When Curdie reached the castle, and ran into the little garden in front of it, there stood the door wide open. This was as he had hoped, for what could he have said if he had had to knock at it? Those whose business it is to open doors, so often mistake and shut them! But the woman now in charge often puzzled herself greatly to account for the strange fact that however often she shut the door, which, like the rest, she took a great deal of unnecessary trouble to do, she was certain, the next time she went to it, to find it open. I speak now of the great front door, of course: the back door she as persistently kept wide: if people could only go in by that, she said, she would then know what sort they were, and what they wanted. But she would neither have known what sort Curdie was, nor what he wanted, and would assuredly have denied him admittance, for she knew nothing of who was in the tower. So the front door was left open for him, and in he walked. But where to go next he could not tell. It was not quite dark: a dull, shineless twilight filled the place. All he knew was that he must go up, and that proved enough for the present, for there he saw the great staircase rising before him. When he reached the top of it, he knew there must be more stairs yet, for he could not be near the top of the tower. Indeed by the situation of the stairs, he must be a good way from the tower itself. But those who work well in the depths more easily understand the heights, for indeed in their true nature they are one and the same; miners are in mountains; and Curdie, from knowing the ways of the king's mines, and being able to calculate his whereabouts in them, was now able to find his way about the king's house. He knew its outside perfectly, and now his business was to get his notion of the inside right with the outside. So he shut his eyes and made a picture of the outside of it in his mind. Then he came in at the door of the picture, and yet kept the picture before him all the time--for you can do that kind of thing in your mind--and took every turn of the stair over again, always watching to remember, every time he turned his face, how the tower lay, and then when he came to himself at the top where he stood, he knew exactly where it was, and walked at once in the right direction. On his way, however, he came to another stair, and up that he went, of course, watching still at every turn how the tower must lie. At the top of this stair was yet another--they were the stairs up which the princess ran when first, without knowing it, she was on her way to find her great-great-grandmother. At the top of the second stair he could go no farther, and must therefore set out again to find the tower, which, as it rose far above the rest of the house, must have the last of its stairs inside itself.