above any one else, on a ledge where there 's just room enough for your hoofs. Then you stand still and keep quiet,—never ask a man to hold your head, young 'un,—keep quiet while the guns are being put together, and then you watch the little poppy shells drop down into the tree-tops ever so far below."
"Don't you ever trip?" said the troop-horse.
"They say that when a mule trips you can split a hen's ear," said Billy. "Now and again per-haps a badly packed saddle will upset a mule, but it 's very seldom. I wish I could show you our business. It 's beautiful. Why, it took me three years to find out what the men were driving at. The science of the thing is never to show up against the sky-line, because, if you do, you may get fired at. Remember that, young 'un. Always keep hidden as much as possible, even if you have to go a mile out of your way. I lead the battery when it comes to that sort of climbing."
"Fired at without the chance of running into the people who are firing!" said the troop-horse, thinking hard. "I could n't stand that. I should want to charge, with Dick."
"Oh no, you would n't; you know that as soon as the guns are in position they'll do all
