68 APPENDIX I. 
EXPERIMENT 2. TO SHOW THE NECESSITY OF SOIL SALTS. 
(a) With alge. 
Place some alga, as spirogyra, in a jar of distilled water. 
Another portion of the same alga is to be put into common 
hydrant or well water, and a third portion is to be placed in 
a nutrient solution, having the following composition : — 
Water . é : . 5 z é é - 1000 c.c. 
Potassium nitrate . : 7 s 5 : i .5 gr. 
Sodium chloride . : : 3 . 5 ‘ -5 gr. 
Calcium sulphate . 3 : A ‘ , . .5 gr. 
Magnesium sulphate Z “ : ‘ 5 gr. 
Calcium phosphate 3 P . 3 : 3 .5 gr. 
Place the three jars in the same conditions, and observe the 
results at the end of several days. 
(6) With seedlings. 
Germinate seeds of peas or corn in a moist chamber, and 
when the root systems are well developed, carefully select 
three of a kind as nearly equal in development as possible; 
place each on a piece of netting, stretched over a wide-mouthed 
bottle containing distilled or common water, or nutrient solu- 
tion, as the case may be. See that the roots pass through the 
netting and enter the solution. Cover each with a bell jar, 
and await results. 
N.B. All will grow equally well for some time. 
EXPERIMENT 3. TO SHOW THE NECESSITY OF OXYGEN. 
(a) In alge. 
Use two large wide-mouthed bottles; in one have some 
water which has been boiled for some time and cooled, in the 
other have ordinary water containing air. 
Into each place a small quantity of a vigorous filamentous 
alga. Pass carbon dioxide but no oxygen into the boiled water, 
and after a few days observe which has died, and explain, 
