Leonard and RichAudson — On. Helium in the Boiling Well at Lucan. 9l 



Spectroscopic examination of the gases. 



The photographed vacuum tube spectra are shown in Plate V. 



The spectrum of the original gas from the well is shown in No. 1. It gives 

 the characteristic band spectrum of nitrogen, the helium and argon lines being 

 completely absent. Nos. 2 and 3 are the spectra of helium from the well and of 

 purchased helium respectively, while No. 4 shows the spectrum of the purchased 

 helium (long) superimposed on that of the helium from the well (short). 



Eleven lines (dotted) appear in the latter, which are not visible in the 

 spectrum of the purchased gas. 



They have been identified as lines of hydrogen, mercury, and argon. 



In No. 5 the purchased argon lines are photographed (long) with those of argon 

 from the well (short) superimposed. 'I'he bands of nitrogen appear faintly in the 

 latter, together with some hydrogen lines. The coincidence of these lines with 

 those of hydrogen is shown in No. 8, where the purchased argon is photographed 

 full length, hydrogen two-thirds length, and argon from the well short. On 

 examination of the latter spectrum with a lens, all the lines are seen to be 

 continued into the hydrogen lines or those of the purchased argon. In No. 7 the 

 spectrum of argon from the well (long) is superimposed on that of the purchased 

 argon (short); the lines appearing in the latter are some of the lines of the blue 

 spectrum of argon, which developed owing to variation in the tension of the 

 contact-breaker of the coil. 



As the gases in the process of purification were passed more than once over 

 heated copper oxide for removal of hydrogen, it is possible that the occurrence of 

 hydrogen in the gases after separation is due to the presence of phosphorous 

 anhydride in the commercial phosphoric anhydride employed for desiccation 

 (Manley, Journ. Chem. Soc, 1922, 331.) 



Radioactivity of the water from the vxll. 



A test of the radioactivity of the water, kindly carried out by Dr. J. H. J. 

 Poole, indicated the presence of about 0-01 x 10-'- gram of radium per c.c, i.e. 

 rather less than the average for sea-water and rather more than that for river- 

 water. 



The authors desire to express their thanks to Dr. R. Leeper,who granted them 

 facility of access to the well. 



Chemical Labokatoey, 



EoYAL College of Science, 

 Dublin. 



