《梦溪笔谈·谬误谲诈附》
有一天，忽然有他的一封信投给执政大臣，执政大臣收信后不敢打开，立即报告给了皇上。
一日，忽有一书与执政。执政得之，不敢发，立具上闻。
One day, a letter from him was suddenly delivered to the Prime Minister. After receiving the letter, the Prime Minister did not dare to open it and immediately reported it to the Emperor.