inadequate for a civilized language, the possible number of two-, three and four-letter words, aggregating thousands, is sufficient to supply the majority of words needed for every-day speech. The word-curve of common conversation may therefore be expected to show a maximum ordinate for three or four letters. Words containing five, six or more letters will occur with diminishing frequencies. Few words of more than ten letters will occur. Now this is exactly what takes place. Swift's 'Polite Conversation,' which is a reproduction of the conversation of the uncultured, yields the word-curve shown in Fig. 1. This, after a correction for an excess of seven-and eight-letter words, due to the frequent occurrence of the words ladyship, lordship and certain proper names, is the typical word-curve of extreme light dialogue.
What now will be the probable variations as we pass from this extreme type of composition to other forms of dramatic prose? As conversation becomes more sustained 
Fig. 1. 5,000 Word-curves from Swift's Polite Conversation.' Corrected curve. the relative frequency of the personal pronoun 'I' will naturally diminish, the use of prepositional phrases will cause two-letter words to increase, words of six and seven letters will become more numerous at the expense of the frequency of three-and four-letter words. The resulting word-curve must, therefore, cross the former in two places, once between the abscissas one and two, and again near the abscissa five. If we pass from the heavier forms of dramatic prose to narrative, in which dialogue alternates with description and still heavier composition, the personal pronoun will diminish still more in frequency, two-letter words will continue to increase as will also words of six, seven and more letters, and to compensate for this there must be a further decrease in the relative number of three-and four-letter words. This law of change will continue as we pass from fiction to pure description and from the essay style to the opposite extreme of scientific and philosophic discourse. Here the personal pronoun 'I' will have disappeared, leaving the indefinite article 'a' the practically sole representative of one-letter words; with the accumulation of phrases and clauses there is a corresponding accumulation of two-letter prepositions, three-and four-letter words will have reached a minimum to make room for longer derivatives, compounds and technical terms.
Throughout these changes the five-letter word will probably vary least, since the variations on opposite sides of it are in contrary directions. We assume it constant. Taking furthermore Swift's 'Polite
