"Then rést, my friénd, and spáre thy précious bréath."
On each of the syllables rést, friénd, spáre, préc-, bréath, there is an accent. Each of these syllables
must be compared with the one that precedes it; rest with then, friend with my, and so on throughout the line. Compared with the word and, the word spare is not only accented, but the accent is conspicuous and prominent. There is so little on and, so much on spare, that the disparity of accent is very manifest.
Now, if in the place of and, there were some other word, a word not so much accented as spare, but still more accented than and, this disparity would be diminished, and the accents of the two words might be said to be at par, or nearly so. As said before, the line was slightly altered from Churchill, the real reading being
"Then rést, my friénd, spare, spare thy précious bréath."
In the true reading we actually find what had previously only been supposed. In the words spare, spare, the accents are nearly at par. Such the difference between accent at par and disparity of accent.
Good illustrations of the parity and disparity of accent may be drawn from certain names of places. Let there be such a sentence as the following: the lime house near the bridge north of the new port. Compare the parity of accent on the pairs of words lime and house, bridge and north, new and port, with the disparity of accent in the compound words Límehouse, Brídgenorth, and Néwport. The separate words beef steak, where the accent is nearly at par, compared with the compound word sweépstakes, where there is a great disparity of accent, are further illustrations of the same difference.
The difference between a compound word and a pair of words is further illustrated by comparing such terms as the following:—bláck bírd, meaning a bird that
is black, with bláckbird = the Latin merula; blúe béll, meaning a bell that is blue, with blúebell, the flower. Expressions like a shárp edgéd instrument, meaning an instrument that is sharp and has edges, as opposed to a shárp-edged instrument, meaning an instrument with sharp edges, further exemplify this difference.
Subject to a few exceptions, it may be laid down, that, in the English language, there is no composition unless there is either a change of form or a change of accent.