24 Sep
2005
24 Sep
'05
12:39 p.m.
On 9/24/2005 at 11:45 AM Fred Cisin wrote:
<nitpick>
grooves "like a phonograph record" would be "SPIRAL", NOT
"helical".
"Helical" would be like a spiral stair case, or threads on a bolt.
Some of the early (Edison?) sound recorders DID cut helical threads on the
outside of a cylinder.
</nitpick>
I think a little leeway can be granted here--after all, the common garden snail, helix
hortensis (whence comes our word "helix") is actually more of a spiral than a
helix:
http://www.weichtiere.at/Schnecken/galerie/galerie_1024.html
And the species of tuba known as a helicon has a distinctly spiral shape:
http://www.horncollector.com/Low%20Brass/Helicon/Helicon%201.jpg
Perhaps an easy way to remember the difference is that a helix is the shape of a spiral
staircase! :)
Cheers,
Chuck
