56 The Discovery of the Atomic Theory. 
vestigation. And accordingly Mr. Higgins, in his work printed in 
the year 1790, gave that theory to the world, ten years, at least, 
before either Mr, Dalton or his learned panegyrist even pub- 
lished a hint of such a doctrine. That work which Mr. Higgins 
styled 4 comparative View of the Phlogistic and Autiphiogistic 
Theories, and which Dr. Thomson calls (and I think disingenu~ 
ously) a work upon Phlopiston, was very generally read, and is 
now to be found in the library of every scientific society and in- 
dividual, with that date for its publication prefixed to it. 
Reference to dates establishes priority; and reference to the 
works of Mr. Higgins and Mr. Dalton will fully establish this, 
that Mr. Higgins left the atomic theory fully as perfect as Mr. 
Dalton ; and | would with confidence cail upon the most zealous 
advocate of the latter gentleman, to show in his work any one 
position, or principle, which is not founded upon, or deducible 
from, the doctrine first discovered and established by Mr, Higgins. 
Dr. Thomson in the note alluded to asserts, that “‘ when Mr. 
Higgins wrote, metallic oxides were so litile known, and so few 
exact analyses existed, that it was impossible to be acquainted 
wiih the grand fact, that oxygen, &c. always unites in deter- 
minate proportions which are multiples of the minimum pro- 
portion.” ‘To set the Dector right on that head, I will beg 
leave to refer him and the reader again to the Comparative View, 
page 295 &c. where they will find that treated of which the 
Doctor asserts to be then unknown; and what he calls the grand 
fact, will be found to be the greatest leading principle which 
Mr. Higgins endeavours to establish in that work, particularly in 
that part where the molecules of different acids are represented 
by diagrams, with their respective number of particles of oxygen 
and bases ; and it was that which first gave a clear idea of definite 
proportions. 
I apprehend the Doctor is not more fortunate in the assertion, 
*¢ that the utomic theory was taught by Bergman, Cullen, Black, 
Cc. gust as far as ly Higgins.” Now 1 have looked over 
. carefully the works of those chemists, and also an accurate ma- 
nuscript note or report of Black’s Lectures; and I affirm, there 
is not in any of them the slightest mention of the atomic theory, 
Indeed I must here remark, that the Doctor has not attempted 
to support any of his assertions by quotations : it was prudent net 
to make the attempt, he could not succeed. 
In contradiction to what the Doctor says, ‘* MZr. Dalton first 
generalised the doctrine, and thought of the weight of atoms of 
bodies,’ 1 need only refer the reader to. Mr. Higgins’s work, 
pages 15, 37, and particularly to pages 0 and 81. As to that 
remark of the Doctor’s with which he closes his note, that “ the 
doctrine would be started Ly others if Dalton had missed it,” 1 
must 
