Back to topic...
Even better about lenght unit, so I am back to the prefered topic in this thread :
From : http://en.wikipedia.org/wiki/List_of...rement#Sheppey
A measure of distance equal to about 7⁄8 of a mile (1.4 km), defined as the closest distance at which sheep remain picturesque. The Sheppey is the creation of Douglas Adams and John Lloyd, included in The Meaning of Liff, their dictionary of putative meanings for words that are actually just place names. It is named after the Isle of Sheppey in the UK."