This is the difference:
She doesn't want them to die
but
I want them
to live.

Magical Elements in Wuthering Heights.

There are three potentially magical or supernatural episodes in Wuthering Heights, in which mirrors or windows – possibly even eyes – act as some sort of lenses, and perhaps portals, through which time seems to slip. The first is when Mr Lockwood breaks the window in Catherine's old bed-chamber and encounters her ghost wailing to get back in, telling him that "it's been twenty years" (which is accurate, but which Lockwood can't yet have known). Entering the room, Heathcliff quickly reads the situation, and, banishing Lockwood, attempts to call Catherine back through the window — to no avail at this point, though it may be through a window that she later comes to join him.

The second event seems to mirror this scene, as though the two are connected across time; it occurs just before Catherine dies at Thrushcross Grange, tended by Nelly Dean. She looks into a mirror and sees a greatly aged Nelly, but sees also her old room at the Heights, with a "black press" to confirm the location. There is no black press in her room at the Grange, but there IS such a black clothes press in Cathy's old bedroom at the Heights (a 'press' or 'clothes press' is an old-fashioned clothes cupboard).
“The black press,” says Nelly, “where is that?” “It's against the wall, as it always is,” says Cathy. But she also sees another face there, which she does not recognise: “Don't you see that face? […] Oh! Nelly, the room is haunted!”

Could this be Lockwood's face, twenty years in the future, peering out from Cathy's old room? No one else in the entire novel looks out of Cathy's room and sees her out there, so if not then whose face? It has no coherent function in the narrative otherwise. Is this the moment when Lockwood and Cathy see each other through the window of Cathy's old bedroom across a gulf of twenty years? Just prior to this episode we are signalled that we have entered some magical space and time when Catherine says that her bed is at this moment the "fairy cave beneath Penistone Crag" – presumably a place with preternatural possibilities.

The third magical event comes when Heathcliff dies: Nelly notices his bedroom window is wide open, with the rain blowing in, and then finds him dead in bed, smiling, with his eyes also wide open, as if to echo these open glassy channels across death and time. What else could have enabled Heathcliff to die smiling like that, unless Catherine has somehow bridged an impossible divide and they have been reunited? Of course Emily Brontë leaves us with the suggestion that their ghosts are indeed now united, and have even been seen walking together, but has this been accomplished by this through-lined literary device of the windows and the mirror, and even the eyes?

Emily clearly devises and constructs these episodes to suggest that the supernatural elements might possibly be real rather than imaginary – for how else would Lockwood know of the twenty years gulf; why would Heathcliff be smiling, even in death; and why would his window (recalling the previous windows and the mirror) be open to the rain?

And – if we are not supposed to consider these supernatural intrusions as real – why would the sheep at the end of the book refuse to walk past "t' nab" after the shepherd boy has sighted the two ghosts there? The boy's weeping and fear might be explicable by superstition and ghostly gossip, but how is one to explain the behaviour of those sheep? Yes, sheep could be influenced by the behaviour and responses of the human shepherding them, but that really is not what Emily meant. She wanted us at least to consider the possibility that Cathy and Heathcliff had genuinely made it, and were together again at last.

(Publication forthcoming in the Brontë Society magazine.)