Prior to the opening of the campaign of 1813, regiments had been unacquainted with the luxury of canvas, and it is wonderful how they managed to exist for so many years in such variations of climate. Whenever possible, the troops were billeted in the towns, villages, and farms; but when actually in the field the bivouac was resorted to, and as time went on the old soldiers became adepts at making themselves comfortable, in shelters formed of boughs of trees, or even in hastily constructed huts, when halting in the more wooded parts of the country. In 1812, tents were improvised out of blankets, two of which were fastened together by tapes sewn on to the sides, and then stretched over a pole supported by the arm piles; but these provided shelter for only four men, who, moreover, had but two blankets among them in which to sleep. The whole matter was one of transport, and Wellington had always refused to allow the movements of his army to be hampered by excessive baggage. By this time, however, the medical officers had learnt by experience that much of the sickness of the army was attributable to exposure, and the authorities at length sanctioned the issue of four tents per company, three for the men and one for the officers, but their carriage was not to entail any increase in the number of transport animals. Hitherto the company mules carried nothing except the heavy iron camp-kettles, or cauldrons, but now these were exchanged for lighter ones of tin, which the men (six to a kettle) took it in turn to carry on their knapsacks, while the mules carried the tents. Meanwhile, Soult had taken advantage of the inaction of his foe, and had caused to be thrown up a complete chain of entrenchments, some thirty miles long, covering St Jean de Luz on his right, and extending along the course of the Nivelle to its upper waters, whence the left of his line stretched eastward to the river Nive. The centre was guarded by outworks, erected about the Smaller Rhune and Sarre, to the east of the Greater Rhune; and so strong was this vast line that the most careful reconnaissances could discover scarcely a single weak spot in it.