Convert from flask to packen [Russia]

Unit Definition (flask)
The flask is a commercial unit of weight formerly used to measure liquid mercury (or quicksilver, as it was called). The flask was equal to 76.5 pounds avoirdupois, which is equivalent to almost exactly 34.7 kilograms.

Unit Definition (packen [Russia])
The packen is a traditional Russian unit of weight equal to 1200 funte, 30 pudi, 1083 pounds, or 491.4 kilograms.