Up to perhaps 50 or 60 years ago, these street lights in Palma were run on gas. I am not a technical expert but, I was told that gas pobre was used to light the lamps which I understand to have been something like coal-gas. In places like Palma, each local barri (borough) had its own man in charge of lighting the street lamps, a so-called Sereno. That person was a night-watchman and guard with extensive responsibilities for neighbourhood safety and security. As well as lighting the gas lamps and turning them off in the morning, his duties included to watch out for fires, prevent mishaps, apprehend thieves and robbers and generally, maintain order and civil behaviour. The local Sereno would have the key to each and every house on his beat just to be able to enter any premise if there was a calamity or, indeed, if somebody returned home to find that he had locked himself out. The neighbourhood guard was generally well-liked and a person of trust and confidence within the community.
The photo (top) was taken in Palma de Mallorca, Baleares, Spain. The date: June 17th, 2011. The time was 14:21:52. The photo (bottom) was borrowed from the Internet, courtesy of elmundo.es/baleares.