(Fr. harpe d’Eole, harpe éolienne; Ger. Äolsharfe, Windharfe; It. arpa eolia, arpa d’Eolo).
A string instrument (chordophone) sounded by natural wind, interesting as much for its symbolic significance as for its musical importance.
Normally four to 12 (but sometimes 24 or 48) strings ‘of catgut or brass wire, equal in length, unequal in thickness’ (Magasin pittoresque, 1845) are stretched over one or two hardwood bridges of triangular cross-section, mounted on a thin pine, maple or mahogany box of variable shape – measuring 75–200 cm (normally 85–110 cm) long, 11–35 cm (normally 12–26 cm) wide and 5–17 cm (normally 5–9 cm) deep. The ends of this soundbox may be of beech, for insertion of iron hitch-pins or wooden tuning-pegs. Most instruments have some device such as a slit draught for concentrating the wind on the strings.
Six variants of this structure exist: (1) A rectangular soundbox with a single horizontal row of strings, the most popular model in England, and, until 1803, in Germany; also the simplest type.
(2) A more practical variant developed only in England, with the strings on an inclined fingerboard over which a lid was mounted, whose horizontal top allowed the wind to blow over the strings where the incline was lowest and funnel up the inclined soundboard to the highest point at the back of the instrument (fig.1). This structure ideally fitted sash windows, being mounted on the sill with the frame brought down on top of the lid to hold the instrument in place.
(3) A vertically strung soundbox with wind-funnelling ‘wings’ used throughout western Europe since its inception by Kircher in 1650 at Rome.
(4) A further development of the vertically strung model (fig.2) with double banks of strings, one on each side of the instrument (always in the same plane as the wind direction), used by Steudal (from 1803) and J.C. Dietz in Germany.
(5) A model on which the strings were mounted on a semicircular soundbox (so that at least one or two strings would present themselves at the correct angle, whatever the wind direction), developed apparently by the Swiss.
(6) An apparently popular variant in France of this semicircular model consisting of a triangular soundbox mounted with strings on two or three faces.
The exact means by which aeolian tones are generated is still not fully understood. Kircher in 1650, noticing that several notes may be heard from one string, suggested that the string was to the wind as a prism to light, separating component sounds from the single energy source. His colleague Daniello Bartoli poured scorn on this theory in Del suono de’ tremori armonici e dell’udito (Rome, 1679). Since then, no exact theory has been propounded. The Abbot Gattoni of Milan in 1783 and H.C. Koch 18 years later experimented with various string metals, and examined the conditions under which aeolian tones were produced. Their findings were quantified by Pellisov in 1822, but V. Strouhal of Würzburg established empirically that the frequency of any one aeolian tone was not dependent on the material or length of the string, but was equal to the product of the airstream speed some way from the string and a constant (normally 0·185, known as the Strouhal number), divided by the string diameter. But Strouhal’s theory depended on the string vibrating in the same plane as the airstream, whereas Rayleigh, characteristically examining through a home-made telescope a string stretched under his chimney, claimed the string vibrated across the airstream. Further researches by E.G. Richardson and in 1956 by Etkin and others in the USA only feebly penetrated the problem. Present theory suggests that it is the eddies creating a vortex pattern behind the string, like the small whirlpools visible when a stick is held in flowing water, that make the aeolian tone, which may occasionally be of the same pitch as one of the string’s natural frequencies, thus causing it to vibrate. An exact solution of the creation of these vortices and their resultant three-dimensional pattern, termed ‘Kármán Street’ (after von Kármán, 1912), appears to be beyond the capability of present mathematical techniques.
Legends from 800 bce (Homer) onwards describe how Hermes invented the lyre by letting the wind blow over dried sinews in a tortoise carapace; in later legends, such as that of David’s harp, God-sent wind blows upon and sounds an already invented instrument. Like David, St Dunstan (d 988) also had his harp sounded by God; it played the anthem Gaudent in coelis, and all nearby marvelled (W. Stubbs, Memorials of St Dunstan, London, 1874). Only later and for different reasons was he convicted of sorcery.
Although G.B. della Porta’s Magia naturalis (Rome, 1540) made reference to aeolian phenomena, the harp’s technological development began with Kircher’s rediscovery of the Aeolian harp (Musurgia universalis, 1650; and Phonurgia nova). He called them ‘musical autophones’. J.J. Hofmann’s Lexicon universale (Basle, 1677) appears to be the first source employing the aeolian adjective to describe the wind harp: he called it Aeolium instrumentum, and quoted Kircher about its construction and sound effect.
A visit to Kircher’s museum inspired an article in the newly founded Breslau University’s Sammlung von Natur of 1726, but the harp did not become fashionable until the 1780s. Then the accumulation of Alexander Pope’s Commentary of Eusthasius, James Thomson’s aeolian poetry of the 1740s, and the report on the structure of the Aeolian harp in a letter from ‘A.Z.’ in the Gentleman’s Magazine (1754) culminated in an article ‘On the Eolian Harp’ in W. Jones’s Physiological Disquisitions (London, 1781). On announcing that he was ‘prepared to dispose of them at a reasonable price to such gentlemen as take a pleasure in this agreeable class of experiments’, Jones and London instrument makers such as Longman & Broderip, Hintz, and Silber &Fleming set a trend that was to prevail in England until at least the announcement of 48-string instruments in Metzler’s catalogue of 1884, and Burkardt and Doebler’s 1862 Manchester patent of ‘Improvements in the Aeolian Harp’.
