Without going minutely into the details of each case, I will now give reference to two classes of acts, in one of which Congress has extended the ordinance of 1787, including the article prohibiting slavery, over different Territories, and thus exerted its power to prohibit it; in the other, Congress has erected Governments over Territories acquired from France and Spain, in which slavery already existed, but refused to apply to them that part of the Government under the ordinance which excluded slavery. Of the first class are the act of May 7th, 1800, (2 Stat. at Large, 58,) for the government of the Indiana Territory; the act of January 11th, 1805, (2 Stat. at Large, 309,) for the government of Michigan Territory; the act of May 3d, 1809, (2 Stat. at Large, 514,) for the government of the Illinois Territory; the act of April 20th, 1836, (5 Stat. at Large, 10,) for the government of the Territory of Wisconsin; the act of June 12th, 1838, for the government of the Territory of Iowa; the act of August 14th, 1848, for the government of the Territory of Oregon. To these instances should be added the act of March 6th, 1820, (3 Stat. at Large, 548,) prohibiting slavery in the territory acquired from France, being northwest of Missouri, and north of thirty-six degrees thirty minutes north latitude. Of the second class, in which Congress refused to interfere with slavery already existing under the municipal law of France or Spain, and established Governments by which slavery was recognised and allowed, are: the act of March 26th, 1804, (2 Stat. at Large, 283,) for the government of Louisiana; the act of March 2d, 1805, (2 Stat. at Large, 322,) for the government of the Territory of Orleans; the act of June 4th, 1812, (2 Stat. at Large, 743,) for the government of the Missouri Territory; the act of March 30th, 1822, (3 Stat. at Large, 654,) for the government of the Territory of Florida. Here are eight distinct instances, beginning with the first Congress, and coming down to the year 1848, in which Congress has excluded slavery from the territory of the United States; and six distinct instances in which Congress organized Governments of Territories by which slavery was recognised and continued, beginning also with the first Congress, and coming down to the year 1822. These acts were severally signed by seven Presidents of the United States, beginning with General Washington, and coming regularly down as far as Mr. John Quincy Adams, thus including all who were in public life when the Constitution was adopted. If the practical construction of the Constitution contemporaneously with its going into effect, by men intimately acquainted with its history from their personal participation in framing and adopting it, and continued by them through a long series of acts of the gravest importance, be entitled to weight in the judicial mind on a question of construction, it would seem to be difficult to resist the force of the acts above adverted to.