2Q2 The Chemistry of the Future. [July* 
conditions have disappeared ; certain others have maintained 
themselves, indeed, but only on a limited scale ; whilst a 
third class are abundant because circumstances have been 
favourable to their formation and preservation. The analogy, 
it must be remembered, is not the closest, and must not be 
pushed too far. There is of necessity a wide difference be- 
tween species composed of lifeless beings, incapable of 
growth, reproduction, and decay, and species consisting of 
living organisms. From the nature of the case there can- 
not occur in the “ elements ” any distinction corresponding 
to that between living and fossil organic forms. The “ stone 
book ” tells us nothing of extinCt elements. Nor would we 
for a moment suggest that any of our present elements, 
however rare, is disappearing ; that any new element is in 
the course of formation ; or that the properties of such as 
exist are in course of modification. All such changes, in as 
far as they took place at all, must have been confined to the 
pre-geological epoch — to the time when our earth, or rather 
the matter of which it consists, was in a state very different 
from its present condition. Making, however, every allow- 
ance for these distinctions, if evolution is the law of the 
universe manifested in the heavenly bodies, in organic indi- 
viduals, and in organic species, we shall probably recognise 
it also — though under an especial aspeCt — in those elements 
from which stars and organisms are, in the last resort, 
compounded. 
But where is the evidence that the elements have been 
formed by the “ expansion ” * of some few antecedent prin- 
ciples, at present hidden, or perhaps from one only primor- 
dial kind of matter ? Were our attention confined to our 
own planet we might perhaps find little either to verify or 
to confute our hypothesis. But if we institute a compara- 
tive examination of the chemical composition of different 
heavenly bodies, as revealed to us by the spectroscope, evi- 
dence will be found. Into its nature and value we will now 
proceed to enquire. 
On an examination of the speCtrum of our sun we recog- 
nise certain elementary bodies as decidedly present in his 
atmosphere. These are sodium, calcium, barium, magne- 
sium, iron, chrome, nickel, copper, zinc, hydrogen, alumi- 
nium, titanium, manganese, and possibly strontium, 
cadmium, and cobalt. The following terrestrial elements, 
however, appear to be absent : — Gold, silver, mercury, rubi- 
dium, tin, potassium, lead, antimony, arsenic, lithium, 
* See Quarterly Journal of Science, January, 1877, p. 26. 
