184 
the lightest substance in nature,, was at once chosen by Dalton 
as the unit in his scale of atomic weights, and the weights in 
the atoms of other elements were established by ascertaining 
directly or indirectly the respective quantities of those 
elements .which unite either with one part of hydrogen or 
with the quantity of some other element which unites with 
one part of hydrogen. 
51. The founder of the doctrine which I have sought to 
explain might, if he had lived to this day, have boasted, with 
more probable truth than the Koman poet, that he had erected 
a monument which even the ravages of time could not 
destroy.* But his was the simplicity of the true philosopher, 
as was specially appreciated by the French savants when they 
welcomed him to their capital. I am struck, in reading over 
my notes of an early meeting of the British Association 
(in 1831), with the absence of self-assertion shown by 
Dalton. I do not find that he took any notice of the half 
atoms talked about by some inferior men. 
52. As a disciple of Dalton, I claim (on his behalf) that his 
views of matter are consistent with common sense and with 
revealed religion. On the other hand, I have proved, beyond 
contradiction, that Professor Tyndall’s views are consistent 
with neither. 
53. On recurring to these notes, I find that a certain 
chemist of less note contended for one-third atoms against 
Dalton. This seemed to me at the time so absurd that 1 kept 
no record of the discussion, except that of “ ultimate atoms 
minimised — the word atom being derived from two Greek 
words which imply that which cannot he divided or cut asunder 
(a, not; rljivo), I cut).t I do not say there are not even now 
some worthy successors to the individual alluded to above, 
who dislike the atomic theory because it interferes with 
their mystical notions ; but to show that modern chemistry 
has been built up altogether in connexion with the theory 
of atoms, J I will refer to the appropriately-coined word, 
Atomicity. 
54. This term is invented to express the combining capacity 
of an element. The atomicity of hydrogen, as exhibited in 
* “ Exegi monumentum sere perennius,” &c.— -Horace, Ode xxx. 
t Ure’s Diet, suh voce. 
| Foreshadowed by Lucretius 
“ Nam si primordia rerum 
Commutari aliqua possent ratione revicta 
Incertum quoque jam constet, quid possit oriri 
Quid ncqueat. 
