On March 9th, 1869, his lecture at University College, London, on "Greek Myths of Cloud and Storm," began with an attempt to explain in popular terms how a myth differs from mere fiction on the one hand and from allegory on the other, being "not conceived didactically, but didactic in its essence, as all good art is." He showed that Greek poetry dealt with the series of Nature-myths with which were interwoven ethical suggestions; that these were connected with Egyptian beliefs, but that the full force of them was only developed in the central period of Greek history, and their interpretation was to be read in a sympathetic analysis of the spirit of men like Pindar and Æschylus. "The great question," he said, "in reading a story is, always, not what wild hunter dreamed, or what childish race first dreaded it; but what wise man first perfectly told, and what strong people first perfectly lived by it. And the real meaning of any myth is that which it has at the noblest age of the nation among whom it was current." In the next chapter he worked out, as a sequel to his lecture, two groups of Animal-myths; those connected with birds, and especially the dove, as type of Spirit, and those connected with the serpent in its various significances. These two studies were continued, more or less, in "Love's Meinie" and in the lecture printed in "Deucalion," as the third group, that of Plant-myths, was carried on in "Proserpina." The volume contained also extracts from the lecture on the Architecture of the Valley of the Somme, and two numbers of the "Cestus of Aglaia," and closed with a paper on The Hercules of Camarina, read to the South Lambeth Art School on March 15th. This study of a Greek coin had already formed the subject of an address at the Working Men's College, and anticipated the second course of Oxford Lectures. For the rest, "The Queen of the Air" is marked by its statement, more clearly than before in Ruskin's writing, of the dependence of moral upon physical life, and of physical upon moral science. He speaks with respect of the work of Darwin and Tyndall; but as formerly in the Rede Lecture, and afterwards in the "Eagle's Nest," he claims that natural science should not be pursued as an end in itself, paramount to all other conclusions and considerations; but as a department of study subordinate to ethics, with a view to utility and instruction. Before this book was quite ready for publication, and after a sale of some of his less treasured pictures at Christie's he left home for a journey to Italy, to revisit the subjects of "Stones of Venice," as in 1868 he had revisited those of the "Seven Lamps." At Vevey, on the way, he wrote his preface (May 1st). By quiet stages he passed the Simplon, writing from Domo d'Ossola, 5th May, 1869: