Unable to select SPAN sibling

Question

Unable to select SPAN sibling

I can’t understand why this code changes the color of the DIV element to blue, but does not change the color of the SPAN element. Any ideas?

<html>
<head>
  <script src="http://code.jquery.com/jquery-latest.js"></script>
  <script>
    $(document).ready(function(){
      $("#prev ~ div").css("color", "blue");
      $("#prev ~ span").css("color", "red");
    });
  </script>
</head>
<body>
  <span id="prev">span#prev</span>
  <div>div sibling</div>
  <span>span sibling</span>
</body>
</html>