In reply to:

all the posts regarding driving on the right (or not) have reminded me of one of my quixotic word quests. there is an actual word, purportedly of Scottish origin, which means "the right-hand hindmost horse that walks in the furrow in plowing" -- the word is 'furrahin' [it's in W3]. so, what is the word (if it exists) for the left-hand hindmost horse; and, if the word doesn't exist, why did they have a word for the right-hand one?

Do you ever have non-quixotic word quests, tsuwm?

'Furrahin' has me intrigued. Ahin is a Scottish word for behind, and fur or furr for furrow, so the word itself gives no clue to the horse being on the right. I found a glossary of Robbie Burns' poems that gave 'fur-ahin' (sic) as "the hindmost plough-horse in the furrow". I can't claim to be an expert on horse-drawn ploughs, but I wondered whether the reason 'right' isn't specified is that the usual configuration would result in the horses on the right walking in the furrow, while those on the left walk on the unploughed ground. As in this photo:
http://www.eastdevon.net/landscapes/old_new/page_90.htm

None of which answers your questions.