Col. Othniel Sweet’s Mysteries of Nature, # 14 (auto-combustion)
You will no doubt have heard reports of those whose bodies burst into flame for no cause accounted for by eye or reason. I do not mean the carnival fire eaters nor arsonists incompetent at their chosen craft. Instead, consider a yellow-clad woman in Radford, Virginia who threw down an apple crate before a dry goods store and stepped upon it, wavered, steadied, then began to gesticulate and rant as if angel-driven about the kind mercies and ruthless vengeance of a God who would not abide the haughty nor cringing, the self-styled mighty nor deceivers of orphans, seducers of maidens, back-stabbers or usurers or peeks, and she was no haggard malcontent but the comely wife of a deacon with sparkle in her blue eyes, it is said, russet hair and skin like buttermilk, but she was angry and summoning wrathful scripture from the white calfskin Bible she raised in her hand. One minute the messenger for Higher Powers, the next shivering and gasping in full flower akin to summer roses and radiating a great heat, no smoke ascending as the red and gold ribbons of flame danced, as if some disbelieving scoffer had doused her in coal oil. The dance was little more than a moment’s horrific quirk, the heat so extreme the many onlookers were forced to retreat, and in two minutes, before one bucket could be summoned to bear, she was a smolder hardly discernible as the ruins of a human. For a day, not even her spouse nor preacher nor a lip-licking undertaker would deign to draw near, her remnants covered and cordoned off. The Holy Book lay shut beside her ashes, undamaged but searing to the touch, according to those few who ventured. Consider that.
The martyrs of old, we must remember, were bound to shaved pines, the bark heaped to supply tinder for the pyre, the long pole pointing heavenward as a mast like unto the one upon which Odysseus was bound, allowing him to listen to the sirens’ song without steering his vessel and crew toward the dulcet tongues endowed with the power to destroy by sheer song and the arrowhead shallows of their island. What the saints discovered, no victims were able to relate. Demise comes unbidden and with no warning, and jeopardy is general, but whence this spontaneous-seeming blaze running like a flash current through the human stream?
Some will seek it or a semblance, soak their garments with ardent spirits and touch a match to the hem or sleeve akin to the prophet who took an ember upon his tongue, but if they combust, they will not burn without smoke and leave the listeners besmitten, as did Jane Meadow Wilcox—for that was her name—who spoke and warbled of salvation and exile to Sheol, the forked path of every Christian decision.
You will recall how in days of old the bestial Caesars made torches of the faithful to line the Appian Way, taunting, “Now angel me that, Christ-lovers,” but such histories will not speak to the current rash of sudden ignitions: a blacksmith in Tifton, Georgia who veritably exploded as he stood to carve a Saturday roast before his family of six, and him a Methodist since birth; or a pious and private jasper who lived alone beside the Tullahoma River and upon his mule on the outskirts of Afton on high market day was seen as he approached the ferry abruptly whooshing up—man and jack beast together—like some sacrifice, the roar of the fire drawing many souls from the buildings to wonder, despite the icy conditions and the beginnings of fresh sleet; also, a Widow Effingham known to be drawn to conflagration as summer moth to candle, but always as a spectator, guest of the flames and never suspected of close connection until one evening at a charity cakewalk, perched alone in a corner with cider in her punch cup and boots tapping to the fiddle’s behest, uttered a hawklike scream and kindled till her voice was a roar and features all lost in waves of flame, the scent of her remains indistinguishable from rubbed cinnamon, and in the days that followed the Neversweats on their courthouse bench whisked the flies away with tracts or funeral fans and speculated, unable to raise one sliver of a credible explanation, until at last the high sheriff himself volunteered this intelligence: she was known to have lost her parents in a stampede and was, it is widely believed and reported, upon her bridal night sorely disappointed.
So neither thunderbolt nor fox fire, not phoenix nor stray rocket from some rogue artillery unit on maneuvers. There you have it, petals of heat born of the human condition, reasonless annihilation and nothing left in its wake but seared air, grief and an astonished society perhaps admonished against the rampant belief that we have mastered the art of reading Nature’s palm. A warning we must heed, for the words fly up as sparks, and where the wind bears them not even the sun star can reveal. 
Col. Othniel Sweet's Mysteries of Nature, #11 (blackbirds)
Col. Othniel Sweet's Mysteries of Nature, #14 (auto-combustion)
Col. Othniel Sweet's Mysteries of Nature, #103 (divining)
Col. Othniel Sweet's Mysteries of Nature, #110 (soiled doves)