premise: To Queen Victoria, Lin addressed a famous letter, pointing out the harm the  poisonous drug  did to China, and asking for an end to the opium trade; his arguments are unanswerable, but the lofty though heartfelt tone of the letter shows how unprepared the Chinese were to negotiate with the West in realistic terms.
hypothesis: Lin noted a letter, which mentioned the harm a drug did and pushes to end opium trade.