Quoting from the jQuery website:
Given a jQuery object that represents a set of DOM elements, the
.add()method constructs a new jQuery object from the union of those elements and the ones passed into the method.
Hence, when you do .add() it will not save the added elements, you would have to explicitly assign the element to the newly created object i.e
var $elements = $('.elements');
$elements = $elements.add($('#anotherelement'));