It may be said, to begin with, that the formation and use of compound epithets has always been one of the distinguishing marks of the special language of poetry in English, as distinct from that of prose. The very ease with which they can be formed out of the almost inexhaustible resources of the English vocabulary has been a constant source of temptation to poets with new things to say, or new impressions to describe. Moreover, the partial disappearance of inflections in modern English has permitted of a vagueness in the formation of compound words, which in itself is of value to the word-maker. Though, of course, it is possible in most cases accurately to analyse the logical relation between the elements of a compound, yet it sometimes happens, especially with the compound epithets of poetry, that this cannot be done with certainty, because the new formation may have been the result of a hasty but happy inspiration, with no regard to the regular rules of composition.[162] Hence, from one point of view, the free formation of compounds is a legitimate device allowed to the poets, of which the more severe atmosphere of prose is expected to take less advantage; from another point of view, the greater prevalence of the compound in poetry may not be unconnected with the rhythm of verse. Viewed in this light, the use of compound epithets in our poetry at any period may well have been conditioned, in part at least, by the metrical form in which that poetry received expression; and thus in the poetry of the eighteenth century it connects itself in some degree—first, with the supremacy of the heroic couplet, and later with the blank verse that proved to be the chief rival of the decasyllabic.