But whereas in England the Aeolian harp’s place was apparently in the home, on the Continent it was usual to place instruments in grottos, gardens, summer-houses or inhabited châteaux (Pierrefonds, Oise, 1830), or uninhabited châteaux (Baden-Baden, 1853) or even strung between the spires of two churches (by Abbot Gattoni of Milan, 1783). Kastner commented that ‘Harps that maintain themselves in decent state in the garden have long been sought after’ (La harpe d’Eole, p.83). The Neue Berliner Musikzeitung (28 June 1854) recommended the Aeolian harp for public parks as well as aristocratic gardens.
Europe’s reaction to England’s enthusiasm was consequently varied. France cared little for the instrument (although Clementi expressed some interest in those developed by Gustave Lyon for Pleyel, Lyon & Cie.) except in the Alsace district, where Kastner, Frost, Echel, Gaïb and Roth developed a number of ingenious vertical models. Kastner’s full study, La harpe d’Eole, added an opera as an appendix for good measure. The Italian Gattoni outdid everyone with his ‘armonica meterologica’ which sounded whenever the Milan weather was about to change (Opusculi scelti, Milan, 1785, p.298). The only country besides England to show any lasting interest was Germany: two articles in the Göttingen Taschenkalendar of 1789 and 1792 were followed by another by Quandt in the Lausizische Monatsschrift for 1795, and by J.F.H. von Dalberg’s fairy tale Die Äolsharfe: ein allegorischer Traum (Erfurt, 1801), which contained some interesting notes. After the review of this work in the Allgemeine musikalische Zeitung (1801) there were further journal articles over the next 50 years, and a lengthy study in H.C. Koch’s Musikalisches Lexicon (Frankfurt, 1801). In the late 1830s W.P. Melhop of Hamburg developed an Aeolian harp in which the wind was funnelled into a box in which the strings were enclosed. He provided a detailed description and drawings of his instrument in his Spaziergänge III (MS, 1835–44, D-Ha 622-1: Familie Melhop–A5: see Pilipczuk). Other German makers included Koch, F.T. Kaufmann of Dresden and C.W. Esslinger of Berlin. Towards the end of the 20th century E. Bäuerle and M. Minssen devised an unresonated electroacoustic Aeolian harp, designed to be sounded either indoors by the human breath or outdoors by strong winds (see Minssen).
The harp’s sufficient epitaph, until the late 20th-century revival in England, the USA and Germany, was Troyte’s gift of an instrument, with the appropriate ‘Enigma’ variation painted on one side, to Elgar in 1904. It typified the Aeolian harp’s European history as one not so much of increasingly sophisticated technology as of individuals working in self-styled directions: rarely taking much notice of each other’s efforts, but often using Kircher as a working basis.
Outside Europe, idiophonic Aeolian harps have been observed in Ethiopia (Begamder tribe), Java, China (feng zheng, yao pian and yao qin kites, shaped like fish or dragons – noted even by Kircher in 1650 – flown each spring, the Chinese words meaning ‘abundance’ and ‘water fertility’ respectively), and Guyana, where the Macoosis and Warrau tribes use the leafstalk of the Itah palm (Mauritia flexuosa) stuck in the ground or on house tops.
Poetry about the Aeolian harp began in England in the 1740s, with James Thomson in his 1748 Castle of Indolence hymning ‘Wild-warbling Nature all above the reach of Art’. 50 years later the poet Robert Bloomfield was writing in much the same vein, and it took Coleridge in his The Eolian Harp (1795) and Dejection (1802) to think less of the Aeolian harp as the man-made medium through which Nature speaks to Man than as the tragic reflection of his own life-experience, an ‘Actor, perfect in all tragic sounds!’. Goethe and Mörike (An eine Äolsharfe, 1867), and Thoreau and Melville in the USA, preferred this interpretation, bearing out M. Abrams’s statement that ‘Not until the nineteenth century did the wind-harp become an analogy for the poetic mind as well as a subject for poetic description’ (The Mirror and the Lamp, New York, 1953, p.51). But with the decline of the harp itself, the imagery changed to mockery, culminating in a derisive reference in R.L. Stevenson’s The Beach of Falesà (1892), such that ‘The music of the spheres died of shame’ (Bonner and Davies, iii, p.90).
For a discussion of further applications of the aeolian harp principle, see Sound sculpture, §2(i).
R. Bloomfield: Nature’s Music (London, 1801)
G. Kastner: La harpe d’Eole (Paris, 1856)
G. Grigson: The Harp of Aeolus, and Other Essays (London, 1947)
B. Etkin, G.K. Korbacher and R.T. Keefe: ‘Acoustic Radiation from a Stationary Cylinder in a Fluid Stream’, JASA, xxix (1957), 30–36
S. Bonner and M.G. Davies, eds.: Aeolian Harp (Duxford, 1968–74)
A. Pilipczuk: ‘Wilhelm Peter (II) Melhop und seine Äolsharfen’, Das Musikinstrument, xlii (1993), 126–36
M. Minssen and others: Äolsharfen: der Wind als Musikant (Frankfurt, 1997; Eng. trans., GSJ, lii, 1999, 334–7)
B. Wackernagel: Europäische Zupf- und Streichinstrumente, Hockbretter und Äolsharfen (Frankfurt, 1997)
STEPHEN BONNER/R