Centuries: 2nd century - 3rd century - 4th century
Decades: 190s 200s 210s 220s 230s - 240s - 250s 260s 270s 280s 290s
Years: 237 238 239 240 241 - 242 - 243 244 245 246 247
Births
Deaths
... to a smaller extent by the slipping friction. The device is covered by US patents 3,726,146 (1973) and 5,353,655 (1994) by L.A. Mishler and US patent ...