Come into the garden, Maud,
until the second line shows us we should read it with three stresses, not four. There is a curious verse in Gay's Beggar's Opera which well illustrates the necessity of consulting the context to determine the pattern, for it can, taken by itself, be scanned in three different ways:
How happy could I be with either.
Air XXXV.
viz., ◡_̷◡◡_̷◡_̷◡_̷◡ or ◡_̷◡◡◡_̷◡_̷◡ or ◡_̷◡◡_̷◡◡◡_̷◡.
But sometimes it is difficult, if not impossible, to say whether a line or series of lines is in rising or falling rhythm, or what sort of foot is predominant—in other words, what is the formal metrical pattern. This difficulty is, of course, no fault of the poet's: it lies in the complexity of the phenomena, and is after all a weakness of our power of analysis. In the spectrum blue merges into green, red into yellow, and though we invent names for various tints, others still escape classification. And just as some verses combine iambic and anapestic (rising), or dactylic and trochaic (falling) movements, so others combine rising and falling rhythms. For example,
The mountain sheep are sweeter,
But the valley sheep are fatter;
We therefore deemed it meeter
To carry off the latter.
Peacock, War-song of Dinas Vawr, from The Misfortunes of Elphin.
This may be trochaic with anacrusis or iambic with feminine endings, but neither quite adequately describes it. Is Shelley's To Night prevailingly iambic or trochaic? All of the twenty-five long lines end with an iamb, but only eleven begin with rising rhythm (thirteen begin with falling or trochaic rhythm, and one is ambiguous). Two of the short lines are definitely iambic, the other eight are doubtful, but apparently trochaic. If it is read as iambic, eleven of the hundred feet in the long lines will be 'irregular'; if it is read as trochaic, eleven likewise will be 'irregular.' Milton's L'Allegro and Il Penseroso contain lines that are purely iambic, as
And oft, as if her head she bow'd;
some that are purely trochaic, as
Whilst the landskip round it measures;