Charlotte Mary Weiss was born on June 30, 1776, in England, and baptised at St Marylebone, London, the next day. She is depicted as an infant in an illustration of her parents, Gaspard and Marie Weiss, and the assumption was that she had died young, possibly in England, because of an inscription on the illustration which said she died early.
Today I was looking at the parish records for Mulhouse (LDS microfilm 715494), specifically the death/burial records. The records went all the way to 1798, which was important for me, because apparently 5 people from Charlotte's family, her mother and four siblings, died in that year. Unfortunately, for some unknown reason, the parish records stopped at the end of March. None of the five Weiss' had died before March that year, which suggests they were all after that. I don't know that the records for the rest of the year are available, annoyingly! Perhaps I'll never know if they all died of the same thing, one after the other.
However, wonderfully, I did come across Charlotte's death record. Surprisingly she died in Mulhouse, after the family had returned there in 1794. She was 19 years old at the time of her death (2nd January 1796), and the cause of her death was given as auf Zehrung, which translates as "of attrition" - presumably this suggests a general weakening of her health, which eventually lead to her death.
The most interesting thing about the death record for Charlotte is the phrase eheliche tochter. I believe this translates as "illegitimate daughter". There is no mother recorded in the death record, though that isn't unusual amongst the death records I have been working on. However, the fact that Mary is Charlotte's middle name suggests Marie was her mother. The death record gives Charlotte's age as 19 years, 6 months and 1 day, which fits with her birth date. The date that Gaspard and Marie married was recorded in English papers at the time - August 1775. I can't see how Charlotte was illegitimate, unless some funny business was going on with her birth date. A mystery.
I checked with a native German speaker, and it turns out that Google Translator cannot always be relied upon to give you the correct translation. Eheliche tochter actually means "daughter born in wedlock", whereas uneheliche tochter means "daughter born out of wedlock". Phew - scandal averted.