Discoveries in science create new perceptions only when they become popular science. When new theoretical models are finally assimilated by the public mind, even if they are imperfectly understood and imprecisely applied, they affect the mental climate by altering the perception of the world. The layman's understanding, or misunderstanding, of science creates a stock of new metaphors.

For this purpose, the artist is a layman like any other, a member of that public whose image of the world has been altered by the progress of science. The imagery in a work of art reveals, not only the personal and unique perceptions of its creator, but also the conventional perceptions of his time. When the popular understanding of a new scientific concept has created a new convention, the imagery employed by artists reflects this change.

Thus, the function of the heart was not understood until the invention of the pump provided a suitable metaphor.[2] When the Copernican revolution gained acceptance in the public mind, the fundamental conceptual change resulted in a corresponding change in poetic imagery.[3] After the whole world watched the Apollo astronauts on television, landing on the moon and exploring among the craters, moon imagery in art will never be the same.

The imagery used to depict thunderstorms in music is yet another example of the same process. After the scientific explanation of the mechanism of thunder and lightning had become public property, the manner in which thunderstorms were portrayed in poetry and music underwent a radical change. 

Ancient and venerable tradition, based upon Greek and Roman mythology, depicts thunder and lightning as missiles which strike the earth. The thunderbolt was the symbol of the power of Zeus. The god exerted his power, or exhibited his anger, by hurling thunderbolts down upon the earth.

Aristotle gave a different description of thunder. His explanation is non-mythological, physical, one might almost say, scientific: 

               But any of the dry exhalation that gets trapped when the air is in the process   
               of cooling is forcibly ejected as the clouds condense and in its course strikes 
               the surrounding clouds, and the noise caused by the impact is what we call 

Aristotle's physical description, however, never fired the popular nor the artistic imagination. For many centuries, the conventional image remained mythological. Thunder and lightning were perceived as missiles from the sky which strike the earth with destructive force. As this perception is expressed in the English language, thunder and lightning are interchangeable. A stroke of lightning is called a lightning bolt, the word bolt being used in the sense of an arrow shot from a crossbow. Alternatively, the same phenomenon is called a thunderbolt, implying that thunder is not a noise, but the same missile by another name. The projectile from the heavens is a lightning bolt, or a thunderbolt, or either, or both. A thunderbolt may also be called a thunderball, perhaps implying an analogy with a cannon ball. An event that occurs without warning is like a bolt from the blue. To be taken by surprise is to be thunderstruck: to be struck by an unexpected thunderbolt from the sky.

This perception is evident in Shakespeare, when John of Gaunt speaks of thunder as striking from above with annihilating force: 

               Be swift like lightning in the execution; 
               And let thy blows, doubly redoubled, 
               Fall like amazing thunder on the casque 
               Of thy adverse pernicious enemy: [5]

Shakespeare's most famous expression of this popular metaphor occurs when King Lear shouts into the storm: 

               You sulphurous and thought-executing fires, 
               Vaunt couriers of oak-cleaving thunderbolts, 
               Singe my white head! And thou, all-shaking thunder, 
               Strike flat the thick rotundity o' the world! [6]

This is a prime example of the equivalence of lightning and thunder in the traditional image. On one hand, the fires which are to singe Lear's head are obviously lightnings. The words vaunt couriers perhaps indicate cognizance of the fact that lightning precedes thunder. On the other hand, this thunder is not merely a noise, but a thunderbolt, no less a juggernaut than the lightning. It cleaves oaks, and it flattens the world. 

In 1808, Beethoven depicted a thunderstorm in the fourth movement of his Symphony No. 6 in F Major, Opus 68, the "Pastoral" Symphony. Although two centuries had elapsed since King Lear, the image had not changed. The manner in which Beethoven uses orchestral sound effects to represent the storm shows that his perception is still the traditional one.

At the transition between the third and fourth movements of the "Pastoral" Symphony, an energetic tutti is cut off in mid-stride. The fourth movement, Gewitter, Sturm, begins with a rustling in the strings, and a three-note, sighing motive. This is obviously meant to represent the meteorological phenomena which presage the storm: the sudden queer, ominous silence, the darkening of the sky, the drop in air pressure, and the sighing wind that springs up from nowhere. Then the storm strikes with sudden fury, and it strikes downward.

The central image is that of the traditional, mythological, Jovian lightning bolts. They are represented as striking the earth like cannon balls, even seeming to rebound due to the force of the impact. In some cases, the rumbling of the thunder precedes the lightning bolt, as if the lightning were the result of the thunder.

During the storm, the original three-note motive returns as a counterpoint to the other sound effects. Later, at m82, the piccolo is added to imitate the whistling of the wind.
At the height of the storm comes Beethoven's most powerful and graphic image. A descending chromatic scale, with a crescendo, ends in a sforzato and a "rebound." We seem to hear the bolts hurtling through the air, to land with crushing force. They sound like falling bombs.

The storm recedes. The music depicts distant mutterings of thunder, and the same motive that formerly represented the "rebound" now seems to indicate a flicker of lightning on the horizon. The subsiding wind is represented by chords descending in parallel motion. At the beginning of the fifth movement, Hirtengesang, the sun emerges from behind the clouds, and the sound of a shepherd's pipe is heard.

