The times., 1900-12-30

| gas, and with the two acids of carbon
| carbonic oxide, carbonic ''acid," he re
| garded the former as compound of on,
| atom of carbon and one of hydrogen anC
the second as a compound of one atom Of
! carbon and two of hydrogen, and similarly
| for the two oxides of carbon. Knowing
| the relative weights in which these ele
ments enter into combination, we can de
duce the relative weights Of the atoms
| Placing the relative weight of an atom ot
hydrogen equal TO unity, we have:
Ole Car Car
| Marsh fant benic bon
Gas. Gas. Oxide. Acid
Carbon ..... Carbon 49,. 5 6
Hydrogen -. / 2 Oxygen 80 10
Thus the first compound, marsh gas
was regarded by Dalton as composed of an
| atom of carbon in union with an atom OF
| hydrogen; or to reproduce his symbols, as
Q O.; while the second, olefiant gas on
| this hypothesis, was compound of two
| atoms of hydrogen with one of carbon, or
Q O @. Similarly the symbols @ O., and
Q @ Q were given to the two compounds
of carbon with oxygen. So water was as
signed the symbol Q o. for Dalton i'm
agined 1t to be a compound of one atom
of hydrogen with one of oxygen. Com
pounds containing only two atoms were
termed by him binary" those containing
three, "ternary;" four, "quaternary," and
so on. The weight of an atom of oxygen
was eight times that of an atom of hydro
gen; while that of an atom of carbon was
six times as great as the unit. BY assign
ing symbols to the elements, consisting of
pf hair ma Of . I,a
first two letters. formulas were developed,
indicating the composition of the COM
pound, the atomic weights of the elements
being assured. Thus, Ma o signified a
compound of an atom of sodium (natrium)
weighing % times as much as a similar
atom of hydrogen. with an atom of oxy-
gen, possessing eight times the weight of
an atom of hydrogen. Therefore 81 pounds
of soda should consist of % pounds of So
dunn in combination with eight pounds of
oxygen, for, according to Dalton, each
smallest particle of soda contains an atom
of each element, and the proportion is not
changed, however many particles be con-
sidered.
/: has been pointed out by Judge StaIlo,
of Philadelphia, in his Concepts of Phys
Dalton is no explanation; that a fact of
nature, as for example, the fact of simple
and multiple proportions, is not explained
by being minified. Allowing the general
truth of this statement, 1t is nevertheless
undoubted that chemistry owes much to
Dalton's hypothesis; a lucky guess at first
1t represents one Of the fundamental truths
of nature, although its form must be
somewhat modified from that N which
Dalton conceived it. Daltons work was
first expounded by Thomas Thomson, pro-
fessor at Glasgow, in his System of
Chemistry" published in 1905, and subse-
quently in Daltons own New System of
Chemical Philosophy" the three volumes
of which were published in 1868, in 1910.
and in 1927.
The determination of these constants
of nature" was at once followed out by
many chemists; Thomson among the first.
But chief among the chemists who have
pursued this branch of work was Jacob
Berzelius. Swede, who devoted his long
life Q7791S4S) to the manufacture of COM
and to the determination of their
composition, or as it is still termed, the
of the atomic weights
more correctly, "equivalents"-o the ele-
ments of which they are composed. 1t is
to him that we owe most of our analytical
few, If any, accurate analyses. Although
Lavoisier had devised method for the
analysis of compounds of carbon, viz, by
burning the organic compounds in an at
mosphere of oxygen contained IN a bell
jar over mercury, and measuring the vol-
ume of carbon dioxide produced, as well
as that of the residual oxygen, Berzelus
achieved the same results more accurate
ly and more expeditiously by heating the
mixed with chlorate of po-
tassium and sodium chloride, and then es-
timating the hydrogen as well as the car
bon; this process was afterward perfected
by Liebig. Berzelius, however, was able
TO show that compounds of carbon, like
those of other elements, were instances of
in constant and in multiple
In 1915 two papers were published in the
annals of Philosophy" by DR.. Prout,
which have had much influence on the
progress of chemistry They dealt with
the figures which were being obtained by
Thomson, Berzelius, and others, at that
time supposed to represent the atomic
weights" of the elements. Prout's hypo-
thesis, based on only a few numbers, was
that the atomic weights of all elements
were multiples of that of hydrogen, taken
as unity. There was much dispute regard
ing this assertion at the time. but as II
was contradicted by Berzelius' numbers,
the balance of opinion was against 1t. But |
about the year 1910 Dumas discovered an
error in the number q212) given by Ber- |
zeliUs as the atomic weight of carbon: and |
with his collaboration, Stas, undertook the |
of the atomic weights of |
he commOner elements, for example, car |
BON, oxygen, chlorine, and calcium. This |
Inc of research was subsequently pursued |
alone by Stas, whose name will always be |
for the precision and accu- |
-acy of his experiments. At first Dumas |
md Stas inclined to the view that Prout's |
hypothesis was just one, but it was COM
1letely disproved by Stas' subsequent |
work, as well as by that of numerous |
)ther observers. 1t is nevertheless Gu
ious that much larger proportion of the
ltomic weights approximate to whole
numbers than would be foretold by the
doctrine of chances, and perhaps the last
las not been heard of Prout's hypothesis,
In its original crude form 1t is
10 longer worthy OF credence
One Of the most noteworthy Of the dis.