引用自 https://launchpad.net/~cassou/+archive/ubuntu/emacs

To ensure a clean installation, please follow these steps:

$ sudo apt-get update
$ sudo apt-get install
$ sudo apt-get purge emacs emacs-snapshot-common emacs-snapshot-bin-common emacs-snapshot emacs-snapshot-el emacs-snapshot-gtk emacs23 emacs23-bin-common emacs23-common emacs23-el emacs23-nox emacs23-lucid auctex apel emacs24 emacs24-bin-common emacs24-common emacs24-common-non-dfsg emacs24-el

To add this PPA:
$ sudo add-apt-repository ppa:cassou/emacs
$ sudo apt-get update

Then, for emacs-snapshot:
$ sudo apt-get install emacs-snapshot-el emacs-snapshot-gtk emacs-snapshot

*Or*, for emacs24:
$ sudo apt-get install emacs24 emacs24-el emacs24-common-non-dfsg