harles Darwin freely
admitted after his own efforts had made the doctrine famous.

ISOTHERMS AND OCEAN CURRENTS

The very next year after Dr. Wells's paper was published there appeared
in France the third volume of the Memoires de Physique et de Chimie de
la Societe d'Arcueil, and a new epoch in meteorology was inaugurated.
The society in question was numerically an inconsequential band, listing
only a dozen members; but every name was a famous one: Arago, Berard,
Berthollet, Biot, Chaptal, De Candolle, Dulong, Gay-Lussac, Humboldt,
Laplace, Poisson, and Thenard--rare spirits every one. Little danger
that the memoirs of such a band would be relegated to the dusty shelves
where most proceedings of societies belong--no milk-for-babes fare would
be served to such a company.

The particular paper which here interests us closes this third and
last volume of memoirs. It is entitled "Des Lignes Isothermes et de
la Distribution de la Chaleursurle Globe." The author is Alexander
Humboldt. Needless to say, the topic is handled in a masterly
manner. The distribution of heat on the surface of the globe, on the
mountain-sides, in the interior of the earth; the causes that regulate
such distribution; the climatic results--these are the topics discussed.
But what gives epochal character to the paper is the introduction of
those isothermal lines circling the earth in irregular course, joining
together places having the same mean annual temperature, and thus laying
the foundation for a science of comparative climatology.

It is true the attempt to study climates comparatively was not new.
Mairan had attempted it in those papers in which he developed his
bizarre ideas as to central emanations of heat. Euler had brought
his profound mathematical genius to bear on the topic, evolving the
"extraordinary conclusion that under the equator at midnight the
cold ought to be more rigorous than at the poles in winter." And
in particular Richard Kirwan, the English chemist, had combined the
mathematical and the empirical methods and calculated temperatures for
all latitudes. But Humboldt differs from all these predecessors in that
he grasps the idea that the basis of all such computations should be
not theory, but fact. He drew his isothermal lines not where some occult
calculation would locate them on an ideal globe, but where practical
tests with the thermometer locate them on our globe as it is. London,
for example, lies in the same latitu