The Adventures of Tintin #18: The Calculus Affair

Tintin and Captain Haddock are on a stroll in the countryside around Marlinspike, but are suddenly caught out by an approaching thunderstorm and rush back to the manor.

Events take a mysterious turn during the storm. Inside Marlinspike, several items of glass within the house break for no apparent reason. Then, Jolyon Wagg, an annoyingly gregarious and impolite insurance salesman, turns up uninvited to seek shelter. He claims that all the windows of his car have somehow blown to bits. What had happened?