352 Mr Ramage, On the Distribution and Spectra 



were cold and the bead was made the anode no red colour appeared 

 in the spark. 



The lithium vapour liberated from a hot anode would appear 

 to carry a positive charge and thus convey part of the current to 

 the kathode, but the lithium vapour liberated from the kathode 

 does not appear to be charged. In no case has it been observed 

 to be repelled by the anode, and it certainly does not appear to be 

 attracted by it; if it is charged negatively at first the charge 

 must be quickly lost. The lithium would appear to be liberated 

 in definite quantity by each spark, in a very short interval of 

 time, but there is no decisive evidence given by these experi- 

 ments to show whether the vapour passes away in an explosion 

 wave or merely by diffusion in the gases heated to a high 

 temperature by the passage of the spark. Sodium vapour passes 

 about as far from a kathode of sodium salt as lithium does ; this 

 is in favour of the former view. 



There is evidently an intense chemical action taking place 

 in the bright spot on the kathode, and there seems no doubt 

 but that lithium is liberated from combination by electrical action 

 at this point. It is probable that the production of the sub- 

 ordinate series is associated with the process of liberation of the 

 metal, that the vibrations producing the lines of these series are 

 peculiar to the atom at the moment of its liberation, perhaps 

 to the atom and the electric charge then given to it, whilst the 

 vibrations producing the lines of the principal series are peculiar 

 to some change, combination or otherwise, of the free atom of the 

 metal. The lines of the subordinate series become broader and 

 apparently brighter as the negative pole of the arc is approached, 

 and this pole, according to Violle, has a temperature of about 

 2700° when the positive pole is about 3500°, and the temperature 

 of the arc itself is still higher. The apparent brightening of the 

 lines is not a temperature effect. 



The results obtained with a compound of sodium are similar 

 to those obtained with lithium. Potassium gives a different result 

 when a bead of its carbonate is on the kathode. There is no 

 flame near the kathode, the spark is reduced to a thin line whilst 

 it retains its original size and greenish colour near the anode. 

 The bright kathode spot gives the subordinate series as strong 

 lines. Rubidium and caesium resemble potassium but they give 

 their colours to a portion of the flame near the kathode. 



Calcium, strontium, and barium give brilliant colours to the 

 flame near the kathode when beads of their chlorides are used, 

 and their spectra at the kathode resemble their oxyhydrogen 

 flame spectra, whilst the spectra of the coloured flames are more 

 like those of their Bunsen flame spectra. 



Experiments have been made with metallic electrodes of 



