A man was telling his neighbor, "I just bought a new hearing aid. It cost me four thousand dollars, but it's state of the art. It's perfect."
"Really," answered the neighbor . "What kind is it?"
"Twelve thirty."
SandblastingIn 1870, sandblasting was patented by Benjamin Chew Tilghman (26 Oct 1821 - 1901). Compressed air forces sand as an abrasive material through the nozzle of a sandblasting gun. A popular myth holds that Tilghman, when a General in the army, had seen the effect of wind blown sand upon glass windows, in the desert. The sand has etched the glass where unprotected and revealed the contrast against parts that were covered by steel mesh. He has been called the "father of shotpeening." In 1866, he found sulphurous acid would dissolve the intercellular matter of wood, freeing the fibres for pulp, and became famous as the inventor of the sulphite process to make wood pulp for paper production. |
