Perhaps only sixty. The pressure of this water against it must be tremendous."
"Of course," said Uncle d.i.c.k thoughtfully; "but you forget the shape of the wall, Jack. It is like an elongated pyramid: broad at the base and coming up nearly to a point."
"No," said Uncle Jack, "I"ve not forgotten all that. Of course it is all the stronger for it, the wider the base is made. But I"m not satisfied, and if I had made this dam I should have made this wall twice as thick or three times as thick; and I don"t know that I should have felt satisfied with its stability then."
"Well done, old conscientious!" cried Uncle Bob, laughing. "Let"s get on."
"Stop a moment," I cried. "Uncle d.i.c.k said he would show us our engine."
"Well, there it is," said Uncle d.i.c.k, pointing to the dammed-up lake.
"Isn"t it powerful enough for you. This reservoir was made by a water company to supply all our little dams, and keep all our mills going. It gathers the water off the moorlands, saves it up, and lets us have it in a regular supply. What would be the consequences of a burst, Jack?" he said, turning to his brother.
"Don"t talk about it man," said Uncle Jack frowning. "Why, this body of water broken loose would sweep down that valley and scour everything away with it--houses, mills, rocks, all would go like corks."
"Why, it would carry away our works, then," I cried. "The place is right down by the water side."
"I hope not," said Uncle Jack. "No I should say the force would be exhausted before it got so far as that, eight or nine miles away."
"Well, it does look dangerous," said Uncle Bob. "The weight must be tremendous. How would it go if it did burst?"
"I say, uncle, I"m only a coward, please. Hadn"t we better go off here?"
They all laughed, and we went on across the dam.
"How would it go!" said Uncle Jack thoughtfully. "It is impossible to say. Probably the water would eat a little hole through the top somewhere and that would rapidly grow bigger, the water pouring through in a stream, and cutting its way down till the solidity of the wall being destroyed by the continuity being broken great ma.s.ses would crumble away all at once, and the pent-up waters would rush through."
"And if they came down and washed away our works just as we were making our fortunes, you would say I was to blame for taking such a dangerous place."
"There, come along," cried Uncle Bob, "don"t let"s meet troubles half-way. I want a ramble over those hills. There, Cob, now we"re safe," he said, as we left the great dam behind. "Now, then, who"s for some lunch, eh?"
This last question was suggested by the sight of a snug little village inn, where we had a hearty meal and a rest, and then tramped off to meet with an unexpected adventure among the hills.
As soon as one gets into a hilly country the feeling that comes over one is that he ought to get up higher, and I had that sensation strongly.
But what a glorious walk it was! We left the road as soon as we could and struck right away as the crow flies for one of several tremendous hills that we saw in the distance. Under our feet was the purple heath with great patches of whortleberry, that tiny shrub that bears the little purply grey fruit. Then there was short elastic wiry gra.s.s and orange-yellow bird"s-foot trefoil. Anon we came to great patches of furze of a dwarf kind with small p.r.i.c.kles, and of an elegant growth, the purple and yellow making the place look like some vast wild garden.
"We always seem to be climbing up," said Uncle d.i.c.k.
"When we are not sliding down," said Uncle Jack, laughing.
"I"ve been looking for a bit of level ground for a race," said Uncle Bob. "My word! What a wild place it is!"
"But how beautiful!" I cried, as we sat down on some rough blocks of stone, with the pure thyme-scented air blowing on our cheeks, larks singing above our heads, and all around the hum of insects or bees hurrying from blossom to blossom; while we saw the gra.s.shoppers slowly climbing up to the top of some strand of gra.s.s, take a look round, and then set their spring legs in motion and take a good leap.
"What a difference in the hills!" said Uncle Jack, looking thoughtfully from some that were smooth of outline to others that were all rugged and looked as if great jagged ma.s.ses of stone had been piled upon their tops.
"Yes," said Uncle d.i.c.k. "Two formations. Mountain limestone yonder; this we are on, with all these rough pieces on the surface and sticking out everywhere, is millstone-grit."
"Which is millstone-grit?" I cried.
"This," he said, taking out a little hammer and chipping one of the stones by us to show me that it was a sandstone full of hard fragments of silica. "You might open a quarry anywhere here and cut millstones, but of course some of the stone is better for the purpose than others."
"Yes," said Uncle Jack thoughtfully. "Arrowfield is famously situated for its purpose--plenty of coal for forging, plenty of water to work mills, plenty of quarries to get millstones for grinding."
"Come along," cried Uncle Bob, starting up; and before we had gone far the grouse flew, skimming away before us, and soon after we came to a lovely mountain stream that sparkled and danced as it dashed down in hundreds of little cataracts and falls.
Leaving this, though the sight of the little trout darting about was temptation enough to make me stay, we tramped on over the rugged ground, in and out among stones or piled-up rocks, now skirting or leaping boggy places dotted with cotton-rush, where the bog-roots were here green and soft, there of a delicate pinky white, where the water had been dried away.
To a London boy, accustomed to country runs among inclosed fields and hedges, or at times into a park or upon a common, this vast stretch of hilly, wild uncultivated land was glorious, and I was ready to see any wonder without surprise.
It seemed to me, as we tramped on examining the bits of stone, the herbs and flowers, that at any moment we might come upon the lair of some wild beast; and so we did over and over again, but it was not the den of wolf or bear, but of a rabbit burrowed into the sandy side of some great bank. Farther on we started a hare, which went off in its curious hopping fashion to be out of sight in a few moments.
Almost directly after, as we were clambering over a steep slope, Uncle Bob stopped short, and stood there sniffing.
"What is it?" I cried.
"Fox," he said, looking round.
"Nonsense!" cried Uncle d.i.c.k.
"You wouldn"t find, eh? What a nasty, dank, sour odour!" cried Uncle Jack, in his quiet, thoughtful way.
"A fox has gone by here during the last few minutes, I"m sure," cried Uncle Bob, looking round searchingly. "I"ll be bound to say he is up among those tufts of ling and has just taken refuge there. Spread out and hunt."
The tufts he pointed to were right on a ridge of the hill we were climbing, and separating we hurried up there just in time to see a little reddish animal, with long, drooping, bushy tail, run in amongst the heath fifty yards down the slope away to our left.
"That"s the consequence of having a good nose," said Uncle Bob triumphantly; and now, as we were on a high eminence, we took a good look round so as to make our plans.
"Hadn"t we better turn back now?" said Uncle Jack. "We shall have several hours" walk before we get to Arrowfield, and shall have done as much as Cob can manage."
"Oh, I"m not a bit tired!" I cried.
"Well," said Uncle d.i.c.k, "I think we had better go forward. I"m not very learned over the topography of the district, but if I"m not much mistaken that round hill or mountain before us is Dome Tor."
"Well?" said Uncle Jack.
"Well, I propose that we make straight for it, go over it, and then ask our way to the nearest town or village where there is a railway-station, and ride back."
"Capital!" I cried.
"Whom will you ask to direct us?" said Uncle Jack dryly.
"Ah! To be sure," said Uncle Bob. "I"ve seen nothing but a sheep or two for hours, and they look so horribly stupid I don"t think it is of any use to ask them."
"Oh! We must meet some one if we keep on," said Uncle d.i.c.k. "What do you say? Seems a pity not to climb that hill now we are so near."
"Yes, as we are out for a holiday," said Uncle Bob. "After to-day we must put our necks in the collar and work. I vote for d.i.c.k."
"So do I," said Uncle Jack.