William Molyneaux wrote about a visit to Leeuwenhoek

January 1, 1692

In a book on optics published in 1692, William Molyneaux (Thomas's older brother) wrote about a visit to Leeuwenhoek's house. Perhaps William accompanied his brother when Thomas visited Leeuwenhoek on behalf of the Royal Society in 1685.


Dioptrica nova, A treatise of dioptricks in two parts: wherein the various effects and appearances of spherick glasses, both convex and concave, single and combined, in telescopes and microscopes, together with their usefulness in many concerns of humane life, are explained

p. 281

The Heer Lewenhoeck of Delft in Holland, has lately apply'd himself with great Diligence to the use of Microscopes: of which Instrument he thinks he has a better kind than was ever yet known. When I visited this Gentleman at Delft, he shew'd me several that indeed were very cu∣rious; but nothing more than what I had ordinarily seen before; being composed only of one single, very minute Glass-Sphere or Hemisphere, placed between two very thin pierced Laminae, or Plates of Brass, and the Object was brought to its due distance before the Glass by a fine Screw: But for his best sort, he beg'd our Excuse in concealing them. The Observations he has made with his Glasses are Printed in several Letters of his in Dutch; but for the most part, they are to be found dispers'd in the Philosophical Transactions.