`` ah , '' hammond said , fumbling , and then stopped , visibly irresolute before saying , `` sir , if i may rely upon your discretion-the utmost secrecy- '' `` i am sure you may , '' temeraire said with interest , pricking forward his ruff as he leaned in ; hammond looked still more uncertain , as a large dragon 's notion of confidential whispering might be heard a good ten yards away .