A fine marriage of science and art, with 12 chromolithographic plates of clouds by Louis Prang

Rudolf Cronau, artist / L. Prang & Co., CLASSIFICATION OF CLOUDS for the WEATHER OBSERVERS OF TRHE HYDROGRAPHIC OFFICE. Washington, D.C.: U.S. Department of the Navy, Hydrographic Office, 1897.


An attractive, eminently-displayable and very rare broadside presenting the classification of cloud types, following the nomenclature adopted by the 1896 Congress of the International Meteorological Organization (IMO).

Luke Howard’s 1803 Essay of the Modification of Clouds is generally accepted as the first attempt at a classification of clouds into four basic types: Cirro-form, cumulo-form, strato-form and nimbo-form. Nearly a century later, the IMO Congress of 1896 elaborated on Howard’s work and approved a classification of clouds into ten basic types, plus variants, and sanctioned the publication of the International Cloud Atlas. This was in keeping with the IMO’s mission of facilitating the exchange of weather data between nations, an endeavor whose success depended on the adoption of standardized nomenclature for meteorological phenomena. 

The following year the Hydrographic Office of the U.S. Navy published a handbook, Illustrative Cloud Forms for the Guidance of Observers in the Classification of Clouds, following the framework laid out by the IMO but adapted for American weather observers. Rather than using the images from the International Cloud Atlas, many of which featured landscapes, the handbook features 16 lovely chromolithographic plates of nautical images by Louis Prang after paintings by Hydrographic Office artist Rufolf Cronau. All feature low-angle nautical views, each illustrating a different cloud type. Some are placid, some rather dramatic, but all are evocative.

“Each plate embraces the horizon and sufficient extension of view, so that the observer can obtain a good idea of cloud perspective. The paintings themselves have been made as accurately and as true to nature as possible, and photographs, printed exemplars, together with the artist’s personal observations and knowledge of clouds, have all been brought to bear on them.” (Nature, vol. 56, no. 1444 (July 1, 1897), p. 96)

Offered here is a very rare Hydrographic Office broadside reprinting 12 of the 16 plates Illustrative Cloud Forms. Plates I-X reflect the basic cloud types standardized by the IMO, with plates XI-XII depict two variant cloud forms. Modestly priced at 40 cents, it was probably intended for classroom use, though the small scale of the plates may have made it challenging for use by teachers standing in front of a large classroom.

A rare and lovely marriage of meteorological science and art, with 12 plates by eminent lithographer Louis Prang.

OCLC 191909227 and 954152840, both referring to an example held by the Boston Athenaum.