Such excitement followed the Kid’s outburst that the very horses seemed imbued with it. The cowboys, keeping well out of the way of that floating, white cloud of gas more or less poisonous, it was not to be doubted had mounted their animals and were on their way, by a roundabout trail, to the ranch house.

“Gold!” muttered Snake. “Do you really think there’s gold in that cave?”

“It would not be beyond the bounds of possibility,” Dick replied. “I’m not a geologist, and I don’t know anything about mining. But the west is the home of gold, and so is Mexico. We’re not far from Mexico. What’s to prevent a ledge or seam of gold from running up into these hills, or small mountains, and cropping out in that cave? What’s to prevent?”

“Nothing!” came from Billee, a new light in his eyes.

“It would be very natural, I think,” added Nort.

“That would account for what Bud saw the men picking away at the stone sides of the cave,” went on Dick. “And the roof and sides are of rock that my brother and I saw.”

“Then we’re on the right track!” cried Snake joyfully. “I been tryin’ to figger out what all this meant, but I see it now. The other poison attacks, where cattle and men died, didn’t have nothin’ to do with the gas we just now ran away from. Somebody else must have been the blame of that, or maybe it wasn’t poison gas at all might ‘a’ been just bad water or loco-weed. But this is different.”

“Yes,” agreed Nort, “this is different. We know, positively, that this gas attack was launched by men.”

“Men who want to keep us out of that cave ’cause it’s full of gold!” murmured Old Billee. “Boys, for once I see daylight ahead of me! I’m goin’ to turn miner! I’m through nursin’ cattle! I’m goin’ to dig gold and retire rich! By golly, I am!”

“You better wait until we see the color of pay dirt!” chuckled Snake.

“And until we get those fellows out!” added another cowboy.

“Oh, we’ll git them out soon as we have them gas masks!” declared Billee, who seldom had shown such enthusiasm. “By golly, at last I see daylight! I’ll soon lay this on the shelf,” and he patted his old lariat.

“I hope he isn’t disappointed,” murmured Dick to his brother.

“Do you really believe there’s a chance of finding gold in that cave?” Nort asked in a low voice.

“I really do. Why else would those fellows want to keep us out? It can’t be that it’s a mere cattle-rustling game.”

“No,” admitted Nort, “I don’t believe it’s that. But gold! Seems sort of far-fetched.”

“Well, maybe I’m wrong,” went on Dick. “But we’ll soon find out, if those gas masks are any good.”

On the way back to the circle of ranch buildings a close lookout was kept for any sign of intruders on the range of Dot and Dash. But no strangers were seen, nor did a casual survey of the various herds scattered over the plains disclose any casualties.

“I guess everything that happens takes place around Smugglers’ Gulch,” observed Dick.

“Seems so,” admitted his brother.

No one had suffered any serious results from the gas attack. It had been discovered so quickly, and the retreat had been made so promptly, thanks to Snake’s vigilance, that aside from a little irritation of their mouths and throats the attackers were not injured. The irritation soon passed away and was about gone when they neared the ranch.

“They were just teasing us that time,” decided Snake. “The next time they’ll shoot some real nasty gas at us.”

“And that’s the time we’ll be ready with the masks,” declared Nort.

Bud Merkel was as excited as either of his cousins when he heard the news. He declared no better plan could be devised than going against the unknown cave dwellers with gas masks and a telephone message was soon on the way, asking the commander of the Los Pompan branch of the American Legion for the loan of as many of the protectors as were needed.

In due time word came back that the Dot and Dash ranchers were quite welcome to the masks. Snake and Kid, as experts in their use, and as judges of the best ones to bring back, were sent as a committee into town to get the life-saving apparatus.

It was next day, when the gas masks had been tried on by the cowboys who were to use them, and plans were being talked over for a second attack, that Nort suggested:

“Maybe we ought to try these masks before we use them. They may be defective in spite of the fact that they look all right.”

“Not a bad idea,” agreed Bud. “But we haven’t any poison gas to try ’em with.”

“If we could go in a room filled with ammonia, or some such vapor as that, we could soon tell if the masks were any good,” Dick suggested.

Dr. Taylor was communicated with and agreed to supply from his somewhat limited laboratory sufficient fumes to make a sure test of the masks. He came out to the ranch, a small room was set aside for the experiment and into this vile chamber the men went one at a time, each one wearing the mask that was designed to protect him in the coming fight.

With the exception of one or two of the affairs, each one was gas proof and the defective ones were quickly replaced with good ones. So that in a comparatively short time the avengers were once more ready to make the attack.

Much the same tactics were observed as on the former occasion. The horses were left well out of reach of any clouds of vapor that might float from the ravine, and the guards were instructed to deploy their reserve cavalry to east or west, according to the direction of the wind, in case gas was noted coming out of the defile.

