174 LIFE AND WORK OF SIR JAGADIS C. BOSE 



to the right or to the left, by which the rate of compensating 

 fall is retarded or accelerated. In this way the rate of 

 growth becomes exactly compensated, and the recorder 

 now dots a horizontal line instead of the former curve of 

 ascent. The turning of the adjusting screw of the Balanced 



FIG. 19. The Balanced Crescograph. Compensation of growth-movement 

 produced by equal subsidence of the holder containing the plant (P). 

 Adjusting screw (S) regulates the speed of the governor (G). W, heavy 

 weight actuating clock-work. 



Crescograph also moves an index against a circular scale (not 

 shown in the figure) so graduated that its reading at once 

 gives the rate at which the plant is growing at that instant. 

 When balanced, the recording apparatus is extraordinarily 

 sensitive. Any change, however slight, in the environment 

 is at once indicated by the upset of the balance with up 

 or down movement of the curve. This method is so 

 extremely sensitive that Bose has been able to detect 

 variation of rate of growth so excessively minute as 

 millionth of an inch per second. 



