402 
NATURE 
[ FEBRUARY 25, 1904 
Prof. Hann shows further that the probabilities of 
positive temperature variations at Greenwich and negative 
pressure variations at Stykkisholm, and vice versd, are 0 83 
and 085 respectively. In the case of the Azores he shows 
that a similar reversal with Stykkisholm occurs. Interest- 
ing results are also obtained when he considers the new 
station at Angmagsalik, in Greenland. 
THE AMERICAN ASSOCIATION. 
THE annual meeting of the American Association for the 
Advancement of Science was held at St. Louis on 
December 26, 1903, to January 1. The address delivered 
by the president of the association, Prof. Ira Remsen, 
appeared in Nature of January 28; and extracts from the 
addresses of presidents of some of the sections are given 
below. 
ATOMS AND ELEMENTS.’ 
Is matter continuous or discrete? argued the opposed 
schools of Grecian philosophy led by Leucippus, Democritus 
and Epicurus, and dominated by Aristotle. Despite the 
clarity of the statements of the Roman Lucretius,? the 
atomic hypothesis received scant attention until the seven- 
teenth century of the Christian era, when Galileo’s experi- 
mental science assailed Aristotelian metaphysics and 
demanded verification of the premises of that philosophy 
which had governed all the schools of Europe for two 
thousand years.* While Gassendi, Boyle, Descartes, New- 
ton, perhaps Boscovich, Lavoisier, Swedeborg, Richter, 
Fischer and Higgins had to do with our modern atomic 
theory, Dalton one hundred years ago “‘ created a working 
tool of extraordinary power and usefulness.’ in the laws of 
definite and multiple proportions. As Clarke* remarked, 
“Between the atom of Lucretius and the Daltonian atom 
the kinship is very remote.’’ Although the lineage is direct, 
the work of Berzelius, Gmelin and others: the laws of 
Faraday, Gay Lussac, Avogadro, Dulong and Petit; the 
reformations of Laurent and Gerhardt, but particularly 
Cannizzaro; the systematisations of de Chancourtois, New- 
lands, Hinrichs, Mendeléeff and Lothar Meyer; the stereo- 
chemistry of van ’t Hoff and Le Bel have imperialised the 
ideas of the Manchester philosopher, so that the conceptions 
of the conservative atomists of to-day are quite different 
from those at the beginning of the closed century.° 
The Daltonian ideas had scarcely reached adolescence 
before Prout (1815), giving heed to the figures concerned, 
would have all the elements compounded of hydrogen. The 
classical atomic mass values obtained by sympathetic Stas 
and the numerous investigations of those who followed him, 
with all the refinements human ingenuity has been able to 
devise, temporarily silenced such speculations, but not until 
Marignac had halved the unit, Dumas had quartered it, 
and Zangerle, as late as 1882, insisted upon the one 
thousandth hydrogen atom. 
The notion, like Banquo’s ghost, will ever up, for if one 
may judge from the probability calculations of Mallet (Phil. 
Trans., clxxi., 1003, 1881) and Strutt (Phil. Mag., (6), i., 
311), a profound truth underlies the now crude hypothesis. 
Crookes (Chem. News, lv., 83, 1886), from observations 
made during prolonged and painstaking fractionations of 
certain of the rare earths, supported his previously 
announced *‘ provisional hypothesis ’’ as to the genesis of 
the elements from a hypothetical protyle, which existed when 
the universe was without form and void. He designated 
those intermediate entities, like yttrium, gadolinium and 
1 Abridged from an address delivered before the Section of Chemistry 
of the American Association by Prof. C. Baskerville. 
2 ‘* Nature reserving these as seeds of things 
Permits in them no minish nor decay ; 
They can't be fewer and they can’t be less.” 
Again, of compounds— 
“* Decay of some leaves others ree to grow 
And thus the sum of things rests unimpaired.” 
; ip « Book ii., 79. 
3 See ‘“‘The Atomic ‘lheory,’’ the Wilde Lecture by F. W. Clarke at 
Dalton Celebration, May, 1903. 
4 Loc. cit. f 
5 While I have examined much of the original literature, Venable's 
“ History of the Periodic Law” has been most helpful. I have, further- 
more, had the privilege of reading very carefully the manuscript of a work 
entitled ‘‘ The Study of the Atom" (in press), by Dr. Venable. 
