Page:"N" Rays (Garcin).djvu/75

Rh state of molecular strain is transitory, as is also the emission of "N" rays.

Torsion produces effects analogous to compression.

To study the dispersion and the wave-lengths of "N" rays, I used methods quite similar to those employed for light. In order to avoid complications which might have resulted from the storing-up of "N" rays, I used exclusively prisms and lenses of aluminium, a substance which does not absorb their rays.

The following is the method employed to study dispersion. The rays are produced by a Nernst lamp, enclosed in a lantern of sheet-iron, pierced with an opening, which is shut by aluminium foil; the rays from the lamp which pass through this opening are sifted by a deal board 2 cms. thick, a second sheet of aluminium, and two leaves of black paper, so as to eliminate