Up until about 1800, there were no general classifications of clouds
Clouds were referred to poetically or as vague essences floating in the sky.
As an English manufacturing chemist and pharmacist, Luke Howard, like many who observed and studied the workings of the atmosphere at that time, was an amateur meteorologist.
Although he produced several landmark works including On the Modification of Clouds, The Climate of London, and Seven Lectures on Meteorology, the first textbook about weather, he was never trained as a scientist but from an early age, he had a fondness for nature and the weather, particularly the clouds.
Luke Howard divided clouds into basic shapes with Latin classifications: cumulus, stratus, cirrus, and nimbus.
Each cloud type is formed under different conditions.
His fascination with clouds started with the incredible skies of 1783 between May and August of that year. The Northern Hemisphere sky was filled with a "Great Fogg", a haze composed of dust and ash that caused brilliant sunrises and sunsets which resulted from the violent volcanic eruptions in Iceland (Eldeyjar) and Japan (Asama Yama).
In addition to the spectacle of the continuous volcanic ash in the sky, there was a fiery meteor which flashed across western European skies during the early evening of August 18, which was observed by the eleven year-old Luke Howard.
Before the beginning of the Nineteenth Century, most weather observers believed that clouds were too transient, too changeable, and too short-lived to be classified or even analyzed.
With few exceptions, no cloud types were named; they were just described by their color and form as each individual saw them: dark, white, gray, black, mare's tails, mackerel skies, wooly fleece, towers and castles, rocks and oxes-eyes.
Clouds were used in a few situations as weather forecasting proverbs, but mostly by their state of darkness or color:
"Red sky in morning, sailor take warning."
"Mackerel skies and mare's tails, make lofty ships carry low sails."