552 Wisconsin Academy of Sciences, Arts, and Letters. 
We shall describe first the experiments with blue light. The 
culture was first placed twenty centimeters from the circular 
opening, which was one centimeter in diameter, and remained 
there twenty-four hours. In making the records the target 
shown in Figure 1 was used. 261 sporanges were found on 
the glass. 161 (61.6%) were over the opening, area 1; 
/6 (29.1% on area 2;15 (5.7%) on area 3;5 (1.9%) on area 
4; and 4 (1.5%) on area 5. In this case a larger percentage 
are on area 1 and a smaller percentage on area 2 than when 
white light was used. 
In the next experiment the culture was placed twenty centi¬ 
meters from an opening four centimeters in diameter, and the 
target shown in Figure 3 was used. The total number of spor¬ 
anges on the glass at the end of twenty-four hours was 668. 
-524 (78.4%) were on area 1; 126 (18.8%) on area 2; 7 (1%) 
on area 3 ; and 11 (1.6%) on area 4. 97% were on the space 
over the opening, compared with 94.5% when white light was 
used under similar conditions. Only 18 of the 668 sporanges 
struck outside the opening. 
Experiments with blue light were made with the culture at 
^different distances from the four-centimeter opening. The 
same target was used as in the preceding experiment. At two 
centimeters distance 52.1 % of the sporanges were on area 1 and 
21.7% on area 2, making a total of 73.8% on the opening. Of 
the remaining 26%, 17% were on area 3. With the culture 
placed successively at distances from 4 to 14 centimeters from 
the opening, all the sporanges in each case were found on the 
opening. At 16 centimeters distance, 51% were outside the 
opening. As the distance from the opening increased still fur¬ 
ther, the proportion striking on the opening gradually de¬ 
creased, until at 30 centimeters 76.8% were on the opening and 
23.1% outside—for the most part below. 
The results of these experiments are given in Table III. 
From the percentages on the different areas at the different 
distances, curves were plotted as in the previous experiments. 
Figure 5 (dot—dash line) shows the curve for the percentages 
on the opening. With the culture from 2 to 30 centimeters dis- 
