KINETIC MEASUREMENT OF THE ELASTICITY OF EOCKS. 21 



Take a rightangled-isoscelestriaiigle ABC with its vertex C below 

 the horizontal base AB. Divide each of the three sides into one 

 hundred equal segments, and also in the produced part BD mark 

 off any number of segments equal to one of the last. Join the 

 vertex A with each of the points of section on the side BG and 

 its produced part. 



Let a and ß be the corresponding values of any physical 

 quantity in two different conditions 21 and ^. From A measure 

 a length Ax equal to a, the length of one segment being 

 taken as the unit of measurement, on the side AC or its pro- 

 duced part. Then, from the end point x measure again a length 

 xy equal to ß in the direction parallel to the other side CB. 

 If the last point y falls on the n^^ of the previously drawn lines 

 numbered from the base AB, then the physical quantity is said 

 to have increased or decreased n percent wdiile the condition 

 varied from 21 to 33, according as the line is above or below the 

 base. 



These premised, we have a new^ system of co-ordinates, in 

 which the radius vector and the percentage are two independent 



