The 'Centella' and the 'Bad Light'
In the darkest South American nights and even when the moon is high and no clouds are seen the peasants tell strange stories of weird lights seen in the middle of the fields, of strange fluorescent spots that vanish as quickly as they had appeared. The Indians (word preferred by them to 'aboriginals' that is, without an origin)- if asked- tell that they are the spirits of the death that go out at night to threaten those foolish enough to go out after sun is down. Others would swear that those shines are the evidence of wondering spirits and old gods, sometimes they'll even speak of Valichu (a dark spirit among their tradition). The gauchos, instead, would speak of mourning souls and of 'Mandinga', better known as the devil.
The times those lights were seen were many and they could make their appearance both in open land, in cemeteries and in fences. They were mainly of two different types: those that stayed in a place or moving a few metres before disappearing, called 'Bad Lights', and could be caused by the dead or by spirits. The centella, on the other hand, was a light whose procedence one didn't knew, but that, as it moved at high velocities, could freeze one's blood quite easily: imagine you being alone in the middle of the night and see a strange light fastly moving through what appears to be the nothing and in an age where cars didn't exist or were too noisy and slow. Moreover, the next day the phenomenon was seen, one could see some corpses of animals lying without any apparent cause of being dead.
With the time, people learnt the cause of the majority of those lights: the shines in the country were most likely to appear always in the same places and then it was discovered that it was not caused by the souls, but by the phosphorus in animal bones. Also in bones in the cemetery that could be in the surface either because of floods or also belonging to dead animals.
With the centella, something similar happened: the lightnings could fall to earth but were most likely to fall on trees or- from the 1880's onwards (years when their use began to be common), on the metal fences that divided each field from the other. The continuity of these metal strings made the electricity of the rays travel through them at high velocities and, if one was near it or if an animal was so unlucky as to be touching the metal when the electricity passed, the result was instant death. But the reasons of the lights were not always so easy to discover, and many tales are still told about encounters with lights and phenomena without any reasonable explanation.