1. The learning of the use and care of apparatus. 2. The learning of methods of actual construction, from materials at hand, of some of the simpler kinds of apparatus. 3. The learning of the importance of careful preparation. An experiment may be performed in a few minutes before a class which has taken an hour or more of time in its preparation. The pupil fully appreciates its importance, and is in the best condition to remember it only when he has had a part of the hard work attending that preparation. Again, conditions under which an experiment is successfully performed are often not appreciated when merely stated in words. "To prepare hydrogen gas, pass a thistle tube and a delivery tube through a cork which fit tightly in the neck of a bottle," etc., is simple enough. Let a pupil try with a cork which does not fit tightly and he will never forget that condition. 4. The learning of the importance of following directions. Chemistry, especially, is full of those cases where this means everything. Sometimes, not often in experiments performed in school, however, it may mean even life or death. The time for experiments should be carefully considered. When performed by the teacher they should be taken up during the recitation: 1. If used as a foundation to build upon, at the beginning of the lesson. 2. If used as a summary, at the close. 3. They should be closely connected with the points which they illustrate. 4. When very short, or when so difficult as to demand the whole attention of the teacher, they may be given and afterward discussed. If long or easy, they may be discussed while the work is going on. Changes which take place slowly, as those which are brought about by the gradual action of heat, for instance, are best taken up in this latter way. 5. Exceptions may be necessary, as when experiments which demand special preparation immediately before they are presented are given when the recitation begins, or cases in which experiments are kept until near the close of a recitation, when the teacher finds that attention flags and the lesson seems to have lost its interest to the pupils as soon as the experiments have been given. When performed by the pupils themselves, experiments should come before the recitation as a part of the preparation for the work of the class room.