I'm trying to wire up a DS1307 RTC to my Model B Pi. I'm following the diagram as shown in this crude image 
and I've also tried it like this
but it isn't recognized by the Pi. When I run
i2cdetect -y 1
I don't see anything registered. When I wire up a complete RTC I bought on ebay, I see it registered as expected. What am I doing wrong?
Parts used:
