generated from Aluminium Electrodes. 



700 



The only positive indication obtained is the following : — 

 It was found impossible to obtain any gas out of the bulbs 

 made in England, which always showed a marked absorption 

 under the same conditions as those in which the bulbs 

 obtained in Germany were generating the unknown gas. 

 Comparing this with the fact previously noted, that the effect 

 could not be obtained with copper nor with iron electrodes, it 

 seemed reasonable to attribute this difference in behaviour 

 to a difference in the aluminium employed. This view proved 

 correct. When the electrodes were interchanged, those from 

 the German tube gave gas when remounted in the new English 

 tube. It is therefore probable that this aluminium contains 

 an impurity responsible for the observed effect. Among 

 the admixtures liable to be found in aluminium, the most 

 likely are carbon, nitrogen, and sodium. The two first- 

 mentioned elements suggested the examination of the cyanogen 

 compounds, and to test the latter possibility one of the English 

 aluminium electrodes was alloyed with sodium on its surface. 

 This electrode now showed a behaviour very similar to the 

 one exhibited by the German electrodes. On applying the 

 coil much gas appeared, the cathode showing a marked 

 scintillation. After a short time this action reversed, the 

 induction current now absorbed gas. -But on applying the 

 steady current given by the Wimshurst machine, a continuous 

 slow production set in, gradually ebbing down as in the case 

 of the old electrodes. The pW values of this gas neither 

 became really constant nor did they reach entirely the quarter 

 of hydrogen value, but they came very near in both these 

 respects. The following table gives a series of final values : — 



p. 



Y. 



p*Y. 

 9408 



28 



12000 



31 



9600 



9224 



36 



8000 



10368 



38 



7000 



10708 



44 



6000 



11616 



The hydrogen value of the tube was 53,000. The values 

 obtained in the beginning of the experiments were much 

 lower and showed a much more decided slope. It is con- 

 sidered as consistent with these results, that the electrode 

 alloyed with sodium behaves like the one made of German 

 aluminium, with the difference that it is polluted by sodium 

 carbonate, decomposing under the influence of the electric 

 discharge, so that the unknown gas is only obtained in an 

 impure state. This result, without solving the question as to 

 the nature of this gas, changes the direction of the research 

 in pointing to the electrode metal as a field of investigation. 



