792 Mr. H. Brereton Baker [March 11, 



The amount of water necessary to . carry on these chemical reac- 

 tions is extremely small, certainly less than 1 mg. in 300,000 litres. 

 There is no accepted explanation of its catalytic effect, and in the 

 same way the catalytic power of platinum is still a mystery. In 

 1893, Sir J. J. Thomson* showed that if the combination of atoms in 

 a molecule is electrical in its nature, the presence of liquid drops of 

 water, or drops of any licfuid of high specific inductive capacity, 

 would be sufficient to cause a loosening of the tie between the atoms, 

 and this might result in chemical combination of the partially freed 

 atoms to form new molecules. He showed in the same paper that 

 drying a gas very completely stopped the passage of a current of 1200 

 volts. In the same year I was able in tbe same way to prevent the 

 passage of discharge from an induction coil, a discharge which would 

 traverse a spark gap of three times the distance in undried gas. 



Shortly after the discovery of Rontgen rays it was found that they 

 would ionise a gas through which they passed. At the time it was 

 thought that this ionisation was similar to that taking place in elec- 

 trolysis. If this were so the rays would probably cause chemical 

 union to take place even in a dried gas, and accordingly Prof. Dixon 

 and I undertook some experiments on the subject which were published 

 in a joint paper. t The results were negative, no chemical action 

 could be detected. Since that time the ionisation of gases has been 

 show'n to be of quite a different nature. The negative ion has been 

 shown to be a particle of the mass of about y^oo^li that of the 

 hydrogen atom, and the positive ion is the residue. Since the ionisa- 

 tion of gases is different from that in electrolysis, the retention of this 

 term is much to be deprecated. It is suggested that the term ionisa- 

 tion should be retained for electrolytic dissociation, and for the differ- 

 ent process wdiich takes place in gases under the action uf Rontgen 

 rays, etc., a new name, electromerism, should be adopted. The elec- 

 tron would tlius be the negative electromer. 



It is probable that electrolysis and true ionisation may take place 

 in gases, as in the decomposition of steam by electric sparks of a 

 particular length. Ai\ experiment, recently devised, seems to show 

 chat in mercury vapour, wliicli ordinarily consists of atoms, something 

 of the nature of ionisation without electrolysis can take place. If 

 oxygen be admitted to the interior of a mercury lamp from which 

 the current has just been cut off, a consideral^le quantity of mercuric 

 oxide is produced, although the temperature of the lamp(al)out 150°) 

 is far lower than would suffice to bring al)out the union of ordinary 

 mercury vapour with oxygen. 



In order to test further the question as to whether electromerism 

 can bring about chemical change, I have investigated the action of 

 radium bromide on very pure and dry hydrogen and oxygen. The 

 gases were sealed up with some radium bromide contained in an 



* Phil. Mag. xxxvi. 321. t Chem. Soc. Jour. 1896. 



