In Caverns Below by Stanton A. Coblentz — Read

Straight on and on the two sets of battle-monsters came, their ugly pointed forms half-concealed in puffs and streamers of black smoke. Waving at the stern of one group, we could distinguish banners of yellow and purple, while the other group displayed green and vermilion flags; but otherwise it was hard to tell them apart. On the decks of all the vessels alike we could see swarms of animated black specks; from the curved tubes at their sides we observed darts of lightning intermittently shooting; and meantime their rumbling and roaring made a pandemonium as of a thousand locomotives in simultaneous action.

As they drew near each other, the two groups did not relax their speed. Indeed, their pace was only accelerated! With the velocity of motor cars on a highway, they raced to within a few hundred yards of each other, as if intending to ram and destroy. There came a prodigious hissing of steam as they rolled toward the death-grip; for a moment, the five rushing monsters were obscured amid clouds of vapor, through which the blue and yellow lightnings flared in innumerable bolts. Then our aching ears caught the shock of a concussion so severe that for a second we were stunned; then other shocks, equally severe, followed one upon the other, as though a mile high giant were delivering blows with a sledgehammer; then, while the earth reeled and staggered, we were too dazed to be aware of anything except a stupendous uproar and commotion.