m 



Meslin seems to be not quite free from a confusion, which is indeed 

 pretty widely spread : between the change of a number occurring 

 in an equation through change of unities, ("formal" change) and its 

 change through transition to other conditions (to other specimens of 

 the quantities which are measured by this number) ("material" 

 change). 



In connection with this the assertion that in case of an equal 

 number of variables and parameters the latter can always be com- 

 pletely expressed in the former-, is to be rejected. 



§ 6. We shall illustrate what we have discussed l\y examples, 

 which though fictitious, are as simple as possible. Their claim to 

 physical signification, can indeed always be vindicated in this way 

 that they are interpreted as equations for the geometric shape of 

 some physical system. 



1. y = ax^ -\- X -\- b {n = 2, ?7i = 2). 



a. Introduction of special values of the variables 



y 



2/o 



+ .^0 - + ^ 

 a;. 



b. Division by 





c. Determination of the numerical values of the special values 

 of the variables satisfying the equation and of the coefficients : 



I 



ax. 



2/o 



1 = 1 



a 



1 



ab 

 1 

 ab 



y 



' = b 



d. Determination of the system of corresponding values : 



ax„ 



1 



2/o' ^^ 



b' 



= 1 



yo = ^' 



b' 



I 



ab 



'■ _ a'b' _ 1 

 a'^b" ab 



