Fugue.
CHAPTER I.
INTRODUCTION.
1. It is absolutely necessary that any one who begins to study fugue should have a thorough knowledge not only of Harmony and Counterpoint, but of Double Counterpoint and Canon. Without such knowledge any attempt to master fugal composition is a mere waste of time. A previous acquaintance on the part of the pupil will therefore be presupposed throughout this work, either with the preceding volumes of the present series, or with other books treating of the same subjects.
2. A Fugue is a composition founded upon one subject, announced at first in one part alone, and subsequently imitated by all the other parts in turn, according to certain general principles to be hereafter explained. The name is derived from the Latin word fuga, a flight, from the idea that one part starts on its course alone, and that those which enter later are pursuing it.
3. Though the definition of Fugue just given may be accepted as generally correct, it should be mentioned here, to prevent misapprehension, that fugues may be written on more than one subject. If there are two subjects, the fugue is said to be a double fugue; if there are three, it is a triple fugue, and so on. In such cases the composition will not begin with one part alone; the subjects will appear together, although in all probability they will not all commence exactly at the same time. It must also be said that we often meet, especially in modern music, with vocal fugues having an independent instrumental accompaniment. In such cases what has been said as to the entry of the subject with one part alone does not apply; a fugue of this kind has some analogy to an accompanied canon.
4. From the description just given of fugue, it would seem at first sight to have a considerable resemblance to Canon. The latter, indeed, was formerly called fuga canonica, and it will greatly assist the beginner to understand the real nature of a fugue if we point out the chief differences between it and the canons which, it may be assumed, he has already studied. One most important difference is that, whereas in a canon the leading voice is imitated throughout by all the parts that follow, this
