Journal April 1839
p10“Shelley shows himself fully possessed by this idea in his preface to Prometheus unbound.”
Fuller, Margaret. "Journal April 1839." Houghton Library, Harvard University; bMS Am 1086 (Box A); Box 5 (99).
Inferred Fuller (in crossed-out note, p. 10) names Shelley and 'his preface to Prometheus unbound' specifically. Fuller observes that Shelley 'shows himself fully possessed by this idea in his preface to Prometheus unbound.' This is a reference to Shelley's famous preface to Prometheus Unbound (published 1820 in Prometheus Unbound: A Lyrical Drama in Four Acts, London: C. and J.