Priori Incantatem - further thoughts (longish)

[Geoff Bannister]

No: HPFGUIDX 100201

Geoff:
Sometimes, a series of posts will trigger off a new line of thought 
and, looking at some of the recent posts about the Priori Incantatem 
spell, my mind began to run off along a track I had not considered 
before. This spell occurs at least twice in GOF, each time under 
different circumstances.

The first is after the Quidditch World Cup Final when the Dark Mark 
is seen and Winky is discovered holding Harry's wand.

`"Well, we'll soon see," growled Mr. Diggory, looking 
unimpressed. "There's a simple way of discovering the last spell a 
wand performed, elf, did you know that?"
Winky trembled and shook her head frantically, her ears flapping as 
Mr.Diggory raised his own wand again and placed it tip to tip with 
Harry's.
"Prior Incantato!" roared Mr.Diggory.
Harry heard Hermione gasp, horrified, as a gigantic serpent-tongued 
skull erupted from the point where the two wands met but it was a 
mere shadow of the green skull high above them, it looked as though 
it were made of thick grey smoke: the ghost of a spell.
"Deletrius!" Mr.Diggory shouted and the smoky skull vanished in a 
wisp of smoke,'

(GOF "The Dark Mark"  p.123 UK edition)

the second occasion is, of course, the graveyard scene.

`Voldemort was ready. As Harry shouted "Expelliarmus!", Voldemort 
cried "Avadra Kedavra!"....


.One of the beads of light was quivering, inches from the tip of 
Voldemort's wand. Harry didn't understand why he was doing it, didn't 
know what it might achieve
 but he now concentrated, as he had never 
done in his life, on forcing that bead of light right back into 
Voldemort's wand.... and slowly
. very slowly.... it moved along the 
golden thread.... it trembled for a moment.... and then it 
connected....
At once, Voldemort's wand began to emit echoing screams of pain.... 
then – Voldemort's red eyes widened with shock -  a dense smoky hand 
flew out of the tip of it and vanished.... `

(GOF "Priori Incantatem" p.577 UK edition)

`He was glad when Sirius broke the silence.
"The wands connected?" he said, looking from Harry to 
Dumbledore. "Why?"
Harry looked back at Dumbledore, on whose face there was an arrested 
look.
"Priori Incantatem," he muttered.
His eyes gazed into Harry's and it was almost as though an invisible 
beam of understanding shot between them.
"The reverse spell effect?" said Sirius sharply.
"Exactly," said Dumbledore. "Harry's wand and Voldermort's wand share 
cores"....

...."So what happens when a wand meets its brother?" said Sirius.
"They will not work properly against each other," said 
Dumbledore. "If, however, the owners of the wands  force the wands to 
do battle.... a very rare effect will take place. One of the wands 
will force the other to regurgitate spells it has performed -  in 
reverse. The most recent first
. and then those which preceded it...."
He looked interrogatively at Harry and Harry nodded.'

(GOF "The Parting of the Ways" p.605 UK edition)

My take on this is that there are two modes of operation for the 
Priori Incantatem spell - voluntary and involuntary. In the voluntary 
case, we see the wand being which is being "questioned" being placed 
point to point with an "interrogating" wand and just the last spell 
being shown.

In the involuntary case, this would only seem to operate when, as 
Dumbledore remarks, they share cores. In this case, the results are 
different. It would appear that the command "Priori Incantatem" is 
not needed because neither Harry nor Voldemort used it. The wand then 
apparently goes on producing former spells in reverse order until the 
link is broken - although there does appear to be a time lag between 
the appearances, long enough to allow the emerging figures to say 
something to Harry. An interesting point here is that the figures 
seem to know what is going on and, even more curious, the fact that 
the "echo" of Bertha Jorkins knows Harry's name; is an 
appearing "echo" so aware of the surrounding as to perhaps see 
Harry's scar? 

It is also recorded that, in this instance, the wands became hot; is 
this perhaps related to the spells which were spoken when the 
connection occurred? Is the golden cage effect only because the 
shared cores are from a phoenix?

Two other points. In both cases, the "echoes" produced are described 
as grey and smoky. The other is that slightly differing forms of the 
spell wording are mentioned. Amos Diggory uses "Prior Incantato" 
which sounds suspiciously like a genitive whereas "Priori 
Incantatem" - which is not actually heard being used in this book - 
looks like an accusative. I am trying to remember whether any of the 
spells used in the books appear in more than one version and, if so, 
if that affects the result.

Anyone care to pick holes or add their two pennyworth?