ECOLOGICAL SUCCESSION. . 7 



There are apparently numerous factors which influence gas 

 content Birge and Juduy, '11, p. 54;. These are temperature, 

 light as affecting photosynthesis, distance between point of col- 

 lection and plants which are giving off o\\ m-n and u-in- CO*, 

 and dirt-ction and velocity of wind a- affecting circulation of 

 water Hir^e and Juday (p. 55) state thai Kun.pean Corker- 

 have noted marked diurnal changes in the amount of dissolved 

 o\\ vjen. 



I- nun three io lour hours were required to make our collections. 

 ( )n Jinn- 2~ . ihr collecting began at pond 14'' ai 9:30 A.M., and 

 ended ai pond 5* at 12:30 P.M., temperature: pond I, Jn (.'.; 

 v and ~n. 2~ : and I4/;, 25. Velocity of \\ind <> mile- per liour. 

 Thi- was a < I'.ndv <lay. The sun broke through the dm id- bet on 

 ihe!a-i i olle< i i"ii ua- made. July 22 was a similar day. Col- 

 lei tin n Li van at |ioild l^l> at 8:30 A.M.. and ended at pond ~n 

 at i-'"" M . temperature: pond I, 25 ('.; 5. and -<i. Ji> ('.. 

 and 14'', -V} . Mining the forenoon, the Mm came out -e\vral 

 time^. I Hi i e\ai i n i ord was not kept of the time i>r len-ih of sinh 



|ieri..i|- n| MIIIM'lille. All t llC Other ( ol li i I ji .11 - \\ el'e made ill full 



Minlight . \\ ind and tem|KTature Were a- !olln\\-: April Jo, tem- 

 perature i, !;-,'_ ; 51, i4 l ->', 7a, 15' _ : -md 14''. 14"; \\ind: 

 3 miles per hour. May io, temperature, 23 . \\iml: )6 miles per 

 hour. Ju^t \\hat elTect distance from plain- \\hirh \\ere d.iiiu 

 photosynthetic \M>rk has on gas conieni i- not kno\\n. It i> 

 highlv jn-obable ih.it colli-ctions made near to Mich plant- \\ould 

 lillereni Iroiu those taken at a greater di-laiue 1-Jir-e and 

 |uda\ , ' I I , |ip. 54 and 60). 



The MI miner col led ions from pond ;./ \\eie taken from beiieaih 



the \\.iiet lil\ leaves at the extreme east end \\ here lilie> h i\ 

 di-placed i In- ( 'liiirn. 



Collections taken after scraping the \ <- elation fnun the bottom 

 sho\\ \ a rim i- reMilts depending upon the character oi the bottom 



licile. illl the \ e-elation. 



2. /}/(/(-/! : : '<i<l. (a) Qualitative Comparison. 



'1 Specie- of Plants and their Abundance. The i|iialitali\e 

 difference- in ]>oiid- a- -ho\\ n in Table- VII. and \ 111. 



(2) (imuih li'rm of the Plain-. Pmid I i- dominated b\- 

 plain-. There are no bn-ad-leax e<l -hade prodm 



