PROCEEDINGS. 



October i$th, 1888. 



President Nipher in the chair ; nine members present. 



Prof. Nipher exhibited proofs of Rain Charts to illustrate his 

 report on ''Ten Years' Rainfall of the State of Missouri," which 

 was referred to the Committee on Publication on March 5th. 



Prof. Nipher also made a communication on the relation be- 

 tween rainfall and river discharge in the Upper Mississippi val- 

 ley. He presented a diagram showing the average monthly- 

 values of rainfall, in cubic feet per second, over the i^egion drain- 

 ing past St. Louis, and simultaneous values of river discharge 

 at St. Louis. It was proposed to continue the investigation for 

 other sections of the Mississippi and Ohio valleys. The commu- 

 nication was referred to the Committee on Publication. 



Mr. J. A. Seddon gave a discussion of the theoretic variation 

 of the intensity of light through a tube filled with various colored 

 solutions, showing that the general equation was 



I 

 CL = 



6y 

 E 

 where 



L represented the intensity of the light, 

 o " a constant dependent on the opacity of the 



solution, 

 and y " the length of the ordinate of any point in 



the tube. 



He also pointed out how this might be used as a measure of light 

 and of the opacity of different solutions. 



