the garrison. Sometimes a wall could be brought down by a battering-
ram. But the quickest and surest way was by mining. The miners
worked their way to the wall, and then began to take some of the
stones of the outer casing out, propping the wall up with beams of
wood. When the hole was big enough, they filled it with firewood;
they greased the beams well, they set fire to them and then retired
to a safe distance to see what happened. When the great wall crashed
down, the soldiers swarmed over it to beat down the resistance of the
garrison. If ever you go to Abergavenny Castle, in the Vale of Usk,
look at the cleft in the rock along which the daring besiegers once
climbed. And if you go to the Vale of Towy, and see Dryslwyn Castle,
remember that the wall once came down before the miners expected, and
that many men were crushed.

In order to prevent mining, many changes were made. Moats were dug
round the castle, and filled with water. Brattices were made along
the top of the towers, galleries through the floor of which the
defenders could pour boiling pitch on the besiegers. The walls were
built at such angles that a window, with archers posted behind it,
could command each wall. Stronger towers were built--round towers
with a coping at each storey, solid as a rock, which would crack and
lean without falling; there is a leaning tower at Caerphilly Castle.
One other way I must mention--the child or the wife of the castellan
would be brought before the walls, and hanged before his eyes unless
he opened the gates.

The newer or Edwardian castles, those of the reigns of Henry III. and
Edward I., are concentric--that is, there are several castles in one;
so that the besiegers, when they had taken one castle, found
themselves face to face with another, still stronger, perhaps, inside