"Back 40" is a term used
colloquially in
America to describe a parcel of land, specifically one sixteenth of a
section, constituting the smallest unit of
agricultural land commonly
surveyed ("back 40," "front 40"); "back 40" also refers to an undeveloped plot of land (as on a farm, ranch, etc.) of unspecified size. Further reading:
Public Land Survey System#Popular culture
I'm going to be busy with construction for the next several days / weeks. But I may put a deposit down before the fellow changes his mind and I'll get some photos. It is a specialty instrument;- but that is why it is interesting to me.