antedating of "clock wise" (1882)

[Mullins, Bill]

Sugars are the chemicals most commonly brought up, when discussing how
chemicals may rotate polarized light.

Jean-Baptiste Biot did the early work on this in the 1830s.  From a
physics text online:

Quote starts *********************

Optically active organic molecules have a spiral structure like a
right-handed or
left-handed screw. It is this spiral nature of the molecule, which
rotates the plane of
polarization of light passing through it. Right-handed molecules will
rotate the plane of
polarization clockwise as viewed in the direction of the beam, while
left-handed
molecules rotate the plane in a counterclockwise direction. If
right-handed and lefthanded
species of a given molecule occurred with equal abundance, then there
would be
no net effect on the polarization of light passing through. However,
naturally occurring
biological molecules of a given species are always either purely
right-handed or purely
left-handed. Probably at the time of origin of life, organic molecules
corresponding to
both right and left-handed forms were produced. Laboratory synthesis
always produces
both types. However, in the first living systems on earth, left or
right-handed activity
could have been adopted purely as a matter of chance and, once a
particular asymmetry
was established, it maintained itself. This conjecture implies that
optical activity is
probably a feature of life on any planet and also that the chances
should be equal for
finding a given terrestrial organic molecule or its mirror image in
extraterrestrial life
forms, if any exist.
Optically active organic compounds are classified as d (dextro-) when
righthanded
and l (lev-) when left-handed. For instance, the most common sugar is
dextrose
or d-glucose (C6H12O6) which is right-handed. There is also l-glucose
(levulose), called
invert sugar of fructose (fruit sugar). Sucrose (C12H22O11), cane sugar,
is right-handed.

Quote ends***************************

As the above says, dextro- molecules rotate linearly polarized light to
the right, and
levo- molecules rotate to the left.  The left/right sense is as follows:
when looking in
the direction of propagation of light, a vertically polarized ray will
rotate CW (right) in
dextro- solutions, and CCW (left) in levo- solutions.  OED has 1853
cites for both of these
prefixes.



> -----Original Message-----
> From: American Dialect Society
> [mailto:ADS-L at LISTSERV.UGA.EDU] On Behalf Of Joel S. Berson
> Sent: Monday, July 11, 2005 10:56 AM
> To: ADS-L at LISTSERV.UGA.EDU
> Subject: Re: antedating of "clock wise" (1882)
>
> ---------------------- Information from the mail header
> -----------------------
> Sender:       American Dialect Society <ADS-L at LISTSERV.UGA.EDU>
> Poster:       "Joel S. Berson" <Berson at ATT.NET>
> Subject:      Re: antedating of "clock wise" (1882)
> --------------------------------------------------------------
> -----------------
>
> And proteins (although I don't know what the technical terms
> are for the
> left- and right-handedness).  I am not sure it is the same
> kind of twist, but the "wrong" one in the relevant protein is
> what leads to mad cow disease and BSE.
>
> Joel
>
> At 7/11/2005 11:04 AM, you wrote:
> >Another context in which direction of spin is significant
> is that of
> >imparting twist to fiber in in the production of thread or
> yarn.  These
> >are referred to as "Z twist" (right-handed) or "S twist"
> (left-handed).
> >Individual rovings are given a twist in one direction to
> produce plies
> >and then the several requisite plies are twisted in the other
> >direction, stabilizing the whole.
> >A. Murie
>