April 16, 1888: Holmes, Watson and Mary Morstan went to Pondicherry Lodge. [SIGN]
We had hardly reached the third pillar, which was our rendezvous, before a small, dark, brisk man in the dress of a coachman accosted us.
“Are you the parties who come with Miss Morstan?” he asked.
“I am Miss Morstan, and these two gentlemen are my friends,” said she.
He bent a pair of wonderfully penetrating and questioning eyes upon us.
“You will excuse me, miss,” he said, with a certain dogged manner, “but I was to ask you to give me your word that neither of your companions is a police-officer.”
“I give you my word on that,” she answered.
He gave a shrill whistle, on which a street arab led across a four-wheeler and opened the door. The man who had addressed us mounted to the box, while we took our places inside. We had hardly done so before the driver whipped up his horse, and we plunged away at a furious pace through the foggy streets.
The situation was a curious one. We were driving to an unknown place on an unknown errand.
April 16, 1897: Brenda Tregennis was murdered, and her two brothers lost their sanity. [DEVI]
Source
A Day by Day Chronology of Sherlock Holmes according to Ziesler and Christ by William S Dorn DWNP, BSI.