Re: SI &c., eh?

[David Bowman <dbowman@TIGER.GEORGETOWNCOLLEGE.EDU>]

Regarding:

> thanks guys!  old habits die hard.  i'm still trying to figure out which
> ones we're supposed to capitalize, and which we're not.  liters?  kelvins?

I think the usual rule of thumb is that units that are named for people are *not*
capitalized when spelled out, but *are* capitalized when abbreviated as a letter.
Thus, the unit the newton is abbreviated as an N, but its namesake is Sir
Issac Newton.  Lord Kelvin has his name on the kelvin unit, so, for example,
room temperature is about 298 K.

I think the typical SI units that are *not* named after people have their
letter abbreviations in lower case.  Thus the second is abbreviated s, the meter
is abbreviated m, etc.  In both cases (when the unit is and is not named after a
person) the the unit name is not capitalized when it is spelled out though.

The case of the liter/litre is much more confused.  First of all its spelling is
not apparently standardized between the American and Anglo-French versions.  Second,
it is not an official SI unit so the SI naming conventions do not necessarily apply.
Its letter abbreviation used to be the lower case l, but that looked too much like
the numeral 1, so the use of a capital L was made acceptable for it as well.  Also,
the use of a script version of the lower case l became common to distinguish it
from the numeral.  There was supposed to be a trial period where both l and L were
acceptable, but after that period the CIPM (Comite International des poids et
Mesures) was supposed to meet and decide which of these two letter cases to make the
one acceptable value.  I have not heard yet if they ever decided on an official
case, and if so, whether or not the various national governments have officially
adopted their recommendation for commercial use.

Does anyone else know more about the current status of the liter (or
litre--whatever)?

David Bowman
dbowman@georgetowncollege.edu