385 
eight out of fifty examined, those of sodium and iron in a 
considerable number, but others are absent. It is perhaps 
too soon to say that the elementary bodies of which these 
suns are composed are different from those we know ; but 
at any rate, we may be sure that the proportions’ must 
differ widely from those in our sun. The results of the ex- 
amination of certain nebulae are even more remarkable; they 
prove to consist of incandescent gases, not of a light-giving 
sphere, surrounded by vapour, as in the other cases. ° This has 
been assumed by some to prove that they are future worlds 
still in a nebulous condition; owing to the dimness of their 
light, it is impossible to speak with certainty of the absence of 
elements ; but so far it is remarkable, that gaseous matter only 
has been shown to be present ; and, as far as chemistry can 
show, no condensation could develop the solid substance of the 
world from these few elementary gases. 
8. These differences of composition among the different 
systems of the heavens are most interesting, carrying us back 
for their origin to the very foundation of the worlds, to that 
first beginning of things when the vast systems round us took 
their form ; and even then we see that no mere chance ruled, 
but that we must look for a cause sufficient to explain these 
diversities of composition. We may go a step further still, 
and ask, “ W hat is the cause of those different forms of matter 
which we call elements?” It is well not to be too certain in 
scientific questions; some day we may fulfil the dreams of the 
alchymists, and transmute one element into another; but if 
that day does come, we shall have to relearn the first prin- 
ciples of chemistry, and perhaps most of our other sciences too; 
and till then Ave may assume that there are about sixty-four 
elementary bodies. We are so used to take this for granted, 
that we do not consider how totally unable we are to explain 
it. All our knowledge of the forces of nature is entirely at 
fault here; yet, till we can give an explanation of this first of our 
problems, we cannot boast of a complete knowledge of creation. 
9. The recent investigations showing that motion, light, 
heat, electricity, magnetism, are mutually interchangeable, 
make this essential diversity of the matter on which they act 
still more remarkable; audit is contrary to all a priori con- 
ceptions that it should be so ; we can much more easily conceive 
of matter as one, and the forces as many ; than of matter as 
various, and the force as one. Even if it should be that all 
these elements arc but forms of one matter, the extraordinary 
