306 cADM US. 
moments to mix with the agitations of the air made by 
this fecond, and the mixed found dies as the firft ceafes: the 
mixed vibrations occafioned by the continuance of both 
firings, will be as. much a compound found as if one of 
the ftrings were to be ftopt; but this found, though differ- 
ent from the twoothers, becomesa diftin& and fimple found, 
as much as purple, produced by a mixture of blue and 
red, becomes.a diftinét colour. If however I wave all this 
and admit that a diphthong can be produced by ¢wo per- 
fons founding two different vowels, at the fame time, as 
the derivation of the word literally imports, it does not 
thence follow that I fhall grant a diphthong can poffbly 
be made by the fame perfon.. 
In Compofing 
Either poetry or profe, attention is paid to the facility of 
uttering whatever is written, but without knowing that 
the founds depend upon certain letters which glide fmooth- 
ly after each other; for there are fome that cannot be read 
after particular founds. without difficulty.. The poet is 
directed by the ear, for the words are generally compofed - 
of fuch clafhing materials, that if they were read as they 
appear the melody would be entirely defeated; and if 
rhyme be examined, we fhall find, provided the words 
be properly fpelled, exa€tly as much refemblance in the 
appearance as in the found. 
Poetry requires a certain number of fyllables or variety 
in the voice confonant with the time required in mufic, 
and not only feeks, when the fubjeGt demands, the moft 
euphonical and flowing words, but thofe whofe divifions 
and emphafes correfpond with each other, and with the 
general tenor of the fubje&t, whether quick or flow, foft 
and captivating—flowry and enchanting—fonorous and 
elevating 
