Henderson[15] found that of 2,989 children from nine to fifteen, least books were read at the age of nine and most at the age of fifteen, and that there was "a gradual rise in amount throughout, the only break being in the case of girls at the age of fourteen and the boys at the age of twelve." For fiction the high-water mark was reached for both sexes at eleven, and the subsequent fall is far less rapid for girls than for boys. "At the age of thirteen the record for travel and adventure stands highest in the case of the boys, phenomenally so. There is a gradual rise in history with age, and a corresponding decline in fiction." Kirkpatrick[16] classified returns from 5,000 children from the fourth to the ninth grade in answer to questions that concerned their reading. He found a sudden increase in the sixth grade, when children are about twelve, when there is often a veritable, reading craze. Dolls are abandoned and "plays, games, and companionship of others are less attractive, and the reading hunger in many children becomes insatiable and is often quite indiscriminate." It seems to "most frequently begin at about twelve years of age and continue at least three or four years," after which increased home duties, social responsibilities, and school requirements reduce it and make it more discriminating in quality. "The fact that boys read about twice, as much history and travel as girls and only about two-thirds as much poetry and stories shows beyond question that the emotional and intellectual wants of boys and girls are essentially different before sexual maturity."