Convert from nanogram to sack [UK, wool]

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

Unit Definition (sack [UK, wool])
The sack [UK, wool] is a traditional unit of weight, varying for different commodities shipped in sacks. In Britain, for example, the sack was a traditional measure for wool, fixed by Edward III at 364 pounds (26 stone) in 1340.