8 Atomic Theory. 
oxygen is just twice, or thrice, or four times that in the low- 
est, there being respectively just twice, or thrice, or four 
times as many atoms of oxygen. 
As Kepler and Newton have taught us how to weigh the 
sun and the planets, so, on the other hand, Dalton and his 
associates, who invented the theory before us, have taught us 
ow eigh the ultimate particles of matter. In the case 
» however, it is not absolute, but relative weights 
that we obtain—it is the ratios of these weights. Magni- 
as many 
particles in a given mass of copper as in another given mass 
When two elements form several different compounds, as oxy- 
gen and nitrogen, it is assumed that the lowest proportion 
consists of h element. 
This appears like a gratuitous assumption ; and resting ‘as it 
ple, and therefore accord best with the known operations of na- 
ture ; and the other is, that the weight of an atom comes out 
