There were, indeed, several varieties of shapes and many names for what were essentially the same instrument. Some were square, some were trapezoid, like our grand piano, and some were upright, but they all had the same plectral action and produced the same kind of tone. It will be readily understood that these instruments were incapable of gradations of power. No matter how forcibly or how gently the key was pressed, the elasticity of the plucking quill remained constant, and so produced just the same amount of twang from the string. Wooden uprights, called jacks, were placed at the inner ends of the key levers, where the tangents were in clavichords, and the quills ran through them. In some instruments pieces of hard leather were used instead of quills. Bach was acquainted with the harpsichord, though he always preferred the clavichord. Handel, Scarlatti, and Mozart were all great harpsichord performers. The instrument held its favor among musicians for a considerable time after the introduction of the piano, to which it finally had to yield the supremacy. The first famous harpsichord builder was Johannes Baffo, Venice, 1574, but the most celebrated makers were: Hans Ruckers, Antwerp, 1575; Andreas Ruckers, his son, 1614, Tschudi and Kirkman, the English builders of Handel's day. Kirkman built harpsichords with two banks of keys and several sets of strings, which were controlled by stops similar to those of an organ. This was an attempt to overcome the dynamic monotony of the instrument, but I can testify from careful trial of the fine Kirkman harpsichords in the Steinert collection that the attempt was not a brilliant success. You can get an approximate idea of the sound of a harpsichord by plucking the strings of a modern piano with the plectrum of a mandolin, or with a common quill toothpick.