274 SCIENCE. 
section B, physics, Ernest Merritt, Cornell University ; 
section C, chemistry, James Lewis Howe, Washing- 
ton and Lee University ; section D, mechanical science 
and engineering, J. A. Brashear, of Pittsburg, Pa. ; 
section E, geology and geography, J. F. Kemp, 
Columbia University ; section F,zoology, C. B. Dav- 
enport, Harvard University; section G, botany, 
W. Trelease, Missouri Botanical Garden; section 
H, anthropology, A. W. Butler, of Indianapolis ; sec- 
tion I, economic science and statistics, C. M. Wood- 
ward, Washington University. 
Permanent Secretary —L. O. Howard, United States 
Entomologist, of Washington. 
General Secretary—Charles Baskerville, the Univer- 
sity of North Carolina. 
Secretary of the Councii—William Hallock, Co- 
lumbia University. 
Secretaries of Sections—Section A, W. M. Strong; 
Yale University ; section B, R. A. Fessenden, of 
Allegheny, Pa.; section C, A. A. Noyes, Massa- 
chusetts Institute of Technology ; section D, W. T. 
Magruder, Ohio State University ; section E, J. A. 
Holmes, University of North Carolina ; section F, C. 
H. Eigenmann, University of Indiana ; section G, D. 
T. Macdougal, New York Botanical Garden ; section 
H, Frank Russell, Harvard University ; section I, 
H. T. Newcombe, of Washington. 
Treasurer—R. S. Woodward, Columbia Univer- 
sity. 
FREDERICK BEDELL, 
General Secretary. 
THE DEFINITION OF THE ELEMENT.* 
Ir is with hesitation that I enter upon so 
speculative a discussion as the nature of 
the elements, and yet there are reasons 
why it should prove of great profit to draw 
the attention of this representative gather- 
ing of the chemists of America to this sub- 
ject. We have nearly reached the close of 
the first century in which these elements 
have been the subject of experimental re- 
search. The ingenuity and the patient 
labor of an army of workers have been 
directed at the solution of the many prob- 
lems connected with these elementary sub- 
* Address of the Vice-President before Section C— 
Chemistry—of the American Association for the Ad- 
vancement of Science, at the Columbus meeting, 
August, 1899. 
[N. 8S. Vou. X. No. 244. 
stances, and the ultimate aim, the goal, of 
all their striving has been the discovery of 
the properties and the nature of the atom. 
It is eminently fitting that, as we stand 
at the threshold of the new century, we 
glance back along the road we have already 
come and take some account of the progress 
we have made. The quicksands of mere 
speculation must be avoided, and yet the 
mental vision, the ‘ scientific imagination,’ 
must be called into service in considering 
that which so far transcends our cruder 
actual vision as the incomparable atom 
itself. There is another reason for consid- 
ering the nature of the elements. At sev- 
eral times during the century a wider vis- 
ion has made it necessary to recast the 
definition of the elements to accord with 
increasing knowledge. It would seem as if 
another such period of change were ap- 
proaching. There may be need of a truer 
definition, and how shall this be realized or 
the new definition properly fitted unless the 
knowledge gained be summed up and ap- 
preciated ? 
The conception of an element among the 
Greek philosophers and the earlier alchem- 
ists was very different from the modern 
idea. This conception sprang from the 
theories as to the formation of the material 
universe. The elements were the primal 
forms of matter seen only combined, im- 
pure, imperfect. They were the essences 
or principles out of which all things were 
evolved. In the four-element theory, 
which was so widely spread among the 
ancients, the fire, air, earth and water were 
not the ordinary substances known under 
these names, but the pure essences bestow- 
ing upon fire and water their peculiar 
properties. These essences were not thought 
of as actual substances capable of a sepa- 
rate material existence, and gradually the 
belief that a transmutation was possible 
between them sprang up. Thus they them- 
selves might be derived from some one of 
