midnight
`` One-eight-nine-seven , '' said Rand . `` Thanks , '' said Holmes , jotting it down coolly in his memorandum-book . `` That 's a good thing to know . '' That night , shortly before midnight , Holmes left me . `` I 've got to finish this job , '' said he . `` The most ticklish part of the business is yet to come . '' `` Great Scott , Holmes ! ''