In his Kitab al-Asrar (Book of Secrets), the physician and chemist Razi described two methods for the production of kerosene, termed naft abyad ("white naphtha"), using an apparatus called an alembic.[48][49] Kerosene lamp: The first description of a simple lamp using crude mineral oil was provided by Persian alchemist al-Razi (Rhazes) in 9th century Baghdad, who referred to it as the "naffatah" in his Kitab al-Asrar (Book of Secrets).[50] Minaret: The first known minarets appeared in the early 9th century under Abbasid rule.[51] Music sequencer and mechanical musical instrument: The origin of automatic musical instruments dates back to the 9th century, when Persian inventors Banū Mūsā brothers invented a hydropowered organ using exchangeable cylinders with pins,[52] and also an automatic flute playing machine using steam power.[53][54] These were the earliest mechanical musical instruments,[52] and the first programmable music sequencers.[55] Nitric acid and aqua regia: First mentioned in the works of Arabic alchemists such as Muhammad ibn Zakariya al-Razi.[56] Kamal: The kamal originated with Arab navigators of the late 9th century.[57] The invention of the kamal allowed for the earliest known latitude sailing, and was thus the earliest step towards the use of quantitative methods in navigation.[58] Observatory and research institute: The oldest true observatory, in the sense of a specialized research institute, was built in 825, the Al-Shammisiyyah observatory, in Baghdad, Iraq.[59][60][61] Petroleum distillation: Crude oil was often distilled by Arabic chemists, with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi (Rhazes).[62] Programmable machine and automatic flute player: The Banū Mūsā brothers invented a programmable automatic flute player and which they described in their Book of Ingenious Devices.