INJECTION. 630 INJUNCTION. article Tbajjsfdsion of Blood. See Hypodebmic Meuratio.n. INJECTOR (from Lat. injicerc. to throw in). An instruiucut for forcinf; wator into a boiler, in which a jet of steam niin^'les with and forces a continuous jet of water into the same hoiler against its own pressure. There are numerous forms of injectors, the chief dilferences between which consist in the relative proportions of the parts and in the means employed for changing these proportions, either automatically or other- wise, so as to adapt the instrument to the varia- tion of steam or water suijjily. The accompanying^ diagram indicates the interior arrangement of the simplest form of injector. Steam from the boiler passing through the pipe a enters the re- ceiving tube 6, where it is joined by the water which enters the pipe c. The water condenses the steam in the combining tube d, and a water-jet is formed which enters the delivery tube e and thence past the cheek valve / into the boiler below the water-line. The operation of the injector is difficult to explain in pojjular terms. Briefly stated, however, steam escaping from under pressure has a much higher velocity than water would have imdcr the same pressure and condition. The escaping steam from the receiving tube unites with the feed water in the combining tube, and gives to this water a velocity greater than it would have if escaping directly from the water-space in the boiler. The injector was invented by Henri .Jacques Giffard. a French mathematician and engineer, and is the most popular boiler-feeder now in use; practically every locomotive engine boiler is fed by injectors. The history of the development of the injector, the principles of its action and descriptions of representative forms, are given in Kneass, Prac- tice and Theory of the Injector (New York, 1898). INJUNCTION (Lat. injunctio, from injun- gere, to coniniand. from in, in + jungerc, to join ; connected with Gk. ^evynvai, zcugnynai, Skt. i/k/, to join, and ultimately with Eng. yoke). A judicial writ or process of a court of equity, com- manding a person or persons named therein to do or not to do a particular thing. It had its origin in the Roman law. under which system a some- what similar process, known as an interdict, was employed. The idea was introduced into England and Scotland by the early Chancellors, as a re- sult of their search for remedies to modify the harshness of the common law and to supplement it where inadequate to meet the ends of justice. In Scotland the remedy is still called an 'inter- dict.' The scope of its u'c and application has greatly widened until to-day it is perhaps the most important remedy of an equitable nature. The purposes for which an injunction may be employed may he described generally as fol- lows: (1) To prevent the commission of certain wrongs of a ci-il nature; (2) to protect rights; (3) to compel the restoration of rights. The greatest proportion of injunctions fall under the two classes first named, and are usually termed prevcnlite, because they operate to prevent wrongs by restraining acts, wliile the third class, called inundalory, as descriptive of their pur|)osc to com|>el the allirmative |K'rfoniiance of an act, are more rarely used. A common example of a preventive injunction is one to restrain the con- tinuance of a nuisance, such as generating un- usual quantities of black smoke and cinders in a great city; whereas one to compel the restoration of running water to its natural cliannel by a person who has wrongfully diverted it therelrom would be cla.ssed as mandatory. . railroad which has wrongfully laid track.s without lirst getting; the right of way may be com|)elle<l to remove them by one of tlie latter class of injunctions. Some other important uses of preventive injunc- tions are: To prevent tlio violation of contracts, as a contract not to sing for any one except the other party to the contract; to restrain or pre- vent waste, or nuisance; to protect patent rights, copyrights, and trademarks from infringement; and to stay proceedings in a court of law. The latter object is effected by enjoining one or both of the parties to the action from proceeding further in the cause. The injunction does not seek to oust the court of law of its jurisdiction or to restrain the judge in the exercise of liis judicial functions. The prerogative will be exer- cised in this way only when the prf)secution of the action or t!ie enforcement of a judgment will result inequitably to one of the jiarlies. Where e(|uitable defenses are permitted in a legal action, as in New York, there is seldom reason for sicli interference. A court of equity will sometimes enjoin a party or parties, within its own jurisdic- tion, from ])rosecuting an action in another juris- diction. A notable example of such exerci.se of power is where a I'nited States court restrains all creditors prosecuting actions in State courts for the enforcement of their claims against a bankrupt from proceeding further in their actions, thus leaving all matters relating to his estate to its own determination. A court of equity follows the same rules in this summary method of procedure as in the exer- cise of its other functions, and tlierefore will only grant an injunction when the remedy at law will be inadequate to give a party who is wronged the complete relief to which he is entitled. One reason for issuing an injunction is to prevent irreparable damage. Where, for example, a per- son maintains an ofTensive nuisance which ope- rates to keep away customers from a near-by shop, the shopkeeper could recover damages in a court of law, but. as a long delay may ensue before his cause can he reached, his business may be ruined in the meantime. His damages, in that event, would be hard to estimate, and the wrongdoer might be financially irresponsible, and. therefore, that relief would be manifestly inadequate to pro- tect him; whereas, if the nuisance is immediately abated, in compliance with an injunction order, he is saved irreparable damage. Much criticism and controversy has been occasioned by the class of cases where the courts have enjoined labor agitators and sympathisers from inducing or coercing contented workingmen to strike, for the purpose of infiictins injury and damace on their employers, and thereby forcing them to grant the concessions demanded by their organizations. This
