Pond life.—Practically the only method of gaining a real knowledge of aquatic organisms is by the help of the aquarium. Specimens may be obtained by means of a net, or of a small wide-mouthed bottle tied to a stick. A pickle bottle is convenient for carrying home the material collected. The conditions of a natural pond should be imitated as closely as possible in the aquarium. At first, some little difficulty will probably be found in obtaining the necessary balance between the animals and plants of the aquarium. When this has been reached, it will only rarely be necessary to change the water, provided that dead or sickly specimens are promptly removed. [Pg 391] THE SCHOOL JOURNEY. In the organisation of school journeys so much depends upon local conditions of various kinds, so much must of necessity be left to the initiative of the teacher, that it is manifestly impossible here to do more than enunciate certain general principles. In the first place, it should be borne in mind constantly that the primary object of the school journey is the cultivation of habits of thoughtful observation; and that the chief danger to be guarded against is that out-of-focus condition into which the mind, like the eye, inevitably falls when it is concerned with too many things at once. To obviate this danger the teacher should go over the route in advance, noting carefully the features, physical and otherwise, which afford material for observation and investigation by the class. The order in which these features may be best studied should be decided upon, and a scheme of several visits, each to be concerned with one special subject of study, can then be drawn up. Such a preliminary survey should suggest a plan by which every member of the class may be allotted a definite task—to find something or do something, or to solve some problem on the spot. These principles may be best illustrated by a special example, but it will be obvious that the same ideas, with modifications in detail, may be applied in any district. The sketch-map (Fig. 237) illustrates a walk through Healey Dell, near Rochdale, Lancashire. The rocks which are exposed at various places along the route belong to the Carboniferous formation, and are composed of shale, coal, or millstone grit. [Pg 392]