American "-ize" words spelled "-ise"

[Mark Spahn]

A sentence in a column today by George Will reads:
"Philip Morris is America's largest maker of cigarettes,
a product legal to use but problematic to merchandize legally."

That spelling "merchandize" gave me a start.
The usual form of this word is "merchandising",
so I would expect the verb to be spelled "merchandise"
(last syllable pronounced the same as the word "dies"),
which is not to be confused with the noun "merchandise"
(things bought and sold; last syllable pronunced "dice").
But a dictionary list both the spelling "merchandise" and
"merchandize" (both pronounced to rhyme with "dies")
for the verb, listing the "-ize" spelling as a variant.

Another such word is "advertising", and its corresponding
verb "advertise" (last syllable pronounced "eyes").

These two words "advertise" and "merchandise" are
exceptions to the general observation that the same
word that is spelled with the ending -ize in American English
is spelled with the ending -ise in British English.

But a few minutes of contemplation leads to the
realization (realisation?) that this -ize/ise spelling
difference only applies when the ending has the
meaning of "convert something into something else"
(e.g., Americanize, crystallize, galvanize), the
same meaning as the Japanese suffix -ka.
Another clue that the "conversion" meaning
does not apply to "advertise" and "merchandise"
is the absence of words "advertisation/advertization"
and "merchandisation/merchandization".
The latter words would mean "conversion into
an advert" and "conversion into a merchand".
I don't know what a merchand is, but "advert"
is an British shortening of the word "advertisement"
(a word that Americans shorten to "ad"),
so "advertize" would mean to take, say, a
public service announcement and use it for
the commercial purpose of selling a product,
thus changing the PSA into an advert.
But "advert" is British, so such a construction
would only occur in Britain, where the spelling
would have to be "advertise", not "advertize".
And this "conversion" meaning of "advertise"
(to advertise a PSA) would in any case be different 
from the normal meaning of "advertise".

Just an observation made many years too late
and only good for remembering how to spell
"advertise" and "merchandise".

-- Mark Spahn  (West Seneca, NY)