Such excursions may be accomplished at the expenditure of very little time. Many of them will take the pupils no farther than the boundaries of the school yard. Of course the locality will influence the character of the excursion, as it will that of the whole of the work done in Nature Study, but in any place the thoughtful teacher may find material for open-air work at his very door. Much outside work can be done without interfering with the regular programme. The teacher may arrange a systematic list of questions and problems for the pupils to solve from their own observations, and these observations may be made by the pupils at play hours, or while coming or going from school, or on Saturdays. The following will serve as an example of the treatment that may be followed: ~Pests of Apple Trees.~--Look on the twigs of your apple trees for little scales. Bring an infected branch to school. Note whether unhealthy-looking or dead branches are infected. Examine scales with a lens. Loosen one, turn it over, and examine with a lens the under side. For eggs, look closely at the twigs in June. Do you see white specks moving? If so examine them with a lens. Are there any small, prematurely ripe apples on the ground in the orchard? Cut into one of these and look for a "worm". Look for apples with worm holes in the side. Are there worms in these apples? What is in them? Note the dirty marks that the larva has left. Keep several apples in a close box and watch for the "worms" to come out. Examine the bark of apple trees for pupae in the fall. FREQUENCY OF EXCURSIONS As to the frequency of excursions, the teacher will be the best judge. It is desirable that they occur naturally in the course of the Nature Study work as the need for them arises. One short trip each week with a single object in view is much more satisfactory than a whole afternoon each term spent in aimless wandering about the woods. EXCURSIONS TO A DISTANCE Long-distance excursions will of necessity be infrequent. If the woods are far away, one such trip in May or June would prove valuable to enable the pupils to become acquainted with wild flowers, and another in October to gather tree seeds, autumn leaves, pupae, and other material for winter study. When a large class is to be taken on an excursion, preparations must be made with special care. The teacher and one or two assistants should go over the ground beforehand and arrange for the work to be done. Some work must be given to every pupil, and prompt obedience to every command and signal must be required. The class, for example, may decide to search a small wood or meadow to find out what flowers are there. The pupils should be dispersed throughout the field to hunt for specimens and to meet at a known signal to compare notes. SUGGESTIONS FOR UNGRADED SCHOOLS 1. The teacher may take all the classes, choosing an object of study from which he can teach lessons suitable to all ages, a bird's nest, for example.