482 
yields least plankton. The factors of vegetation of the coarser 
sort and of tributary waters serve here to modify and overbal- 
ance light as a controlling factor in production. 
From the data of the U. 8S. Weather Bureau at Springfield, 
Mr. W. G. Burns, Section Director, has kindly furnished me the 
records of the number of cloudy days per month in 1894-1899 
observed at Peoria, Havana, and Springfield. These are given 
in the accompanying table. The records for Havana have also 
been plotted on Plates VIII.—XIII. in the uppermost row of 
squares. 
NUMBER OF CLOUDY DAYS. 
= i Le i] 
ee | rea lsecall etal es 2|2/5/2/8|/—|~ 
¢ |S/S/2 El elels|Slelslelelsle 
R a 5 aj || Se s o/s] t| oe Sloljo]o|]s 
mA s|ols < 2)S5|3)6, B 219 1m 
ta pA here = 
a bee | 
1894 | 13] 13° 8} 12| 19] 5! 9) 7] 9) 9} ral 35]133] 5 
1895 | 11 7} 11{ 13] 2] 9} 7) 4] 4] 4} 15) 18]105) 1 
Serneeeld 1896 | 14| 12); 16} 8! 9] of 7| 2] 12| 7| 18! 15|120] 4 
Seager aes te 1897 | 16] 15! 20] 17} 4) to} 5) 2] 1) 4] 12] 21/127] 3 
1898 | 12] 12 16] 13] 11] 5] 3 8i 10} 15) o} 12|126] 1 
1899 | 16 14) 21) 12) 17) 7] 13) 7 6} 8] 16) 10/147] 6 
Total | 82] 73) 92} 75| 62| 45] 44) 391 42| 47| 84] o1|767 
1894 | 7 8, 7| 6} 4} of of 3] 3] 6] ro] 7] 61) 1 
1895 | 6] 3 10! o} 3) 4) 4] 3] 4} 2) 13] 13] 74] 3 
Hayanaye screenees 1896; 7) 6 4] 3] 5] 6) 4] 2] 11) 3] 10] 9! 70] 2 
1897 | 10] 10} 17] 13] 6! 6! o| 4, 2] 4} 12) 15) go] 6 
1898 | 11] Io} 11 8) 4) 3) 8 2) 16} 5) 7] ot| 5 
1899 | 7) §| 16 4) 5] 3] 5] 3) 3] 6] 10) 7| 75] 4 
Total | 48) 43] 65] 41] 3t| 23] 16] 23] 25] 37] 60 381470]... 
1894 | 11] 9] 6 8] 9] of 3] 5] 8] 6] 12] 11 88) 1 
1895 | 10] 8 io 8] 4) 5) 6) 5] 4} 2] 18] 19} go} 2 
Peoria erase cee 1896 | 17| 10 8 3} 6 8) 6 2) ro) ro} 16 14)r10) 4 
1897 | 13] 14] 18) 16] 5s} 6} 1} 4} 3! 3] 15] 1olrI7| 5 
1898 | 15 14; 14] Io} 13] 6} 2) 8) 4} 16) 11 13/126 6 
1899 | 12] 12) 16| 10} 8] 2) 5) 5] 6) 6] 13] 11106] 3 
Total ' 78! 6 | 721 55! 45! 27| 23! 29) 35) 43! 85 78.646)... 
6g The variations in the relative cloudiness in the three local- 
ities in many months and in the total number of cloudy days 
in the several years in the three localities render any correla- 
tion with production largely conjectural and close comparisons 
