淳熈二年臣大昌備數(shù)講官因講禹貢壽皇問(wèn)曰卿言中國(guó)山川悉矣北方地里亦能詳知之否大昌對(duì)曰塞外無(wú)文史間有可傳者多弗詳實(shí)臣安敢強(qiáng)以不知為知也后暨紹熈大昌乃得奉祠家居無(wú)為常愧前此淺學(xué)無(wú)以酬塞顧問(wèn)追采古來(lái)中華北狄樞紐相闗者條列而推言之則北方事雖不盡知而亦可云渉獵矣初時(shí)奉訓(xùn)指問(wèn)者惟北狄故專主北以言不容雜舉他方也紹熈辛亥八月新安程大昌敘