HOW TO PROCEED TO BREAK A LARGE MASS OF BRONZE.
If you want to break up a large mass of bronze, first suspend it, and then make round it a wall on the four sides, like a trough of bricks, and make a great fire therein. When it is quite red hot give it a blow with a heavy weight raised above it, and with great force.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.