It is not clear if the joule was "first used" before being officially adopted by the congress, but given that Joule died the same year, it may have been proposed then as a memorial.The joule did not die. What happened that made you think it had?
You have to distinguish Joule from joule. One refers to the man the other to the measurement unit. The man Joule died in 1889 but the unit name joule was in his honor so in a sense 1889 was the year of its birth.
Phil Hall
