Final answer:
Antonie van Leeuwenhoek was talking 'snail mail' with Robert Hooke in England.
Step-by-step explanation:
The person to whom Antonie van Leeuwenhoek was talking 'snail mail' in England was Robert Hooke. Van Leeuwenhoek and Hooke were contemporaries who both made important contributions to microscopy. Van Leeuwenhoek observed 'animalcules' under the microscope, while Hooke observed the structures that we now know as cells.