Luke Howard -- "The Godfather of Clouds"

Where was experimental physical science at the turn of the 19th century? A listing of the major scientific discoveries of the 17th and 18th centuries shows that many of the principles necessary for understanding the atmosphere had been set forth, even if they were not fully incorporated into the thought processes of the scientific community of the day. For example:

Seventeenth Century
	1643	Torricelli's barometer
	1662	Boyle's Law
	1665-6	Newton's Law of gravitation
	1672	Variation of "g" with latitude
	1687	Law of Conservation of Momentum
Eighteenth Century
	1714	Fahrenheit scale of temperature
	1742	Law of Angular Momentum
	1743	Celsius scale of temperature
	1755	Hydrodynamics; equations of motion
	1761	Latent Heat of water
	1782	Law of Conservation of Mass
	1784	Variation of temperature with height
Very Early 19th Century
	1801-3	Dalton's Laws of pressure in the vapour
	1802	Gay-Lussac's Law; Charles' Law
	1805	LaPlace's Law of variation of pressure with height

Prior to the year 1800 A.D., approximately, clouds had been thought of as outside the realm of classification and analysis. This was due to their ephemeral character -- coming and going, appearing and disappearing. And yet this point of view was not to persist. One reason was the impact on human thought of Swedish taxonomist, Linnaeus, through his landmark studies of natural history. Linnaeus -- Carl von Linne -- had greatly influenced Howard and this influence resulted in a paper on pollens, read in 1800 before the Linnean Society of London. It seems quite reasonable to assume that young Howard, at that time, had developed a mind-set that was favorably oriented toward classification in the Linnean scheme.

One of the curiosities of the growth of science is that new ideas quite frequently emerge independently and at about the same time in different countries. We have an example of this in conjunction with cloud nomenclature. As the story is told in the Preface of the International Cloud Atlas:

"The first published classification of clouds only dates back to the beginning of the 19th century and was the work of Lamarck (1802). This distinguished naturalist did not set out to classify all possible clouds. He confined himself to distinguishing certain forms which seemed to him to be a manifestation of general causes which it would be useful to recognise. But this work, in spite of its real value, did not make any impression even in France, his own country, and his nomenclature does not seem to have been used by anyone. Perhaps this was due to his choice of somewhat peculiar French names which would not readily be adopted in other countries, or perhaps the paper was discredited through appearing in the same publication (Annuaire Meteorologique) as forecasts based on astrological data. Four out of Lamarck's five principal types appear under different names in Howard's nomenclature. It is remarkable that these two men, of different scientific cultures, and never having come in contact with each other, should have arrived independently at such compatible results." From Preface to the 1939 Edition Vol.1 World Meteorological Organization International Cloud Atlas

Luke Howard's principal scientific achievement, as judged by history, is his "Essay on the Modification of Clouds". This Essay stands out because of its originality. It provided a new insight when it was needed. This insight was expressed in language -- Latin -- that was acceptable to the larger community of nations.

What enabled him to do this? Being steeped in Latin as a schoolboy? Initial captivation by the 1783 skies? Having the habit of observing nature with persistence and care? Curiosity as to why it rains? Being utterly convinced that orderly Providence would not make a disorderly sky? It is difficult, if not impossible, to rank these factors according to priority. No doubt, all played some part.

We take a closer look at the sequence of events that led to the Essay. We find Luke Howard, returning to London in 1787 as a chemist's apprentice, and twenty years later (1807) the sole owner of a prospering chemical manufacturing laboratory. But while he carried on his business activities and commitments, he continued his vocation of "natural philosopher", with sharp focus on meteorology. As he said in his later years, "meteorology is my real penchant".

More pictures from Luke Howard's Sketch Book

An outlet for, and a stimulus to, this side of his life was the Askesian Society ( Askesian derives from a Greek work meaning "philosophical exercise") to which he belonged as a charter member from its 23 March 1796 beginning. Howard had other like-minded friends, some his age and others older, who were interested in expanding their knowledge on all fronts of various subjects. It seems that his close friend, William Allen, was the principal moving agent in starting the small society. Whether or not Allen made the suggestion for the name, we do not know. Howard comments about the society:

"My friend Allen and myself belonged to a select Philosophical Society which met every fortnight during the winter, each member being required by the rules to bring in an essay, in turn, for discussion, or pay a fine. It was the obligation thus contracted, which occasioned me to present to that society the Essay on Clouds. The papers deemed worth of publication by this Society were inserted in Tilloch's Philosophical Magazine, the editor being one of our members". From a letter to Goethe, German literary giant who had become very interested in Howard's ideas.

The circumstances that led to the Essay were probably along the following lines. Howard's consuming interest in atmospheric phenomena had been well established. He had already given one paper to the Askesians on Causes of Rain (23 February 1802) so he was deeply involved in thinking about the total problem at times when his attention was not taken with the problems of the "chemical works". The setting: the home of Wm Allen in Plough Court, London on 16 December 1802 (evidence of the precise place and date strangely is missing from the Askesian Society minutes, so this is a probable conclusion). Howard's subject: "Essay on Modifications of Clouds" (in today's English a better word is Classifications). The full essay can be found in Rees' Cyclopaedia in Tilloch's Philosophical Magazine vols. xvi, xvii.

For our purposes the key idea set forth by Howard is that it is possible to identify, from within the complexity of changing skies, a number of simple categories. Howard's "genius" lay in the use of Latin names, thus transcending national boundaries. The categories are:

1. Cumulus (L. for heap) Convex or conical heaps, increasing upward from a horizontal base. 2. Stratus (L. for layer) Widely extended horizontal sheet. 3. Nimbus (L. for rain) Systems of clouds from which rain falls. 4. Cirrus (L. for curl) Flexuous fibres extensible by increase in any or all directions. Then there are intermediate categories: Cirro-cumulus, Cirro-stratus, Cumulo-stratus.

In his paper, Howard presents a lengthy description of, and rationale for, these various forms of cloud.

With some minor adjustments in nomenclature, these are the categories and names used by meteorologists of all countries, 200 years later! This is a remarkable testimony to Howard's perceptive insight into cloud forms, the primary observable phenomena of meteorology.