CONSTITUTION OF MATTER BECQUEREL. 289 



Such ideas as these, whose boldness needs no remark, have already 

 been confirmed in a remarkable manner. Radium gives birth to a gas 

 called the emanation of radium. Messrs. Ramsay and Soddy have 

 shown that this emanation produces helium. Rutherford has proved 

 that the ol rays of radioactive bodies are nothing more nor less than 

 atoms of helium. Moureau has recognized the presence of helium in 

 radioactive gases from thermal sources. 



We know to-day that radioactive substances undergo an evolution 

 in which there appears a whole series of more or less ephemeral bodies 

 whose duration of existence may be as small as a few days, or even a 

 few seconds, as in the case of the emanation of actinium. All these 

 bodies are new elements. 



These transformations are veritable transmutations. They are not 

 chemical decompositions. They appear to be independent of tempera- 

 ture; they bring into play a considerable amount of energy; for 

 instance, the emanation of radium is, as a matter of fact, capable of 

 setting free 2,500,000 times as much energy as the explosion of a mix- 

 ture of hydrogen and oxygen of equal volume. 



Radium and polonium form part of the series of elements deriving 

 their origin from uranium, and it is very probable that in addition to 

 helium the relatively stable residue of these transformations is nothing 

 other than lead. 



Sir William Ramsay at present is carrying out some remarkable 

 experiments. He has announced the transmutation of copper into 

 potassium, sodium, and helium under the action of the concentrated 

 energy which the radium emanation brings to bear on them. In some 

 recent experiments, which appear to be beyond criticism, he has at- 

 tained the transmutation into carbon of silicon, titanium, zirconium, 

 lead, and thorium. All these bodies belong in the same column in 

 Mendelejeff's table. 



These results show the possibility of a transformation of heavy 

 atoms into more simple atoms; that is to say, the possibility of a 

 degradation of elements. It is impossible to imagine for an instant, 

 however, the possibility of realizing the inverse transformation, for 

 example, of copper into gold. Such a transmutation would unques- 

 tionably require a colossal amount of energy, and we have as yet no 

 means of disposing of the intra-atomic energy, of which our only 

 knowledge is that it is considerable. 



It is probable that all matter is undergoing a process of evolution. 

 The slowness of the transformation, however, or the rarity of con- 

 ditions favorable to quick change gives us an illusion of stability. 



A while ago I recalled several very ancient theories; we know of 

 nothing to-day that contradicts them. Four principal ideas may be 

 derived from these theories, the conception of the atom, the existence 

 97578°— sm 1910 19 



