... actual weaponry have been unearthed from the three vaults, including arrow-heads, swords, spears and halberds. Two long-handled swords dug ... the study of Qin technology was the discovery of bronze arrow-heads and swords treated with a preservative that has prevented ... and various other elements, including nickel, magnesium, and cobalt. The arrow-heads which contain 7.71 percent lead are considered by ...