I admit that an odd, prickly sensation at the base of my scalp annoyed me while I watched this fire race up the slope and leave no red trail behind it.  Then it disappeared, blinked out again.  I opened my mouth to call Casey’s attention to it—­though I felt that he was watching it with that steady, squinting stare of his that never seems to wink or waver for a second—­but there it was again, come to a stop just under the crest of the mountain where the white slide was topped by a black rim capped with bleak, bare rock like a crude skullcap on Tippipah.  The fire flared, dimmed, burned bright again, as though some one had piled on dry brush.  I caught up the glasses and watched the light for a full minute.  They were good glasses,—­I ought to have seen the flicker of flames; but I did not.  Just the reddish yellow glow and no more.

“Must be fox fire,” I said, feeling impatient because that did not satisfy me at all, but having no other explanation that I could think of handy.  “I’ve seen wonderful exhibitions of it in low, swampy ground—­”

Casey spat into the dark.  “I never heard of nobody boggin’ down, up there on Tippipah.”  He put his cold pipe in his mouth, removed it and gestured with it toward the light.  “I’ve seen jack-o’-lanterns myself.  You know darn well that ain’t it; not up on them rocks, dry as a bone.  A minute ago you said it was lightnin’ burnin’ a yucca.  Why don’t yuh come out in the open, an’ say you don’t know?  Mebby you’ll come closer to believin’ what I told yuh about that devil’s lantern I follered.  He’s lit another one—­ kinda hopin’ we’ll be fool enough to fall for it.  You come inside where yuh can’t watch it.  That’s what does the damage—­watchin’ and wonderin’ and then goin’ to see.  I bet you wanta strike out right now and see just what it is.”

I didn’t admit it, but Casey had guessed exactly what was in my mind.  I was itching with curiosity and trying to ignore the creepiness of it.  Casey went into the tent and lighted the candle and proceeded to unlace his high hiking boots.  “You come on in and go to bed.  Don’t yuh pay no attention to that light—­that’s what the Old Boy plays for first, every time; workin’ your curiosity up.  You ask anybody.  He played me fer a sucker and I told yuh about it, and yuh thought Casey was stringin’ yuh.  Well, I can take a joke from the devil himself and never let out a yip—­ but once is enough for Casey!  I’m goin’ to bed.  Let him set out there and hold his darn lantern and be damned; he ain’t going to make nothin’ off’n Casey Ryan this time.  You can ask anybody if Casey Ryan bites twice on the same hook.”

He got into bed and turned his face to the wall with a finality I could not ignore.  I let it go at that, but twice I got up and went outside to look.  There burned the light, diabolically like a signal fire on the peak, where no fire should be.  I began to seek explanations, but the best of them were vague.  Electricity playing a prank of some obscure kind,—­that was as close as I could get to it, and even that did not satisfy as it should have done, perhaps because the high, barren mesas and the mountains of bare rocks are in themselves weird and sinister, and commonplace explanations of their phenomena seem out of place.