The first U.S. patent is issued, to inventor Samuel Hopkins for a potash process.

Potash () is the name used for various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, which refers to plant ashes or wood ash soaked in water in a pot, the primary means of manufacturing the product before the Industrial Era. The word potassium is derived from potash.Potash is produced worldwide in amounts exceeding 90 million tonnes (40 million tonnes K2O equivalent) per year, with Canada being the largest producer, mostly for use in fertilizer. Various kinds of fertilizer-potash constitute the single greatest industrial use of the element potassium in the world. Potassium was first derived in 1807 by electrolysis of caustic potash (potassium hydroxide).

A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention. In most countries, patent rights fall under private law and the patent holder must sue someone infringing the patent in order to enforce their rights. In some industries patents are an essential form of competitive advantage; in others they are irrelevant.: 17 The procedure for granting patents, requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims that define the scope of protection that is being sought. A patent may include many claims, each of which defines a specific property right. These claims must meet various patentability requirements, which in the US include novelty, usefulness, and non-obviousness.Under the World Trade Organization's (WTO) TRIPS Agreement, patents should be available in WTO member states for any invention, in all fields of technology, provided they are new, involve an inventive step, and are capable of industrial application. Nevertheless, there are variations on what is patentable subject matter from country to country, also among WTO member states. TRIPS also provides that the term of protection available should be a minimum of twenty years.