From equations (1) and (2)

d1 l22 X

V = ----- ----- --- ,

d2 l12 H

and

e 2d1 V

---- = ------ --- .

m l12 H

The values of V and e/m are thus completely determined from the combined results of the electric and magnetic deviation. It was found that

V = 2·5 × 109 cms. per sec.