Feb., 1921] 
GERICKE^ — ^ INFLUENCE OF TEMPERATURE 
61 
number following the letter "R" indicates the number of eighths (of the 
total molecular concentration) that are due to the potassium salt, the 
number following the letter "S" indicates the number of eighths due to 
the calcium salt, and the difference between 8 and the sum of these two 
numbers is the number of eighths due to the magnesium salt. 
Table i . Good nutrient solutions of the six different salt types tested at two different maintained 
temperatures 
Tempera- 
ture 
Type I 
KH.2PO4. 
Ca(N03)2, 
MgS04 
Type II 
K2SO4, 
Ca(N03)2, 
Mg(H2P04)2 
Type III 
KNO3, 
Ca(H2P04)2, 
MgS04 
Type IV 
K2S()4, 
Ca(H2P04)2, 
Mg(N03)2 
Type V 
KNO3, 
CaS04, 
Mg(H2PU4)2 
Type VI 
KH2PO4, 
CaS04, 
Mg(N03)2 
28° c. 
R1S3 
RIS3 
R1S3 
RIS4 
RIS3 
R1S3 
R1S4 
RIS4 
RiSd 
RIS5 
RIS5 
R1S4 
R3S4 
R2SI 
R1S6 
R2SI 
R3S4 
R4S1 
R2S1 
R4S2 
R4S2 
R2S2 
R4S3 
R5S1 
R5S2 
17° c. 
R3S2 
R3S3 
R2S5 
R4SI 
R5SI 
R4S3. 
R3S3 
R5SI 
R3S4 
R5SI 
R5S2 
R5S1 
R4S1 
R5S2 
R4S1 
R5S2 
R5S2 
R4S3 
R5S1 
R5S1 
It is seen at once that the "good" group of each type of solution com- 
prises from two to seven different solutions. It appears that there is 
generally a marked difference between the sets of salt proportions that 
proved good with the higher temperature, on the one hand, and those that 
proved good with the lower ones, on the other. For types II, III, IV, and V, 
low partial concentrations (i or 2 eighths) of the potassium salt characterize 
the group for 28°, while high partial concentrations (2-5 eighths) of this 
salt characterize the group for 17°. There is a suggestion of this same 
generalization for types I and VI also. For type I the potassium salt has 
partial concentrations of from i to 4 units for the higher temperature, 
while the corresponding values for the lower temperature lie between 3 and 5. 
Similarly, for type VI, the potassium-salt values lie between i and 5 for 
the higher temperature and between 4 and 5 for the lower. It is thus 
indicated that the proportion of the potassium salt should be high for the 
low temperature, and low for the high temperature, if the solution is to give 
good growth values. Since three different potassium salts are involved, it 
appears that this suggested generalization really applies to the partial 
concentration of potassium itself rather than to that of the salt that supplies 
this element. 
It is to be noted that the two types (I and VI) for which this statement 
concerning potassium is least definitely applicable, are both characterized 
by the fact that the potassium salt is the phosphate. But, for three other 
