This uncommon instrument displays one of the expedients employed to gain a more brilliant effect by the addition of an octave string, before such a string was permanently attached to the sound-board of the harpsichord itself by means of an additional row of strings placed beneath the ordinary unison strings. Octave spinets were, as Mersenne (1636) describes, made independent of the ordinary spinet, and there are frequent examples to be met with. These little spinets were placed upon the larger ones for performance, as Praetorius (1619) says, like turrets on a tower. In this double spinet it is a removable part of the instrument, and constitutes the left-hand key-board, the right-hand key-board being a fixture. The maker, as is proved by his initials, HR, and his device in the rose of the sound-hole, is no other than the famous Hans Ruckers the elder, of Antwerp. This Spinet is numbered 9 of the sixty-six existing instruments by the Ruckers family catalogued by the present writer in Sir George Grove's _Dictionary of Music and Musicians_. It can now be extended to sixty-eight. On the jack rails of both spinets may be read "Joannes Rvqvers me fecit." There is another double spinet at Nuremberg made in 1580 by Martin Vander Beest, which has been figured and is the frontispiece to Dr. August Reissmann's _Illustrirte Geschichte der Deutschen Musik_ (Leipzig, 1881). The Ruckers double spinet can hardly be much later. The earliest examples known to me of the octave string attached, as above mentioned, in the harpsichord itself, are to be found in a double clavecin (French for harpsichord) by Hans Ruckers the elder, dated 1590, and preserved in the Museum of the Paris Conservatoire, and in a clavicembalo (Italian for harpsichord), made at Pesaro, and also in 1590,--lately brought to England by Messrs. Hill, the violin-makers, and now acquired by the South Kensington Museum. The latter is an instrument with only two strings to each note. The invention of the octave string, as well as of double key-board, has been attributed to Hans Ruckers. The latest evidence, however, does not favour these attributions, although both inventions most likely belong to the Netherlands. Ruckers and his sons, it may be said, made instruments that were never surpassed for quality of tone. To return to the Double Spinet--both key-boards are of four octaves, the fixed right-hand one being from the second C below, to the second above, middle C, and the removable left-hand one is an octave higher throughout. The complete instrument rests upon the original arcaded stand.