Page:Fugue by Ebenezer Prout.djvu/36

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55. In our first chapter (§ 9) we defined the answer as "the transposition of the subject into the key of the perfect fourth or fifth above or below the key of the subject." It is most necessary that the student should know how to find the correct answer to any given subject; unfortunately there is hardly any point on which the rules given in the older text-books differ so widely from the practice of the greatest composers. The rules to be given in the present chapter will therefore not be taken from existing treatises, but deduced from the works of the great masters themselves.

56. In by far the largest number of cases, the keys in which the subject and answer are found are the tonic and dominant. If the subject be in the tonic, the answer will be in the dominant; if the subject be in the dominant, the answer will be in the tonic. If the subject begin in the tonic and modulate to the dominant, the answer will begin in the dominant and modulate to the tonic, and vice versa. Occasionally, however, as will be seen presently, the place of the dominant is taken by the subdominant.

57. The answer of a subject may be either real or tonal. It is said to be real when it is an exact transposition (with one possible exception, to be noticed in its proper place—see § 69) of the subject; it is called tonal when certain alterations, the nature of which we shall explain later, have to be made in transposing it.

In the above examples the subject is marked S and the answer A. At (a) the answer is real; at (b) it is tonal, the interval of a third from G to B being answered by a second from D to E. Let the student also notice that at (a) the last note of the answer is longer than the last note of the subject. We shall meet with