The two great explorers of the microscopic world were from different cultures, one trained in a trade while the other was university educated.

Let’s start in 1632, when Antonie van Leeuwenhoek was born in Holland. The small country was becoming the center of European trade with more ships than Spain, Portugal, England and Austria combined. The Dutch had become the great traders of Europe, moving goods from their remote colonies, as well as Java in Indonesia and New Amsterdam (now New York City).

With wealth came freedom, which allowed Holland to become a center of scientific progress. That freedom extended to religion, allowing communities of Calvinists, Jews, Lutherans and Catholics to coexist. Holland was the first country to publish Galileo’s banned work, “Mechanics (on the heavens).”

Now about Antonie van Leeuwenhoek. His father died when he was 5. His mother and stepfather sent him away for primary schooling. When at age 16, Antonie’s stepfather died, his mother sent him away to Amsterdam to learn a trade. Van Leeuwenhoek took a job as an apprentice in a linen draper’s shop, eventually to be a clerk and cashier. Globes of glass, acting to magnify had been used as far back as the first century AD.

In the early 1600s, Galileo built a compound microscope (using multiple lenses). By Leeuwenhoek’s time, lens grinding was an important occupation in Holland. The best lenses went into telescopes for navigation and military uses. For Leeuwenhoek, high quality lenses were used as magnifying glasses to determine the quality of cloth and needlework. In 1665, interest in microscopy was stirred by the publication of the book Micrographica, a collection of exquisite drawings made by the English scientist Robert Hooke using a compound microscope.

By the time that Hooke’s Micrographica appeared, van Leeuwenhoek was back in Delft (the town of his birth), married and settled in a comfortable house in town. Antonie built his own microscopes, each with a single lens, using special lighting and background to allow him to magnify five or six times as much as Hooke’s microscopes could achieve. Leeuwenhoek found that he could see details not shown in the specimens in “Micrographica.”

Antonie was the first to see bacteria, protozoa, human blood cells and sperm. But Leeuwenhoek never revealed how he manufactured his lenses. He employed a local artist to draw what was visible. Antonie’s friends included Regnier de Graaf, a physician, “natural philosopher” (that was the early term for scientist) and the inventor of an early version of a hypodermic needle.

De Graaf soon put Leeuwenhoek in touch with Henry Oldenburg, an important natural philosopher in England. Through Antonie’s letters to Oldenberg, Leeuwenhoek became known as the greatest microscopist in the world and a member of the Royal Society. Leewenhoek worked through his death at age 90.

Robert Hooke was born on the Isle of Wight in 1635, three years after Leeuwenhoek. His father John was a priest of the Church of England. Robert went to Westminster school, mastering Latin and Greek, Euclid’s Elements and began a life long study of mechanics. Hooke doubted the age of the Earth based on the Bible’s chronology. Hooke hypothesized that some species of animals had gone extinct. He worked as an assistant to the Irish scientist Robert Boyle and built a vacuum pump that was used to discover Boyle’s Law (that the product of the pressure and volume are constant for the same temperature and mass).

In 1662, Hooke was appointed to be the curator of experiments to the Royal Society. After the Great London Fire of 1666, Hooke did over half the surveying. Hooke suggested that the force of gravity was proportional to 1/(distance sq.); this was later proven by Isaac Newton in his book, the “Principia.

Sky sights ahead

This week has morning twilight at 6:30 a.m., sunrise at 7:30 a.m., midday at 1 p.m., sunset at 6:30 p.m., dusk ending at 7:30 p.m., giving us daily sunlight of 11 hours. The sun is now in front of the stars of Virgo. Both the bright planet Jupiter and Saturn are in the South at 7 p.m.

The bright planet Mars is in the Southeast as it gets dark. The brilliant planet Venus is low in the East at 5:30 a.m. On Oct. 22, Jupiter and Saturn are above the moon with Jupiter to the right and Saturn to the left.

Bob Doyle is a retired science teacher at Frostburg State University who is available to talk to adult and student groups about matters related to his columns. Contact him at

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