Beethoven's "Pastoral" Symphony served as a precedent for the program music of the nineteenth century. One reason for this is the fact that the progress of the music can be construed, not only as a musical form, but also as representing a sequence of events in the real world. Another reason is the fact that Beethoven's sound effects, his imitations of the wind, the thunder, and the shepherd's pipe, are convincingly realistic. The twentieth-century listener, however, hears his depiction of lightning bolts as stylized, not realistic. We submit that, in Beethoven's own terms, the image of the lightning bolts is no less realistic than the other images in the movement. It simply represents the conventional perception of his time. 

Meanwhile, science had made great strides toward an understanding of the physical mechanism of thunderstorms. The crucial research was carried out by De L'Isle (1688-1768). In 1738, he published his measurements of the time that elapsed between a flash of lightning and the sound of the thunder[7] Benjamin Franklin's famous experiment with a kite in 1752 established the fact that lightning is a discharge of electricity. By the end of the eighteenth century, physicists had developed theoretical models of clouds, of gas pressures, of heat exchange, and of the discharge of electricity.

Thus, at the time of the "Pastoral" Symphony, in 1808, there already existed a physicist's model of the mechanism of thunder and lightning. But the imagery in the art of the early nineteenth century demonstrates that this model had not yet become popular science. Beethoven was not alone in seeming oblivious of the progress of science. His whole generation, and even the subsequent generation, persisted in employing the traditional image of thunderbolts.

Shelley's poem A Vision of the Sea (1820) will serve as an example. This poem describes a ship wrecked by a thunderstorm. Shelley's imagery is traditional. The fiery projectiles which strike from the sky are called thunder and thunder-balls. Two excerpts will illustrate this: 

               The intense thunder-balls which are raining from heaven 
               Have shattered its mast, and it stands black and riven. [8] 

                              One after one 
               The mariners died; on the eve of this day, 
               When the tempest was gathering in cloudy array, 
               But seven remained. Six the thunder has smitten, 
               And they lie black as mummies on which Time has written 
               His scorn of the embalmer; [9]

An even more cogent example is provided by a piece of music composed two decades after the "Pastoral" Symphony. In 1829, Rossini depicted a thunderstorm in the overture to his opera, Guillaume Tell. Rossini's depiction is so like Beethoven's, that it smacks of plagiarism.

Rossini also begins with a sudden, ominous quiet. There is a distant rumble of thunder, a rustling in the strings, and a little three-note motive, which here seems to represent distant flashes of lightning. When the storm strikes with sudden fury, Rossini begins immediately with descending chromatic scales. Here also, in some cases the sound of thunder precedes the bolt of lightning.

Toward the end of the section, the three-note motive returns as a counterpoint to the thunder. The storm recedes with the same distant thunder and flickering lightning. The wind subsides with similar descending chords. The following section, representing the calm after the storm, begins with an English horn solo similar to the shepherd's pipe in Beethoven.

Apparently, it was in the middle of the nineteenth century that the physicist's model finally penetrated the public mind, and was assimilated. The popular perception of thunder and lightning changed, and became modern.

An article by M. Hirn, published in the Scientific American in 1888, exemplifies the new perception, now commonly understood and accepted: 

               ...the sound which is known as thunder is due simply to the fact that the air 
               traversed by an electric spark, that is, a flash of lightning, is suddenly raised to 
               a very high temperature, and has its volume, moreover, considerably 
               increased. The column of gas thus suddenly heated and expanded is 
               sometimes several miles long, and as the duration of the flash is not even a 
               millionth of a second, it follows that the noise bursts forth at once from the 
               whole column, though for an observer in any one place it commences where 
               the lightning is at the least distance.... The beginning of the thunder clap gives 
               us the minimum distance of the lightning, and the length of the thunder clap 
               gives us the length of the column. [10]

A century later, this explanation was still more or less accepted. 

               Hirn's explanation of the mechanism of thunder, with the exception of an error 
               in the stated time duration of the flash, remains today the consensus view. [11]

The development of the physicist's model of thunderstorms is documented in the publications of scientists. But the change in the mental climate, which occurred much later, is documented in works of art. In the second half of the nineteenth and the beginning of the twentieth century, the imagery is no longer that of the traditional thunderbolts and thunderballs, but reflects the modern perception of the mechanism of lightning and thunder.

