—29— 



This apparatus may be balanced on a pair of scales, or a pot with a 

 gruwing plant in it may be thus balanced, and it will soon show loss of 

 weight. (A simple and effective pair of scales may be made by the 

 children of a rod of wood eighteen inches long, strings and two pieces 

 of board six inches square.) To show that the water escapes from the 

 plant by the leaves, allow the leaves to rest on the polished surface of a 

 cold piece of glass or steel. 



If this plant, or a plant in a pot is inclosed by a bell-jar or glass shade, 

 the water coming from the plant will be condensed on the sides of the 

 glass. 



To trace the course of the water absorbed by the roots, place a solu- 

 tion of some analine dye in the water (eosin is good.) The coloring can 

 be traced in the stem, if translucent, and through the veins of the 

 leaves after some hours or a day. 



These experiments may well be followed by an examination of the 

 epidermis of a leaf with the microscope to see the stomata, the openings 

 through -which the water passes. By tearing the leaf cross ways portions 

 of the thin transparent skin which covers the leaf can be obtained, 

 mounted in water, and the outlines of the epidermal cells may be seen. 

 Notice also the curved cells bordering and making the stomata. 



Through these not only does the water go out, but the oxygen some- 

 times passes out and the carbonic acid passes in (sometimes oxygen 

 comes in). Now it is seen that through the root-hairs on the roots and 

 stomata on the leaves, the foods of the plant come in. The veins of the 

 leaf, and the parts of the interior of the stem and root, carry these up 

 and down. This will be taken up later. 



That the water can dissolve something from the soil may be shown by 

 soaking some soil in rain water or distilled water, then filtering this out 

 and evaporating the water that comes through the filter. A small 

 amount of substance will remain. This was dissolved in the water. 



Note. — Some of these experiments, or similar ones, and others may 

 be read in greater detail in an excellent little book. The Food of Plants, 

 by Laurie — Macmillan & Co., publishers. 



Currents in Water. 



In observing boiling water, the upward currents from the lamp-flame 

 and the descending currents down the sides of the flask were noticed. 

 These may again be more carefully studied. Differently shaped vessels 

 will show the currents in different conditions. The course of the cur- 

 rents will be seen better if a small amount of fine dust of crayon or 

 gawdust is sprinkled in the water. If a few very small particles of an 

 analine dye be placed on the surface of a flask or jar of water which is 

 perfectly quiet, beautiful vertical lines of color will form in the water. 

 The slightest warming of the jar at any spot will show currents by 

 swaying the lines. 



