And out of a great, jagged slit in the side of the cliff, perhaps a thousand feet below them, there poured down into thunderous dimness a waterfall whose breadth seemed not less than half a mile. It spouted seventy or eighty yards before it began to curve, and its din was like the voice of all creation.

Ismail came and stood by King in silence, taking his hand, as a little child might. Presently he stooped and picked up a stone and tossed it over.

"Gone!" he said simply. "That down there is Earth's Drink!"

"And this is the 'Heart of the Hills' men boast about?"

"Nay! It is not!" snapped Ismail.

"Then, where—"

But the one-eyed guide beckoned impatiently, and King led the way after him, staring as hakim or prisoner or any man had right to do on first admission to such wonders. Not to have stared would have been to proclaim himself an idiot.

The least of all the wonders was that the secret of the place should have been kept all down the centuries; for it was the hollow middle of a limestone mountain, that could neither be looked down into from above, because the heights were not scalable, nor guessed at from the conformation of the country. The river, that flowed out of rock and went plunging down into the chasm, must be snow from the Himalayan peaks, on its way to swell the sea. There was no other way to account for that; but that explanation did explain why at least one Indian river is no greater than it is.

The road they followed was a fold in the natural rock, rising and falling and curving like a ribbon, but tending on the average downward. It looked to be about two miles to the point where it curved at the chasm's end and swept round and downward, to be lost in a fissure in the cliff.

They soon began to pass the mouths of caves. Some were above the road, now and then at crazy heights above it, reached by artificial steps hewn out of the stone. Others were below, reached from the road by means of ladders, that trembled and swayed over the dizzying waterfall. Most of the caves were inhabited, for armed men and sullen women came to their entrances to stare.

Ears grow accustomed to the sound of water sooner than to almost anything. It was not long before King's ears could catch the patter of his men's feet following, and the shod clink of the mule. He could hear when Ismail whispered:

"Be brave, little hakim! She loves fearless men."

As the track descended caves became more numerous. In one there were horses, for as they passed there came a whiff of unclean stables, and the litter of fodder and dung was all about the entrance. The mouths of other caves were sealed, with great wax disks, strangely stamped, affixed to stout wooden doors. One cave smelt as if oil were stored in it, and King wondered whence the oil was brought—for the sirkar knows to a pint and an ounce what products travel up and down the Khyber.

At last the guide halted, in the middle of a short steep slope where the path was less than six feet wide and a narrow cave mouth gave directly on to it.

"Be content to rest here!" he said, pointing.

"Thy cave?" asked King.

"Nay. God's! I am the caretaker!"

(The "Hills" are very pious and polite, between the acts of robbing and shedding blood.)

"Allah, then, reward thee, brother!" answered King. "Allah give sight to thy blind eye! Allah give thee children! Allah give thee peace, and to all thy house!"

The guide salaamed, half-mockingly, half-wondering at such eloquence, pausing in the passage to point into the side-caves that debouched to either hand. There was a niche of a place, where a man might lie on guard near the entrance; another cave in which horses could be stabled, with plenty of fodder piled up ready; another beyond that for servants and baggage, with a fireplace and cooking pots; and at the last at the rear of all a great cavern full of eerie gloom, that opened out from the end of the passage like a bottle at the end of a long neck.