+48.  Development by Comparison.+—­In Section 29 we found that comparison, whether literal or figurative, aided us in forming mental images of objects.  In a similar way events and general principles may be explained by making suitable comparisons.  We are continually comparing one thing with another.  Every idea tends to recall other ideas that are similar to it or in contrast with it.  When an unfamiliar idea is presented to us we at once seek to associate it with similar ideas already known to us.  A writer, therefore, will make his meaning clear by furnishing, the desired comparisons.  If these are familiar to us, they enable us to understand the new ideas presented.  Even when both ideas in the comparison are unfamiliar, each may gain in clearness by comparison with the other.

In comparing two objects, events, or principles we may point out that they are not alike in certain respects.  A comparison that thus emphasizes differences, rather than likenesses, becomes a contrast.  The contrast may be given in a single sentence or in a single paragraph, but often a paragraph or more may be required for each of the two ideas contrasted.

EXERCISE

Notice how comparisons and contrasts are used in the following paragraphs:—­

1.  Niagara is the largest cataract in the world, while Yosemite is the highest; it is the volume that impresses you at Niagara, and it is the height of Yosemite and the grand surroundings that make its beauty.  Niagara is as wide as Yosemite is high, and if it had no more water than Yosemite has, it would not be of much consequence.  The sound of the two falls is quite different:  Niagara makes a steady roar, deep and strong, though not oppressive, while Yosemite is a crash and rattle, owing to the force of the water as it strikes the solid rock after its immense leap.

2.  It is not only in appearance that London and New York differ widely.  They also speak with different accents, for cities have distinctive accents as well as people.  Tennyson wrote about “streaming London’s central roar”; the roar is a gentle hum compared with the din which tingles the ears of visitors to New York.  The accent of New York is harsh, grating, jarring.  The rattle of the elevated railroad, the whir of the cable cars, the ringing of electric-car bells, the rumble of vehicles over the hard stones, the roar of the traffic as it reechoes through the narrow canyons of down-town streets, produce an appalling combination of discords.  The streets of New York are not more crowded than those of London, but the noise in London is subdued.  It is more regular, less jarring and piercing.  The muffled sounds in London are due partly to the wooden and asphalt pavements, which deaden the sounds.  London must be soothing to the New Yorker, as the noise of New York is at first disconcerting to the Londoner.—­Outlook.