634 



BOWMAN— ECOLOGY AND 



in minutes and fractions of minutes, and these intervals then aver- 

 aged for each set of three tests on a culture, and then general aver- 

 ages made of the series and finally all the sets of records made at 

 different times on each series were averaged for each series. These 

 final averages, as expressed for each series, are as follows, in the 

 Water Concentration Class of experiments. 



Series A — lOO per cent. Fresh — 1.6 minutes. 



Series B — 75 per cent. Fresh — 1.7 minutes. 



Series C — 50 per cent. Fresh — 2.4 minutes. 



Series D — 20 per cent. Fresh — 2.8 minutes. 



Series E — 10 per cent. Fresh — 3.2 minutes. 



Series F — 05 per cent. Fresh — 3.9 minutes. 



Series G — 100 per cent. Salt — 4.1 minutes. 



By arranging the data in curves, a graphic idea may be gained 

 of the rates of transpiration of these plants in their various concen- 

 tration cultures, and by applying certain mathematical formulae 

 definite laws may be deduced for the phenomena. In a preliminary 

 report on the work^"° before the data were all tabulated a formula 

 was used with almost the same result as that given in the follow- 

 ing curve. 



/'£/iixeyvr ■s/^^t so^e/r/o/v 



Graph No. i. 



But a better formula appears to be the one here given y=^ah^. 

 In the curve the time intervals in minutes are arranged as ordinates 



10'' Bowman, H. H. M., " Physiological Studies on R]nzophora',' Proc. 

 Nat. Acad. Sciences, Vol. 2, No. 12, Dec, 1916, p. 685-688. 



