Exercises on Lesson I.
1. An apple will keep sound for months if the skin is unbroken. If we remove a small piece of the skin, the apple soon shrivels up. How is this? 2. Can you explain why we ought not to eat the outer skins of the plum, grape, tomato, pear, etc.? 3. Cut a stout twig of any tree straight through. Make a rough sketch showing the different layers, and tell how old the twig is. 4. Get stout twigs of different trees, such as ash, elm, holly, sycamore. Take about an inch length of each. Split these down the centre, and see if you can make out the different layers on each side of the pith. Make an enlarged drawing of one of these.