IN the opening years of the 19th century, while Francis Beaufort was working on his famous Scale of Wind Forces, a London chemist called Luke Howard was busy sorting out another important aspect of meteorology. In a famous paper entitled "Essay on the Modification of Clouds", published in 1804, Howard suggested the detailed classification which, with only minor changes, is still in use today.
Of his own early education, Howard was heard to remark that he was taught "too much of Latin grammar and too little of anything else." Perhaps it was for this reason that when he addressed the question of putting some sort of order into the celestial miscellany of clouds, he followed the lead of the 18th century Swedish scientist Karl Linnaeus, and did so in the Latin tongue.
Linnaeus's main interest had been in botany, but in a book called System a Naturae he had laid down principles of classification that came to be used in nearly all the natural sciences, and that have varied little in the intervening years.
In the methodology devised by Karl Linnaeus, species resembling each other are grouped into a "genus"; related genera comprise an "order"; and a group of similar orders form a "class". As regards nomenclature, each species has (at least) a double name made up of its genus and the species.
Thus in the genus "eats" we find Felis domestic us, the common pussycat, and Felis leo, the majestic lion; Canis lupus, meanwhile, is the European wolf, while Canis familiaris, as its name implies, is the familiar dog.
Howard borrowed features of this system for his clouds. The genera of clouds are 10 in number, and most are quite well known, Cirrus, Altocumulus and Cumulonimbus are examples, and they specify the broad category into which a cloud type fits, according to its height, shape and texture. Then, within each genus, are the species, a further sub division which may again he based on shape or structure, or perhaps on the physical process in which a particular cloud has had its origin.
There are 14 species altogether, with names like fibratus (meaning "composed of filaments"), congestits (sprouting energetically upwards), flouccus (being composed of tufts), or fractus (meaning "ragged"). And these are further subdivided into "varieties" which describe - in Latin naturally - the further characteristics of an individual cloud.
Thus a meteorologist anywhere in the world, on hearing about a fine example of Altocumulus stratiformis translucidus perlucidus, will know immediately precisely what to visualise.