Although the Italians were undoubtedly the first to introduce the horn into the orchestra, it figured at first only as the characteristic instrument of the chase, suggesting and accompanying hunting scenes or calls to arms. For a more independent use of the horn in the orchestra we must turn to Germany. Reinhard Keiser, the founder of German opera, at the end of the 17th century in Hamburg, introduced two horns in C into the opening chorus of his opera Octavia in 1705, where the horns are added to the string quartette and the oboes; they play again in act i. sc. 3, and in act ii. sc. 6 and 9. The compass used by the composer for the horns in C alto is the following:—
Wilhelm Kleefeld draws attention to the characterization, which differed in the three acts. In Henrico (1711), in Diana (1712) and in L’Inganno Fedele (1714) F horns were used. This called forth from Mattheson[60] his much-quoted eulogium, the earliest description of the orchestral horn: “Die lieblich pompeusen Waldhörner sind bei itziger Zeit sehr en vogue kommen, weil sie theils nicht so rude von Natur sind als die Trompeten, teils auch weil sie mit mehr Facilité können tractiret werden. Die brauchbarsten haben F und mit den Trompeten aus dem C gleichen Ambitum. Sie klingen auch dicker und füllen besser aus als die übertäubende und schreyende Clarinen, weil sie um eine ganze quinte tiefer stehen.”
Lotti in his Giove in Argo, given in Dresden, 1717, scored for two horns in C, writing for them soli in the aria for tenor[61] (act iii. sc. 1). Examples of C. H. Graun’s[62] scoring for horns in F and G respectively in Polydorus (1708-1729) and in Iphigenia (1731) show the complete emancipation of the instrument from its original limitations; it serves not only as melody instrument but also to enrich the harmony and emphasize the rhythm. A comparison of the early scores of Cavalli and Lulli with those of Handel’s Wasserfahrtmusik[63] (1717) and of Radamisto, performed in London in 1720, shows the rapid progress made by the horn, even at a time when its technique was still necessarily imperfect.
While Bach was conductor of the prince of Anhalt-Cöthen’s orchestra (1717-1723), it is probable that horns in several keys were used. In Dresden two Bohemian horn-players, Johann Adalbert Fischer and Franz Adam Samm, were added to the court orchestra in 1711.[64] In Vienna the addition is stated to have taken place in 1712 at the opera.[65] It is probable that as in Paris so in Vienna there were solitary instances in which the horn was heard in opera without attracting the attention of musicians long before 1712, for instance in Cesti’s Il Pomo d’Oro, printed in Vienna in 1667 and 1668 and performed for the wedding ceremonies of Kaiser Leopold and Margareta, infanta of Spain. A horn in E (former F pitch) in the museum of the Brussels conservatoire bears the inscription “Machts Michael Leicham Schneider in Wien, 1713.”[66] Fürstenau[67] gives a further list of operas in Vienna during the first two decades of the 18th century.
It will be well before the next stage in the evolution is approached to consider the compass of the natural horn. The pedal octave from the fundamental to the 2nd harmonic was altogether wanting; the next octave contained only the 2nd and 3rd harmonics or the octave and its fifth; in the third octave, the 8ve, its major 3rd, 5th and minor 7th; in the fourth octave, a diatonic scale with a few accidentals was possible. It will be seen that the compass was very limited on any individual horn, but by grouping horns in different keys, or by changing the crooks, command was gained by the composer over a larger number of open notes.
An important period in the development of the horn has now been reached. Anton Joseph Hampel is generally credited[68] with the innovation of adapting the crooks to the middle of the body of the horn instead of near the mouthpiece, which greatly improved the quality of the notes obtained by means of the crooks. The crooks fitted into the two branches of U-shaped tubes, thus forming slides which acted as compensators. Hampel’s Inventionshorn, as it is called in Germany (Fr. cor harmonique), is said to date from 1753,[69] the first instrument having been made for him by Johann Werner, a brass instrument-maker of Dresden. The same invention is also attributed to Haltenhof of Hanau.[70] Others again mention Michael Wögel[71] of Carlsruhe and Rastadt, probably confusing his adaptation of the Invention or Maschine, as the slide contrivance was called in Germany, to the trumpet in 1780. The Inventionshorn, although embodying an important principle which has also found its application in all brass wind instruments with valves as a means of correcting defective intonation, did not add to the compass of the horn. At some date before 1762 it would seem that Hampel[72] also discovered the principle on which hand-stopping is founded.
