Scroll without the mouse in Firefox and Evolution mail windows

Both Firefox and Evolution have a hidden caret browsing feature. This
is where a cursor appears in a web page or received email, just like in
a word processing document. Just like in a word processor, its position
can be controlled using the cursor keys. When the cursor reaches the
bottom or top of the screen, the page (or email) scrolls.
Caret browsing was designed as an accessibility feature for those who
find reading difficult but it’s proved popular for every kind of user. This
is because it allows people to navigate web pages or emails without tak-
ing their hands off the keyboard (there’s no need to reach for the mouse
scroll-wheel, for example), and also keep track of where they were last
reading should they walk away from their computer. In addition to navi-
gation, text can be highlighted in the usual way by holding down Shift
and using the cursor keys. It can then be copied in the usual way by
typing Ctrl + c .
To activate caret browsing in either application, just hit F7 while the
program is running. The cursor will appear at the top of the web page
or email preview window, although can be repositioned by clicking the
mouse anywhere.