PLANTS AND THE ATMOSPHERE. 91 



and character of the roots in : Sugar-cane, 



dagger, Agace, eddoes, canna (Tous-les-mois), 

 lettuce, mango, cabbage, violet, corn (mai/i 1 ). 

 pine-apple, tobacco, cacao, beet and croton. 



PLANTS AND THE ATMOSPHERE. 



1. Put about an ounce of slaked lime 

 (building lime) into a wine bottle full of water, 

 shake well and allow to settle. The clear 

 liquid is lime-water, and should be carefully 

 poured off and kept ready for use in another 

 bottle. 



2. Take a dry wide-mouthed bottle, such 

 as a jam bottle, pour into it a little lime-water 

 and shake gently. The lime-water remains 

 clear showing that in ordinary air very little, 

 if any, carbon dioxide is present. 



3. Fasten a small piece of charcoal to a 

 thin wire, ignite the charcoal, and, using the 

 wire as a handle, hold it in a dry wide-mouth- 

 ed bottle similar to that used in the previous 

 experiment. It is well to pass the wire through 

 a cork or piece of cardboard so as to close the 

 mouth of the bottle while the burning char- 

 coal is in it. After the charcoal has been 

 burning for a few minutes the flame will 

 go out, all the oxygen in the bottle having 

 been used up. Remove it, pour in some 



