The same may be said of Michael PrÊtorius, a distinguished Kapellmeister at Brunswick, who is the author of 'De Organographia,' Wolfenb¸ttel, 1619. This valuable treatise forms the second volume of a work entitled, 'Syntagma Musicum,' etc. The first volume treats on the history of music, chiefly sacred; it is written in Latin, and was published in 1615. The third volume, which like the second is written in German, contains an account of the different vocal compositions in use at the time when the work was written. The wood-engravings of 120 instruments belonging to Volume II. were published with the separate title: 'Theatrum Instrumentorum seu Sciagraphia,' Wolfenb¸ttel, 1620. The proper German name of PrÊtorius is Schulz. It was not unusual with the old German authors to Latinize their names on the title-page of their books. The works just noticed are now so scarce that the musician rarely finds an opportunity to consult them. Hardly more accessible is the 'Harmonie universelle,' Paris, 1636, by F. Marin Mersenne,--a work which is valued especially on account of its comprehensiveness. The second volume contains descriptions with illustrations of the musical instruments in use about the year 1600. Mersenne was a monk,--as was also Athanasius Kircher, whose 'Musurgia universalis' appeared in Rome in the year 1650. Kircher's work is less scarce than that of Mersenne, but also less important. The illustrations in 'Musurgia universalis' are however, interesting, and it is principally on account of them that the work is still appreciated by musical historians. The 'Musurgia universalis' is written in Latin. Athanasius Kircher occupied himself also in making acoustic experiments, and he wrote a treatise on the subject, illustrated by engravings. He also constructed various acoustic instruments, which after his death, were deposited with other curiosities left by him, in a Museum at Rome. Dr. Burney, who saw them in Rome in the year 1770, remarks in his Journal: "They are now almost all out of order; but their construction is really curious, and manifests an ingenuity as well as zeal of this learned father in his musical inquiries and experiments." Filippo Bonanni, who like Athanasius Kircher was a Jesuit Father, published at Rome in the year 1722, a work entitled 'Gabinetto armonico pieno d'istromenti sonori,' which contains 138 copper-plate engravings of musical instruments, most of them with representations of the performers. It is written in Italian. A second edition, in Italian and French, appeared in 1776. Bonanni's work is an amusing picture-book rather than a scientific treatise. The illustrations are inexact, and the explanations are meagre and unsatisfactory. The author had evidently never seen most of the instruments which he describes, and many of the illustrations appear to have been drawn from his description and not from actual specimens.