been reached at last, since nothing less would have burst the iron casing." Borehole drilling: By at least the Han Dynasty (202 BC – 220 AD), the Chinese used deep borehole drilling for mining and other projects; The British sinologist and historian Michael Loewe states that borehole sites could reach as deep as 600 m (2000 ft). K.S. Tom describes the drilling process: "The Chinese method of deep drilling was accomplished by a team of men jumping on and off a beam to impact the drilling bit while the boring tool was rotated by buffalo and oxen." This was the same method used for extracting petroleum in California during the 1860s (i.e. "Kicking Her Down"). A Western Han Dynasty bronze foundry discovered in Xinglong, Hebei had nearby mining shafts which reached depths of 100 m (328 ft) with spacious mining areas; the shafts and rooms were complete with a timber frame, ladders and iron tools. By the first century BC, Chinese craftsmen cast iron drill bits and drillers were able to drill boreholes up to 4800 feet (1500 m) deep. By the eleventh century AD, the Chinese were able to drill boreholes up to 3000 feet in depth. Drilling for boreholes was time consuming and long. As the depth of the holes varied, the drilling of a single well could up to nearly one full decade. It wasn't up until the 19th century that Europe and the West would catch up and rival ancient Chinese borehole drilling technology. Breeching strap: The breeching strap traces its roots back to the Chinese invented breast-strap or "breastcollar" harness developed during the Warring States (481–221 BC) era. The Chinese breast harness became known throughout Central Asia by the 7th century, introduced to Europe by the 8th century. The breeching strap would allow the horse to hold or brake the load as horse harnesses were previously attached to vehicles by straps around their necks as previously designed harnesses would constrict the horses neck preventing the horse from pulling heavier loads. The breeching strap acted as a brake when a cart tries to run forward when moving downwards on a slope and also make it possible to maneuver the cart in the reverse direction. Brine mining: Around 500 BCE, the ancient Chinese dug hundreds of brine wells, some of which were over 100 meters (330 feet) in depth. Large brine deposits under the earth's surface were