How to read a refractometer?

So my friend broke my hydrometer right as we started brewing. It wasn't a complete bust b/c my bro has a refractometer... the problem is it doesn't have instructions with it and he is unreachable (on vacation). I have googled how to read it but they honestly don't tell me anything. It tells me that whatever reading I have is in percentage Brix, but I have yet to find a place that converts Brix into a gravity reading (i.e. 1.050 or whatever). Right now it reads 15.8 brix...

If you're using it on wort before there has been any fermentation, you can multiply the Brix reading by 4. This will give you a close idea of the SG. So if you have a Brix reading of 15, the SG would be 60, or 1.060. If the Brix is 10, the the SG is 40 or 1.040.
Once fermentation has started the alcohol content skews the reading and you will need to run the Brix reading through a spreadsheet like the one on Morebeer.

Good Luck...

I use this one:

http://onebeer.net/refractometer.shtml