By hand-stopping (Fr. sons bouchés, Ger. gestöpfte Töne) is understood the practice of inserting the hand with palm outstretched and fingers drawn together, forming a long, shallow cup, into the bell of the horn; the effect is similar to that produced in wood wind instruments, termed d’amore, by the pear-shaped bell with a narrow opening, i.e. a veiled mysterious quality, and, according to the arrangement of the hand and fingers (which cannot be taught theoretically, being inter-dependent on other acoustic conditions), a drop in pitch which enables the performer merely to correct the faulty intonation of difficult harmonics or to lower the pitch exactly a semitone or even a full tone by inserting the hand well up the bore of the bell. J. Fröhlich[73] gives drawings of the two principal positions of the hand in the horn. The same phenomenon may be observed in the flute by closing all the holes, so that the fundamental note of the pipe speaks, and then gradually bringing the palm of the hand nearer the open end of the flute. As a probable explanation may be offered the following suggestion. The partial closing of the opening of the bell removes the boundary of ambient air, which determines the ventral segment of the half wave-length some distance beyond the normal length; this boundary always lies beyond the end of the tube, thus accounting for the discrepancy between the theoretical length of the air-column and the practical length actually given to the tube.[74] Hampel is also said to have been the first to apply the sordini[75] (Fr. sourdine) or mute, already in use in the 17th century for the trumpet,[76] to the horn. The original mute did not affect the pitch of the instrument, but only the tone, and when properly constructed may be used with the valve horn to produce the mysterious veiled quality of the hand-stopped notes. No satisfactory scientific explanation of the modifications in the pitch effected by the partial obstruction of the bell, whether by the hand or by means of certain mechanical devices, has as yet been offered. D. J. Blaikley suggests that in cases when the effect of hand-stopping appears to be to raise the pitch of the notes of the harmonic series, the real result of any contraction of the bell mouth (as by the insertion of the hand) is always a flattening of pitch accompanied by the introduction of a distorted or inharmonic scale, of such a character that for instance, the c, d, e, or 8th, 9th and 10th notes of the original harmonic scale become not the c♯ d♯ e♯ of a fundamental raised a semitone, but D♭, E♭, and f due to the 9th, 10th and 11th notes of a disturbed or distorted scale having a fundamental lower than that of the normal horn.
With regard to the discovery of this method of obtaining a chromatic compass for the horn, which rendered the instrument very popular with composers, instrumentalists and the public, and procured for it a generally accredited position in the orchestra, the following is the sum of evidence at present available. In the Kgl. öffentliche Bibliothek, Dresden, is preserved, amongst the musical MSS., an autograph volume of 152 pages, entitled Lection pro Cornui, bearing the signature A. J. H[ampel], the name being filled in in pencil by a different hand. There is no introduction, no letterpress of any description belonging to the MS. method for the horn, nor is any book or pamphlet explaining the Inventionshorn or the method of hand-stopping by Hampel extant or known to have existed. He has apparently left no record of his accomplishment. A few typical extracts copied and selected from the original MS., courteously communicated by the director of the Royal Library, Hofrath, P. E. Richter (a practical musician and performer on horn and trumpet), do not prove conclusively that they were intended to be played on hand-stopped horns, with the exception, perhaps, of the A, 13th harmonic from C, which could not easily be obtained except by hand-stopping on the hand-horn. On the blank sheet preceding the exercises is an inscription in the hand of Moritz Fürstenau, former custodian of the Royal Private Musical Collection (incorporated with the public library in 1896): “Anton Joseph Hampel, by whom these exercises for the horn were written, was a celebrated horn-player, a member of the Orchestra of the Electoral Prince of Saxony. He invented the so-called Inventionshorn. Cf. Neues biog.-hist. Lexicon der Tonkünstler by Gerber, pt. i. col. 493; also Zur Gesch. der Musik u. des Theaters am Hofe zu Dresden, by M. Fürstenau, Bd. ii.” It will be seen that Fürstenau gives Gerber as his authority for the attribution of the invention to Hampel, although he searched the archives, to which he had free access, for material for his book.