Invention and Engineering
J. George Leyner (1860–1920) was a machinist who invented mining equipment that enhanced safe mining operations while also improving efficiency. He held a significant number of United States patents and established his own equipment manufacturing companies. In particular, he invented a drill that used water to suppress generation of airborne particles during mining, thereby reducing the risk of miners' developing silicosis. The device later became known as the Leyner drill.
4-2-2.
History of rockets.
Text from Wikipedia; plate via Wikimedia Commons. Text CC BY-SA 4.0; plate freely licensed (see Commons). Source record. Images and catalogue data are reproduced from open-access collections.