Chemistry and Physics. 271 
siderations we may always start from the constitution of atoms, and avail 
ourselves of the simplified expression thus obtained, that is to say, of the 
eng that the atomic hypothesis itself is true 
gots, even now assert that the published results, and especially the 
| : i d possess no vantage 
ule given for the elements and compounds, They contain, like 
For the elements, Brodie, as is well known, comes to the conclusion 
that there exist three groups, expressible by the symbols— 
a y’ at+y’. ee 
__ All elements belonging to the third group pats bromine, iodine, 
nitroge: 
n, etc.) are regarded as compounds. They are not, indeed, sup- 
ae ated spection, ss 
Even admitting at the outset that Brodie’s speculation i fan re 
that it leads to hypotheses of most astoundi charset 392 on 
ination we are inevitably led to the conclusion that the entire 
