184 A MODEL OF NATURE. 



The two conclusions will mutually support each other if it can be 

 shown that a mis! is easily formed in ionized air. This was tested 

 by Mr. Wilson, who showed that in such air mist is formed as though 

 nuclei were present, and thus in the cloud we have visible evidence of 

 the presence of the divided atoms. If, then, we can not handle the 

 individual molecules we have at least some reason to believe that a 

 method is known of seizing individuals, or parts of individuals, which 

 are in a special state, and of wrapping other matter round them till 

 each one is the center of a discrete particle of a visible fog. 



I have purposely chosen this illustration, because the explanation is 

 based on a theory— that of ionization which is at present subjected 

 to hostile criticism. It assumes that an electrical current is nothing 

 more than the movement of charges of electricity. But magnets placed 

 near to an electric current tend to set themselves at right angles to its 

 direction; a fact on which the construction of telegraphic instruments 

 is based. Hence, if the theory be true, a similar effect ought to be 

 produced by a moving charge of electricity. This experiment was 

 tried many years ago in the laboratory of Helmholtz by Rowland, who 

 caused a charged disk to spin rapidly near a magnet. The result was 

 in accord with the theory; the magnet moved as though acted upon by 

 an electric current. Of late, however. M. Cremieu has investigated 

 the matter afresh, and has obtained results which, according to his 

 interpretation, were inconsistent with that of Rowland. 



M. Cremieu's results are already the subject of controversy/ and 

 are, I believe, likely to be discussed in the section of physics. This is 

 not the occasion to enter upon a critical discussion of the question at 

 issue, and 1 refer to it only to point out that though, if M. Cremieu's 

 results were upheld, our views as to electricity would have to be mod- 

 ified, the foundations of the atomic theory would not be shaken. 



It is, however, from the theory of ions that the most far-reaching 

 speculations of science have recently received unexpected support. 

 The dream that matter of all kinds will some day lie proved to be fun- 

 damentally the same has survived many shocks. The opinion is con- 

 sistent with the great generalization that the properties of elements 

 are a periodic function of their atomic weights. Sir Norman Lockyer 

 has long been a prominent exponent of the view that the spectra, of 

 the stars indicate tin 1 reduction of our so-called elements to simpler 

 forms, and now Prof. J. J. Thomson believes that we can break oil 

 from an atom a part, the mass of which is not more than one-thou- 

 sandth of the whole, and that these corpuscles, as he has named them, 

 are the carriers of the negative charge in an electric current. If atoms 

 are thus complex, not only is the a priori probability increased that 

 the different structures which we call elements may all be built of 



a See Phil. Mag., .Inly, 1901, \>. Ill; and Johns Hopkins University Circulars, XX, 

 No. L52, May-June, 1901, p. 78. 



