Mary doesn’t explain this point, and only mentions once more in her diary the subject of Gulliver’s daily defecating.
But putting together the various hints in her manuscript, we can deduce that Gulliver, in his ingenuity, realised that the volcano, with its flowing water, would serve as a perfect ‘water-closet’, or ‘Ajax,’ as it was known in the times of Mary and Lemuel.
The ‘Ajax’ was invented in 1596, by Sir John Harington (1561–1612,) Godson of Queen Elizabeth I (1533–1603).
The first ever flush-toilet in England was built and installed at the Queen’s chambers at Richmond Palace. At first everybody wanted to have one in their homes, of course, but as soon as it was known that the Queen refused to use it because it made too much noise, the ‘Ajax’ fell into disrepute and even talking about it became Taboo.
The fact that Mary writes about this shows, that some wise people did go about using the ‘Ajax’, though more discretely.