866 



H. A. Baker — Loose Arenaceous Sediments. 



comparison for the fineness or coarseness of grain of arenaceous 

 sediments. 



From the mathematical point of view the question presents great 

 difficulties. It does not appear to be possible to apply any simple 

 mathematical process to the data afforded by elutriation, which 

 does not deprive them of their uniqueness. Moreover, the applica- 



'tluym.ujjLaXi/u^ 'i%ir~CjeyTtix!Ui^ 'Ti/'hZyaJitd 



Fig, 2. — Elutriation curves of sediments (reduced) to show naeaning of 

 " Equivalent Grade ". 



tion of the ordinary processes of mathematics to the elutriation- 

 curve of a sediment would only give some result or results based 

 upon a series of mathematical curves agreeing more or less 

 approximately with portions of the actual curve. The latter being 

 available, the present writer is of opinion that it is better to obtain 

 some result or results from actual treatment of the graph itself. 



