After the Antwerp make declined, London became pre-eminent for harpsichords—the representative makers being Jacob Kirck mann and Burckhard Tschudi, pupils of a Flemish master, one Tabel, who had settled in London, and whose business Kirck mann continued through marriage with Tabel's widow. Tschudi was of a noble Swiss family belonging to the canton of Glarus. According to the custom with foreign names obtaining at that time, by which Haendel became Handel, and Schmidt Smith, Kirckmann dropped his final n and Tschudi became Shudi, but he resumed the full spelling in the facies of the splendid harpsichords he made in 1766 for Frederick the Great, which are still preserved at Potsdam. By these great makers the harpsichord became a larger, heavier-strung and more powerful instrument, and fancy stops were added to vary the tone effects. To the three shifting registers of jacks were added the "lute," the charm of which was due to the favouring of high harmonics by plucking the strings close to the bridge, and the "harp," a muting effect produced by impeding the vibration of the strings by contact of small pieces of buff leather, Two pedals were also used, the left-hand one a combination of a unison and lute.
The right-hand pedal was to raise a hinged portion of the top or cover and thus gain some power of "swell" or crescendo, an invention of Roger Plenius, to whom also the harp stop may be rightly attributed. The first idea of pedals for the harpsichord to act as stops appears to have been John Hayward's (?Haward) as early as 1676, as we learn from Mace's Musick's Monument, p. 235. The French makers preferred a kind of knee-pedal arrange ment, known as the "genouillere," and sometimes a more com plete muting by one long strip of buff leather, the "sourdine." As an improvement upon Plenius's clumsy swell, Shudi in 1769 pat ented the Venetian swell, a framing of louvres, like a Venetian blind, which opened by the movement of the pedal, and becoming in England a favourite addition to harpsichords, was early trans ferred to the organ, replacing the rude "nag's-head" swell.
To keep his collection of musical instruments in playing order Prince Ferdinand dei Medici engaged a Paduan harpsichord maker, Bartolommeo Cristofori, the man of genius who invented and pro duced the pianoforte. We fortunately possess the record of this invention in a literary form from a well-known writer, the Marchese Scipione Maffei ; his description appeared in the Giornale dei letterati d'Italia, a publication conducted by Apostolo Zeno. The date of Maffei's paper was 1711. Rimbault reproduced it, with a technically imperfect translation, in his History of the Pianoforte. We learn from it that in 1709 Cristofori had com pleted four "gravecembali col piano e forte"—keyed-psalteries with soft and loud—three of them being of the long or usual harpsichord form. The sketch of his action in Maffei's essay shows
an incomplete stage in the invention, although the kernel of it— the principle of escapement or the controlled rebound of the ham mer—is already there. He obtains it by a centred lever (linguetta mobile) or hopper, working, when the key is depressed by the touch, in a small projection from the centred hammer-butt. The return, governed by a spring, must have been uncertain and incapable of further regulating than could be obtained by modify ing the strength of the spring. Moreover, the hammer had each time to be raised the entire distance of its fall. There are, how ever, two pianofortes by Cristofori, dated respectively 1720 and 1726, which show a much improved construction, for the whole of an essential piano movement is there. The earlier instrument (now in the Metropolitan Museum, New York) has undergone consider able restoration, but the 1726 one, which is in the Kraus Museum at Florence, retains the original leather hammer-heads. Both in struments possess alike a contrivance for determining the radius of the hopper, and both have been unexpectedly found to have prior to J. S. Bach's visit to him in 1747, we find the Cristofori framing, stringing, inverted wrest-plank and action complete. Fig. II represents the instrument on which J. S. Bach played in the Stadtschloss, Potsdam.
It has been repeatedly stated in Germany that Frederici, of Gera in Saxony, an organ builder and musical instrument maker, in vented the square or table-shaped piano, the "fort bien," as he is said to have called it, about 1758-60. No square piano by this maker is forthcoming, though an "upright grand" piano, made by Domenico del Mela in 1739, with an action adapted from Cristo fori's has been discovered by Signor Ponsicchi of Florence. Victor the "check" (Ital. paramartello), which regulates the fall of the hammer according to the strength of the blow which has impelled it to the strings.
Thicker stringing, to withstand even Cristofori's light hammers, demanded in its turn a stronger framing than the harpsichord had needed. Accordingly to make his structure firm Cristofori con siderably increased the strength of the block which holds the tuning-pins, and as he could not do so without materially adding to its thickness, he adopted the bold expedient of inverting it; driving his wrest-pins, harp-fashion, through it, so that tuning was affected at their upper, while the wires were attached to their lower, ends. Then, to guarantee the security of the case, he ran an independent string-block round it of stouter wood than had been used in harpsichords, in which block the hitch-pins were driven to hold the farther ends of the strings, which were spaced at equal distances (unlike the harpsichord), the dampers lying between the pairs of unisons.