Obviously, this presentment of ideas through graphic designs into which metaphor often bordering on enigma had to be read, implied good memories and clear grasp of association on the part of the interpreter. Any doubt or ambiguity, with resulting confusion, as to the meaning of the symbol, rendered it worse than useless. Hence the addition of "determinants," concerning which something was said when treating of the Chinese script (see p. 85). These are of two classes--the special and more numerous, whose use was confined to one word or idea; and the general, numbering about two hundred, which, like the Chinese "keys," refer to whole groups of words. But ideas have to be arranged in sentences, and these are made up of nouns, adjectives, verbs, and other parts of speech for which symbolism, however ingenious, can make no provision. Moreover, while the characters are limited in their application, the ideas to be expressed graphically are ever growing, and hence, in course of time, there are not enough symbols "to go round." A way of escape opened itself, and thereby led to an invention undreamed of, when recourse was had to the use of pictures of things which were different in sense, but the names of which had the same _sound_; in other words, to the pictorial pun known as the rebus (see p. 79). As an amusing instance of the formation of a compound phonogram out of syllabic signs, Canon Taylor quotes from an inscription of Ptolemy XV. at Edfu, in which, as he says, "it seems not impossible to detect a faint flavour of ancient Egyptian humour. The name of _lapis lazuli_ was _khesteb_. Now the word _khesf_ meant 'to stop,' and the syllable _teb_, 'a pig.' Hence the rebus 'stop-pig' was invented to express graphically the name of _lapis lazuli_, which is figured by the picture of a man stopping a pig by pulling at its tail." Probably the Canon is right, but in western lands that action is often intended to make the pig move on. Another example of the rebus occurs in the name of Osiris, which in Egyptian is _Hesiri_ (Wallis Budge gives it as _Ausir_). The god, on this showing, is represented, presumably, by a figure on a seat, _hes_, and by an eye, _iri_. But with the constant revision of interpretations by Egyptologists, it behoves us to quote with caution. There is a stock illustration as to the adoption of the supposed picture of a lute (used by the Egyptian scribes to denote "excellence"), as a phonogram to express the word _nefer_, "good." But it seems that what was thought to be a lute is the picture of a heart and windpipe! At last, we know not when, and we cannot, speaking of Egypt alone, guess where, there dawned upon some mind the fact that all the words which men uttered are expressed by a few sounds. Hence, what better plan than to select from the big and confused mass of ideograms, phonograms, and all their kin, a certain number of signs to denote, unvaryingly, certain sounds?