Definition of "downfal"

Look at the arduous exertion required of middle life; the thronging anxieties that spring up for others more than for ourselves; the constant downfal of our best-laid projects; the disappointment attending on the result of those which had mocked us with success;...

1834, L[etitia] E[lizabeth] L[andon], chapter XXX, in Francesca Carrara. […], volume II, London: Richard Bentley, […], (successor to Henry Colburn), page 312