NATURE 
be referred with much probability to the particular way in which 
our earth developed into a member of our solar system. [f this 
be so it may be that on our earth only these blanks occur, and 
uot generally throughout the universe. 
\What comes after uranium? I should consider that there is 
little prospect of the existence of an element much lower than 
this. Look at the vertical line of temperature slowly sinking 
from the upper to the lower part of the curve ; the figures repre- 
senting the scale of atomic weights may be also supposed to 
represent, inversely, the scale of a gigantic pyrometer dipping 
into the cauldron where suns and worlds are in process of forma- 
tion. Our thermometer shows us that the heat has been sinking 
gradually, and, fari passu, the elements formed have increased 
in density and atomic weight. This cannot go on for an in- 
definite extent. Below the uranium point the temperature may 
be so reduced that some of the earlier formed elements which 
have the strongest affinities are able to enter into combination 
among themselves, and the result of the next fall in temperature 
will then be—instead of elements lower in the scale than uranium 
—the combination of oxygen with hydrogen, and the formation 
of those known compounds the dissociation of which is not beyond 
the powers of our terrestrial sources of heat. 
Let us now turn to the upper portion of the scheme. With 
hydrogen of atomic weight = 1, there is little room for other 
elements, save perhaps for hypothetical helium. But what if we 
get “through the looking-glass,” and cross the zero-line in search 
of new principles-—-what shall we find the other side of zero ? 
Dr. Carnelley asks for an element of negative atomic weight ; 
here is ample room and verge enough for a shadow series of such 
unsubstantialities. Helmholtz says that electricity is probably 
as atomic as matter :! is electricity one of the negative elements, 
and the luminiferous ether another? Matter, as we now know 
it, does not here exist; the forms of energy which are apparent 
in the motions of matter are as yet only latent possibilities. A 
substance of negative weight is not inconceivable. But can we 
form a clear conception of a body which combines with other 
bodies in proportions expressible by negative quantities ? 
A genesis of the elements such as is here sketched out would 
not be confined to our little solar system, but would probably 
follow the same general sequence of events in every centre of 
energy now visible as a star. 
Before the birth of atoms to gravitate towards one another, 
no pressure could be exercised ; but at the outskirts of the fire- 
mist sphere, within which all is fyo¢y/e—at the shell on which 
the tremendous forces involved in the birth of a chemical element 
exert full sway—the fierce heat would be accompanied by gravi- 
tation sufficient to keep the newly-born elements from flying off 
into space. As temperature increases expansion and molecular 
motion increase, m>lecules tend to fly asunder, and their chemi- 
cal affinities become deadened ; but the enormous pressure of 
the gravitation of the mass of atomic matter outside what I 
may for brevity call the birth-shell would counteract this action 
of heat. 
Beyond this birth-shell would be a space in which no chemical 
action could take place, owing to the temperature there being 
above what is called the dissociation point for compounds, In 
this space the lion and the lamb would lie down together ; phos- 
phorus and oxygen would mix without union; hydrogen and 
chlorine would show no tendency to closer bonds ; and even 
fluorine, that energetic gas which chemists have only isolated 
within the last month or two, would float about free and 
uncombined. 
Outside this space of free atomic matter would be another 
shell, in which the formed chemical elements would have cooled 
down to the combination-point, and the sequence of events so 
graphically described by Mr. Mattieu Williams in ‘* The Fuel of 
the Sun” would now take place, culminating in the solid earth 
and the commencement of geological time. 
And now I must draw to a close, having exhausted not indeed 
my subject, but the time I may reasonably occupy. We have 
glanced at the difficulty of defining an element ; we have noticed 
* “Tf we accept the hypothesis that the elementary substances are com- 
posed of atoms, we cannot avoid concluding that electricity also, positive as 
well as negative, is divided into definite elementary portions, which behave 
like atoms of electricity.".—HrtMHoLTz, Faraday Lecture, 1881. 
