There is no room for the impurities of literature in an essay. Somehow or other, by dint of labour or bounty of nature, or both combined, the essay must be pure--pure like water or pure like wine, but pure from dullness, deadness, and deposits of extraneous matter. Of all writers in the first volume, Walter Pater best achieves this arduous task, because before setting out to write his essay ("Notes on Leonardo da Vinci") he has somehow contrived to get his material fused. He is a learned man, but it is not knowledge of Leonardo that remains with us, but a vision, such as we get in a good novel where everything contributes to bring the writer's conception as a whole before us. Only here, in the essay, where the bounds are so strict and facts have to be used in their nakedness, the true writer like Walter Pater makes these limitations yield their own quality.