The electrical conductivity of most glasses at a temperature of about 100°C is barely a measurable quantity.

For this reason, and on account of the fact that glass conforms to the general rule applicable to non-conductors in showing an increase of resistivity for a fall of temperature, this material has come to be regarded .as practically incapable when cold of allowing the passage of an electric current.

With a view to the further study of electrical conduction in glass, and also because of certain experimental advantages which a conducting glass would possess, I have endeavoured to produce a transparent vitreous substance having that property.