Period 5 - 1702-1712

The table below summarizes this decade of Leeuwenhoek's scientific career, from spring 1702 through the middle of 1712. Hans Sloane was editor of Philosophical Transactions. Almost all of the letters that Leeuwenhoek sent to the Royal Society were published by them.

Letters in Period 5

Of the 58 letters in this period, Leeuwenhoek addressed 50 to members of the Royal Society, with the intention that they be published.

• Members of the Royal Society - 39
• John Chamberlayne - 6
• Hans Sloane - 2
• James Petiver - 1
• Francesco Corner - 1
• Antonio Magliabechi - 1

The rest were addressed to a variety of people, five to Anthonie Heinsius and one each to Angelus van Wikhuysen, Govert Bidloo, and Petrus Valckenier.

This left a large body of letters from those periods that remained untranslated into English until the late 20th century's Alle de Brieven / Collected Letters.

Note: Birch's History stops at the end of 1687, so we do not have as complete an idea of what happened as we did during earlier years.

On November 30, 1693, Hans Sloane, only 33 years old, was appointed Secretary of the Royal Society, joining Waller, who had been there for several years. E.S.J. Brooks wrote in Sir Hans Sloane: The Great Collector and His Circle London, (1954, p. 82):

Sloane was the owner and editor of the journal, responsible for obtaining the items to be published. Profits were rare and losses were made up from his assets.

From then, for the next twenty years (excepting only 1710 when John Harris replaced Waller for one year), these two, Waller and Sloane, were the Royal Society's secretaries and Sloane was Philosophical Transactions' editor. It appeared regularly. For Leeuwenhoek, beginning in 1695, the tide turned.

In Delft

During this period, Leeuwenhoek sent every letter with scientific observations to London, and Hans Sloane published all but one of them.

Compare this to how Sloane treated Halley. After the first year of Sloane's editorship, from 1698 to 1713, volumes 20 - 28, Halley had only 5 articles published while Leeuwenhoek had 57, half his career total. And then during period 6, Halley was editor and not publishing Leeuwenhoek. However, he published 13 of his own articles in volume 16.

The bulk of the letters written during this period were not published in Dutch/Latin. Some of them remained in the English translation only until the Alles de Briven / Collected Letters project caught up with them at the end of the 20th century and published the full letters in both Dutch and English.

Unfortunately, Edmond Halley replaced Hans Sloane as secretary and Philosophical Transactions editor in 1713. It would be six years until Leeuwenhoek would see another of his letters in Philosophical Transactions.