Seeds and Seedlings. 13 



half an inch of the moist sawdust, and press down firmly. 

 Cork the four bottles tightly (two containing the seeds in 

 moist sawdust, and two containing sawdust only) and leave 

 over night in a warm place. The following day fasten a 

 piece of tallow candle or wax taper to a wire handle ; light 

 the candle ; remove the cork from one of the bottles con- 

 taining sawdust only, and slowly lower the lighted candle 

 into the bottle until it rests upon the sawdust. Leave the 

 candle in this position for some time, and note whether 

 there is a tendency for the flame to become extinguished. 

 Remove the cork from one of the bottles containing the 

 seeds and lower the lighted candle into it. If the seeds 

 have been germinating properly, the flame will quickly 

 expire. What do you conclude from these observations .' 



36. Prepare limewater as described on page 387 ; pour 

 some of the clear Hquid into a clean, wide-mouth bottle ; 

 then remove the cork from the remaining bottle of seeds, 

 and, holding the mouth of the bottle close down over the 

 mouth of the bottle of limewater, pour the gas from the 

 bottle of seeds (as if pouring water) into the bottle of lime- 

 water. Cork the bottle of limewater tightly and shake 

 vigorously. The white precipitate of calcium carbonate 

 now appearing in the water has resulted from the reaction 

 between the carbon dioxide gas from the bottle of seeds, 

 and the calcium hydrate of the limewater. See whether 

 the air in the second bottle containing sawdust only gives 

 a like result. Shake up some limewater in a bottle contain- 

 ing only ordinary atmosphere, to see whether the precipi- 

 tate is really produced by the gas poured from the bottle 

 of seeds. 



37. To demonstrate the identity between the gas given 

 off by germinating seeds and a gas produced by a burning 

 candle, or by breathing, perform the following experi- 



