Therefore, after much meditation as to how it could be accomplished in the simplest and least expensive manner, he set about it as follows.
First of all he cleared away the floor about the well, and built up the circular wall of it a foot or two higher, with stones picked from those lying about, and with mortar which he made himself.

By means of a spirit-level, he laid the top layer of stones quite horizontal; and he introduced into it several blocks of wood instead of stones.
Next he made a small wooden frame, which, by driving spikes between the stones, he fastened to the opening of the underground passage, so that a well-fitting piece of board could move up and down in it, by means of a projecting handle, and be a more manageable sluice than he had hitherto had.
Then he made a strong wooden lid to the mouth of the well, and screwed it down to the wooden blocks he had built in.

Through a hole in it, just large enough, came the handle of the sluice.
Next, in the middle of the cover, he made a hole with a brace and centre-bit, and into it drove the end of a strong iron pipe, fitting tight, and long enough to reach almost to the top of the vault.

As soon as this was fixed he shut down the sluice, and in a few seconds the water was falling in sheets upon him, and flooding the floor, dashed back from the vault, against which it rushed from the top of the pipe.
This was enough for the present; he raised the sluice and let the water escape again below.

It was plain, from the force with which the water struck the vault, that it would yet rise much higher.
He scrambled now on the top of the vault, and, examining the ruins, soon saw how a pipe brought up through the breach in the vault could be led to the hole in the wall of his room which he had shown his father as a ventilator.