536 Mr. Jackson on the Method of Transmission of 



inexact method of determining the value of ~ In the 



accompanying figure, the maximum activities have all been 

 reduced to 100, and the three curves are calculated by 



assuming the mean value of ^ to be '1 cm. 



The values of N and -rv were determined as follows :<— 



Assuming that the set of n points in question, i. e.(x x , yi), . . . 

 (%n, y n ) belong to a curve of form 





k 



y = a > 



J X 



we make 



2 (?/,-« + -)=o, 



and 



SI yr~ a-\ J a minimum. 



By differentiation this leads to the equations 



k= 



p-(4) 2 c") 



na — k%- + %y 



x J 



In the curves for vessels II. and III. all the points for which 

 the deposit was greater than 70 per cent, of the maximum 

 were used in the above formulae. 



In the curve for vessel I. the point slightly below this value 

 was used because the next point was clearly inaccurate. The 

 result so obtained was practically identical with that obtained 

 by leaving out both the points in question. On account of 



the difference in the values of ■— caused by omitting even 



single points, this value is reliable only to one figure. The 

 results are given in the following table : — 



N . ~-° in cm. 



Vessel 1 187 -71 



Vessel II 221 -73 



Vessel III 414 *64 



