In Atlantic Cleaners & Dyers, Inc. v. United States, 286 U. S. 427 (1932), the Supreme Court held that the word "trade" has a more encompassing meaning in 3 than in 1 of the Sherman Act, see id., at 433-435, and explained: "Undoubtedly, there is a natural presumption that identical words used in different parts of the same act are intended to have the same meaning. . . . But the presumption is not rigid and readily yields whenever there is such variation in the connection in which the words are used as reasonably to warrant the conclusion that they were employed in different parts of the act with different intent. . . . "It is not unusual for the same word to be used with different meanings in the same act, and there is no rule of statutory construction which precludes the courts from giving to the word the meaning which the legislature intended it should have in each instance." (Id., at 433.) In Atlantic Cleaners & Dyers v. United States, 286 U.S. 427, 52 S.Ct. 607, 76 L. Ed. 1204 (1932), it was held the words "trade" and "commerce" had a broader meaning in Sec. 3 of the Act than in Sec. 1, 15 U.S. C.A. 3, 1, and that, under the paramount power of Congress to legislate for the District of Columbia, the use of the words in that section should be held to embrace the exercise of that paramount power to its fullest extent. - "We are, therefore, free to interpret section 3 dissociated from section 1 as though it were a separate and independent act, and, thus viewed, there is no rule of statutory construction which prevents our giving to the word `trade' its full meaning, or the more extended of two meanings, whichever will best manifest the legislative purpose." 286 U.S. at page 435, 52 S.Ct. at page 609, 76 L.Ed. 1204.