In Stephens v. Cady (1852) 55 U.S. 528, the point decided was that, by a sale of the copperplate engraving of a map on execution from a State court against the owner of the copyright, the purchaser acquired no right to strike off and sell copies of the map..It was held that a copyright was not subject to sale on execution, but it could be reached by a creditor's bill. The court doubted, however, whether a transfer by sale under a decree would so pass the title as to protect a purchaser, unless by a conveyance in conformity with the statute. Mr. Justice Nelson, delivering the opinion of the court, said (p. 530): "But from the consideration we have given to the case, we are satisfied that the property acquired by the sale in the engraved plate, and the copyright of the map secured to the author under the act of Congress, are altogether different and independent of each other, and have no necessary connection. The copyright is an exclusive right to the multiplication of the copies, for the benefit of the author or his assigns, disconnected from the plate, or any other physical existence. It is an incorporeal right to print and publish the map, or, as said by Lord Mansfield in Millar v. Taylor, 4 Burr, 2396, `a property in notion, and has no corporeal tangible substance.'" The Supreme Court held, where the copyright for map had been taken out under the act of Congress, a sale upon execution of the copper-plate engraving from which it was made did not pass the right to print and sell copies of the map.