A HISTORY OF SCIENCE

BOOK II

THE BEGINNINGS OF MODERN SCIENCE

The studies of the present book cover the progress of science
from the close of the Roman period in the fifth century A.D. to
about the middle of the eighteenth century. In tracing the course
of events through so long a period, a difficulty becomes
prominent which everywhere besets the historian in less degree--a
difficulty due to the conflict between the strictly chronological
and the topical method of treatment. We must hold as closely as
possible to the actual sequence of events, since, as already
pointed out, one discovery leads on to another. But, on the other
hand, progressive steps are taken contemporaneously in the
various fields of science, and if we were to attempt to introduce
these in strict chronological order we should lose all sense of
topical continuity.

Our method has been to adopt a compromise, following the course
of a single science in each great epoch to a convenient
stopping-point, and then turning back to bring forward the story
of another science. Thus, for example, we tell the story of
Copernicus and Galileo, bringing the record of cosmical and
mechanical progress down to about the middle of the seventeenth
century, before turning back to take up the physiological
progress of the fifteenth and sixteenth centuries. Once the
latter stream is entered, however, we follow it without