15. To show that air is necessary for germination: Fill a pint sealer with hydrogen (the gas collected over water in the usual way, as shown in any Chemistry text-book). Put a few sunflower seeds in a small sponge or wrap them loosely in a piece of soft cloth. Keeping the mouth of the jar which has been inverted over water and filled with hydrogen, under the surface of the water, introduce the sponge containing the seeds, by putting it under the water and pushing it up into the jar. Seal the jar without letting the gas get out. Put some seeds in another jar in a wet sponge and leave the jar uncovered. Compare results after several days. Here is a second experiment to prove this. Boil some water in a beaker in order to drive out all the air, put a few grains of rice in the water, and then add enough oil to make a thin covering on the water. This covering will prevent air from mixing with the water again. Put some rice in a second beaker without boiling or adding the oil. Leave the beakers side by side in a warm room for a week. The seeds will not germinate in the boiled water. It is not always easy to get rice that will germinate, but when it has been procured, the experiment is easy and very interesting. Any other seeds, such as those of pond lily and eel-grass, that germinate readily under water, will do as well as rice. WEEDS Pupils in this Form should learn to identify a large number of weeds and weed seeds. The collecting and mounting of weeds and weed seeds the previous summer and autumn will have helped to prepare them for this work. In the spring, when flower and vegetable seeds are coming up in the garden, it is often difficult for pupils to distinguish the weeds from the useful plants. To help in this work of distinguishing the good from the bad, the teacher should arrange for a plot having, say, ten rows, one row for each variety of weed selected. Each row should be designated by a number instead of a name. The identification of these growing weeds by name may be given as a problem to the pupils. This plot should remain until the pupils have observed the manner of growth of each variety, the blossoming and seed formation, and then the root growth, as they are being uprooted previous to the ripening of the seed. Each pupil should prepare a brief description of each of the ten varieties studied, and make drawings of the plant and its parts, especially the leaf, flower, seed, and root. They should learn the best methods of eradication and add these in their notes. _Farm Weeds_ will be of great value in such weed studies. VINES