The Royal Society read the former part of Letter L-154 about salts in wormwood, alum, and other substances

April 4, 1685

The last known letter of Francis Aston to Leeuwenhoek is the letter of 26 February 1684. There is no evidence that Aston ever wrote the letter noted below.


Birch, History, vol. IV, p. 383, 25 March 1685 (O.S.) in London:

Part of a letter of Mr. LEEWENHOECK to the society, dated at Delft, January 23, 1685, was read, concerning the figures of the salt of carduus benedictus, of the salt of wormwood, of alum, salt-petre, and vitriol of Cyprus.

Dr. LISTER remarked, that there were figures of common salt and alum among the salts of wormwood and some others; and that it was to be wished, that Mr. LEEWENHOECK had prepared all his salts himself. He queried, whether Mr. LEEWENHOECK had ever seen salt of nitre finished at both ends, and how many fides it had; and he desired, that Mr. LEEWENHOECK would describe a large crystal of alum and a large crystal of vitriol.

Mr. ASTON was desired to take instructions from Dr. LISTER , when he shall next write to Mr. LEEWENHOECK.