THE CHEMICAL ELEMENTS. 603 



In all this work they have taken for granted that in the spectrum 

 thus produced in their laboratoi-ies, they have been dealing with the 

 vibration of one unique thing, call it atom, molecule, or what 3'ou will ; 

 that one unique thing has by its vibrations produced all the lines 

 visible, which they have persistently seen and mapped in each instance. 



It is at this point that my recent work comes in, and raises the 

 question whether what has been thus taken for granted is really true. 

 And now that the question is raised, the striking thing about it is that 

 it was not asked long ago. 



One reason is this : Time out of mind — or, rather, ever since 

 Nicolas Le Fevre, who was sent over here by the French King at the 

 request of our English one at the time the Royal Society was estab- 

 lished, pointed out that chemistry was the art of separations as well as 

 of transmiitatioyis — it has been recognized that, with every increase of 

 temperature, or dissociating power, bodies were separated from each 

 other. In this way Priestley, from his " plomb rouge," separated 

 oxygen, and Davy separated potassium ; and as a final result of the 

 labor of generations of chemists, the millionfold chemical complexity 

 of natural bodies in the three kingdoms of nature has been reduced by 

 separations till only some seventy so-called elements are left. 



Now this magnificent simplification has been brought about by the 

 employment of moderate temperatures — moderate, that is to say, in 

 comparison with the transcendental dissociating energies of electricity 

 as employed in our modern voltaic arcs and electric sparks. 



But, in the observations made during the last thirty years on the 

 spectra of bodies rendered incandescent by electricity, we have actually, 

 though yet scarcely consciously, been employing these transcendental 

 temperatures, and, if it be that this higher grade of heat does what all 

 other lower grades have done, then the spectrum we have observed in 

 each case is not the record of the vibrations of the particular substance 

 with which we have imagined ourselves to be working only, but of all 

 the simpler substances produced by the series, whether short or long, 

 of the " separations " effected. 



The question, then, it will be seen, is an appeal to the law of conti- 

 nuity, nothing more and nothing less. Is a temperature higher than 

 any yet applied to act in the same way as each higher temperature, 

 which has been applied, has done ? Or is there to be some unexplained 

 break in the uniformity of nature's processes ? 



The definite reason for my asking the question at the present time 

 has been this : The final reduction of four years' work at a special 

 branch of the subject to which I will refer presently, on the assumption 

 that at the temperature of the electric arc we do not get such " simpHfi- 

 cations," has landed me in the most helpless confusion, and, if I do not 

 succeed in finding a higher law than that on which I have been working, 

 my four years' work, in this direction at all events, will have been 

 thrown away. 



