424 



Calkins ('04), it certainly becomes evident that there is an efficient adapta- 

 tion to wind distribntion. 



Attention may be called to the analogous transportation of volcanic 

 dnst Avhich has been known to drift round the world. Volcanic dust has a 

 higher specific gravity than that of protoplasm but, on the other hand, 

 it is blown to a very high altitude, while organic spores usually start from 

 the surface. 



The exact nature of the spore while in the air nnist be known before 

 its distribution by wind can be even approximated by direct methods. -c 



Distribution. — Of the complicated cet of factors that condition the ex- 

 istence of these organisms, only four can be discussed at this time. These 

 are level, light, teuiperature and food relations. The chemical composition 

 of the water and its variations have not been determintxl. The determina- 

 tion of the dissolved tixygen. carbon dioxide and ammonia will probably 

 yield valuable results in a comparative study of several ponds. 



Level. — The factor that affects the organisms in this pond most vitally 

 is the extreme chan.ges in level. The level varies from zero to 46 inches 

 above tlie lowest point. So far as ascertained, its level has been reduced 

 to zero (i. e., it has dried up) but once in its history and that was in the 

 late summer and early autumn of '08. It did not overflow until the follow- 

 ing March. From March. '09 to August, '09, the lowest observed level was 

 352 inches. The summer of 'OS was the dryest in 13 years (local records 

 are not available Itefore 1S96). That of '09 was rather wet. 4.75 inches of 

 rain falling on July 14. For these two rather extreme years, the minima 

 have been 35.5 and 0; or to put it another way, the level has decreased 

 25% and 100% from the maxinmm. This point will be discussed more fully 

 later. As the destructive forces gradually elevate the bottom of the pond, 

 it is probable that in future the pond will go dry more often. Level is 

 determined by preci])itation and evaporation. The extreme variability of 

 these factors in this pond and similar ones in this region is indicate;d by 

 the weather i-ecords of the local station and those from Indianapolis. Rec- 

 ords of sunshine, wind velocity and relative humidity are not available for 

 any station nearer than Indian.rpolis (.50 miles distant). 



In the accomiJ.-inying table I Inne compiled all the cliuiatological data 

 available foi- this Iccalitv. 