2 “] can easily conceive that there are plenty of bodies about us not 
subject to this intermutual action, and therefore not subject to the law 
of gravitation.”’—Sir GreorGE Arry, “ Faraday’s Life and Letters,” vol. ii. 
D. 254+ 
too the revolt of many leading physicists and chemists against 
the ordinary acceptation of the term element. We have weighed 
the improbability of their eternal self-existence, or their origina- 
tion by chance. Asa remaining alternative we have suggested 
their origin by a process of evolution like that of the heavenly 
bodies according to Laplace, and the plants and animals of our 
globe according to Lamarck, Darwin, and Wallace. In the 
general array of the elements, as known to us, we have 
seen a striking approximation to that of the organic world. 
In lack of direct evidence of the decomposition of any 
element, we have sought and found indirect evidence. 
have taken into consideration the light thrown on this sub- 
ject by Prout’s law, and by the researches of Mr. Lockyer in 
solar spectroscopy. We have reviewed the very important 
evidence drawn from the distribution and collocation of the 
elements in the crust of our earth. We have studied Dr. 
Carnelley’s weighty argument in favour of the compound nature 
of the so-called elements from their analogy to the compound 
radicals, We have next glanced at the view of the genesis of 
the elements ; and, lastly, we have reviewed a scheme of their 
origin suggested by Prof. Reynolds’s method of illustrating the 
periodic classification. 
Summing up all the above considerations we cannot, indeed, 
venture to assert positively that our so-called elements have been 
evolved from one primordial matter ; but we may contend that 
the balance of evidence, I think, fairly weighs in favour of this 
speculation. 
This, then, is the intricate question which I have striven to 
unfold before you, a question that I especially commend to the 
young generation of chemists, not only as the most interesting, 
but the most profoundly important, in the entire compass of our 
science. 
I say deliberately and advisedly the most interesting. ‘The 
doctrine of evolution, as you well know, has thrown a new light 
upon and given a new impetus to every department of biology, 
leading us, may we not hope, to anticipate a corresponding 
wakening light in the domain of chemistry ? 
I would ask investigators not necessarily either to accept or to 
reject the hypothesis of chemical evolution, but to treat it as a 
provisional hypothesis ; to keep it in view in their researches, 
to inquire how far it lends itself to the interpretation of the 
phenomena observed, and to test experimentally every line of 
thought which points in this direction. Of the difficulties of this 
investigation none can be more fully aware than myself. I sin- 
cerely hope that this my imperfect attempt may lead some minds 
to enter upon the study of this fundamental chemical question, 
and to examine closely and in detail what I, as if amidst the 
clouds and mists of a far distance, have striven to point out. 
NOTES 
A ReEUTER’s telegram dated Grenada, August 29, states that 
during the solar eclipse of that morning good photometric obser- 
vations were made by Prof. Thorpe. The light during the 
middle of totality was less than from the full moon. We 
learn from later telegrams dated Grenada, August 31, that the 
eclipse of the sun has been well observed by the British Astro- 
nomical Expedition, and that in the observations taken it was 
noticed that the corona extended nearly two diameters from the 
sun, and exhibited a feathery structure at the poles. Good 
photographs have been obtained of the coronal spectrum in the 
blue end. The spectrum was similar to that of the eclipse of 
1883, observed on the Caroline Islands. 
THE celebrations connected with the Chevreul centenary took 
place in Paris on Tuesday last. The first demonstration was 
that of the National Society of Agriculture, to which M. 
Chevreul was elected member forty-six years ago, and of which 
he is elected President every alternate year. A commemoration 
medal was struck by the same Society. At three o'clock 
M. Chevreul received the congratulations of the members of the 
Academy of Sciences. The principal ceremony of the day was 
the unveiling of the statue of M. Chevreul in the hall of the new 
Museum at the Jardin des Plantes. The walls of the room, 
which are of vast dimensions, were hung with red velvet, and 
[ Sept. 2, 1886 
We 
sent 