“Well, I reckon we’re all ready,” observed Old Billee on a certain morning a few days after the first failure. “How about it, Bud?”

“All set,” answered the ranch owner’s son, for he had recovered from the gas he had inhaled and was quite fit again. “Let’s go!” he cried.

The cavalcade moved forward, and when within about the same distance as before from the defile, the horses were led aside, the guard posted and the men again advanced up the gorge.

“Don’t make any more noise than you can help,” warned Bud, as one of the men rattled some of the loose stones.

“Oh, I think they know we’re coming,” said Dick.

“You do? How?”

“Well, naturally they have scouts posted. We’d do the same if we were in their position. They know we’re coming, all right.”

“Perhaps so,” Bud admitted. “Well, everybody have his mask ready to slip on as soon as gas is smelled.”

“What if they use a kind we can’t smell until it’s too late?” asked Dick.

“Well, that’s a chance we have to take,” said Bud with a shrug of his shoulders.

“I think I shall smell it all right,” Snake interjected. “I was pretty good at that sort of thing in the war. The officers said I had a mighty good nose for smelling I mean,” he made haste to add for fear his pals would accuse him of personal vanity. “In some of the trenches they used rats and canary birds to give warning of gas. But I was the official smeller for my bunch, and I got so I was pretty good at it if I do say it myself.”

“Then we’ll make you the advance guard,” decided Bud, and so it was arranged.

Up the gulch they marched, with guns and gas masks ready, and once more, as on the former occasion, they were just within sight of the cave when Snake cried:

“Gas! Gas!”

At once each man donned his protector, and then, looking like prehistoric monsters the crowd, led by Bud, Nort, Dick and Old Billee rushed to the attack. The same white wisps of vapor floated down into the faces of the avengers, but there was no turning back now. There was no choking or gasping. The gas masks were a perfect protection.

Dick’s surmise that the advancing party was being spied on seemed to be correct, since before they reached the cave shots came from the cavern, and there was the vicious whine and ping of bullets. One or two of the cowboys were hit, one seriously, and then the avengers began shooting on their own account.

Bud gave the signal for a rush attack and eagerly he and his comrades sprang forward. They passed a little trench near the mouth of the cave. In this shallow ditch were several iron cylinders from holes of which was pouring a white vapor. This was the gas, how deadly could only be surmised for the masks kept all fumes and effects of it from the attackers.

There was a current of air from the cave blowing down the defile and this carried the fumes away from the hidden men and into the ranks of the attackers. This direction of the wind explained why no gas masks were needed by the foe. The wind was their protection. And the fact that they wore no masks was soon demonstrated.

For as the attackers swept on and up to the cave they dislodged several of the first line fighters of their foes rough, ugly-looking men who sprang up from amid the rocks and, after firing their last shots, turned and ran into the cavern. Not one wore a mask.

In a few minutes the attackers were safely back of the gas-emitting cylinders and could take off their masks for the wind carried the fumes away from them. Yanking his protector off, Bud shouted:

“Into the cave after them!”

The rush was made. A sight was had of a crowd of men retreating into the black depths of the cavern. The cowboys fired at them and were shot at in turn, Nort receiving a nasty scratch from a bullet along his shoulder, and his brother stopping a lead slug in the fleshy part of his thigh. Bud was nipped on the hand and several of the other cowboys were more or less painfully injured.

Some damage was inflicted on the foe, for there were yells of pain from several and one man was seen to fall. He was quickly picked up by his pals, however, and carried into the far end of the cave.

Then, when it grew dark as the daylight faded, a short distance beyond the entrance, Bud called a halt on further pursuit.

“No use going back there when we don’t know what’s beyond,” he said. “We’ve driven ’em out, and we can have a look, now, and see what secret they have been guarding.”

When Snake and Kid, again donning their masks, had shut off the flow of gas from the cylinders, a precaution taken against a possible change of wind, flashlights were produced and a close inspection of the cave was begun. It was evident that the men who had been in it, and who had relied on gas to keep intruders out, had made their escape through some rear exit, or they might still be hiding in the depths of the cavern.

Extra powerful portable electric torches had been brought by the exploring party and these were turned, now, on different parts of the rocky walls and roof of the cave. Bud showed where he had been held a prisoner, and it did not take long to find places where digging had been going on.

As the lights flashed over the rough, rocky walls, there were reflected back glistening yellow slivers of illumination.

“Look!” cried Dick, pointing. “There it is! Gold!”

“Gold! Gold!” came in joyful shouts from the exulting cowboys. “We’ve found a gold mine!”

And truly it seemed so.