[Footnote 70: I learn from the Abbe Dobos, (Reflexions sur la
Poesie et la Peinture, tom. iii. p. 174, 175,) that the
simplicity of the Ambrosian chant was confined to four modes,
while the more perfect harmony of the Gregorian comprised the
eight modes or fifteen chords of the ancient music. He observes
(p. 332) that the connoisseurs admire the preface and many
passages of the Gregorian office.]