How can I hide certain tr's?

How can I hide certain tr's?

I am working on a webapp that, if there are more than 10 rows to a table, has any rows in excess of 10 initially hidden, but discoverable via clicking on a link.

In the source, I marked the rows that should be hidden with two classes, one of them named "additional", and tried the following: 
$.ready( function() { $(".additional").hide(); } );
That didn't seem to do anything. So, as a test, I moved the script to the bottom of the page and simply had: 
$(".additional").hide();
That still didn't do anything.

I can workaround by using CSS to initially set display to "none" for the tr's that should not be initially displayed, but I'd like to know why the hide didn't work, and what I need to know to use .hide() and show() for my document.

Jonathan Hayward