. . . . . . "Letters" . . "Letters"@en . . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg,... &c. Read at the Royal Society, June 3, 1779" . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg, of the Royal Society at London, and of the Royal Academy at Berlin, &c. Read at the Royal Society, June 3, 1779" . . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg, of the Royal Society at London, and of the Royal Academy at Berlin, &c. Read at the Royal Society, June 3, 1779"@en . . . . . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg, ... &c. Read at the Royal Society, June 3, 1779" . . . . . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg ... &c. Read at the Royal Society, June 3, 1779" . "Early works" . . "Early works"@en . "A letter to Mr. Euler, professor of philosophy, and member of the Imperial Academy of Sciences at Petersbourg ... &c. Read at the Royal Society, June 3, 1779"@en . . .