I saw this girl on Oprah... found just what you need here:
http://grammar.qdnow.com/2007/02/01/further-versus-farther.aspx
The quick and dirty tip here is that you use farther to talk about physical distance and further to talk about metaphorical, or figurative, distance. It's easy to remember because farther has the word far in it, and far obviously relates to physical distance.
For example, you might say, “Squiggly and the aardvark walked to a town far, far away. After many miles, Squiggly grew tired. 'How much farther?' he asked in despair.”
Did you hear that? Squiggly used farther because he was asking about physical distance.
If the aardvark was frustrated with Squiggly, he might say, “Squiggly, I'm tired of your complaining; further, I'm tired of carrying your marimbas.” In this case, the aardvark used further because he isn't talking about physical distance, he's talking about a metaphorical distance: further along the list of irritations.
Sometimes the quick and dirty tip breaks down because it's hard to decide whether you're talking about physical distance or not. For example, Lisa asked about the sentence “I'm further along in my book than you are in yours.” You could think of it as a physical distance through the pages and use farther, or as a figurative distance through the story and use further.
The good news is that in these ambiguous cases it doesn't matter which word you choose. The Oxford English Dictionary, Fowler's Modern English Usage, and a number other sources say that, in most cases, it's fine to use further and farther interchangeably when the distinction isn't clear. People have been using them interchangeably for hundreds of years!
Just remember that farther has a tie to physical distance and can't be used to mean moreover or in addition. Grammar Girl says she doesn't know why, but when she means in addition she has always used furthermore instead of further. For example, if you had asked her last night how she was doing, she might have responded by saying, “I'm tired, and furthermore, we are out of Kleenex(R).” Because furthermore and farther are more different from each other than further and farther, she never gets confused.
So there you go. The quick and dirty rule is that farther relates to physical distance and further relates to figurative distance. If you can't decide which one to use, you're safer using further because farther has some restrictions, and if you tend to get confused, try using furthermore instead of further.
Which of the following is correct?
but here goes... )
