what is the Spanish affair? what was the purpose of giving false information?

The Count also sends a telegram to Debray in this chapter (chapter 34) relating a contrived news bulletin of a political chaos in Spain. Debray thus rushes to Danglars' wife telling her to recommend to her husband that he sell all his Spanish bonds. He does so, though he loses money. At the end of the day when the news is proven false, the bonds rise to twice their original value. The net loss for Danglars is thus a million francs. Monte Cristo has succeeded in ruining a million francs of Danglars' fortune by providing false knowledge to Debray. Danglars consequently falsely speculated after his wife relayed Debray's false information. Thus Monte Cristo is on the road to destroying the man who was the mastermind behind his incarceration. His destruction must occur slowly, however, just as he was made to rot slowly away in prison.