EXPERIMENTS 11 
and place it under the beil-jar. Now siphon the water 
out of the large bottle by fastening a rubber tube to the 
elass tube which extends to the bottom of the boitle. 
After the water has run long enough to replace nearly 
all the original air in the bell-jar with air whicn has 
passed thru lime water in the first two bottles, close the 
rubber tubes leading from the bell-jar with pinch cocks 
and change the lime water in the two small bottles near- 
est the siphon, making sure that it is clear. Now fill 
the large bottle with water and siphon it off drop by 
drop so as to force the air thru the apparatus very 
slowly. The flow of water can be nicely regulated by 
means of an adjustable pinch cock. After the apparatus 
has been in operation several hours, note changes in the 
lime water. 
(a) Results with peas under the jar. 
I. In strong diffused sunlight? 
2. In total darkness? ‘ 
(b) Results with a frog under the jar? 
Conclusions? 
Draw the apparatus in outline side view. 
Exp. 10, Class: Put 10 or 12 soaked peas mixed 
with moist pieces of blotting paper into a 50 c. c. wide 
mouthed bottle. After the radicles have broken thru 
the testa and are growing rapidly, take another botile 
of the same size and fill it nearly full of water. Bend 
a 3 or 4 mm. glass tube in the form of a U large enough 
so that one arm can be put into each bottle. Pass one 
of the arms thru one of two holes in a rubber stopper 
in the bottle containing the peas, and the other thru a 
hole in a cork in a small test-tube containing an opening 
