Remarks on the preceeding memories of M. Bernoulli
A translation of selections of E213 is published in D. J. Struik's A Source Book in Mathematics, 1200-1800 (Harvard University Press, 1969). Struik's book also includes a partial translation of E140 and several papers of Bernoulli and D'Alembert, in a survey of the the vibrating string problem.
Euler looks at two earlier treatises by Daniel Bernoulli on the vibration of strings.
Original Source Citation
Mémoires de l'académie des sciences de Berlin, Volume 9, pp. 196-222.
Opera Omnia Citation
Series 2, Volume 10, pp.233-254.