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Phelps Lake ........... SES CCOSOE CECE L HOBIE SHES Ona COSSCCOORA A ADE CA ROLOFS ineocnostaquspooChe 181 
(Conkovr toi 1t®. Sy FIG pedce-nocdanccoococan codec poqooenaSonos sos Soc Sec Hocadan ApSHOcaonnRAorohen 181 
(CEYOERS (OH (OEMS yig50 cosccndosscnecpagancniposous cosets assasc estos cog Sean HRCOCORQISAADEES 182 
Siltinicatches andimethod!of estimation. ..-..0..-0-s:sss---+---s---4secsseseeeonoas 183 
Solids in suspension as determined by Berkefeld filter......... 184 
Silt and turbidity in fluviatile and lacustrine environments... 185 
(CHETNEC AL COMDLIEONNianntassanndsavencntyaesess sms -neaecassinessiissedeasaes se Jace =e LOS 
Source of data.....- peeera=ss LOO 
PNG Leow led pin GUS eecamnewetcer satan dens suey vices veka deesennnnnaemnstranere-sne cece ae ncr= es 187 
Comparison of chemical conditions and plankton at stations, from 
Aveta eS Oliva VS Sseeeteeewansar-nne snaneeeessscrarenncenmnes ses nmee nieces cae 187 
Residue upon evaporation... 188 
Residue in solution..........- « 189 
Chlorinevarsscescassssce 190 
Oxygen consumed. .. IgI 
NitTOeD:.-:2..-...00.0-00s 192 
Total organic nitrogen... 193 
ZA TAT NOIG AWA Oa serronsneaanaennscnesecrsnasee ssescutsnsecensiesecuscae= + 194 
Hie Ce AIITUOM Id ensesensvensascsseecraseserssncvdaerasccsssesistaccsren ep-coned ++ 194 
INStUIteS) sseceeersos es paaenens pacers scccuusacvassss aceeesertovemteeeceeraverdstas se 195 
UNIT rae Seemed sccrisevechssctccrines saniprecerrels inasnnsussuertantaseecn easeencaiccecssiactore 196 
Sewage in the Illinois River.............02. ceseseeeeeeeeee Scasntence teeetecntreciaar sae 198 
Cities in drainage basin of river with sewage SySteMS.. ......+.-seseeeeeeee 199 
GCifiest without Sewage) SYStCWISie« -csscccass\scsensecverrcesescearlerasncesccnissnseees-) 200 
EWA elo HiGA pO tn eseetacestendessssccacsnaarceyenevceliacs ten anriiesecctvesssscass = 201 
NEWaPelOl sPCOL Ass sescsssenressccccccass Sabsndao: gosasscogconconcnsaeseccosvoasssecpoaos 202 
Chemical Conditions and Plankton Production... saccese Soeeceeencneacce: 203 
Comparison of nitrogenous matters and plankton production on the 
DaASisiond VerAares OlialitanalySeS..csossasscnsaciessrercpruunanace-accexesaeso-\ce==s- 203 
MNEMOIS ARV ETnecrec-sve~ccesceseneees antconn-scesesswecesonetcesss Rantact amen pr eccriess vases: 204 
IPO MMMM CX ptacanlaceccstebessenssccsecccccatearaseccrserestasdertsvuaenstenderccccsevertces 204 
OWIVierMEakKGieecessncosasvxoccevecedaj-cursasssdesssenccatees estes) ascnnvecoenes: os sceseet a0 205 
eHom pson siilealce.yesccns-sstcceescsastiecerscssrecsereensere deenaon=coccoan Stoo: =p icnooce 206 
S<asonal changes in chemical conditions and plankton production......... 206 
General character of seasonal changes in chemical conditions............ 206 
Comparison of the years 1896-1890.........ee.ee:eeeeerane Benenson Sr AOCOS OCS 207 
Relation of chemical changes to plankton production................0000000- 208 
Illinois River.............++ auosesentisesaareces en sntacaetnceenseenscieasane SrERROCORCORE 208 
SOCOM INI Vie Iaearencwernncnstlenssecedcnncest soe cccarrseretessscecestes seectancnornenccoce: 209 
Quiver Lake........... 
Thompson's Lake......... 5 
Comparison of nisekton auction mite Senora! chases in nitrog- 
ENOUS SUDSLANGES..-cccu>ssscanaceerser 
With seasonal changes in nitrates.. 
Pibeimaximam-oainMOAUM) CYCIEC:..c-cadecreccnccecsaecaosssseavirerenes> os sseers 
Relation to plankton maxima in the several localities... 
Whthyseasonaliichan ges) in DIfTiteS, -c..ccesusoesetsccnsaq<eseincence a 4ueeslatenccves 
With seasonal changes in albuminoid ammonia and total organic 
MItTOPEN,..<se~- 0-5-6 “peacoceosctorue coeckescenesccs aonoos cocoesece. concen Sa nannodeeee 216 
