Leeuwenhoek’s critical secret of creating of Lenses

Antonie Philips van Leeuwenhoek (October 24, 1632 – August 30, 1723) commonly known as "the Father of Microbiology", and considered to be the first microbiologist.

Leeuwenhoek's interest in microscopes and a familiarity with glass processing led to one of the most significant, and simultaneously well-hidden, technical insights in the history of science. By placing the middle of a small rod of lime glass in a hot flame, Leeuwenhoek could pull the hot section apart like taffy to create two long whiskers of glass. By then reinserting the end of one whisker into the flame, he could create a very small, high-quality glass sphere. These spheres became the lenses of his microscopes, with the smallest spheres providing the highest magnifications. An experienced businessman, Leeuwenhoek realized that if his simple method for creating the critically important lens was revealed, the scientific community of his time would likely disregard or even forget his role in microscopy. He therefore allowed others to believe that he was laboriously spending most of his nights and free time grinding increasingly tiny lenses to use in microscopes , even though this belief conflicted both with his construction of hundreds of microscopes and his habit of building a new microscope whenever he chanced upon an interesting specimen that he wanted to preserve.

During his lifetime Van Leeuwenhoek ground over 500 optical lenses. He also created over 400 different types of microscopes, only nine of which still exist today. Van Leeuwenhoek possessed some microscopes that could magnify up to 500 times.

Amongst Van Leeuwenhoek's many discoveries are:

• in 1674 he discovered infusoria (protists in modern zoological classification)
• in 1676 he discovered bacteria, (e.g. large Selenomonads from the human mouth)
• in 1677 he discovered spermatozoa (sperm)
• in 1682 he discovered the banded pattern of muscular fibers

With skills, however, Leeuwenhoek maintained throughout his life that there were aspects of their construction "which I only keep for myself", including in particular his most critical secret of how he created lenses. For a long time nobody could reconstruct Leeuwenhoek's know-how. But in the 1950s, D.L. Stong used thin glass thread fusing instead of polishing, and successfully created some working samples of a Leeuwenhoek design microscope.