As an example, we may consider Emily Dickinson's poem, The Farthest Thunder.[12] This poem was written ca. 1883, so that it is contemporaneous with Hirn's description. The complete text of the poem follows: 

               The farthest Thunder that I heard 
               Was nearer than the Sky 
               And rumbles still, though torrid Noons 
               Have lain their missiles by -- 
               The Lightning that preceded it 
               Struck no one but myself -- 
               But I would not exchange the Bolt 
               For all the rest of Life -- 
               Indebtedness to Oxygen 
               The Happy may repay, 
               But not the obligation 
               To Electricity -- 
               It founds the Homes and decks the Days 
               And every clamor bright 
               Is but the gleam concomitant 
               Of that waylaying light -- 
               The Thought is quiet as a flake -- 
               A Crash without a Sound, 
               How Life's reverberation 
               Its Explanation found --

In this poem, the traditional imagery is still operative: the words missiles (line 4) and bolt (line 7) are used. On the other hand, the consciousness of modern physics is evident, for example in the mention of oxygen (line 9) and electricity (line 12). What is directly relevant to the present discussion, however, is line 5: "The Lightning that preceded it." This line of poetry provides direct evidence that the poet is cognizant of the fact that the sound of thunder is the result of a flash of lightning. Such a line is possible only after the change in the popular perception of thunderstorms. 

An outstanding example of the modern depiction of a thunderstorm in music is found in the Grand Canyon Suite, composed in 1931 by Ferde Grofe (1892-1972). The fifth and final movement of the suite, Cloudburst, is a dramatic portrayal of a storm.

The sequence of events in Grofe's storm is very like that in Beethoven's. It begins with the ominous quiet and the sighing of the wind. Being a twentieth-century composer, Grofe is able to make this sighing quite realistic, with dissonant glissandi in the violins. There is a three-note motive which is suspiciously like Beethoven, as is its use as a counterpoint to the sound effects of lightning and thunder.

The depiction of the fury of the storm is extremely violent, exploiting to the full the resources of the modern orchestra. At the conclusion, the subsiding wind is represented by descending violin glissandi similar in conception to those at the beginning of the storm. There is one last flash of lightning, and one last clap of thunder. Then a brilliant tutti depicts the sun emerging from the clouds.

This portrayal is, of course, more dissonant, more graphic, and more realistic than those composed in the nineteenth century. The sound effect that represents the lightning consists of a forzato of winds and cymbal, and a glissando on the piano. That of the thunder consists of a tremolo on the tympani and the low registers of the piano, cello, and double bass, beginning forte and continuing diminuendo. But the essential difference between Grofe's storm and those of Beethoven and Rossini is in the timing of the imitations of lightning and thunder. Grofe's thunder is always separated from his lightning, and always follows it. As the music progresses (as the storm approaches) the interval between the flash of lightning and the clap of thunder decreases, in accordance with the modern understanding of the mechanism of a thunderstorm. 

The examples given here indicate that tradition is strong, except where popular acceptance of new scientific concepts forces the adoption of new metaphors. Rossini and Grofe retain Beethoven's order of events, just as Dickinson retains the traditional missiles and bolt. But both Dickinson and Grofe cannot escape their cognizance of modern science. Both describe thunder that comes after lightning, as a result of lightning. Note also, that Aristotle's "scientific" explanation never became popular science, while that of De L'Isle and Franklin became common property only after a century. Today, of course, mass communications have greatly accelerated the process.
The orchestral effects invented by Grofe to depict lightning and thunder seem today more realistic than those of Beethoven, because they conform to the modern perception of these phenomena. Both are stylized, in that they are musical representations of nature. Each is realistic for its own mental climate, in that each conforms to the conventional perception current in its time.

In the second half of the twentieth century, we are no longer convinced by Beethoven's effect of a descending chromatic scale with a crescendo. For us, this effect imitates the dive bombers of World War II (although these are obsolete as well).
For us, destructive missiles that fall from the sky are not a Classical myth, but a grim reality. We have the advantages of modern science, but also its terrors. Twentieth-century mentality requires twentieth-century musical images.  

1. This article is a revised version of a paper delivered at the conference "Resonant Intervals" at the University of Calgary in May 1991.

2. Jonathan Miller, The Body in Question (New York: Random House, 1978), pp. 181-184. 

3. Marjorie Hope Nicolson, The Breaking of the Circle: Studies in the Effect of the "New Science" Upon Seventeenth Century Poetry (Evanston, Ill.: Northwestern University Press, 1950). 

4. Aristotle, Meteorologica, translated by H. P. D. Lee (Cambridge, Mass.: Harvard University Press, 1951), p. 225.

5. William Shakespeare, The Life and Death of King Richard II, Act 1, Scene 3, lines 80-83.

6. Shakespeare, The Tragedy of King Lear, Act 3, Scene 2, lines 4-7. 

7. Joseph-Nicolas De L'Isle, Memoires pour servir a l'histoire et au progres de l'astronomie de la geographie et de la physique (St. Petersbourg: L'Impremerie de l'Academie des Sciences, 1738).

8. Percy Bysshe Shelley, A Vision of the Sea, lines 29-30, in Shelley: Poetical Works, ed. Thomas Hutchinson (London: Oxford University Press, 1943).

9. Ibid., lines 58-63.

10. M. Hirn, "The Sound of Thunder," Scientific American, Vol. 59 (1888), p. 201. 

11. Martin A. Uman, Lightning (New York: McGraw-Hill, 1969), p. 183. 

2. Emily Dickinson, The Farthest Thunder, in The Complete Poems of Emily Dickinson, ed. Thomas H. Johnson (Boston: Little Brown: 1957), no. 1581, pp. 655-656.