Euler wrote over 200 letters to her in the early 1760s, which were later compiled into a best-selling volume entitled Letters of Euler on different Subjects in Natural Philosophy Addressed to a German Princess.
Euler menulis lebih dari 200 surat kepadanya pada awal tahun 1760-an, yang kemudian dikumpulkan menjadi suatu volume terlaris berjudul Letters of Euler on different Subjects in Natural Philosophy Addressed to a German Princess.