For the boys' spirits had risen as they rode through the bright sunny day, and they only found disappointment in one thing--the fact of being compelled to regulate the pace of their mustangs by that of the heavily-laden mules, whose rate of progress was about equal to that of an ordinary British donkey driven in from a common.

Over and over again they longed to give their st.u.r.dy, well-chosen little nags a touch with the heel to send them racing along through the dusty-looking sage-brush; but they had to be contented with plodding steadily along behind the train, save when Chris found that there was something he wanted to ask Griggs, who kept on by the leading mule and its bell, and then the question seemed to be so important and weighty that it took two boys to carry it.

The first few times the doctor had taken no notice, but after Chris had cantered forward four times to rein up on one side of the American, with Ned on the other, his father said dryly when he overtook him--

"There's a good old saying that has to do with thoughtfulness, Chris.

It is this: Let your head save your heels. To apply it in this case, it should be, Save your pony's heels."

"I don't understand you, father," said the boy.

"Don't you? I only meant, the next time you want to ask about something that has been left behind, keep it in your head till you think of the next thing, and the next. You might collect half-a-dozen, and then you could go and ask them altogether. Do you see?"

"Yes, father," said Chris, who turned rather red.

"Be patient, my boy, and you'll have plenty of hard riding, perhaps more than you antic.i.p.ate."

There seemed to be no necessity for the precaution so near home, but the doctor said that they had better begin as they would have to go on "when in the enemy's country," as he put it, with a smile.

"Before long we may be where there will be risk of our animals stampeding, or being stolen. Later on, when we are in the Indians'

country, we shall have to guard against attack, so we will divide the night into watches."

This was before settling down for the night in and about the deserted fruit-farm.

"Oh," cried Wilton; "but surely this is being too particular. Every one is tired. We have had a very wearing day, beginning so early as we did with the packing and getting off."

"Yes," said the doctor coldly, "but the success or failure of the expedition depends upon our being punctilious. A st.i.tch in time saves nine, my dear boy."

"But--" began Wilton, in a tone of protest.

"One moment," said the doctor. "Let me make a suggestion. We want to start early every morning for Unknownia, if you will let me coin a name for the place of our search."

"Of course," said Bourne.

"We must always break the neck of our journey by getting over a good many miles before the heat of the day sets in."

"That's good advice," cried Griggs.

"Very well, then," continued the doctor; "we don't want to waste time in lighting fires and hunting up horses and mules that have strayed no one knows where in the course of the night, do we?"

"No, of course not. I see," said Wilton. "I give in."

"The man who takes the morning watch will have breakfast ready before daybreak, and then there will be nothing to do but load up the mules and start off the moment it is light enough."

There were no dissenters from the leader's practical proposals, and he elected to take the first half of the night's watch himself, Griggs to take the second, and soon afterwards the animals were hobbled and left to graze, one of the barn-like buildings was chosen for resting-place, and those who were free from duty lay down to sleep. The two boys naturally enough made up their bed of dry sage-brush on the decaying floor of the building, and then, in response to the doctor's orders to get off to sleep at once so as to be well rested and fresh for the next day's work, they lay wide awake, talking in whispers.

To do them justice, this was no fault of theirs. They were tired enough, but their eyelids felt as if they were furnished with springs which held them wide open, to stare through the open side of the barn at the glittering stars, while their ears were all on the strain to listen to the different sounds that came from all around.

At first there was the cropping of the horses and mules, as they feasted on the fresh shoots of the abundant growth, owing to the moisture beneath the little dry river-bed having kept the coa.r.s.e gra.s.ses pretty succulent. There was the hum of mosquitoes and the boom of big beetles, and every now and then the cry and answering cry of some animal unknown from out in the sage-brush. But for a time the lads lay silent, till a peculiar mournful shout, as it seemed to be, came from the direction of the lagoon, sounding so mournful and human that it was too much for Ned, who whispered--

"Awake, Chris?"

"Of course. Who's to go to sleep with millions of things getting up your legs and arms and down your neck? I wish I'd taken off my clothes.

Isn't it hot!"

"Yes, yes; but did you hear that?"

"Yes."

"What was it?"

"Owl," said Chris shortly.

"I know it was a howl," said Ned, "but it was more like a shout or hail."

"Owl, owl, hunting about over the brush for young hares or rats and mice."

"Oh, of course. I never thought of that," said Ned, and he settled down quietly for a few minutes, before saying in a whisper: "I say, isn't it queer that one seems to hear hundreds of things now that one never noticed at home?"

"I don't know. Perhaps we should have heard some of these ticks and squeaks and rustlings if we had lain awake. I say, Ned, I believe all the wild things from round about are coming to see what we want here."

"Very likely. What's that?"

"What?"

"That flash of light. Is it a storm coming?"

"Pooh! No. Father threw some bits of dry stuff on the fire."

"To be sure. But I say, Chris, that's why all these insects and things come creeping up. It's the light that attracts them."

"Of course it is. I wish you'd go to sleep."

"I will as soon as I can, but you needn't be so disagreeable."

"Enough to make me. I'm tired, and you keep on talking like an old woman. Not frightened, are you?"

"Nonsense! No. Ugh!"

Ned started up, his action following the e.j.a.c.u.l.a.t.i.o.n belying his words, for all of a sudden from near at hand came a dull thud as if a heavy blow had been struck, followed by what sounded in Ned's ears like a shriek of agony. "What's that?" he gasped.

"One mule tried to bite another in the back, had a kick for his pains, and called 'Murder!' in mulese," said Chris sourly. "I say, I shall have a bed-room to myself to-morrow night if you're going on like this."

Ned was silent, for his companion's words rankled.

"Perhaps I ought to have known," he said, "but it's all so strange lying out here in the darkness."

He turned over on the other side, determined to sleep now, and he tried hard for quite a quarter of an hour, the effort seeming to make him more wakeful than ever, for his senses were all upon the strain, while as the night progressed fresh noises, some of them quite peculiar, seemed to arise. Once he started, for there was a heavy splash which in the clear air sounded quite near, but which was evidently from the lagoon; and it put to flight an idea he had been nursing up of going down to the sheet of water and ridding himself of his hot tickling clothes so as to have a good swim before breakfast. That was all over now, for that splash told of alligators swimming in the lagoon to his heated imagination. He had never heard of the reptiles existing in that part of the country, but he knew that there were plenty in the swamps farther to the south, and there was no reason why there might not be some in the wild districts into which they were plunging.

Another splashing noise succeeded, and he felt that it might have been made by a fish, and others which succeeded have been caused by waterfowl. But all idea of bathing was dismissed.