The Science Book

72

A

t the end of the 17th
century, Isaac Newton set
down his laws of motion
and gravity, making science more
precise and mathematical than it
had ever been before. Scientists
in various fields identified the
underlying principles governing
the universe, and the various
branches of scientific enquiry
became increasingly specialized.

Fluid dynamics
In the 1720s, Stephen Hales,
an English curate, performed a
series of experiments with plants,
discovering root pressure—by
which sap rises through plants—
and inventing the pneumatic
trough, a laboratory apparatus
for collecting gases, which was
to prove useful for later work
identifying the components of air.

Daniel Bernoulli, the brightest in

a family of Swiss mathematicians,

formulated the Bernoulli principle—

that the pressure of a fluid falls

when it is moving. This allowed

him to measure blood pressure.

It is also the principle that allows

aircraft to fly.

In 1754, Scottish chemist

Joseph Black, who would later

formulate the theory of latent heat,

produced a remarkable doctoral

thesis about the decomposition

of calcium carbonate and the

generation of “fixed air,” or carbon

dioxide. This sparked a chain

reaction of chemical research and

discovery. In England, reclusive

genius Henry Cavendish isolated

hydrogen gas and demonstrated

that water is made of two parts of

hydrogen to one of oxygen. Dissident

minister Joseph Priestley isolated

oxygen and several other new

gases. Dutchman Jan Ingenhousz

picked up where Priestley left off

and showed how green plants give

off oxygen in sunlight and carbon

dioxide in the dark. Meanwhile, in

France, Antoine Lavoisier showed

that many elements, including

carbon, sulfur, and phosphorus,

burn by combining with oxygen

to form what we now call oxides,

thus debunking the theory that

combustible materials contain a

substance called phlogiston that

make them burn. (Unfortunately,

French revolutionaries would send

Lavoisier to the guillotine.)

In 1793, French chemist Joseph

Proust discovered that chemical

elements nearly always combine

in definite proportions. This was a

vital step toward figuring out the

formulae of simple compounds.

INTRODUCTION

1727

1735

1749

1754

1735

1738

1766

Georges-Louis Leclerc,

later the Comte de

Buffon, publishes

the first volume of

Histoire Naturelle.

Swedish botanist Carl

Linnaeus publishes

Systema Naturae, the

beginning of his

classification of

flora and fauna.

George Hadley explains

the behavior of the trade

winds in a short paper

that remains unknown

for decades.

American diplomat

and scientist Benjamin

Franklin publishes

a chart of the

Gulf Stream.

Daniel Bernoulli publishes

Hydrodynamica, which

lays the foundation for

the kinetic theory

of gases.

English clergyman

Stephen Hales

publishes Vegeta ble

Statick, demonstrating

root pressure.

Henry Cavendish

makes hydrogen, or

inflammable air, by

reacting zinc with acid.

Joseph Black’s

doctoral thesis on

carbonates is a

pioneering work in

quantitative

chemistry.

1770