326 ILLINOIS ACADEMY OF SCIENCE 



a third intercision may be anticipated with some degree 

 of reason. 



The rapid retreat of the cliffs is proving of serious 

 import to property owners along the lake shore. In 

 some cases the slumping of the cliff material is facili- 

 tated by the tile drainage of the uplands. The small, 

 artificial streams directed by the tiles aid materially in 

 the erosion of the steep cliffs. The retreat of the cliffs 

 and the possibilities of the future intercision of the river 

 give the situation a certain economic as well as physi- 

 ographic interest. 



NOTE OF A NEW INDICATOR IN WATER 

 ANALYSIS 



R. E. Geeenfield and Edwaed Baetow, State Watee 

 SuEVEY, Uebana 



The selection of an indicator for use in the titration 

 of the Ficarbonate alkalinity of natural waters has al- 

 ways presented some difficulty. Probably the first indi- 

 cator used for this purpose, of which we have any rec- 

 ord, was the coloring matter of red wine, for we are told 

 that the Romans titrated natural waters with sour wine 

 the red coloring matter of the wine acting as a natural 

 indicator. Since that time other and better indicators 

 have been suggested, it is true however that the selection 

 of those suggested has often been made with very little 

 more regard to the needs that the indicator must fill than 

 was the original red wine of the Romans. 



An examination of some of the more recent textbooks 

 and reference books shows the following recommenda- 

 tions. Thresh (1913), Mason (1912), and Stocks (1912) 

 recommend Methyl Orange. Leffman (1909) and Chem- 

 iker Kalender (1917) recommend Alizarin with Methyl 

 Orange as an alternate. The first two editions of Stand- 

 ard Methods of Water Analysis A. P. H. A. recommend 

 the use of either Lacmoid in hot solution or Erythrosine 

 cold and advise against the use of Methyl Orange due to 

 the difficulty of getting supplies of that indicator of sat- 



