When my mind had dwelt for some time on this blissful idea, it seemed to me that I might perhaps test it by an exertion of my will.  The vision had begun when my father was speaking of our going to Prague.  I did not for a moment believe it was really a representation of that city; I believed—I hoped it was a picture that my newly liberated genius had painted in fiery haste, with the colours snatched from lazy memory.  Suppose I were to fix my mind on some other place—Venice, for example, which was far more familiar to my imagination than Prague: perhaps the same sort of result would follow.  I concentrated my thoughts on Venice; I stimulated my imagination with poetic memories, and strove to feel myself present in Venice, as I had felt myself present in Prague.  But in vain.  I was only colouring the Canaletto engravings that hung in my old bedroom at home; the picture was a shifting one, my mind wandering uncertainly in search of more vivid images; I could see no accident of form or shadow without conscious labour after the necessary conditions.  It was all prosaic effort, not rapt passivity, such as I had experienced half an hour before.  I was discouraged; but I remembered that inspiration was fitful.

For several days I was in a state of excited expectation, watching for a recurrence of my new gift.  I sent my thought