"Both the Italian tempo indications in Purcell's sonatas and the occasional English words in the fantasias imply differences of character as well as speed. The melodic and harmonic motion, and the presence of dissonance or chromaticism serve as superior guides to the finer nuances of speed and Articulation than does the examination of meter. Several of the apparent inconsistencies in Purcell's tempo marks may be resolved when they are considered in the context of three categories--fast, moderate, and slow."
"Tempo gradations in Purcell's sonatas,"
Performance Practice Review:
2, Article 9.
Available at: http://scholarship.claremont.edu/ppr/vol7/iss2/9