Radioactive kryptonate of selenium sulfide is suggested for the determination of the concentration of mercury vapour in air.
Selenium sulfide was applied as a coating to paper; upon the exposure to an atmosphere containing mercury vapor, a black color
of mercuric sulfide and mercuric selenide developed. The fractional decrease in the radioactivity of the paper (related to
the original specific activity) was found to be proportional to the concentration of mercury vapor and time of exposure. Other
factors which can be controlled were found to be affecting the determination significantly.