Dorothy followed the keeper across the hall, the size of which, its height especially, and the splendour of its windows of stained glass, almost awed her; then across the next court to the foot of the Library Tower forming the south-east corner of it, near the two towers flanking the main entrance. Here a stair led down, through the wall, to a lower level outside, where were the carpenters' and all other workshops, the forges, the stables, and the farmyard buildings. As it happened, when Dorothy entered the smithy, there was her own little horse being shod, and Marquis and he interchanged a whine and a whinny of salutation, while the men stared at the bright apparition of a young lady in their dingy regions. Having heard her business, the head-smith abandoned everything else to alter an iron collar, of which there were several lying about, to fit the mastiff, the presence of whose mistress proved entirely necessary. Dorothy had indeed to put it on him with her own hands, for at the sound of the chain attached to it he began to grow furious, growling fiercely. When the chain had been made fast with a staple driven into a strong kennel-post, and his mistress proceeded to take her leave of him, his growling changed to the most piteous whining; but when she actually left him there, he flew into a rage of indignant affection. After trying the strength of his chain, however, by three or four bounds, each so furious as to lay him sprawling on his back, he yielded to the inevitable, and sullenly crept into his kennel, while Dorothy walked back to the room which had already begun to seem to her a cell. CHAPTER XIII. THE MAGICIAN'S VAULT.