microscopium

Microscope comes from New Latin microscopium, coined from Greek mikrós (small) and skopeîn (to look at, to examine). The word was formed in the early 1600s, modeled on 'telescope' (far + look). The first compound microscopes appeared in the Netherlands around 1620, built by lens grinders like Zacharias Janssen and his father Hans. But it was Antonie van Leeuwenhoek of Delft who, starting in the 1670s, ground single lenses of such quality that he saw what no human had seen before.

Leeuwenhoek was not a scientist. He was a draper — a fabric merchant — who ground lenses as a hobby. His single-lens microscopes achieved magnifications of 270x, far beyond anything the compound microscopes of his day could produce. He looked at pond water and saw 'animalcules' — tiny creatures swimming, spinning, dividing. He looked at his own dental plaque and saw bacteria. He wrote letters to the Royal Society in London, describing organisms that the Society's members could barely believe existed.

Robert Hooke, the English polymath, had already published Micrographia in 1665 — the first major work of microscopy. Hooke coined the word 'cell' after looking at cork under magnification and seeing small chambers that reminded him of monks' cells. The microscope did not just reveal new things. It required new words. Cell, bacteria, protozoa, microbe — the vocabulary of the invisible world was built one observation at a time.

Modern electron microscopes can resolve objects 0.1 nanometers across — roughly the size of a single atom. The optical microscopes of Leeuwenhoek and Hooke have been surpassed by factors of a million. But the word remains unchanged: to look at small things. The scale of 'small' keeps shrinking. The verb keeps working.