Problem with classes, functions and hooks

Hi,
I am currently developing some extensions for a theme and I got stuck on a problem:
I have a class

class myClass
{
function myFunction()
{
return "Anything";
}
}
$myClass = new myClass();

I also have a function which creates a tag for easier use inside the theme called the_extension :

function the_extension()
{
global $post;
if($post->ID == '1')
{
add_action('init', array('myClass', 'myFunction'));
}
}

This doesn’t work… Where did I go wrong???

Thanx in advance