On helium in saline minerals, and its probable connection with potassium

Abstract

In a former paper I mentioned that saline minerals were often comparatively free from contamination with radio-active material of the uranium-radium series. Accordingly they afford special opportunities of testing whether or not helium is generated by the other elements present, namely, sodium, potassium, magnesium, calcium, sulphur, chlorine, oxygen, hydrogen. In this paper determinations are given of helium and radium in some of the saline minerals of Stassfurt. These minerals occur in strata of triassic age, though the age of some of them may be less, for there is evidence that secondary alterations have taken place in the salt deposits. Helium was liberated by solution of the mineral in water. The powdered substance was placed in a flask fitted up as shown in the preceding paper. The flask was exhausted, washed out with oxygen, again exhausted, and sealed off from the pump. Water, well boiled, and allowed to cool in a vacuum, was admitted through a tap. Heat was applied to promote solution, and when this was complete the gases set free were driven out by boiling and collected over mercury. Carbonic acid was removed by potash, and other constituents by sparking. The small residue was then examined as described in ‘Roy. Soc. Proc.,’ A, vol. 80, p. 592, liquid air being generally used to cool the charcoal.