eXl

tan θ = ----- .

mu2

The photographic plate was at a distance h above the extremity of the field. Thus the particles struck the plate at a distance d2 from the original path given by

In the experimental arrangement the values were

d2 = ·4 cms.;

X = 1·02 × 1012;

l = 3·45 cms.;

h = 1·2 cms.