FUNGICIDES, ETC. 285 



concentrate is 1-27 (about 31 Beaume), to get a spray 

 of 1-03 density we divide the -27 by -03 and obtain 9, 

 which is the number of dilutions required, and which of 

 course is obtained by adding eight volumes of water. 

 In this we are simply applying the general fact that 

 the density of the solution heavier than water varies 

 inversely with the number of dilutions. The workings 

 of the process may be seen further in the following : 

 (A) To determine number of dilutions. 



Rule : 



Decimal of concentrate 

 Decimal of spray desired 



Examples : 



= No. of dilutions. 



(B) To determine density of spray used. 



Rule: 



Decimal of concentrate 



r ,., . - = Decimal ot spray. 

 Number of dilutions 



Examples : 

 -yxr- = -026, .-. Spray = 1-026 specific gravity. 



= -0054, .*. Spray = 1-0054 specific gravity. 



50 



This method gives final sprays of definite density, 

 and the importance of this is obvious when we consider 

 the relatively small margins between safe and unsafe 

 densities in the use of these solutions on foliage. 



The following is a table which gives readings of 

 equal value for either specific gravity scale or Beaume 

 scale of densitv. 



[TABLE 



