Bordering on a parody this is an early Connington novel with an unusual light-hearted tone not found in his later books with Sir Clinton Driffield. The characters are here are stock, speak in phonetic dialects, and behave a little less than real. The detective elements are well done and the book is a good example of what the mystery novel was like in the early 1920s.
The story involves the invention of a lethal ray and the attempts of Jimmy Leigh, the inventor, to acquire financing to start a manufacturing business. His mistake is that he chooses as his primary backer William Hubbard, a wealthy, lisping, butterfly collector who also happens to be a despicable blackmailer. As is the case with most blackmailers in crime fiction he meets a violent end. He is discovered apparently stabbed by a paper knife in his suffocatingly hot study.
At the inquest expert testimony reveals that the knife wound was done post mortem and that he died from cyanide poisoning. But why stab him as well? Inspection of the crime scene reveals a broken display case with a stolen butterfly, some papers and documents burned in the fireplace, and a .022 caliber pistol lying on the carpet. While the main characters are looking over the crime scene, Hubbard's pet parrot, disturbed by some earlier altercation that took place in the room, suddenly erupts in a stream of foul language much to the amazement of the three men who discover the body. Other unusual aspects in the story include three characters who own motorcycles (one of them being a butler) and a village idiot obsessed with finding and keeping beautiful things. There is a bit thrown in about a local superstition of the Green Devil whose ghostly appearance signals the approaching death of someone in the village. This never really amounts to anything unfortunately.
This was Connington's first detective novel after his science fiction novel Nordenholt's Millions. An admirable and entertaining job. Solution is actually presented at the half way point by the culprit but is touted as a theory and then dismissed by the Colonel, the local magistrate who is acting as the story's primary detective. It is one of the early rule-breaking detective stories in that the culprits manage to escape punishment for their actions. There are various ethical and moral rationales discussed throughout the book (primarily the evil of blackmail) that the Colonel uses to justify his decision. He's not as Old Testament in his retribution as Beatrice Bradley sometimes behaves, still it is worth noting for a detective novel written in the 1926.
Interestingly, like many writers who introduce supernatural elements into their detective novels only to rationalize them, the science fiction element introduced at the start of the book turns out to be completely phony. Question: what happened to Connington's sense of humor in the later Driffield books? Maybe I've not read enough of his work but this seems almost farcical compared to other novels.