WORK ON RADIUM 167 



microbalance as already mentioned he was troubled by 

 the condensation of air, and in a letter to Dr. Travers 

 he mentions (27th Nov., 1910) that " All water leaves a 

 weighable residue from a drop, and that introduces 

 fresh difficulties in working on a small scale." This 

 residue is doubtless derived from the atmosphere, if 

 the water has been in contact with ordinary air even for 

 an instant. 



The position of these interesting speculations is still 

 unsettled. But it may be pointed out that hypothesis 

 has been lavished on the question as to the origin of 

 the known elements. It seems to be generally admitted 

 that they were formed by the condensation, under 

 suitable but probably varying conditions, of one or more 

 primary forms of matter, and that the comparatively 

 stable forms of the condensed material have ranged 

 themselves in groups and series which are summed up 

 in the periodic scheme of Mendeleeff or some modification 

 of it. There seems to be some evidence of the reverse 

 operation proceeding spontaneously in the disintegration 

 of the radio-active substances, and there is surely justi- 

 fication for an attempt to utilise the enormous energy 

 which becomes available in this process in the endeavour 

 to break down the atoms of those common elements 

 which are not appreciably radio-active and which are 

 apparently permanent under conditions now prevailing 

 in this part of the universe. It is true that other experi- 

 menters have not confirmed Ramsay's published state- 

 ments, but in such a field of work it is not surprising 



