1749: 80-Year-Old Woman’s Fiery Death
A French priest named Boineau reported that an 80-year-old woman was reduced to a "carbonized skeleton" while she was sitting and sipping brandy.
Not Quite Right...
The above account comes from Jenny Randles and Peter Hough's 1992 book, Spontaneous Human Combustion. It is appears to be a confused version of the death of Madame de Boison in February 1749, which they actually present as a separate case on the same page of their book. I'm digging to see where the name "Boineau" came from, as it is the only element that suggests the possibility of a separate account... until I find something, however, I'm marking this account as 'Unreliable.'