Well, summer can't be all play, sad to say, and in the summer of 1889, there came a day at the end of June when everybody had a little work to do.
The guard at Paddington station, Dr. Watson, a hansom cab driver, Sherlock Holmes, Inspector Bradstreet, an un-named plain-clothes policeman, the crew running a train, the Eyford station master . . . all of them had work to do that June, and much of it revolved around Mr. Victor Hatherly and the results of a job he had taken that summer.
Some of that list were public servants. Some, the the cabman and the rail folk, we can assume got their pay as a part of the natural course of things. But Dr. Watson and Sherlock Holmes? Did they bill Hatherly later, or were they just working pro bono due to his tragic situation crossing their paths?
"If it is anything in the nature of a problem which you desire to see solved, I should strongly recommend you to come to my friend Mr. Sherlock Holmes before you go to the official police," Dr. Watson suggests to Hatherly, with no mention of Holmes's rates and a tone of "I have this friend . . ."
Of course, Watson is the one who really has anything to bill for services rendered in this case. Sherlock Holmes is pretty much along for the ride with the police to see if there's anything interesting in it.
In fact, Sherlock Holmes's payment in this particular case is exactly what he tells Victor Hatherly that the hydraulic engineer got for his thumb-costing job out in Berkshire: Experience. Holmes had probably learned to take that in payment a lot as he first worked his self-directed internship at a profession the world had never seen before, making his first inroads with Scotland Yard and his clients. The big money would come later, at least for Holmes.
The thumbless engineer probably didn't do too badly for himself either, as his story surely made him stand out among all the other candidates for any job he put in for later in life.
For a story that is, in the end, all about money, there is very little of it floating around in "The Adventure of the Engineer's Thumb," but it doesn't keep people from being on the job. And as we head into July, staying on the "job" of the Summer of Sherlock continues as well.