(c) Where these inequalities of numbers and ages exist there is a lack of that class spirit which is an essential element of power in a well-ordered Sunday school. Every class should be a unit, with a strong social bond; but this ideal cannot be realized when there are in the class two or three youths in the noisy, assertive, self-conscious stage of early adolescence, and others who are several years younger. Nor can there be a proper social bond in a class with only two or three members. They are likely to be irregular in attendance, to find excuses for absence or for leaving the school, until at last the discouraged teacher and the listless scholars together drop out of sight. For the correction of these evils of inequality in numbers and in ages, and of this lack of class spirit, the only successful method is to grade the school, and resolutely to keep it graded. (3) _Difficulties of Administration._ The difficulties which confront the superintendent in the management of an ungraded school are many and great. (a) The first and ever-present difficulty is in obtaining teachers for new classes. The constant growth of the Primary Department is his perennial perplexity. To relieve the congestion in the crowded Infant Class its older pupils must be brought into the main school, and teachers must be found for them. The superintendent is always seeking, and often seeking vainly, for new teachers. (b) Another difficulty is found in the attempt to transfer scholars from one class to another. No matter how much out of place a pupil may be, it is almost impossible to transfer him to another class without incurring the displeasure of the teacher, the scholar, or the scholar's family. And however overgrown or ill-assorted a class may have become, to divide it is a delicate task, almost sure to cause ill feeling. Also, when there arises the need of a teacher for a new class just emerging from the Primary Department, the natural plan would be to combine some of the skeleton classes in the other departments, and thereby release a teacher for service with the new class. But the superintendent who attempts this plan finds that almost invariably it results in some of the older scholars leaving the school because their teacher is taken from them. 2. =The Essentials of a Graded School.= Briefly stated, the essentials of a graded Sunday school are the following:[4]