John Ruskin letter to Ellen Heaton, 1855 November 12?

Ruskin tells Heaton he has sent her the Rossetti works which he suggests she look at extensively but that she should "keep them locked up -- lest the one should be laughed at for its errors." He remarks that Rossetti's Francesca di Rimini is a "bold -- but perfectly true reading of Dante.". He tells Heaton that he is going to make Rossetti redo Guinevere & Lancelot "without mistakes" and that he will keep "the best of the two" and let Heaton have the other. Ruskin explains that Turner's Parnassus depicts a scene in the afternoon, not at noon and, in a postscript, remarks that the work's "immediate foreground shadows" are "indefensible ... [Turner] was very careless about scientific matters." [Date provided by Surtees: ? November 12th 1855]