Convert from electron to keel [coal]

Unit Definition (electron)
The electron is the mass of the electron, often used as a unit of mass in particle physics. An electron has a mass of about 9.109 382 x 10E-31 kilogram, 9.109 382 x 10E-28 gram, or 0.510 9989 million electronvolts.

Unit Definition (keel [coal])
The keel is a traditional British unit of weight for coal. After considerable variation, the keel of coal was standardized in 1695 as 21.2 long tons, or 47 488 pounds (21.5402 metric tons). This is the approximate weight of coal carried at that time by barges on the river Tyne in northern England; the barges were also called keels, from the Dutch word kiel for such a ship.