XXIV. OF THE LETTER X.
The consonant "X has a sharp sound, like ks; as in ox: and a flat one, like gz; as in example. X is sharp, when it ends an accented syllable; as in exercise, exit, excellence: or when it precedes an accented syllable beginning with a consonant; as in expand, extreme, expunge. X unaccented is generally flat, when the next syllable begins with a vowel; as in exist, exemption, exotic. X initial, in Greek proper names, has the sound of z; as in Xanthus, Xantippe, Xenophon, Xerxes"—See W. Allen's Gram., p. 25.