Changes I would make

[Geoff Bannister]

No: HPFGUIDX 177454

--- In HPforGrownups at yahoogroups.com, "eggplant107" <eggplant107 at ...> wrote:

 
"Steve::
> > 'Spiral' is a lot more simple and
> > straight forward that 'Helix'. 
> 
> It is also incorrect, the steam could not be rising in a spiral. A
> spiral is 2 dimensional, a Helix is 3. And far from being "fancy"
> helix has one fewer letter than spiral.
 
Geoff:
 > > I know a fair bit about helices because 
> > I am a mathematician 

Eggplant: 
> I was a math major.

Geoff: 
> > DNA and its double helix is not the 
> > usual stuff of casual conversation
> > over coffee and biscuits. 
> 
> And if JKR had the opportunity to do a little something to help change
> that sorry fact then she should have done so. I'm not saying this
> spiral business is earth shattering or anything, its just a little
> thing that nags at me for some reason. 

Geoff:
Well, you've made a bit of an issue about it....

Speaking from a Maths point of view, I quite agree with you that a 
spiral should be two-dimensional and a helix three-dimensional.

However, in the vernacular, this subtlety is not always recognised. 
Speak to the ordinary British man-in-the-street, and probably 
also to his counterpart in the US, and talk about a 'helix staircase' 
and you would probably get a puzzled look and a "Come again?".

Say 'spiral staircase' and a little bulb would light up over their heads. 
Another case of the common use of a word not completely matching 
its correct definition.

So perhaps we may allow Hermione the luxury of her interpretation:

'"It's the most powerful love potion in the world!" said Hermione.

"Quite right! You recognised it, I suppose, by its distinctive 
mother-of-pearl sheen?"

"And the steam rising in characteristic spirals," said Hermione 
enthusiastically...'

(HBP "The Half-Blood Prince" p.176 UK edition)