The dimensions of this, and many other Spanish towns, must not be adopted as a base for estimating their amount of population. Irun, at the frontier of France, stands on a little hill, the surface of which would scarcely suffice for a country-house, with its surrounding offices and gardens: it contains, nevertheless, four or five thousand inhabitants, and comprises a good-sized market-place and handsome town-hall, besides several streets. Nor does this close packing render the Spanish towns less healthy than our straggling cities, planned with a view to circulation and purity of atmosphere, although the difference of climate would seem to recommend to each of the two countries the system pursued by the other. The humidity of the atmosphere in England would be the principal obstacle to cleanliness and salubrity, had the towns a more compact mode of construction; whilst in Spain, on the contrary, this system is advantageous as a protection against the excessive power of the summer sun, which would render our wide streets--bordered by houses too low to afford complete shade--not only almost impassable, but uninhabitable. The Plaza of Burgos (entitled "de la Constitucion," or "de Isabel II.," or "del Duque de la Victoria," or otherwise, according to the government of the day,) has always been the resort of commerce. The projecting first-floors being supported by square pillars, a sort of bazaar is formed under them, which includes all the shop population of the city, and forms an agreeable lounge during wet or too sunny weather. Throughout the remainder of the town, with the exception of the modern row of buildings above mentioned, almost all the houses are entered through Gothic doorways, surmounted by armorial bearings sculptured in stone, which, together with their ornamental inner courts and staircases, testify to their having sheltered the chivalry of Old Castile. The Cathedral, although by no means large, appears to fill half the town; and considering that, in addition to its conspicuous and inviting aspect, it is the principal remaining monument of the ancient wealth and grandeur of the province, and one of the most beautiful edifices in Europe, I will lose no time in giving you a description of it. This edifice, or at least the greater portion of it, dates from the thirteenth century. The first stone was laid by Saint Ferdinand, on the 20th of July 1221. Ferdinand had just been proclaimed king by his mother Doña Berenguela, who had invested him with his sword at the royal convent of the Huelgas, about a mile distant from Burgos. Don Mauricio, Bishop of Burgos, blessed the armour as the youthful king girded it, and, three days subsequently to the ceremony, he united him to the Princess Beatrice, in the church of the same convent. This bishop assisted in laying the first stone of the cathedral, and presided over the construction of the entire body of the building, including half of the two principal towers.