NO. 179I, VOL. 69| 
“cc 1 
didymium, meta-elements,’’* a species of compound! 
radicles, as it were. Urstoff, fire mist, protyle, the ultra-. 
gaseous form, the fourth state of matter (Crookes, Royal! 
Societies, June 10, 1880) was condensed by a_ process. 
analogous to cooling; in short, the elements were created 
The rate of the cooling and irregular condensation produced 
“the atavism of the elements,’’ and this caused the form- 
ation of the natural families of the periodic system. 
Marignac (Archives des Sciences Physiques et Naturelles, 
17-5; Chemical News, l|vi., 39), criticising this hypothesis, 
states :—‘‘ I have always admitted* the impossibility of 
accounting for the curious relations which are manifested 
between the atomic weights of the elements, except by the 
hypothesis of a general method of formation according to 
definite though unknown laws; even when these relations. 
have the character of general and absolute laws.’’ 
Further, “‘ I do not the less acknowledge that the effect of 
constant association of these elements is one of the strongest 
proofs that can be found of the community of their origin. 
Besides, it is not an isolated fact; we can find other ex- 
amples such as the habitual association in minerals of 
tantalum, niobium, and titanium.’’ 
The peculiar discharge from the negative electrodes of a 
vacuum tube was investigated many years ago by Hittorf 
and Crookes, who arrived at the conclusion that it was. 
composed of streams of charged particles. All are familiar 
with the very recent proposed ‘‘electrons’’ and “ cor— 
puscles '’ resulting from the beautiful physical researches. 
of Lodge and J. J. Thomson. These appear to have caused 
a trembling in the belief of many in the immutability of the- 
atom, and the complete abandonment of the atom is seriously 
discussed by others. 
Although by chemical means, so far, we have been unable . 
to break up the atoms, apparently electrical energy, in the 
form of kathode rays, for example, follows the grain of 
atomic structure. Some advanced thinkers look upon the 
atoms as disembodied charges of electricity. Ostwald has 
taught it. Electric charges are known only as united to 
matter, yet Johnstone Stoney and Larmor, have speculated 
on the properties of such charges isolated. ‘‘ Such a charge 
is inertia, even though attached to no matter, and the in- 
crease of inertia of a body due to electrification has been 
caleulated by both Thomson and Oliver Heaviside, the con- 
ception accordingly being advanced that all inertia is 
electrical, and that matter, as we know it, is built up of 
interlocked positive and negative electrons. If it were 
possible in any mass of matter to separate these electrons: 
then matter would disappear and there would remain merely 
two enormous charges of electricity.’’ We are aware of 
phenomena attributed to the negative electrons; we await 
anxiously the announcement of the positive electrons. 
We do know, however, as A. A. Noyes says, that “‘ there 
exists in the universe some thing or things other than matter 
which, by association with it, give rise to the changes in 
properties which bodies exhibit, and give them power of 
producing changes in the properties of other bodies.” 
Shall we say, as does Remsen, ‘* An element is a substance: 
made up of atoms of the same kind?’’ Can we say that 
it is not? Venable (the ‘* Definition of the Element,’’ Am. 
Chemist, 1875, 23) truly says: ‘*‘ An element is best defined’ 
by means of its properties.’’ These conceits are not ex- 
clusive. The properties are the result of the action of 
physical forces and chemical affinity, whatever that may be. 
Certain of the novel atmospheric gases have so far re- 
sponded but poorly to the latter, as predicted before their 
discovery by Flawitzsky, Julius Thomsen and de Boisbaudran: 
in 1887. 
The following simpler definition has finally served as my 
guide: An element is that which has not been decomposed,. 
so fay as we are aware, into anything other than itself. Im 
short, it is consistent. 
We have decided to define an element by its properties. 
The alterations produced in the properties of the most 
characteristic elements by the presence of small amounts of 
foreign substances are evident in steel. The influence of 
arsenic upon the conductivity of copper is well known, and 
Le Bon (Compt. rend., cxxxi., 706, 1900) has recently shown 
1 Address before Chemical Section of the British Association, Chee 
News, liv., 117, 1885. 
2 Remarks made in 1860-5 after publication of Stas's ‘‘ Researches om 
Atomic Weights,” Archives, ix., 102, 24-376. 
