国富论第一章题目of the division of labor,为什么要加of,of起什么作用是什么意思

B.国富论是经济学成为一门学科的鼻祖,通论是宏观经济学的开山之作,马歇尔是古典经济学的集大成者,其代表作经济学原理主要是讨论微观经济理论的.

he intends only his own gain,and he is in this,as in many other cases,led by an invisible hand to promote an end which was no part of his intention ...By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it
The Wealth of Nations,Book IV Chapter II
全文为：
But the annual revenue of every society is always precisely equal to the exchangeable value of the whole annual produce of its industry,or rather is precisely the same thing with that exchangeable value.As every individual,therefore,endeavors as much he can both to employ his capital in the support of domestic industry,and so to direct that industry that its produce may be of the greatest value; every individual necessarily labors to render the annual revenue of the society as great as he can.He generally,indeed,neither intends to promote the public interest,nor knows how much he is promoting it.By preferring the support of domestic to that of foreign industry,he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value,he intends only his own gain,and he is in this,as in many other cases,led by an invisible hand to promote an end which was no part of his intention.Nor is it always the worse for the society that it was not part of it.By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it.I have never known much good done by those who affected to trade for the public good.It is an affectation,indeed,not very common among merchants,and very few words need be employed in dissuading them from it.

自然价格是指商品的生产成本和商品运至出售处所需的金额之和,而供求均衡时的均衡价格等于这个自然价格,但本质不同