Reading a document in two columns

[Saswat Anand]

Hi,

I have a wide monitor. So I usually split emacs into two columns. 
Although I can see different parts of the same document in the two 
columns, I wish emacs would know that it is the same document shown in 
the two columns and do the following:
At any point of time if the last line of the left column corresponds nth 
line of the document, the first line in the right column corresponds to 
(n+1)th line of the document.

So whenever the content of the one column changes due to scrolling or 
cursor movement, I wish the content of the other column is also changed 
to maintain the above invariant.

I suspect this functionality is already there. Could anyone please point 
it out.

Thanks a lot.
Saswat