Legal Definitions - X-patent

An X-patent refers to a United States patent that was issued before the standardized numbering system was established by the Patent Act of 1836. Prior to this Act, patents were not assigned sequential numbers in the way they are today. When the 1836 Act introduced a new, continuous numbering system starting from number 1, an "X" was added to the identification numbers of these older, pre-1836 patents. This was done to distinguish them from the newly issued patents and prevent any confusion or duplication in the numbering sequence.

• Imagine an inventor named Samuel Hopkins, who in 1790, received the very first U.S. patent for a new method of making potash. At the time, there was no formal numbering system for patents. Years later, after the 1836 Patent Act, when the Patent Office began organizing and cataloging all existing patents under the new system, Samuel Hopkins' original patent would have been designated as an X-patent. This classification would ensure it was recognized as a valid, early patent without conflicting with the new numerical sequence that began with the 1836 Act.

• A historian researching early American industrial machinery might discover a patent granted in 1820 for an improved cotton gin. The original patent document might only bear the inventor's name and the date of issue. However, if this patent were to be referenced in a modern legal or historical context, it would be identified as an X-patent. This designation immediately tells researchers that it belongs to the era before the standardized numbering system and was retroactively assigned an "X" prefix to integrate it into the comprehensive historical record of U.S. patents.

• Consider a museum curator who is cataloging a collection of early American agricultural tools. They find a unique seed planter from 1834 with an inscription indicating it was patented. When the curator searches for the patent documentation, they would find that this invention's patent is listed as an X-patent. This signifies that the patent was granted before the 1836 Patent Act, and its "X" designation helps to differentiate it from patents issued under the subsequent, sequentially numbered system, while still acknowledging its legal validity and historical significance.