82), which see, the design is as follows:--Part I is a period of eight measures.

Part II is also an 8-measure period, ending upon the tonic chord of B-flat major (the dominant key), as first eighth-note of the 16th measure; the following eighth-note, b-natural, represents what we have called the Retransition (in its smallest conceivable form), as it fulfils no other purpose than that of leading back into the first tone of the First Part.

Part III is _only a phrase_, and therefore shorter than Part I; but it corroborates the _beginning_, and, in fact, the entire contents of the First Part.
The plan of Mendelssohn's 28th Song Without Words is as follows:--First number the 38 measures, _carefully_.

The first four measures are an introductory phrase, or prelude; Part I begins in the second half of measure 4 (after the double-bar) and extends, as regular 8-measure period, to measure 12.

Part II follows, during the same measure; its form is a period, extending to measure 20, and closing with a very distinctly marked semicadence on the dominant chord (chord of D).