At first thought most expository writing might be considered to make slight appeal, if any, to emotions. That is not necessarily true; the more effective the exposition, the more real is usually the call to feeling. Often this call is subtle, usually it is subordinate to the appeal to the understanding, but in most effective expository writing it will be found. In an explanation of the Panama Canal certainly there would be roused the reader's admiration and wonder at the magnitude of the operation. The mere analysis of the facts in a criminal trial often settles the case, so great is the emotional appeal. In didactic writing the call to emotion is less strong, though such a writer as Jonathan Edwards could explain the writhing of man like a spider before the Almighty in a profoundly moving way. In axiomatic mathematical propositions we find perhaps the least strong appeal: that the sum of the angles of a triangle is equal to two right angles might seem to be divorced from all excitement. But in most exposition when emotional appeal is overlooked the writing suffers.
In an account of the American Civil War, for example, the writer might set out to show that the conflict was the culmination of the struggle between yeoman and cavalier begun long since in England. But the war meant more than that. The author will then see the emotional significance of the fight and will add to his purpose the intention to thrill the reader at the magnificent exhibition, on both sides, of devotion to an idea. So Emerson, in his essay on "Fate" in _The Conduct of Life_, fills the reader with gloom for page after page, detailing how thoroughly the individual is bound down by conditions of birth, sex, breeding, wealth--and then in two wonderful sentences he turns the whole course of thought and emotion by saying, "Intellect annuls fate. So far as a man thinks, he is free," and the reader is stirred as with a trumpet call to renewed courage, which, to use Emerson's words, "neither brandy, nor nectar, nor sulphuric ether, nor hell-fire, nor ichor, nor poetry, nor genius" can overcome. And the historian Greene, in his well-known account of Queen Elizabeth, states his controlling purpose in the words, "Elizabeth was at once the daughter of Henry and of Anne Boleyn." But these words are not the whole of his purpose; he intends, besides the intellectual grasping of the Queen's character, an intense admiration and wonder at the resourcefulness, the shrewd judgment, and a reaction of amusement to the strange outbreaks of unwomanly freaks or of feminine wiles.