Master of This School

[dungrollin]

No: HPFGUIDX 111802

Zendemort:

<snip>
Why did he call himself "Master of this school" as opposed 
to "Professor of this school"? It's the emphasis on the 
word "master" which shows dominance and power. 
--------------

Tonks:

<snip>
It is sort of like saying "with the full power invested in me I 
hereby demand that you show yourself" It is in sense a spell 
directed to the map to show itself, and it is a spell that requires 
a show of dominance and power.

Ginger chimes in:
 <snip>
What strikes me is the context of his statement.  Going to p. 286 of 
the US paperback, he first asks Harry what it is, gets nowhere with 
that, then taps the paper with his wand and says "reveal your 
secret".  Nothing happens.  He says "show yourself" and taps it 
again.  Nothing happens.  

Then he gives it the "Professor Severus Snape, master of this 
school, 
commands you to yield the information you conceal." and *hits* it 
with his wand.  Immediately, the paper responds.

My little theory is that at some time in the past, Masters and 
Mistresses of the school (as they would have been known then) were 
given a spell to force magical things found in the possession of 
students to reveal themselves.  
<snip>
We have seen that the map is semi-sentient, so it would have known 
that this would be a really good time to stay incognito as a scrap 
of 
paper, and it tries to do so.  But under that command (or spell?) it 
is forced to say something, so it does so in its own charming way.  
It insults Snape.

Dungrollin can't stop herself:

The map didn't respond at first, because he didn't say `I
solemnly 
swear that I am up to no good' (or whatever it was exactly), but
I 
always assumed that the map eventually did respond because he used 
the words `Severus Snape', (rather than the pompous
`Master of this 
school' bit) and it couldn't resist insulting him.  

If Snape was always sneaking around trying to work out what the 
marauders were up to, and trying to get them expelled, it seems in 
keeping with their characters that when building in the `insult-
anyone-who-tries-to-read-you-without-the-proper-incantation'
charm, 
they'd have added a few personalised insults in case Snape was
the 
one who found it.

Dungrollin