Convert from nanogram to flask

Unit Definition (nanogram)
The nanogram is a metric unit of mass equal to 10E-9 gram, or one millionth of a milligram.

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.