INCLINED PLANE.--If a plank twelve inches long has one end on the ground and the other on a cart four inches high, one man can roll up the plank the same weight that would require three men to lift, but he has to move the object three times as far. PROBLEMS 1. Why is a long-handled spade easier to dig with than a short-handled one? 2. Which is easier, to dig when the spade is thrust full length or half length into the earth? 3. Can a small boy "teeter" on a board against a big boy? How? 4. In helping to move a wagon, why grasp the wheel near its rim? 5. In making a balance, why should the arms be equal? In a balance with unequal arms, compare the weights used with the article weighed. 6. In using shears, is it better to place the object you wish to cut near the handles or near the points? 7. Where is the best place to put the load on a wheel-barrow? 8. Notice how three horses are hitched to a plough or binder. 9. Where would you grasp the pump-handle when you wish to pump (1) easily, (2) quickly? 10. Stretch out your arm and see whether you can hold as heavy a weight on your hand as on your elbow. 11. Count the pulleys used in a hay-fork and determine the use of each. 12. If a ton of hay is unloaded at five equal forkfuls, what weight has the horse to draw at each load? 13. Count the cogs on the wheels of a fanning-mill, washing-machine, apple-parer, or egg-beater, and determine how the direction or rate of the motion is changed thereby. 14. Measure the diameter of the large fly-wheel of a thrashing-machine engine, and of that which turns the cylinder in the separator. Decide how many times the cylinder revolves for one turn of the fly-wheel. 15. Think of all the uses of a wedge. Draw one. Compare the axe, knife, and chisel with the wedge. 16. How are heavy logs loaded on a sleigh or truck? How are barrels of salt and sugar loaded and unloaded? 17. There are two hills of the same height. One has a gradual slope, the other a steep one. Which is easier to climb? In what case is it farthest to the top? 18. Why does a cow or horse take a zigzag path when climbing a steep hill? CHAPTER XIV FORM IV SPRING METHODS OF IMPROVING HOME AND SCHOOL GROUNDS The study of plants should lead to an intelligent appreciation of their beauties and a desire to have them growing about. Many of our native trees, shrubs, vines, and herbaceous plants are quite as beautiful as some that are procured at considerable expense from nurserymen. A great work remains to be done in cultivating and popularizing our best native species. Up to this point the pupils have been getting acquainted with them in their own natural habitat; the next step should be to use them in covering up harsh and offensive views about the school and home grounds, in softening and giving restful relief to barren yards and bare walls, to ugly fences and uninteresting walks and driveways.