H2 A FIELD GUID*E IN NATURE-STUDY 



10. Fix a cork to the neck of a long-necked bottle or flask. Cut it in 

 half and file out a groove in each half, so as to form a hole that will receive 

 the stem of a plant. Fill the flask nearly full of water. Root out a nastur- 

 tium plant or a small geranium with several leaves; wash off the soil from 

 the roots and set it in the flask, the stem held by the cork, the roots in the 

 water. A twig of cottonwood or other tree may serve in place of the small 

 plant. Put it into the water immediately when it is cut off the tree. See 

 that the cork fits tightly and that water cannot escape where the plant stem 

 emerges from the cork. Mark the level of the water in the neck of the 

 flask. Let it stand for several days and mark again. Measure the volume 

 of water that has gone from the flask. Measure roughly in square centi- 

 meters the several leaves on the twig or plant. Estimate the number of 

 leaves on a good-sized tree. How much water would it transpire daily ? 

 State the results of your estimate. 



11. Inclose the pot of a small potted nasturtium, freshly watered, in 

 sheet rubber (dentist's rubber) or paraffined paper, fastening . the rubber 

 snugly around the stem of the plant with a cord. Weigh it, rubber and all, 

 at once. Let it stand for several days and weigh again. What does this 

 experiment show that the foregoing one did not? Compare the results 

 with the results of the above. Record. 



12. Mount a strip of the epidermis peeled from the under side of the 

 leaf of Wandering Jew in a drop of water on a slide and cover with a cover 

 glass. Examine under a microscope. Draw to show the stomata. Con- 

 sult books to find some estimate of the number of them to a square centi- 

 meter of leaf surface and give the data here. 



13. See a cross-section of a leaf under the microscope and draw to show 

 upper epidermis, palisade tissue, parenchyma, lower epidermis with its 

 stomata. Make diagrammatic drawing. 



14. Add a teaspoonful of red ink to a half-tumbler of water. Put in it 

 a stalk of celery and a white carnation on a short stem. Let stand for 

 twenty-four hours. What happens? Cut open the celery stalk. This 

 shows two things: (i) that fluids are conducted in the stem along the 



, (2) that not only water but substances 



are carried up to the leaves. (How is the 



red ink made ?) 



15. Take two quart fruit jars. On the bottom of each place a small 

 potted plant and a short piece of candle. Light each candle and screw on 

 the tops. Why does the flame go out ? What is there in each jar ? Let 

 stand in good sunlight for at least twenty-four hours. Make some lime- 

 water (find out how to do it) and test your own breath for carbon dioxide. 

 Pour a couple of teaspoonfuls of limewater into one jar, removing the 



