"But pleasures are like poppies spread;

You seize the flower—its bloom is shed;

Or like the snow-falls in the river,

A moment white, then gone for ever;

Or like the Borealis race,

That flit ere you can point their place;

Or like the rainbow's lovely form,

Evanishing amid the storm."

Long and short syllables alternately form the regular rhythm of this kind of verse; but occasional changes of rhythm and accentuation are used by all good writers. In the following lines Andrew Marvel introduces finely such a change:—

"He hangs in shades the orange bright,