DECAY OF IONS. 



97 



would not be of any value. The table and chart show clearly enough 

 how rapid a reduction of efficient nuclei is produced by the presence of 

 but a few thousand ions. The results would have been much more 

 striking if a more efficient form of apparatus had been used, since for 

 dp = 31 cm. it is customary to obtain four or more times as many col- 

 loidal nuclei in the absence of ions. 



Table 39. 



-Graduation of high pressure curve, b =0.002; n =75 X io _s ; 

 \/n = 0.0133 = a. 



* (i + n)X 10- 3 . 



tt'Xio-s. 



140 



160 



180 



ZOO 



20 tO 60 BO 100 120 



Fig. 49. Decay of ions (i per cubic centimeter) in dust-free air, evidenced by 

 increase of efficient colloidal nucleation (n per cubic centimeter). Table 39. 



64. The same, continued. In conclusion I may state that a number 

 of experiments were made to test the rate at which the ions are gener- 

 ated. If a is the number of ions produced by the rays per cubic centi- 

 meter per second and b the coefficient of decay , 



dn/dt = a bn 2 



