Newbie jQuery question

Newbie jQuery question

I am trying to understand how chaining works with jQuery.  Why is it that the variable "allOptionsPool1" in line 5 below correctly contains the value of the array contained in "allOptions", but "allOptionsPool2" in line 8 is undefined after its execution?

Also, after execution the 'Pools' element contains an object named "allOptions", but not "allOptions2".
  1. var allOptions = [{ key: '0', value: '0', text: 'Text 0' }, { key: '1', value: '1', text: 'Text 1' }, { key: '2', value: '2', text: 'Text 2' }];

  3.     var pools = $('#Pools');
  4.     pools.allOptions = allOptions;
  5.     var allOptionsPool1= pools.allOptions;

  7.     $('#Pools').allOptions2 = allOptions;
  8.     var allOptionsPool2 = $('#Pools').allOptions;