上句见：Day76
The Story of Philosophy的第77句：第1章Plato第1节The Context of Plato第6段第3句：

At first this philosophy was physical; it looked out upon the material world and asked what was the final and irreducible constituent of things. The natural termination of this line of thought was the materialism of Democritus(460-360 B.C.) — “in reality there is nothing but atoms and space.” This was one of the main streams of Greek speculation; it passed underground for a time in Plato’s day, but emerged in Epicurus(342-270), and became a torrent of eloquence in Lucretius(98-55 B.C.). But the most characteristic and fertile developments of Greek philosophy took form with the Sophists, traveling teachers of wisdom, who looked within upon their own thought and nature, rather than out upon the world of things. They were all clever men (Gorgias and Hippias, for example), and many of them were profound (Protagoras, Prodices); there is hardly a problem or a solution in our current philosophy of mind and conduct which they did not realize and discuss. They asked questions about anything; they stood unafraid in the presence of religious or political taboos; and boldly subpoenaed every creed and institution to appear before the judgementseat of reason. In politics they divided into two schools. One, like Rousseau, argued that nature is good, and civilization bad; that by nature all men are equal, becoming unequal only by class-made institutions; and that law is an invention of the strong to chain and rule the weak. Another school, like Nietzsche, claimed that nature is beyond good and evil; that by nature all men are unequal; that morality is an invention of the weak to limit and deter the strong; that power is the supreme virtue, and the supreme desire of man; and that of all forms of government the wisest and most natural is aristocracy.
浙江大学版本：这一理论是古希腊哲学的主要猜想之一，曾在柏拉图时代悄然流传，于伊壁鸠鲁（前342一前270)期间呈现于世，并在卢克莱修②那儿得以发扬光大。

解析

这句介绍原子论从沉默（underground）到再现（emerged）再到有力（a torrent of eloquence）的过程。
1、This was one of the main streams of Greek speculation；
原子论定性为希腊式思辨主要流派之一。

2、**it passed underground for a time in Plato’s day, **
在柏拉图时代暗中流传。
underground：always used before a noun : secret and usually illegal
They are accused of organising and financing an underground youth movement.他们被指控组织并资助地下青年运动。
for a time： 【phrase】 used for saying what happened or existed during a short period before it changed 曾经
We were quite happy for a time, until his brother moved in.

3、but emerged in Epicurus(342-270),
在伊壁鸠鲁时期重新出现。
伊壁鸠鲁（Epicurus，公元前342年-公元前270年）的哲学思想主要集中在自然主义及快乐主义。他认为快乐就是最大的善，倾向于摆脱活动与责任。同时他信奉德谟克利特的原子论，但却未采纳原子运动严格受法则支配的观点。

4、and became a torrent of eloquence in Lucretius(98-55 B.C.).
原子论的极大集成在卢克莱修时期。
torrent：a large amount of something that is released suddenly
— usually + of
A few moments after, the funnel of the Henrietta vomited forth torrents of smoke.过了一会，亨利埃塔号的烟筒又冒出了滚滚的黑烟。——《八十天环游地球》
卢克莱修（公元前98年-公元前55年）：是罗马诗人，是伊壁鸠鲁传统中的另一位代表人物。他的《物性论》（De Rerum Natura）被拉丁文学中最重要的哲学作品之一，被视为原子论的百科全书，集哲学、科学、文学为一体，反映了古希腊罗马朴素唯物主义的最高成就。在书中，他阐发了虚空论、原子论和宇宙无限论等观点。

这一理论是希腊式思辨的主流之一；在柏拉图时代暗中流传，在伊壁鸠鲁（公元前342年-公元前270年）时期重现，在卢克莱修（公元前98年-公元前55年）时期迸发。