Out in the Pennsylvania oil regions in the early days, while nitroglycerin in the liquid state was being used experimentally as a blasting agent, some boys found in a creek an old felt hat, which had been used as a filter for nitroglycerin.

One of the boys accidentally discovered that when laid upon a stone and the edge of the hat hit with a hammer, it would crack, so they took it to a blacksmith’s shop, where they could have some fun by hammering it on an anvil.

At the first blow the old hat exploded. Two of the boys were killed outright, and two more were badly injured.

The blacksmith at the time of the accident, happened to be standing outdoors, which thereafter constituted his blacksmith shop until he could rebuild.