Convert from barleycorn to micron

Unit Definition (barleycorn)
The Barleycorn is an old English unit of length. The custom of using seeds as units of length or weight is very common in farming societies. In Anglo-Saxon England, where barley was a basic crop, barleycorns played this traditional role. The weight of a barleycorn, later renamed the grain, is the original basis of all English weight systems including the older troy system and the later avoirdupois system. As a length unit, 3 barleycorns were equal to the Saxon ynce (inch). The English foot was actually defined as 12 of these ynces, that is, as 36 barleycorns.

Unit Definition (micron)
A unit of length. One Micron = 39 millionths of an inch (.000039"). Contaminant size is usually described in microns. Relatively speaking, a grain of salt is about 60 microns and the eye can see particles to about 40 microns. Many hydraulic filters are required to be efficient in capturing a substantial percentage of contaminant particles as small as 5 microns. A micron is also known as a micrometre, and exhibited as µm.