424 
Calkins ('04), it certainly becomes evident that there is an efficient adapta- 
tion to wind distribution. 
Attention may be called to the analogous transportation of volcanic 
dust which 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 must be known before 
its distribution by wind can be even approximated by direct methods. 
Distribution.—Of the complicated set of factors that condition the ex- 
istence of these organisms, only four can be discussed at this time. These 
are level. light, teuperature and food relations. The chemical composition 
of the water and its variations have not been Getermined. The determina- 
tion of the dissolved oxygen, 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 changes in level. The level varies from zero to 46 inches 
above the 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 ‘OS. It did not overflow until the follow- 
ing March. From March, 09 to August, 09, the lowest observed level was 
302 inches. The summer of ‘OS was the dryest in 13 years (local records 
are not available before 1896). ‘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 maximum. 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 precipitation and evaperation. The extreme variability of 
these factors in this pond and similar ones in this region is indicated by 
the weather records of the local station and those from Indianapolis. Ree- 
ords of sunshine, wind velocity and relative humidity are not available for 
any station nearer than Indianapolis (56 miles distant). 
In the accompanying table I have compiled all the climatological data 
available for this lecality. 
