9. Effect of different fertilizers (1) on the same crop, (2) on different crops: This can be done either out-of-doors in small plots or indoors, using pots or boxes. (1) Effect on the same crop: For example, oats on plots four feet square. The following standard fertilizers may be used: stable manure, nitrate of soda, muriate of potash, and bone meal. On plot No. 1, a dressing of stable manure, On plot No. 2, four oz. nitrate of soda, On plot No. 3, four oz. muriate of potash, On plot No. 4, eight oz. bone meal, On plot No. 5, two oz. nitrate of soda, two oz. muriate of potash, and four oz. bone meal. On plot No. 6, use no fertilizer. Record results. (2) Effect on different crops: Try a series of experiments similar to the above, using (a) peas instead of oats, (b) using corn, (c) using cabbage, (d) using potatoes. FUNCTION OF PARTS OF PLANTS This may be introduced in Form III and continued in the next Form. Already the attention of the pupils has been directed to the essential organs of the flower, namely, stamens and pistil. They have noticed the two kinds of flowers on pumpkins, corn, and many trees. They have seen that only the pistillate flowers produce fruit and seeds, and that when the staminate flowers have shed their pollen, they die. They have seen the yellow dust that the stamens contain and have seen bees laden with it as they emerge from the heart of the flower. Have them watch the bee as it enters the flower and notice how it invariably rubs some part of its pollen-covered body against the pistil. When on the moist, sticky top of the pistil, these little pollen-grains soon begin to grow, sending a delicate tube down to the bottom of the pistil to the ovary. Inside the ovary are little bodies called the ovules that are moistened by a fluid that comes from this delicate pollen tube, and at once they begin to enlarge and eventually become the seeds. The coverings surrounding them complete the true fruit. The use of the root in supporting the plant in its normal position is apparent to every pupil. To demonstrate the firm hold it has upon the soil, have the pupils try to pull up some large plants by the roots. They will then notice the branching roots of some plants and the long conical roots of others. Compare the colour and other surface features of the root and stem. To prove its feeding power, try two plants of equal size, taking the root off one and leaving it uninjured in the other. Set them side by side in moist earth and notice which withers. Take all the leaves off a plant and keep them off for a few weeks. The plant dies if its leaves are not allowed to grow. Keep it in the dark for a long time, and it finally dies even when water and soil are supplied. The leaves, therefore, are essential and require sunlight in doing their work. Their complete work will be considered later. HOW THE PLANT GETS ITS FOOD FROM THE SOIL