28 On Residual Phenomena. [January, 
The difference between these figures and a whole number, 
or the fraction 0*5, is therefore — 
Oxygen 
0*0 
Silver 
0*1 
Nitrogen 
0*0 
Bromine 
0*1 
Chlorine 
0*1 
Iodine 
0*0 
Lithium 
0*1 
Potassium ... 
0*2 
Sodium 
0*2 
Or an average of 0*0888, whilst according to the atomic 
weights as determined by Stas, the margin is only 0*0688. 
The divergence, according to the older atomic weights, 
reached the first decimal place in six out of the nine in- 
stances, whilst in the numbers of Stas we find this occur in 
three cases only. Thus far, therefore, the labours of the 
illustrious Belgian chemist are more favourable to Prout’s 
hypothesis than might appear at first glance. An eminent 
authority also calls attention to the fadf that “ the smallest 
atomic weights, which, as a general rule, are those of the 
best known and most easily estimated elements, accord the 
most precisely with Prout’s law.” Thus in addition to the 
instances of oxygen, nitrogen, lithium, and sodium, we have 
carbon, whose atomic weight has been re-determined by 
Dumas and Stas as 6*o and by Liebig as 6*oo8, and sulphur, 
which Stas has investigated along with the above-mentioned 
nine elements, and which — taking oxygen as 15*960 — he 
finds to be 31*976, showing a divergence from the calculated 
cipher of 0*024. According to the old notation, oxygen 
being — 
W9!° = 7 - 9 8o, 
2 
sulphur would be— 
SW 76 = 15-983, 
2 
the difference from the whole number being then merely 
0*017. 
If, then, we take these eleven elements, — viz., oxygen, 
silver, nitrogen, bromine, chlorine, iodine, lithium, potassium, 
sodium, carbon, and sulphur, and fix our attention on the 
first decimal place, we shall find it scarcely what might have 
been expected if we had to deal with a set of distinct entities 
