Pat Naughtin wrote:
>
> Dear Jim and All,
>
> To add to Jim's scholarship on the matter of micron (mikron or mikrom?).
>
> I looked up my 1971 edition of 'The Compact Edition of the Oxford English
> Dictionary On Historical Principles'.
>
> It had two relevant entries 'mikrom' and 'micron, mikron'
>
> Mikrom
>
> 1898 Lord Kelvin 'Nature' 17 Nov 57/1
> 'Langley, fourteen years ago used ... the word 'mikron' to denote the
> millionth of a metre. The letter n has no place in the metrical system, and
> I venture to suggest a change of spelling to 'mikrom'.
What is it about this citation that tickles me so? Where on Earth did
Lord Kelvin (William Thompson, 1824/1907) come up with the notion that
"n" has no place in the "metrical" system? Of course, "nano" had not yet
been assigned. On the other hand, this is a possible link to
"micrometer", which is possibly why Lord Kelvin stated a preference for
"microm" over "micron", taking the last letter to be the symbol for
"meter". This then raised the question in my mind about "micro" as a
prefix.
Now that I have finished writing an interesting test for my students to
enjoy taking tomorrow, I've spent a few minutes and have dug a little
deeper. Here is what I have learned from "Le Syst�me M�trique" by Henri
Noreau (Chiron, Paris, 1975). I'll put the French first then my rough
translation. This is from Tableau 6, "Pr�fixes SI", footnote 2 and in
case � does not reproduce on your browser, it is the lowercase Greek
letter mu:
[quote:]
Les pr�fixes "m�ga" et "micro" �taient d�j� employ�s vers 1870 par les
�lectriciens; ils furent officiellement adopt�s en France par le d�cret
sur les unit�s de mesure du 26 juillet 1919.
Les mot "micron" (symbole �), propos� en 1870-1872, fut adopt� par le
C.I.P.M. en 1879 pour d�signer le milli�me de millim�tre. Dupuis 1967,
l'unit� "micron" est supprim�e; le symbole � est r�serv� pour le pr�fixe
"micro" et le milli�me de millim�tre est maintenant d�sign� par
"microm�tre", symbole �m.
[end quote]
[translation:]
The prefixes mega and micro first came into being around 1870 for [the
field of] electricity; they were officially adopted in France for
multiples of the units of measure on 1919 July 26.
The word "micron" (symbol �), proposed in 1870/72, was adopted by the
CIPM in 1879 as a designation for the thousandth part of a millimeter.
Since 1967, the unit "micron" has been superseded; the symbol � is
reserved for the prefix "micro" and a thousandth of a millimeter is now
named "micrometer", symbol �.
[end translation, with my apologies to the people of France*]
Jim
* caveat: I refused -- as an exercise -- to let myself use a dictionary
or translation program.
--
Metric Methods(SM) "Don't be late to metricate!"
James R. Frysinger, CAMS http://www.metricmethods.com/
10 Captiva Row e-mail: [EMAIL PROTECTED]
Charleston, SC 29407 phone/FAX: 843.225.6789
