xi,¢,2 Brown and Heise: Carbon Dioxide Assimilation 93 
in Table IV. In the absence of numerical data in the original 
paper, we have been obliged to interpolate values from the curve 
(p. 381) representing the mean of all his experiments. In this 
table the values for light intensity are given on the basis: 
direct insolation equals 1.0. The carbon dioxide decomposed 
is expressed in terms of a maximum assimilation equal to 100. 
TABLE IV.—Timiriazeff on photosynthesis. 
Light in- Difference 
emnstly (Gl dient | BOM, 
ation=1). absorbed. in light. 
0.05 20 20 
0.10 38 18 
0.15 56 18 
0.20 67 11 
0.25 76 9 
0.30 84 8 
0.35 89 5 
0. 40 93 4 
0. 45 95 2 
0.50 97 2 
0.55 98 1 
0. 60 99 1 
0.7 100 0.5 
0.7-1.0 100 0 
Just as in Reinke’s work(18) there is, per unit increase in light 
intensity, a progressively smaller augmentation of the rate of 
bubble emission. Timiriazeff’s view of. the relation between 
light and assimilation is expressed in the following statement: 
On voit que la décomposition de l’acide carbonique augmente d’abord 
rapidement, ensuite de plus en plus lentement, atteint un maximum (corres- 
pondant 4 4 environ de l’insolation directe), pour devenir définitivement 
stationnaire. 
This seems to us to be the most accurate interpretation of the 
published data on the relation between light intensity and carbon 
dioxide assimilation that we have been able to find in the 
literature. 
An exhaustive review is beyond the scope of the present article. 
The papers discussed are, however, those which are the most 
prominent in the literature and those on which the idea of a 
direct proportionality between carbon dioxide assimilation and 
light intensity are usually based. ; 
Unfortunately, most of the work on the relation of carbon 
dioxide assimilation and light intensity has been done by the 
bubble-counting method. An exhaustive study by Kniep(11) has 
