Again. It is a principle of law that the right of traffic is a natural right, and that all commerce (that is intrinsically innocent) is therefore lawful, except what is prohibited by positive legislation. Traffic with the slaves, either by people of foreign nations, or by people belonging to other states than the slaves, has never (so far as I know) been prohibited by congress, which is the only government, (if any,) that has power to prohibit it. Traffic with the slaves is therefore as lawful at this moment, under the constitution of the United States, as is traffic with their masters; and this fact is entirely inconsistent with the idea that their bondage is constitutional. _Third._ "The congress shall have power to establish post offices and post roads." Who, but congress, have any right to say who may send, or receive letters by the United States posts? Certainly no one. They have undoubted authority to permit any one to send and receive letters by their posts--"any thing in the constitutions or laws of the states to the contrary notwithstanding." Yet the right to send and receive letters by post, is a right inconsistent with the idea of a man's being a slave. _Fourth._ "The congress shall have power to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." Suppose a man, whom a state may pretend to call a slave, should make an invention or discovery--congress have undoubted power to secure to such individual himself, by patent, the "_exclusive_"--(mark the word)--the "exclusive right" to his invention or discovery. But does not this "_exclusive right_" in the inventor himself, exclude the right of any man, who, under a state law, may claim to be the owner of the inventor? Certainly it does. Yet the slave code says that whatever is a slave's is his owner's. This power, then, on the part of congress, to secure to an individual the exclusive right to his inventions and discoveries, is a power inconsistent with the idea that that individual himself, and all he may possess, are the property of another. _Fifth._ "The congress shall have power to declare war, grant letters of marque and reprisal, and make rules concerning captures on land and water;" also "to raise and support armies;" and "to provide and maintain a navy."