THE CHEMICAL ELEMENTS—RAMBAY. 185 
lime, barytes, strontia, and magnesia. Some years later Scheele’s 
dephlogisticated marine acid, obtained by heating pyrolusite with 
spirit of salt, was identified by Davy as in all likelihood elementary. 
His words are: ‘‘All the conclusions which I have ventured to make 
respecting the undecompounded nature of oxymuriatic gas are, I 
conceive, entirely confirmed by these new facts. * * * It has 
been judged most proper to suggest a name founded upon one of its 
obvious and characteristic properties, its color, and to call it chlo- 
rine.” The subsequent discovery of iodine by Courtois in 1812 and 
of bromine by Balard in 1826 led to the inevitable conclusion that 
fluorine, if isolated, should resemble the other halogens in propreties, 
and much later, in the able hands of Moissan, this was shown to be 
true. 
The modern conception of the elements was much strengthened by 
Dalton’s revival of the Greek hypothesis of the atomic constitution 
of matter and the assigning to each atom a definite weight. This 
momentous step for the progress of chemistry was taken in 1803; the 
first account of the theory was given to the public with Dalton’s 
consent in the third edition of Thomas Thomson’s System of Chem- 
istry in 1807; it was subsequently elaborated in the first volume of 
Dalton’s own System of Chemical Philosophy, published in 1808. 
The notion that compounds consisted of aggregations of atoms of 
elements united in definite or multiple proportions familiarized the 
world with the conception of elements as the bricks of which the 
universe is built. Yet the more daring spirits of that day were not 
without hope that the elements themselves might prove decompos- 
able. Davy, indeed, went so far as to write in 1811: “‘It is the duty 
of the chemist to be bold in pursuit; he must recollect how contrary 
knowledge is to what appears to be experience. * * * To inquire 
whether the elements be capable of being composed and decomposed 
is a grand object of true philosophy.” And Faraday, his great pupil 
and successor, at a later date, 1815, was not behind Davy in his aspira- 
tions when he wrote: ‘‘To decompose the metals, to re-form them, 
and to realize the once absurd notion of transformation—these are 
the problems now given to the chemist for solution.”’ 
Indeed, the ancient idea of the unitary nature of matter was in 
those days held to be highly probable. For attempts were soon 
made to demonstrate that the atomic weights were themselves mul- 
tiples of that of one of the elements. At first the suggestion was 
that oxygen was the common basis; and later, when this supposition 
turned out to be untenable, the claims of hydrogen were brought 
forward by Prout. The hypothesis was revived in 1842 when Liebig 
and Redtenbacher, and subsequently Dumas carried out a revision 
of the atomic weights of some of the commoner elements and showed 
that Berzelius was in error in attributing to carbon the atomic 
