Thus the intensity of the γ rays is always proportional to the rate of expulsion of β particles, and this result indicates that there is a close connection between the β and γ rays. Such a result is to be expected if the β particle is the parent of the γ ray, for the expulsion of each electron from radium will give rise to a narrow spherical pulse travelling from the point of disturbance with the velocity of light. =108.= There is another possible hypothesis in regard to the nature of these rays. It has been shown (sections 48 and 82) that the apparent mass of an electron increases as the speed of light is approached; theoretically it should be very great when the velocity of the electron is exceedingly close to the velocity of light. In such a case, a moving electron would be difficult to deflect by a magnetic or electric field. The view that the γ rays are electrons carrying a negative charge and moving with a velocity nearly equal to that of light has recently been advocated by Paschen[173]. He concluded from experiment that the γ rays like the β rays carried a negative charge. We have seen (section 85) that Seitz also observed that a small negative charge was communicated to bodies on which the γ rays impinged, but the magnitude of this charge was much smaller than that observed by Paschen. I do not think that much weight can be attached to observations that a small positive or negative charge is communicated to bodies on which the γ rays fall, for it will be shown later that a strong secondary radiation, consisting in part of electrons, is set up during the passage of the γ rays through matter. It is not improbable that the small charge observed is not a direct result of the charge carried by the γ rays, but is an indirect effect due to the secondary radiations emitted from the surface of bodies. There is no doubt that a thick lead vessel, completely enclosing a quantity of radium, acquires a small positive charge, but this result would follow whether the γ rays carry a charge or not, since the secondary radiations from the lead surface consist of projected particles which carry with them a negative charge.