Spry Effect issue

I’m playing with Spry and am trying to acheive a horizontal slide. There is an option for it in here:
http://labs.adobe.com/technologies/spry/articles/effects_api/index.html
but it’s not working for mine, vertical scrolling works great.

Current;y i’m trying

 <a onclick="Spry.Effect.Blind('topslide', {duration: 1000, from:  '35px', to:  '90px',horizontal:true,toggle:true});" >

and it’s vertically scrolling still