no emacs server variable `server-name'

[Harry Putnam]

I've only been using emacsclient a short while.
I thought maybe I'd like to try having two servers.  One with gnus
running and another for some perl scripting I'm working on.

Reading parts of the documentation I see:
(info "(emacs)Emacs Server")
     You can run multiple Emacs servers on the same machine by giving
  each one a unique "server name", using the variable `server-name'.
  For example, `M-x set-variable <RET> server-name <RET> foo <RET>'
  sets the server name to `foo'.  The `emacsclient' program can
  specify a server by name, using the `-s' option (*note emacsclient
  Options::).
  
In a recent cvs of emacs-23