed on all sides,’ wrote Wellington. Yet Soult lingered, and meanwhile the Army of Portugal, rallied in a shorter time than could have been expected, returned to Valladolid, and assumed the offensive in the valley of the Douro. The trouble in that direction became so acute that Wellington resolved to march against Clausel, with a force sufficient to drive him back to the Ebro, intending afterwards to return to Madrid to pick up the other half of his own army, to join with Hill, and then to deal with Soult, whose tardy resolve to evacuate Andalusia was only just becoming evident. The march against Clausel was necessary; and it seems a misfortune that Wellington left three of his best divisions at Madrid--which was obviously in no danger for the present, and where Hill was expected to arrive ere long. It turned out that the force put in motion against Valladolid and Burgos was too small--even after it had been joined by Clinton and the Galicians--to secure the complete predominance in the North which was necessary. Clausel retreated, but was pursued in a somewhat cautious fashion, and only as far as Burgos. It would appear that if Wellington had brought 10,000 men more with him from Madrid, and if he had invested Burgos with the Galician Army, and followed hard upon Clausel with all his Anglo-Portuguese, he might have driven the French not only beyond the Ebro, but as much farther as he pleased. For Clausel could not have stood for a moment if Wellington’s power had been a little greater, and Caffarelli was in September so entirely taken up with the operations of Home Popham, Mina, and Mendizabal that he had not a man to spare. But Wellington advanced no farther than Burgos, and allowed Clausel to lie opposite him at Briviesca unmolested, till he had drawn great reinforcements from France, and had at last induced Caffarelli to come to his aid with 10,000 men. Meanwhile, he was devoting himself to the siege of Burgos, where, by his own fault, he had no sufficient artillery resources to subdue an improvised fortress of the third class. The fault was exactly the same as that which had been committed before the Salamanca Forts in June. And--as has been demonstrated above--Wellington had been pressed to take more heavy guns with him, both by Sir Home Popham and by officers at Madrid. And if he had called for them, even after the siege began, they could have reached him in time. His own curious comments on the facts are not convincing: