00000128.htm

CONSECUTIVE FIELDS uy

different velocities which produces the beading of the
parabolas is, however, not due to special foci of production
but to the splitting up of molecules and perhaps also to the
formation of. new systems after the particles have passed
through the cathode.

Since the positive particles will not be able to get through
the fine tube in the cathode unless they are moving along the
axis of the tube, it. is only those particles which are formed
in the region adjacent to the prolongation of this axis in
the discharge tube which can pass through the cathode.
Those formed in outlying regions would not be moving in
the right direction when they struck the cathode. Thus
to get a copious supply of positive rays it is desirable
to concentrate the discharge as much as possible along the
axis of the tube, and we can understand the great influence
which the shape of the front of the cathode has upon the
brightness and range of velocities in the positive rays.

THE METHOD OF CONSECUTIVE SYSTEMS OF
ELECTRIC AND MAGNETIC FIELDS

A considerable amount of information about the behaviour
of the positive particles can be obtained by an extension
of the method described on p. 45. This extension consists
in having two systems A and B of electric and magnetic
fields placed at some distance apart in the path of the positive
rays, the displacements due to the magnetic and electrostatic
fields are respectively vertical and horizontal. Suppose A
is the system nearest the cathode, and that we take a
photograph which we shall denote by L with the electric and
magnetic fields at A in action, but those at B out of action,
and compare this with another photograph II. taken with A
still in action and in addition a magnetic field at B. Let us



	CONSECUTIVE FIELDS uy different velocities which produces the beading of the parabolas is, however, not due to special foci of production but to the splitting up of molecules and perhaps also to the formation of. new systems after the particles have passed through the cathode. Since the positive particles will not be able to get through the fine tube in the cathode unless they are moving along the axis of the tube, it. is only those particles which are formed in the region adjacent to the prolongation of this axis in the discharge tube which can pass through the cathode. Those formed in outlying regions would not be moving in the right direction when they struck the cathode. Thus to get a copious supply of positive rays it is desirable to concentrate the discharge as much as possible along the axis of the tube, and we can understand the great influence which the shape of the front of the cathode has upon the brightness and range of velocities in the positive rays.

	THE METHOD OF CONSECUTIVE SYSTEMS OF ELECTRIC AND MAGNETIC FIELDS A considerable amount of information about the behaviour of the positive particles can be obtained by an extension of the method described on p. 45. This extension consists in having two systems A and B of electric and magnetic fields placed at some distance apart in the path of the positive rays, the displacements due to the magnetic and electrostatic fields are respectively vertical and horizontal. Suppose A is the system nearest the cathode, and that we take a photograph which we shall denote by L with the electric and magnetic fields at A in action, but those at B out of action, and compare this with another photograph II. taken with A still in action and in addition a magnetic field at B. Let us