Answer:
necessitate the conditions of both the employers and labors.
Explanation:
In the article "The Plea for Eight Hours" by Terence V. Powderly, the writer stresses on the need to educate the labors to understand the reasons why their working hours should be reduced. He says that a labor should work for less hours so that he/she would have time to read and understand what is happening around him/her.
Most employers would disagree to shorter hours of work by bringing different reasons like taxation, interest on borrowed capital, freight charges, etc. However, Powderly says that to get these problems addressed, the employers must unite with the labors.
Thus, the statement "Justice seldom enters into the adjustment of wages: necessity is the standard by which they are regulated." develops the central ideas of the article as the only way to reduce working hours was to necessitate the conditions of both the employers and labors.