"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: