|Karl Schwarzschild's Pocket Watch|
This pocket-watch was originally owned by the Germain physicist, Karl Schwarzschild and was imbued with time altering abilities.
He provided the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced general relativity. The Schwarzschild solution, which makes use of Schwarzschild coordinates and the Schwarzschild metric, leads to a derivation of the Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole.
This artifact is housed in Warehouse 13 and was used by Paracelsus to travel through time to June 10th 1541.