180 
(rightly or wrongly) as independent of the faculty which it 
possesses of attracting one or more atoms of this last. 
Molecules. 
23. I have now to address myself to the attempted explanation 
of molecules, and I acknowledge to myself the difficulty, perhaps 
impossibility, of presenting to a non-chemical mind any exact 
idea of what is meant by this term. It has been well said that 
“ in the least grain of dust, which appears to us inert, there 
exists an assemblage of vibrating atoms of magnificent arrange- 
ment, placed in lines, with a fabulous precision amongst them- 
selves ; and in such great numbers, that the most lively imagina- 
tion is confounded.”* Let me, then, clearly explain that a 
molecule is an aggregation of chemical atoms . We cannot call 
it a compound atom, for this would be a contradiction in terms, 
but the aggregation must be understood to act in certain senses 
as a unit. , ,. 
24. In the gaseous state, the molecule of simple bodies is 
composed of many atoms of the same nature united together 
thus : the molecules of oxygen [a), of hydrogen (b), of chlorine 
( C ) and of azote [d), are composed of two atoms turning one 
round the other, absolutely as the stars which form double stars 
are understood to do, and by constraint of the same laws.! 
25. They may be represented thus : 
abed 
Their oscillation round each other may be figured thus 
* Monde des Atomes, avant-propos, X. 
f Monde des Atomes , p. 24. 
