INTRODUCTION

At 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, sulphur, 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 towards sorting out the formulae of simple compounds.

Earth sciences

At the other end of the scale, understanding of Earth processes was making great advances. In the Americas, Benjamin Franklin, in addition to performing a dangerous experiment to prove that lightning is a form of electricity, demonstrated the existence of large-scale ocean currents with his investigations of the Gulf Stream. George Hadley, English lawyer and amateur meteorologist, published a short paper explaining the action of the trade winds in relation to the rotation of Earth, while Nevil Maskelyne seized on an idea from Newton and camped out for several months in dreadful weather to measure the gravitational attraction of a Scottish mountain. In doing so, he worked out the density of Earth. James Hutton became interested in geology after inheriting farmland in Scotland, and realized that Earth was a great deal older than anyone had previously thought.

Understanding life

As scientists learned of Earth’s extreme age, new ideas about how life originated and evolved began to emerge. Georges-Louis Leclerc, Comte de Buffon, a larger-than-life French author, naturalist, and mathematician, took the first steps towards a theory of evolution. German theologian Christian Sprengel spent much of his life studying the interaction of plants and insects, and noted that bisexual flowers produce male and female flowers at different times, so they cannot fertilize themselves. English parson Thomas Malthus turned his attention to demography and wrote An Essay on the Principle of Population, predicting catastrophe as the population grows. Malthus’s pessimism has proved unfounded (so far), but his idea that a population will grow to outstrip resources if left unchecked was later to have a profound influence on Charles Darwin.

  At the end of the century, Italian physicist Alessandro Volta opened up a new world by inventing the electric battery, which was to accelerate advances in the decades that followed. Such had been the progress through the 18th century that English philosopher William Whewell proposed the creation of a new profession distinct from that of philosopher: “We need very much a name to describe a cultivator of science in general. I should incline to call him a Scientist.”