DYK With very few exceptions (a few copper hatchets and spear heads in the Great Lakes region), the peoples of the Americas and the Pacific remained at the Neolithic level of technology, with no metal making ability, up until the time of European contact.
DYK In the 1800s, studies of the optical spectrum of the the Sun's visible surface yielded absorption lines that did not match any atomic elements that were at that time known on Earth. In 1868, Norman Lockyer hypothesized that these absorption lines were there because of the presence of a new element which he named "helium", after the Greek Sun god Helios. It was not until 25 years later that helium was isolated on Earth.
DYK A recent innovation in bandage material has been made that has significantly improved clotting ability compared to gauze bandages. These new bandages contain a mixture of ground shrimp shells and vinegar, a mixture that has been found to clot blood almost instantly. The chitosan in the shrimp shells has a positive charge, while the cells present in blood have negative charges. The negative charge of the cell is attracted to the positive charge of the chitosan. As soon as they touch, the cells fuse to the chitosan and form a clot. Bandages of this type are already in use by the US Military in Afghanistan and Iraq.