few general rules can be given to determine the question. The statute affords no definition; it grants to the patentee, for a term not exceeding 17 years, the “exclusive right to make, use, and vend” his invention or discovery throughout the United States. It is therefore an infringement either to make, use, or sell without license what another has patented. In determining the question of infringement, the leading inquiry is whether there is substantial identity between the two things; if so, there is an infringement. If there is a difference, the inquiry is whether it is substantial or merely colorable. When a machine or a process is patented, it is not an infringement to sell the article produced, unless the product is also patented. Thus, where one person owned the patent right for using a machine for making bedsteads in a certain county, it was held to be no infringement for another person operating a similar machine in an adjoining county to sell his bedsteads in the county first named. A combination is not infringed by the use of one or more of its parts, if those parts are not specially patented, and if they do not substantially constitute the combination. As to infringement by the sale of the thing patented, it must be a sale of the whole thing, and not of the different parts or materials out of which it may be made, unless they be sold with the intent that they should be put together and so make the whole machine. The owner of a patented machine may prolong its existence and utility by repair as long as he can; but he may not construct a new machine under pretence of repairing the old one. A patentee is seldom permitted to call that an infringement which imitates nothing that is directly and explicitly stated in the specification. In case of infringement, the statute provides for the recovery of damages in the circuit courts of the United States. An injunction may also be obtained restraining the alleged offender from further using or selling the patented article. Frequently an injunction will not be granted until the plaintiff's right and the defendant's wrong doing have been established at law. But when the infringement is certain, a court of equity will proceed at once; and sometimes, on petition of the patentee, they direct a trial at law, and order the defendant to keep an exact account of all that he makes or sells in supposed infringement of the patent, to be rendered if the trial results in establishing the infringement.—The average annual number of applications for American patents is about 20,000. In 1874 there were 21,602 applications, and 13,599 patents were granted, including reissues and those for designs; 2,561 applications were allowed for which patents did not issue on account of non-payment of fees. The number of caveats filed was 3,181. The receipts of the patent office amounted to $738,278, and the expenditures to $679,288. From 1836 to 1875 more than 158,000 patents were issued. Since 1866 illustrated specifications have been printed by the government; but information concerning patents granted prior to that year is accessible to the public only in manuscript records, the commissioners' annual reports, judicial reports, &c.—Foreign Patent Systems. The English patent system and that of the United States have much in common, but there are some marked differences. The former dates from the reign of James I.; but in 1852 the entire system was regulated by act of parliament. The term “manufactures” in the statute of monopolies has been construed to embrace anything made by the hand of man, including machinery and products, as well as processes or methods of producing manufactured articles, and improvements of the same. In recent statutes the term “inventions” is used, which has the same comprehensive meaning. Prior to 1852 separate patents were necessary for England, Ireland, and Scotland, and were obtained, at a cost of between £300 and £400. One patent is now sufficient for the whole United Kingdom. It may be obtained for 14 years, and at the expiration of that term the owner, by petition to the queen in council, may have an extension for 7 or even 14 years. The cost of obtaining a patent for 14 years amounts to about £175; but the patentee may secure a term of three years for £25, or seven years for £50 more, to be paid at the end of the first three years. At the expiration of seven years he may extend the patent for seven years more, by the payment of £100. By filing a provisional specification, the applicant may secure protection for his invention for six months. The commissioners of patents are the lord chancellor and master of the rolls, the law officers of the crown for England, Scotland, and Ireland respectively, and such other persons as the queen may appoint. A marked difference between the English and American system is, that the former gives a patent to any person who first introduces an invention into the realm, without regard to who is the inventor or in what country the invention may have been patented. The practice therefore has been common, when an invention has been patented or made public in a foreign country, for some other than the owner to send a description to England and obtain a patent for it there. In 1875 a bill was introduced into the house of lords by the lord chancellor to amend the law concerning patents by removing several important defects, one of the most prominent of which was the granting of letters patent without any examination into the merits or novelty of the invention. It was proposed in the new law to issue patents only after examination of the invention; to abolish the practice of granting patents to those who merely introduce inventions from abroad; and to fix the term at 14 years without privilege of extension. The policy of granting patents has been recently much questioned in England. The number of English patents annually issued is between 4,000
