All this, however, with moderation; a subject is not to be ridden to death; no neglect of proportion, no childish engrossment, but easy transitions. He should call a halt here, while he crosses over to another set of operations which demands attention; that settled up, he can return to the first set, now ripe for him; he must pass swiftly to each in turn, keeping his different lines of advance as nearly as possible level, fly from Armenia to Media, thence swoop straight upon Iberia, and then take wing for Italy, everywhere present at the nick of time. He has to make of his brain a mirror, unclouded, bright, and true of surface; then he will reflect events as they presented themselves to him, neither distorted, discoloured, nor variable. Historians are not writing fancy school essays; what they have to say is before them, and will get itself said somehow, being solid fact; their task is to arrange and put it into words; they have not to consider what to say, but how to say it. The historian, we may say, should be like Phidias, Praxiteles, Alcamenes, or any great sculptor. They similarly did not create the gold, silver, ivory, or other material they used; it was ready to their hands, provided by Athens, Elis, or Argos; they only made the model, sawed, polished, cemented, proportioned the ivory, and plated it with gold; that was what their art consisted in--the right arrangement of their material. The historian's business is similar--to superinduce upon events the charm of order, and set them forth in the most lucid fashion he can manage. When subsequently a hearer feels as though he were looking at what is being told him, and expresses his approval, then our historical Phidias's work has reached perfection, and received its appropriate reward. When all is ready, a writer will sometimes start without formal preface, if there is no pressing occasion to clear away preliminaries by that means, though even then his explanation of what he is to say constitutes a virtual preface. When a formal preface is used, one of the three objects to which a public speaker devotes his exordium may be neglected; the historian, that is, has not to bespeak goodwill--only attention and an open mind. The way to secure the reader's attention is to show that the affairs to be narrated are great in themselves, throw light on Destiny, or come home to his business and bosom; and as to the open mind, the lucidity in the body of the work, which is to secure that, will be facilitated by a preliminary view of the causes in operation and a precise summary of events. Prefaces of this character have been employed by the best historians--by Herodotus, 'to the end that what befell may not grow dim by lapse of time, seeing that it was great and wondrous, and showed forth withal Greeks vanquishing and barbarians vanquished'; and by Thucydides, 'believing that that war would be great and memorable beyond any previous one; for indeed great calamities took place during its course.'