JlLY 24, 1903.] 



SCIENCE. 



123 



existed in such concentrated small portions, 

 which were called ' electrons,' and could either 

 be associated with atoms of matter, to form 

 the well-known chemical ions, or could fly 

 separate, as was observed in the cathode rays 

 of vacuum tubes, and in the loss of negative 

 electricity when ultra-violet light fell upon a 

 clean negatively charged surface. The lec- 

 turer went on to say : The hji^othesis sug- 

 gested on the strength of these facts is that 

 the atoms of matter are actually composed of 

 these unit electric charges or electrons, an 

 equal number of positive and negative charges 

 going to form a neutral atom, a charged atom 

 having one electron in excess or defect. On 

 this view a stable aggregate of about 700 elec- 

 trons in violent orbital motion among them- 

 selves would constitute a hydrogen atom, 16 

 times that number would constitute an oxygen 

 atom, and about 150,000 would constitute an 

 atom of radium. The attractiveness of this 

 hypothesis is that it represents a unification 

 of matter and a reduction of all material sub- 

 stance to a purely electric phenomenon. The 

 strongest argument in its favor is that mass 

 or inertia can certainly be accounted for elec- 

 trically, and that there is no other known way 

 of accounting for it. If matter is not elec- 

 trical, then there are two distinct kinds of 

 inertia which exactly simulate each other's 

 properties. Assuming this electrical theory 

 of matter, that the atoms are aggregates of 

 electric charges in a state of violent motion, 

 two consequences follow. One of these con- 

 sequences depends on the known fact that 

 radiation or light, or an ether wave of some 

 kind, is emitted from any electron subject to 

 acceleration ; consequently the revolving con- 

 stituents of an atom must be slowly radiating 

 their energy away, must thus encounter a 

 virtual resistance, and must in that way have 

 their velocity increased. The second conse- 

 quence is that when the speed of an electrified 

 body reaches that of light its mass becomes 

 suddenly infinite; and in that case it appears 

 not improbable that a critical condition would 

 have been reached at which the atom would 

 no longer be stable, but would break up into 

 other substances. And recently during the 



present year a break-up of the most massive 

 atoms has been observed by Kutherford, and 

 has been shown to account for the phenom- 

 enon of radio-activity, some few of the atoms 

 of a radio-active substance appearing to reach 

 a critical stage, at which they Hing away a 

 small portion of themselves with great vio- 

 lence, the residue having the same property 

 of instability for some time, until ultimately 

 it settles down into presumably a different 

 substance from that at which it started. The 

 matter flung away appears to be a light sub- 

 stance not very different in atomic weight 

 from hydrogen or helium, and it is surmised 

 that possibly certain chemical inert elements 

 may be the by-products of radio-activity; and 

 that this process of dissociation of the atom 

 may constitute the evolution of the chemical 

 elements, such as has, on theoretical grounds, 

 already been speculatively surmised. An 

 analogy, the lecturer said, may be drawn be- 

 tween this supposed gradual collapse of an 

 atom and the contraction of a nebula, which 

 at certain stages becomes unstable and shrinks 

 off a planet, the residue constituting an ex- 

 tremely radio-active mass or sun. But, where- 

 as the astronomical changes observed in cos- 

 mic configurations of matter occur in a time 

 reckoned in millions of years, the changes to 

 be expected in the more stable atoms would 

 seem likely to require a time reckoned in mill- 

 ions of millions of centuries; but, neverthe- 

 less, according to known laws, and on the 

 hypothesis of electric constitution, the change 

 seems bound ultimately to occur; and so a 

 state of flux and decay is hypothetically recog- 

 nized, not only in the stars and planets, but 

 in the foundation-stones of the universe, the 

 elemental atoms themselves. A process of re- 

 generation, however, is also thinkable, and 

 would occur if the separate electrons were ever 

 to aggregate themselves together by their mu- 

 tual attractions into fresh material. And, 

 inasmuch as the life of a highly radio-active 

 substance must be very limited, being, per- 

 haps, not more than a few thousands of years 

 in some extreme cases, it appears necessary to 

 assume that some such regenerative process is 

 constantly at work, and that, just as we have 



