NIPHER — REPORT ON MISSOURI RAINFALL, iS'J'J-S'J. 393 



used in constructing the normal maps. They were however used 

 in constructing anew the rain maps of the individual months, in 

 order to obtain interpolated values where observations were miss- 

 ing in the ten-year series. 



An interesting question which suggested itself, was to compare 

 the total amount of rainfall on the entire state, in cubic feet, with 

 the amount of water flowing past the city of St. Louis in the Mis- 

 sissippi river during the same time. 



In order to solve this problem, the map showing the normal 

 annual rainfall was used. The map area of the whole State as 

 determined by a planimeter was 0.443 square decimeter. The 

 area of the whole state is given as 69,415 square miles. Hence 

 i{ s be the planimeter area of any portion of the map of the State, 

 the area square miles of that portion of the State represented 

 will be 



a = ^9Alls= 1566935. 

 0-443 

 Also if r = the annual rainfall in inches over any part of the 

 state having a map area of s, the total fall of water in cubic feet 

 per second on that area will be 



jR = 69415 X (5280)^ ^^^ 



0.443 X 1 2 X 365 X 86400 



= ii543-^''- 

 The area of the regions bounded by the consecutive lines of 

 equal rainfall and the boundary lines of the State were deter- 

 mined by planimeter. For instance, the region between the rain 

 lines of 42" and 44" annual fall was 0.037 square decimeters. 

 Over this area the rainfall was assumed to be 43", as is shown in 

 the table below. The fifth column of the table gives the number 

 of square miles, where the rainfall has the value given in the cor- 

 responding place in column one. The total rainfall in the state 

 in cubic feet per second is 



i? = 11543 Isr 



= 1 1545 X 16.96 



= 195,800. 



The average annual rainfall in the state is 



Isr 



^ 38 28 inches, 



0.443 • 



