426 



Table 3 — .Contmucu 



IXDIAXAPOLIS, IXD. 























C 





si 



t^ 







11 



CO 



o - 



3 

 S 



3 



. 3 



1 



1 



a. 



< 



i 



S 



c 



3 





3 

 3 





S 



o 



J2 



i 



> 

 o 



J2 



s 



3 



c 

 c 

 < 



Relative humidity (percentage) . . - 



21 



79 



77 



73 



66 



67 



68 



65 



67 



68 



68 



73 



77 



71 





1'' 



41 



47 



4n 



t1 



=i3 



fi"? 



68 



6? 



66 61 



5'' 



4n 



54 



Average hourlv wind velocity (in 































miles) 



U 



11.7 



11.5 



12.1 11.3 



1 



9.9 



8.9 



8.2 



7.4 



8.3 



9.4 



10.4 



11.5!10.0 



During the pericd Nov.^ — June, the level of the pond is not rapidly re- 

 duced. September and October are on the average the dryest months of the 

 year. July and August are the hottest. It is during this period (July — 

 Oct.) that the level is reduced most rapidly and the stress on tiie organisms 

 is most acute. In this period occurs tlie ininiLnum precipitation, lowest rela- 

 tive humidity and smallest number of rainy days ( i. e.. .01 inch or more pre- 

 cipitation), the maximum teni]ierature and tlie greatest sunshine per- 

 centage. All of these factors tend to reduce the level of ponds by evapora- 

 tion. The lower wind velocity tends to reduce the evaiwration to a slight 

 degree. 



The amount of stress produced by a reduction of the level varies in 

 different years. In thirteen years of precipitation records for Blooming- 

 ton, the minimum for four months. Juh- — October, was in 1908. The maxi 

 mum occurred in 1896. Lu 1908 the amount of precipitation for the foui 

 months was 4.99 inches. In 1896 the maximum was 20.78 inches. The 

 average for the entire thirteen years for these months was 12.66 inches. 

 To state it another way : the minimum for this period was 39h-% of the 

 average and 23.5+% of the maximum. That is, between four and five times 

 as much rain fell during this period of one year as fell during the same 

 period of another year. This irregularity, more than any other factor, 

 prevents the fauna of this pond and all .sinall solution ponds from becom- 

 ing even relatively static. In the larger ponds the effect is less acute. 



The drying up of the pond in 'OS killed all the amphibian larvie, the 

 corethra larvie and caused the emigration of some of the aquatic beetles. 



