as accurately as possible, giving all meanings where there are more than one, depth and accuracy as well as breadth of knowledge may be tested. In college classes where twenty of the hundred words were defined, 114 out of 246 students were found to have denned the same proportion of words that they marked as known and only seventeen showed a difference of as much as three words of the twenty from the corresponding proportion of the hundred words marked. The overestimations slightly exceeded the under estimations.
The author is convinced that one hundred words selected as has been described and marked with care gives sufficient basis for an approximate estimate of the size of the understanding vocabulary of college and high-school students, and of the higher grades of the grammar school. In the author's own classes where students were ranged in three grades according to the number of words marked as known in one list of words, other lists of words similarly selected resulted in 60 per cent, to 80 per cent, of them being again in the same grade, while none were changed from the lowest to the highest grade.
Using Webster's Academic Dictionary as a basis it appears from averaging about two thousand papers that the size of vocabularies are likely to approximate the following:
The average for normal school students is 19,000 and for college students 20,120. The colleges represented in this test were Bryn Mawr, Smith, Columbia, Brown University and Pratt Institute, while the grades and high schools were mostly in Massachusetts cities.
There seems to be no constant difference between the sexes. On only a part of the papers was age given, but there is reason to believe that vocabularies increase up to thirty. In Pratt Institute where students varied greatly in age, those above twenty-five knew from five to ten per cent, more words than those in the same classes who were below twenty years of age. It is not likely that the growth of vocabulary is great after thirty, when deeper specialized and executive activities have taken the place of general advancement into new fields of knowledge and many words once known are forgotten.
One important factor in the growth of vocabularies was investigated by accompanying the list of words with a request to write names of