THE 16-TH AND 17-TH CENTURIES

"At the beginning God created matter in
the form of hard, massy, impermeable,
moveable particles (...) And that primary
particles are so hard bodies that they
never wear and never crumble (...)"
- Isaac Newton

The time between the end of the 15-th century and the beginning of the 18-th century marked an epoch of great scientists, who worked over different problems and secrets of nature. The most important place among other sciences took physics, mathematics and astronomy. Scientists exercised earlier attainments, particularly the ones of the ancients. Among other problems scientists were interested in matter's constitution. They knew the works of Democritus and his attainments in atomistics. They tried to develop his knowledge to come to know world's microstructure.

Leonardo da Vinci, who lived in the years 1452-1518, was the first to try to understand features of matter (like friction, water's conversion into ice etc.) in experimental way.

Galileo Galilei, who lived in the years 1564-1642, was the scientist who laid the foundations of experimental researching of nature. Among other things he did, he was also atomist; the one thanks to whom ideas of Democritus reappeared. Galilei was of the opinion that matter and light consisted of punctual particles. He imagined that world consisted of countless atoms separated by quantitatively infinite vacuum. In his work- "Dialogo sopra i due massimi sistemi del mondo" he enclosed (among the other problems) his opinion on atomistics. By some historians of science in the work he described atom as indivisible formation but without a shape and also without dimensions at all. So from the mathematical point of view it was an abstract point. That was at variance with the theorem of Democritus that basal particles had different shapes. Galilei was the first scientist, who used experimental methods in the process of world's researching. Unfortunately experiments couldn't help him enough by creating his opinions of world's microstructure. Everything he achieved in atomistics he did thanks to mental experiments and to logical considerations.

Pierre Gassendi, born in 1592, another great scientist of the 16-th century, maintained that world should be researched mostly by making experiments. Most of his opinions on microstructure he took from Epicurus. Gassendi assent the subsistence of vacuum with atoms situated in it. Atoms were subordinated to deterministic laws of dynamics (in his theory there were no abberate at random). Atoms could bound and gather together. He also said that there were a force between atoms, thanks to which atoms could combine. He was the first real atomist of the contemporary times.

Evangelist Torricelli, who lived in the years 1608-1647, was Galilei's prominent disciple. By analysing problems connected with pumping water and by making experiments in which he replaced water by mercury he proved the subsistence of vacuum.

Robert Boyle, who lived in the years 1627-1691, was another great scientist of the 17-th century. He made many experiments. He researched on the effect of air resistance, on its pressure and on changes of its volume while changing its pressure. He discovered the law describing interdependence between these two quantities (Boyle's law). This law was experimentally discovered by Boyle but formulated later by Marriotte. The experiments with pressure were quiding later scientists, who were researching air structure. The experiments testified that air composes of separate, moving atoms which stay in quite a big distance one from another. Thanks to such structure air can change its volume in considerable range. Pressure, which Boyle researched, is caused by the movement of particles, which collide with other things influencing them with some force. When air's volume is smaller, there are more collisions in each square centimetre (what Bernoullie's researches showed later). This interdependence discovered Boyle in the experimental way. Boyle had also many other attainments in researching world's microstructure. He refuted the public accepted statement that mercury is in every (also alive) body (he grew bean in a utensil filled only with water). He was looking for basal matter's components. That's why he was trying to decompose different substances. When he couldn't decompose something more he called it "simple body". All other things were to be composed of that simple bodies. The four, Aristotle's elements were replaced by Boyle with his simple bodies. Nobody knew the number of them. That complicated the vision of the world, so most of the scientists of this epoch was against Boyle propositions. The other Boyle's theorem was the subsistence of elusive, fire substance- "fire matter". That substance were to fly away as fire while burning something down. Its subsistence were to be also shown as rust and verdigris.

Antonie von Leeuwenhoek, Dutch scientist, who lived in the years 1632-1723, in 1670 constructed the first microscope.

Isaac Newton, the greatest of the 17-th century, lived in the years 1643-1727. In the midst of many other attainments in physics, mathematics and astronomy, he was also researching world's microstructure. Like the earliest scientists he was of the opinion that matter consisted of atoms. Their subsistence was to be proved only by intellectual, reason experiments. He maintained that light also composed of some kind of atoms. Solar rays were to be streams of particles. Interaction between different bodies he perceived as interaction between atoms of that bodies. He paid much attention to the problem of influencing in distance. For a long time he was considering the subsistence of ether, which as an ideal, immaterial medium was to penetrate whole space making the contact between bodies possible. But ether also had to be composed of particles and that made logical contradictions.

The 17-th century completely changed opinions on laws ruling the universe and on microstructure. That was the time of many astronomical discoveries and mathematical attainments. But physic's development was the fastest. It used new mathematics. Newton's discoveries created new opinion which, with no important changes, stayed up to the beginning of the 20-th century. After one and a half thousand years Democritus's atomistics conception reappeared. The subsistence of vacuum was proved (Torricelli). Atomistics developed. But still it wasn't known if atom subsists or not; Boyle's experiment was only an indirect proof. The attainments of the 17-th century atomists were mostly logical considerations. Scientists didn't have researching equipment. It was the time of constructing first experimental instruments like the first microscope.