using "lein repl" as the Emacs Inferior Lisp REPL as opposed to a custom script that does "java -jar clojure-1.4.0.jar"

different even from what */usr/bin/clojure* is: mperdikeas@ubuntu:~# $ which clojure /usr/bin/clojure mperdikeas@ubuntu:~# $ /usr/bin/clojure Clojure 1.1.0 user=> mperdikeas@ubuntu:~# $ lein repl REPL started; server listening on localhost port 4840 user=> (clojure-version) "1.2.1&

Emacs 23 error: Package `clojure-mode' is not available for installation

I am using* Emacs GNU Emacs 23.3.1* on Ubuntu and I am following the instructions found here: https://github.com/technomancy/clojure-mode/blob/master/README.md on how to setup clojure-mode for Emacs. But launching my Emacs reports the following error: error: Package `clojure-mode' is not avail