Dr. Archibald Adams wrote a letter to Hans Sloane about the making of microscopes after he had visited Leeuwenhoek

August 22, 1709

This letter was published in Philosophical Transactions, vol. 27, no. 325, dated 31 March 1710, Adams’s third publication there. Adams explained how he made a microscope similar to those he had seen at Leeuwenhoeks house. He mounted a melted drop of glass between two metal plates, the method that Robert Hooke had first described in 1665 in Micrographia. Adams did not describe a focusing system, but he did describe his microscopic observations of blood. In no. 325, editor Hans Sloane placed Adams’s letter directly after Leeuwenhoek’s Letter L-476 of 6 June 1710 to the Royal Society.

Dr. Archiballd Adams studied medicine in Leiden and graduated from medical school in Utrecht in 1705. Practicing in Norwich, England, in 1707, he tried in vain to interest Hans Sloane in buying the anatomical collection of Frederik Ruysch. Adams wrote to Sloane in July 1707, “Ruysch tells me that if any British subject, corporation or college shall purchase his closet he will make me as perfect as himself in the art of embalming, injecting & preserving in animated bodies” (British Library, MS Sloane 4041). Sloane did not follow through on the purchase.


On 11 August 1709 O.S., Dr. Adams addressed a letter to Royal Society secretary and Philosophical Transactions editor Hans Sloane.

Pursuant to what I wrote some time ago concerning Microscopes, I think that all the Microscopes which preceded Mr. Leeuwenhoek's are so much outdone by his, that it will be proper for me only to take notice of these and the rest of later invention, not designing to lessen their Usefulness, but only to add a few thoughts which may be of service.

I had not an opportunity of examining Mr. Leeuwenhoek's glasses particularly, which is a favour, he allows to none; therefore I am not capable at this distance to describe either their make or life, any further than that to me they appear’d to be spherules lodg’d between two plates of gold or brass, in a hole whose diameter might not be bigger than that of a small pins head, and the objects I saw through them were pretty and diverting; but still their make and truth are unknown.