dispute it unless he desired the reputation of an oddity inclined to
paradoxical ideas.

It is important, however, to remark that, under fallacious
metaphysical appearances, we are in reality using empty words
when we repeat the aphorism, "Nothing can be lost, nothing can be
created," and deduce from it the indestructibility of matter. This
indestructibility, in truth, is an experimental fact, and the
principle depends on experiment. It may even seem, at first sight,
more singular than not that the weight of a bodily system in a given
place, or the quotient of this weight by that of the standard
mass--that is to say, the mass of these bodies--remains invariable,
both when the temperature changes and when chemical reagents cause the
original materials to disappear and to be replaced by new ones. We may
certainly consider that in a chemical phenomenon annihilations and
creations of matter are really produced; but the experimental law
teaches us that there is compensation in certain respects.

The discovery of the radioactive bodies has, in some sort, rendered
popular the speculations of physicists on the phenomena of the
disaggregation of matter. We shall have to seek the exact meaning
which ought to be given to the experiments on the emanation of these
bodies, and to discover whether these experiments really imperil the
law of Lavoisier.

For some years different experimenters have also effected many very
precise measurements of the weight of divers bodies both before and
after chemical reactions between these bodies. Two highly experienced
and cautious physicists, Professors Landolt and Heydweiller, have not
hesitated to announce the sensational result that in certain