Charles Waterton was just another typical eccentric. In his 80s the eminent country squire was to be seen clambering around the upper branches of an oak tree with what was aptly described as the agility of an “adolescent gorilla.” The beloved 27th lord of Walton Hall also devoted his distinguished old age to scratching the back part of his head with his right big toe. Such displays of animal high spirits were not, however, confined to the gentleman’s later years. When young, Waterton made four separate trips to South America, where he sought the wourali poison , and once spent months on end with one foot dangling from his hammock in the quixotic hope of having his toe sucked by a vampire bat. James Warren Jones, by contrast, was something of a weirdo. As a boy in the casket-making town of Lynn, Ind., he used to conduct elaborate funeral services for dead pets. Later, as a struggling preacher, he went from door to door, in bow tie and tweed jacket, selling imported monkeys. After briefly fleeing to South America , the man who regarded himself as a reincarnation of Lenin settled in Northern California and opened some convalescent homes. Then, one humid day in the jungles of Guyana, he ordered his followers to drink a Kool-Aid-like punch soured with cyanide. By the time the world arrived at Jonestown, 911 people were dead. The difference between the eccentric and the weirdo is, in its way, the difference between a man with a teddy bear in his hand and a man with a gun. We are also, of course, besieged by other kinds of deviants — crackpots, oddballs, fanatics, quacks and cranks. But the weirdo and the eccentric define between them that invisible line at which strangeness acquires an edge and oddness becomes menace. The difference between the two starts with the words themselves: eccentric, after all, carries a distinguished Latin pedigree that refers, quite reasonably, to anything that departs from the center; weird, by comparison, has its mongrel origins in the Old English wyrd, meaning fate or destiny; and the larger, darker forces conjured up by the term — Macbeth’s weird sisters and the like — are given an extra twist with the slangy, bastard suffix -o. Beneath the linguistic roots, however, we feel the difference on our pulses. The eccentric we generally regard as something of a donny, dotty, harmless type, like the British peer who threw over his Cambridge fellowship in order to live in a bath. The weirdo is an altogether more shadowy figure — Charles Manson acting out his messianic visions. The eccentric is a distinctive presence; the weirdo something of an absence, who casts no reflection in society’s mirror. The eccentric raises a smile; the weirdo leaves a chill.