Brown : Algal periodicity 225 



sufficient to change the water in a day or so, but since the spillway 

 is j ust opposite the feedway and the pond is wide compared with 

 its depth, the water is not changed frequently enough to keep it 



very pure. A 



this adds to the 



impurities. On October 29 the amount of mineral matter in the 

 water was .013 g. in 42 g. water or .0003 per cent. The pond is 

 in the open, so is not shaded in any way. But few of the. higher 

 plants grow here, a few specimens of Eleocharis and Alisma; a few 

 frogs and tadpoles are found in the pond the greater part of the 

 year and some small catfish and sunfish. 



Pond no. 3 is a small body of water about 30 feet by 50 and two 

 feet deep. It is fed by a wet-weather branch during the greater part 

 of the year. During July, August, and September, the pond goes 

 almost dry. The water is not changed very frequently, hence be- 

 comes stagnant. It is not shaded. Eleocharis plants grow in tufts 

 over a part of the pond, especially when the water is low. On 

 December 17 the water contained .0003 per cent, mineral matter. 



rond no. 4 is a body of water covering three or four acres and 



is about 20 feet deep in deepest part. It is formed by a levee built 



across a small valley and is fed by a small stream. The water is 



comparatively pure and clear. It overflows but occasionally. On 



November 3, there were .011 g. of solid matter in 40 g. water or 



.00027 per cent. The pond is practically free from animal life ; it 



nas but few of the higher plants growing in it and there is but very 



scant vegetation on the surrounding hillsides, hence it is not 

 shaded. 



Pond no. 5, or the water- works reservoir, consists of two large 

 bodies of water fed by several springs. Each covers.several acres 

 and is from 10 to 20 feet deep. During late summer and in the fall 

 e water becomes low, but on the whole the depth of the water is 

 not su bject to much variation. The water is pure and clear the 

 greater part of the time. There are very few cormophytes growing 

 w these bodies of water, but there are forests on three sides of one 

 and on two sides of the other. Hence they are somewhat shaded 

 along the edges and humus from the woods is washed down into 



th 



the ponds, the sloping banks being made rich. On October 17 the 

 water contained .00021 per cent, solid matter. Animal life in the 

 Ponds is scant — only a few fish. 



