顾炎武先生在给友人的一封信中称:“尝谓今人纂辑之书,正如今人之铸钱。古人采铜于山,今人则买旧钱名之曰废铜以充铸而已。所铸之钱既以粗恶,而又将古人传世之宝舂挫碎散,不存于后,岂不两失之乎?承问《日知录》又成几卷,盖期之以废铜。而某自别来一载,早夜诵读,反复寻究,仅得十余条,然庶 Mr. Gu Yanwu said in a letter to his friends: ”taste of today’s compilation of books, as today’s money casting .Ancient copper mining in the mountains, today people buy old money, said the name of scrap copper to cast However, the money cast both coarse, but handed down the ancients handed down treasure, do not exist, it is not lost? Feelings, “Nikkei” into a few volumes, the cover of the To scrap copper. And a self-contained a, read the night and night, repeated research, only had more than ten,