Those who would attain the heights reached and kept by great men must keep their faculties polished by constant use,

有些人想取得伟人所获得并保持的成就，他们就必须不断运用自身才能，

so that they may unlock the doors of knowledge, the gate that guard the entrances to the professions, to science, art, literature, agriculture--every department of human endeavor.

以便开启知识的大门，即那些通往人类努力探求的各个领域的大门，这些领域包括各种职业：科学，艺术，文学，农业等。