467 



nections with and contributions from the remaining backwaters. 

 The complications arising from the combination of these vari- 

 ous factors in varying degrees and the seasonal shifting of the 

 two periods in the several years, render any sweeping general- 

 izations impossible. 



The following table gives in parallel columns the monthly 

 means of plankton per m. 3 and of river stages in feet above low- 

 water mark. 



PLANKTON PRODUCTION AND RIVER LEVELS. 





January 



February 



March 



April 



May 



June 



to 



> 



bo 



re 2 



CX 



re 

 d/2 





OX) 



a) 



C/3 



2 2 



P-, 



DO 



CO 



00 



c c 



2 2 

 5 



bo 



55 



a a 

 2 2 



Pl, 





 bx> 

 n! 



6o 



I 2 



PL, 



1894 

 1895 

 1896 

 1897 



1898 

 1899 























4-63 

 1.88 

 7.38 

 5-54 

 n-53 



•74 



30.42 



•72 



•27 



3-96 







3-51 



8.83 



11 . 13 



5-94 

 7.02 



.01 

 .02 

 .04 



•27 

 .81 







5-41 



7.28 



13-40 



14.00 



3.18 



5.67 

 5. 11 

 4.40 







10.24 



.01 



9.4I 

 I3.89 

 12.99 

 13-05 



■07 



■38 



■33 



.28 



6.58 



9.41 



11.55 



I .30 



5.62 



II.30 



5.08 

 7-99 



•45 

 .18 















Mean 



7-77 



.21 



7.29 



•23 1 12.34 



.27 



10.02 



4-59 



9.18 



6.08 



6. 19 



7.22 



July 



Au 



gust 



Sept. 



Oct. 



Nov. 



Dec. 



Ann'l Mean 



Stage 



■a* 



re2 



PL, 



0) 



bfl 



5 

 (J5 



Plank- 

 ton 



bo 



M 

 CO 



C G 

 re O 



PL, 



DC 



a 

 C/3 



2 2 



OJ 

 00 



re 



tJ5 



S 2 



PL, 



OJ 



bo 



re 



c/2 



si 



PL, 



0) 



bo 



re 



CO 



c *-< 



2 2 



PL, 



2.32 



5.12 



1.99 



9.67 



4-43 



I.36 



2.96 



.61 



2.97 



.IO 



3-41 



.10 



4-63 



2-53 



3-17 



9-33 



2.43 



4-03 



3-42 



1-52 



1-93 



•57 



2.20 



3.02 



6.16 



1 -14 



3-bl 



5.91 



4-55 



1.44 



7.42 



1 . 12 



4.62 



•38 



6.04 



1. 11 



5.89 



.02 



5.48 



.76 



6.98 



1.05 



6.05 



4.69 



2.29 



3-65 



2.01 



8.83 



2.01 



5-95 



2.82 



I .00 



3.22 



-56 



6.90 



3-5i 



5.70 



.58 



3-°b 



.91 



4-44 



.69 



4.86 



• 24 



7-44 



•25 



6.59 



• 99 



8.02 



2.03 

 .42 











3.82 



















4-36 



4 23 



3-56 



3-88 



2.56 



3-56 



1.70 



4.26 



.88 

 1 



4-97 



•71 





2.71 



An inspection of the table shows at once the complexity of 

 the problem, and yields the following generalizations. 



In January-February, a period of sustained minimum tem- 

 peratures, high levels are attended by a small, and low levels 

 by a larger, plankton content, with the exception of stagnation 

 conditions in February, 1895. This contrast results from the 



