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molecular organization are immensely in advance of the theory 
of atoms propounded by John Dalton. 
When Tyndall, therefore, builds his doctrine of Pantheism 
on “ molecular force becoming structural,” he appears to the 
most part of his hearers to be crowning the edifice of well- 
established modern Science by an effort of scientific Imagina- 
tion quite in accordance with, if passing a little beyond, the 
boundaries of rigid Baconian induction. But I trust to show 
that this is all delusion. 
He begins with the doctrine advocated by Lucretius, which 
we have seen to be entirely mechanical. The poet’s atoms take 
their place side by side, like the letters in a book, and their 
combination (if such it may be termed) entirely resembles that 
of the combination of letters to form a word. 
This is not modern chemistry, nor is it, in any sense, con- 
nected with the doctrine of combination in definite proportions , 
from which (already laboured upon in measure by others) this 
great and profound thinker educed his theory of the Universe. 
To illustrate this by a comparison. Some one, in ages past, 
must have invented the merely mechanical mode of expressing 
numbers by the juxtaposition of units, thus representing ten 
1111111111 . 
This was an achievement quite beyond the mind of a monkey, 
but how poor, after all, compared with the decimal system. 
Every one sees that it was a discovery to express the same by 10, 
and that the whole system of modern arithmetic is founded on 
the latter, and not on the former. It is remarkable that when 
Dalton leaned to a mechanical view of combination, as in advo- 
cating the one atom to one atom constitution of water, he fought 
against the strongest elucidation of his own theory from the 
beautiful researches of Gay-Lussac on the combination of gases 
by volume. 
The doctrine of atomicity , in a somewhat similar manner, 
comes in to supplement without overthrowing the doctrine of 
affinity. 
I had the opportunity of meeting John Dalton at the 
assembly of the British Association at Edinburgh, in 1834, and 
find by my notes that he then contended against Dr. Thompson, 
who advocated the existence of one-third-parts of atoms. I cannot 
find in the “ Transactions” any mention of this discussion, and, 
therefore, give this simply as the record of my own impressions 
at the time. I was there with my father, who was with Dalton 
on the Committee of the Chemical Class, and contributed a 
paper on meteorology. 
I have little doubt that the discussion was connected with the 
then somewhat transitional state of chemistry. This science 
