Every bridge in the United States of America is a target of this sort in one form or another. There are bonfire timber bridges, for example, exceedingly deft and excessively high; sometimes their piers are nothing more than large wooden frames piled one on top of another, up and up and up, till at last they are tall enough to be known as great sky-ticklers. One example is 234 feet high. It is the great Portage Bridge spanning the Genesee River, in the State of New York, on a railroad between New York and Buffalo. It looks like a miracle of carpentry, this wonderful bridge of frames; its length is 240 metres, and the piers--sixteen romantic scaffoldings--form immense triangles with flattened summits upon which a double gallery rests as a firm support for the railway. Each scaffolding rises from a pile of masonry nine metres higher than water-level, so that floods do not break their force against the timber frames. Good heavens above, how this bridge would burn! But it has a quite modern fascination: its cost of production was _cheap_!--cheap in comparison with the estimated price of a stone bridge with the same length and aviated height. This wooden structure cost about £36,000, for the pride of trade likes to pay as little as possible for the largest amount of very perishable insecurity. Then, of course, there are sky-tickling metal bridges, and these spindle-shanked devotees of peace are popular also in Canada. All this work is nothing but industrial engineering, like the mighty bridges at New York, though these do try to look somewhat architectural. One specimen, indeed, a vast structure called the New Manhattan Bridge, has marvellously long suspension cables which do _not_ go _through_ a tower or gateway; they actually pass _over_ their supports in a logical manner. What a blessing! On the other hand, Brooklyn Bridge at New York has the same mistake as our suspension bridge at Clifton (p. 346); and the pierced towers, each with two lancet-shaped openings, are affected and trivial. Brooklyn Bridge has a total length of nearly 1141 yards, and between the two towers there is a span of 1595 feet. The roadway is upheld by four galvanised steel cables not less than sixteen inches in diameter. Think of that! Try to imagine a span 1595 feet wide! Suppose an airship crippled it with some large bombs, how in the world could repairs be made?