Cirrus, cumulus and stratus clouds

This plate, published in the Philosophical Magazine in 1803, presented the classification of clouds by meteorologist Luke Howard.
Howard had introduced his classification in 1802 in a lecture to the Askesian Society and later moved on to observations of the weather over-time using self-recording barometers as well as developing ground-breaking visual representations of those observations.
Howard opted for Latin terms to depict the clouds and proposed rigorous definitions for each of the forms.
Cirrus: 'Parallel, flexuous, or diverging fibres, extensible by increase in any or in all directions'.
Cumulus: 'Convex or conical heaps, increasing upward from a horizontal base.
Stratus: 'a widely extended, continuous, horizontal sheet, increasing from below upward.'
Many studies discuss the influence of Howard's classification on the representation of clouds in art, and particularly his influence on John Constable's own cloud studies and its inclusion in Goethe's poetry.
Howard describes the plate as 'a.a. represents different appearances of the cirrus; b, a regular cumulus; c. a stratus occupying a valley at sun-set, in the midst of which is supposed a spot of higher ground, with trees, &c. '