Excerpt from Ida Tarbell’s The History of the Standard Oil Company, 1904 In the fall of 1871, . . . certain Pennsylvania refiners brought to [Rockefeller and his partners] a remarkable scheme, the gist of which was to bring together secretly a large enough body of refiners and shippers to persuade all the railroads handling oil to give to the company formed [the new trust] special rebates on its oil, and drawbacks [refunds] on that of other people. If they could get such rates, it was evident that [other companies] could not compete with them long and that they would become eventually the only refiners. They could then limit their output to actual demand, and so keep up prices. . . . [They] began at once to work up a company—secretly. It was evident that a scheme which aimed at concentrating in the hands of one company the business now operated by scores [a “score” is twenty] . . . must be worked with fine discretion if it ever were to be effective.
. . . In order that their great scheme might not be injured by premature public discussion they asked of each [potential partner] whom they approached a pledge of secrecy.
1904 Political cartoon by Udo J. Keppler in Puck magazine

In paragraph form, explain how the primary sources above relate to each other and to the topic of the Progressive Era.