no 
Journal of Agricultural Research 
Vol. XXIII, No. 2 
expression represents a factor F which is constant for any given 
temperature. Substituting F in (i) gives: 
(2) Vol. 7 60 = Vol. ‘XFXP. 
Values for F for different temperatures have been determined and 
are given here for convenience in calculations. 
Fforo° C. = 0.001316 
for 5 0 C. = 0.001292 
for io° C. = 0.001269 
for 15 0 C. = 0.001247 
for 20 0 C. = 0.001226 
for 25 0 C. = 0.001205 
for 30° C. = 0.001185 
for 35 0 C. = 0.001166 
Values for F for intermediate temperatures can be derived with suffici¬ 
ent accuracy by interpolation in the series given. 
2. For changing from gas volumes to milligrams per gram dry weight 
per 24 hours. 
Let a =number of cubic centimeters at o° C. 760 mm. 
b = weight in milligrams of 1 cubic centimeter at o° C. 760 mm. 
c=dry weight in milligrams of respiring material 
&=respiration period in hours. 
( 3 ) 
/24 a b\ /i,ooo\ 
\ h ) \ ~c~ ) 
=# = milligrams per gram dry weight in 24 hours. 
For oxygen, 6= 1.4289; for C0 2 , 6= 1.9768. 
By substitution of these values and the use of Y in place of one X, 
equation (3) becomes; 
, . __ 24 x1.4289 x1,000 a. 34293.6 a. 
(4a ) x= 4 --= c h for oxygen. 
U h) F = 24X I-9768X 1,000 s = 4 Z 44 ^ for CQ 
' ch ch 1 
3. For calculating temperature coefficients. Either of the formulae 
given by Kanitz ( 12 ) and reported by Denny may be used. Kanitz’s 
/K ^ 10 
second formula is Q 10 =[ ^2 represents the rate of any 
reaction at temperature t 2 and K x represents the rate of the same reac¬ 
tion at temperature t v The easiest form in which to use this equation 
in logarithmic solutions is 
( 5 ) Log Q 1(l = (Log K 2 -Log KJ (Jzjj 
With the simplified equations (2), (4a), (4b), and (5) all of the com- 
phtations can be easily performed. 
RECORDING DATA AND CALCULATING RESULTS 
Before beginning a respiration experiment the following data must 
be determined or provision made for its determination: 
1. The volume of air in each apparatus without the respiring material 
(to 0.1 cc.). 
