"there must be some mistake," said tom, wondering if the irish foreman were given to joking. yet he did not seem that kind of man.

"mistake? how can there be a mistake, sor? i wint in there to tell th' black imps t' come out, but they're not there to tell!"

"what's the trouble?" asked job titus, coming out of the office near the tunnel mouth. "what's wrong, tom?"

"why, i sent tim in to tell the men to come out, as i was going to set off a blast, but he says the men aren't in there. and i'm sure the last shift hasn't come out."

by this time koku, mr. damon and walter titus had come up to find out what the trouble was.

"the min have disappeared—that's all there is to it!" tim said.

"perhaps they have missed their way—the lights may have gone out, and they might have wandered into some abandoned cutting," suggested tom.

"there aren't any abandoned cuttin's," declared tim. "it's a straight bore, not a shaft of any kind. i've looked everywhere, and th' min aren't there i tell ye!"

"are the lights going?" asked job. "you might have missed them in the dark, tim."

"the lights are going all right, mr. titus," said the young man in charge of the electrical arrangements. "the dynamo hasn't been stopped to-day."

"come on, we'll have a look," proposed walter titus. "there must be some mistake. hold back the blast, tom."

"all right," and the young inventor disconnected the electrical detonating switch. "i'll come along and have a look too," he added. "don't let anybody meddle with the wires, jack," he said to the young englishman who was in charge of the dynamo.

into the dimly-lit tunnel advanced the party of investigators, with tim sullivan in the lead.

"not a man could i find!" he said, murmuring to himself. "not a man! an' i mind th' time in oireland whin th' little people made vanish a whole village like this, jist bekase ould mike maguire uprooted a bed of shamrocks."

"that's enough of your superstitions, tim," warned job titus. "if some of the other indians hear you go on this way they'll desert as they did once before."

"did they do that?" asked tom.

"yes, we had trouble that way when we first began the work. the place here was a howling wilderness then, and there were lots of pumas around.

"a puma is a small sized lion, you know, not specially dangerous unless cornered. well, some of the men had their families here with them, and a couple of children disappeared. the story got started that there was a big puma—the king of them all—carrying off the little ones, and my brother and i awoke one morning to find every laborer missing. they departed bag and baggage. afraid of the pumas."

"what did you do?"

"well, we organized ourselves and our white helpers into a hunting party and killed a lot of the beasts. there wasn't any big one though."

"and what had become of the children?"

"they weren't eaten at all. they had wandered off into the woods, and some natives found them and took care of them. eventually, they got back home. but it was a long while before we could persuade the indians to come back. since then we haven't had any trouble, and i don't want tim, with his superstitious fancies, to start any."

"but the min are gone!" insisted the irish foreman, who had listened to this story as he and the others walked along.

"we'll find them," declared mr. titus.

but though they looked all along the big shaft, and though the place was well lighted by extra lamps that were turned on when the investigation started, no trace could be found of the workmen, who had been left in the tunnel to finish tamping the blast charges. the party reached the rocky heading, in the face of which the powerful explosive had been placed, and not an indian was in sight. nor, as far as could be told, was there any side niche, or blind shaft, in which they could be hiding.

sometimes, when small blasts were set off, the men would go behind a projecting shoulder of rock to wait until the charge had been fired, but now none was in such a refuge.

"it is queer," admitted walter titus. "where can the men have gone?"

"that's what i want to know!" exclaimed tim.

"are you sure they didn't come out the mouth of the tunnel?" asked job titus.

"positive," asserted tom. i was there all the while, rigging up the fires."

"we'll call the roll, and check up," decided job titus. "get serato to help."

the indian foreman had not been in the tunnel with the last shift of men, having left them to tim sullivan to get out in time. the indian foreman was called from his supper in the shack where he had his headquarters, and the roll of workmen was called.

ten men were missing, and when this fact became known there were uneasy looks among the others.

"well," said mr. titus, after a pause. "the men are either in the tunnel or out of it. if they're in we don't dare set off the blast, and if they're out they'll show up, sooner or later, for supper. i never knew any of 'em to miss a meal."

"if such a thing were possible," said walter titus, "i would say that our rivals had a hand in this, and had induced our men to bolt in order to cripple our force. but we haven't seen any of blakeson & grinder's emissaries about, and, if they were, how could they get the ten men out of the tunnel without our seeing them? it's impossible!"

"well, what did happen then?" asked tom.

"i'm inclined to think that the men came out and neither you, nor any one else, saw them. they ran away for reasons of their own. we'll take another look in the morning, and then set off the blast."

and this was done. there being no trace of the men in the tunnel it was deemed safe to explode the charges. this was done, a great amount of rock being loosened.

the laborers hung back when the orders were given to go in and clean up. there were mutterings among them.

"what's the matter?" asked job titus.

"them afraid," answered serato. "them say devil in tunnel eat um up! no go in."

"they won't go in, eh?" cried tim sullivan. "well, they will thot! if there's a divil inside there's a worse one outside, an' thot's me! git in there now, ye black-livered spalapeens!" and catching up a big club the irishman made a rush for the hesitating laborers. with a howl they rushed into the tunnel, and were soon loading rock into the dump cars.