:D No, actually that's not the case, the original letters are in French, and probably not even available anymore. They must have OCRed an old edition like this

:D No, actually that's not the case, the original letters are in French, and probably not even available anymore. They must have OCRed an old edition like this https://archive.org/details/lettersofeuleron01eule/page/n71/mode/2up?ref=ol&view=theater https://archive.org/details/lettersofeuleron01eule/page/n71/...