This is the first appearance of Clason's mild mannered, absurdly erudite professor of ancient history and sometime archaeologist Professor Theocritus Lucius Westborough (why is it professors of archaeology must have such goofy names?). As with many of his cases he just happens to be on the premises when a baffling murder occurs, usually one of the impossible crime nature or a locked room murder. The title of his first sleuthing adventure hints at the recurring motif of locks and keys and does not refer to a drinking glass nor an acrobat.
The story is almost exclusively set in the Hotel Equable on Michigan Avenue in Chicago. Elmo Swink, a dislikable man with a habit of womanizing and drinking heavily is found dead in his locked room. He has been poisoned by an ingeniously contrived booby trap - when he opened his door he caused a test tube containing a solution of potassium chloride and sulfuric acid to fall to the hard floor. When the two liquids mixed upon impact it released the poison hydrocyanic gas so popular with mystery fiction murderers. Lt. Mack is stumped as to how anyone could have procured the ingredients and fashioned the booby trap, then locked the door without anyone seeing all the activity that must have been involved in staging the crime. Westborough asks meekly and politely if he may sit in on the interviews of the hotel residents and begins taking notes.
Anyone who has read Clason's books (many have been re-issued by the wonderful couple at Rue Morgue Press) will know that these mysteries can get very eggheady as the investigation proceeds. Clason likes to populate his books with characters who have technical and scientific knowledge, characters who are well read and have a habit of alluding to their favorite works and writers, and characters who have other arcane bits of info that will somehow find itself into the dialog. Westborough, of course, is the main lecturer and allusion dropper - much of his prattle is just that and has nothing whatsoever to do with the story. This kind of pretentious malarkey is also found in the works of Ellery Queen and S.S. Van Dine. Some may find this quaint, some may find it eye-opening, with me it gets old very fast.
We have mini lectures on organic chemistry, the various methods of creating prussic acid, and the numerous uses of potassium cyanide (one of its ingredients) in business and industry. The night clerk Chris Larson just happens to be taking a course in chemical engineering and willingly shows off what he knows to help the police. But whereas a few sentences might suffice to relay this information to the reader Clason goes on for pages. There is also a lecture on how locks work, emphasizing the difference between a cylinder lock and a "paracentric" lock which is apparently the lock of choice at the Hotel Equable. While I was finally satisfied that a mystery writer had the smarts to explain it's not easy to pick many types of locks, I did think that Clason was indulging himself with the lock business as well. But then locks and keys have an awful lot to do with this book. The preponderance of locked doors, locked rooms mysteriously accessed, lock picks and hotel passkeys in the book makes The Fifth Tumbler a fitting title. Especially so when Westborough uses the inner workings of a lock as a metaphor for his approach in solving the crime:
"Let me elucidate by means of an analogy. The situation is not unlike the mechanism of a pin-tumbler lock."
"I'll be taking locks to pieces in my sleep," Mack declared with emphasis. "There's five pin tumblers, and the wedges on the key have to raise 'em all in a line before the plug can turn. That what you mean?"
"Exactly. To carry the parable a step further, I might add that four of my tumblers have reached the proper height, but an obstinate fifth prevents the lock from opening."When the time comes for Westborough to reveal the identity of the murderer we get yet another long lecture and a killer who, when faced with his mistakes, crumbles under pressure and confesses. But his motive is kept secret for yet another chapter when the requisite surprise is delivered with a resounding thud. This is the only part of the book that fails to honor the fair play tenets of the detective novel. Although some background is given earlier in the book only the most imaginative reader could have made the outrageous leap required to connect the murderer and his motive. For me this was not so much a surprise as it was one of those eleventh hour tricks found in many of Carolyn Wells' mysteries. You expect a rabbit to be pulled out of the hat, but instead a kangaroo jumps out, hops all over the page, and practically thumbs its nose at you. You feel kind of stunned and cheated, no smile on your face and no desire to applaud.
UPDATE: The Clyde B. Clason bibliography. All books feature Prof. Westborough as the detective.
The Fifth Tumbler (1936)
The Death Angel (1936)
Blind Drifts (1937)
The Purple Parrot (1937)
The Man From Tibet (1938)*
The Whispering Ear (1938)
Murder Gone Minoan (1939)*
Dragon's Cave (1939)*
Poison Jasmine (1940)*
Green Shiver (1941)*
*These titles are available in trade paperback reissues from Rue Morgue Press. Tell them I sent you.