In all this work they have taken for granted that in the spectrum thus produced in their laboratories, they have been dealing with the vibration of one unique thing, call it atom, molecule, or what you 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 Fèvre, who was sent over here by the French King at the request of our English one at the time the Royal Society was established, pointed out that chemistry was the art of separations as well as of transmutations—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 continuity, 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 "simplifications," 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.
