An attempt to detect the passage of helium through a crystal lattice at high temperatures

In a previous paper (Rayleigh 1936), comparative studies were made of the passage of helium through various kinds of glass at the ordinary temperature. Silica glass, pyrex glass, and boron trioxide glass all allow helium to pass through. Ordinary soda glass or flint glass do not pass measurable quantities of helium unless the temperature is raised. Tests were made at the ordinary temperature on various single crystals, including quartz, mica, beryl, and some others. No passage of helium could be detected.