Cloud atlas was published in 1802. It followed a similar effort in French by Jean-Baptiste Lamarck in 1801. Howard's nomenclature defined four fundamental types of clouds: cirrus or thread-cloud, cumulus or heap-cloud, stratus or flat cloud (level sheet), and nimbus or rain-cloud (see Classification of clouds). There followed a long period of development of the field of meteorology and the classification of clouds, leading up to 1896, the International Year of Clouds. The history of this period is the subject of a popular book, "The Invention of Clouds". During that time, the Englishmen Rev. Clement Ley and Hon. Ralph Abercromby, were influential.
Sheet pan steel core (in this process, the aluminum surface is typically 90% aluminum and 10% silicon, which is not quite the same as pure aluminum). Common features that may be found in sheet pans include: one or more flat edges to assist food removal, one or more raised edges (lips) to retain food, a contiguous rim to retain either food or shallow liquid, handles to assist in moving the pan into and out of the oven, a layer of insulation (typically air) designed to protect delicate food from burning (air bake pan), or perforations to aid in speeding cooking (pizza tray).