why doesn't work this simple code ?

why doesn't work this simple code ?

  1. <div id="d-source">
       <div>       
         <img src="8.jpg" class="pic" id="pic1" /> </div>

       <div>
         <img src="9.jpg" class="pic" id="pic2" /> </div>       
    </div>

      <script type= "text/javascript" language= "javascript" >  
         $( '#pic1' ).append($( '#pic2' ))  
    </script>