research of the last fifty years had thrown on the subject of the
Daltonian atoms, in the three-fold aspect of their size,
indivisibility, and mutual relationships, and their motions.


SIZE OF THE ATOM.

As to the size of the atom, Loschmidt, of Vienna, had come to the
conclusion that the diameter of an atom of oxygen or nitrogen was the
ten-millionth part of a centimeter. With the highest known magnifying
power we could distinguish the forty-thousandth part of a centimeter.
If, now, we imagine a cubic box each of whose sides had this length,
such a box, when filled with air, would contain from sixty to a
hundred millions of atoms of oxygen and nitrogen. As to the
indivisibility of the atom, the space of fifty years had completely
changed the face of the inquiry. Not only had the number of distinct,
well-established elementary bodies increased from fifty-three in 1837
to seventy in 1887, but the properties of these elements had been
studied, and were now known with a degree of precision then undreamt
of. Had the atoms of our present elements been made to yield? To this
a negative answer must undoubtedly be given, for even the highest of
terrestrial temperatures, that of the electric spark, had failed to
shake any one of these atoms in two. This was shown by the results
with which spectrum analysis had enriched our knowledge. Terrestrial
analysis had failed to furnish favorable evidence; and, turning to the
chemistry of the stars, the spectra of the white, which were
presumably the hottest stars, furnished no direct evidence that a
decomposition of any terrestrial atom had taken place; indeed, we
learned that the hydrogen atom, as we know it here, can endure
unscathed the inconceivably fierce temperature of stars presumably