Barcelona (Freddie Mercury and Montserrat Caballé song) sessions. The song was co-written by Mercury with Mike Moran, who also appeared in its video and played piano and all keyboards for the studio recording. The song starts with an orchestral introduction, which fades and is followed by Mercury and Caballé singing alternately their solo lines, sometimes merging into a duet. When singing the chorus "Barcelona" and a few other parts for the studio version, Mercury dubs over his voice in his usual multi-tracking style. Mercury leads the song whereas Caballé provides a powerful "background" soprano. Since Caballé covers the soprano part, Mercury sings in his natural baritone voice
Mercury battery popular power source for portable electronic devices. Due to the content of toxic mercury and environmental concerns about its disposal, the sale of mercury batteries is now banned in many countries. Both ANSI and IEC have withdrawn their standards for mercury batteries. The mercury oxide-zinc battery system was known more than 100 years ago but did not become widely used until 1942, when Samuel Ruben developed a balanced mercury cell which was useful for military applications such as metal detectors, munitions, and walkie-talkies. The battery system had the advantages of long shelf life (to 10 years) and steady voltage output.