On 3/7/2012 4:12 PM, ng_reader wrote:

What gives?

To wire the second light, you should have run the cable from the first
light, not the switch. You have only two wires coming into the switch
from the existing light. This is a switch leg and a return. You don't
have a feed, which consists of a hot leg and a neutral. What you've done
is wired the second light in series with the first.

My first thought was to run off the first light, but I had no more
knock-outs to knock out. It had all the cables it could manage! I could
have added a junction box right next to it, but, opted instead to remove
and replace the light switch with a larger box able to accommodate the
additional cables. I think I will try the 3-way switch as that sounds
logically like it might work.

It's not going to work. You don't have the necessary wires to do what
you want