Up to then, most shot was cast. That was very labor-intensive. Shot was also made by pouring lead into a sieve over a barrel. That really did give tear-shaped drops.

Watts's invention teaches us the two essential elements of good invention. The first is perception. Watts gazed more closely at nature and saw what other people had missed. The other element is simplicity. Others had labored to control the process with their own hands. Watts had the grace to stand aside and let nature do the work for him. The real beauty of this process is that, in the end, there is no human process at all.