Accordian Defaults

Accordian Defaults

When using the Accordian, I have two things I'm trying to figure out: #1 the default is to have he first div open.  I have 4 div's in my accordian and want the 4th div to default as open, not the first.  #2 the default is when you open one panel the other one that is open, closes.  I want it to remain open until the user closes it.  My code:

<script>
          $( function() {
            $( "#accordion" ).accordion({
          collapsible: true
            });
          } );
  </script>

<div id="accordion">
      <h3 class="Accordian">Panel One</h3>
                  <div> test 1</div>
      <h3 class="Accordian">Panel Two</h3>
                  <div> test 2</div>
      <h3 class="Accordian">Panel Three</h3>
                  <div> test 3</div>
      <h3 class="Accordian">Panel Four</h3>
                  <div> test 4</div>
</div>