The Business of Love (1925)

Young college graduate Edward Burgess, who prefers mechanics to the law, helps James Scarborough, an old inventor, market a revolutionary new invention. Edward, who is in love with Scarborough's niece, Barbara Richmond, further helps by keeping various lawyers away. Edward's Uncle Noah thinks his nephew has wasted his education, but Edward tallies up the cost of college and soon pays back the entire amount to Uncle Noah from the money he made with the invention.