WHITE V. HBA.TH. ���293 ���sage of the gas to the inside of the reservoir and to the flame is insured." �These details relate mainly to the coni5triiction of the gas recepta- cle, it having "grooves or flutes" running down into the oil reservoir; the defendant claiming that by his invention the gas chamber is less liable to get broken, at the same time the gas cornes into more im- mediate contact with the flame in case of an explosion. But admit- ting that the defendant hasworked ont an improvement in details in the gas receptacle, still he had no right to use all the main elements of the Westland patent. Westland's patent was the application of the power of carbonic acid gas, in ; extinguishing fiames, to an ordi- nary lamp containing any inflammable oil, like kerosene, by means of a closed receptacle holding such gas. Changes in the details of con- struction of such receptacle might be patentable as improvements, but would not protect the party against the charge of an infringement of the former patent. �But the general idea of a receptacle with tubes extending into the oil is not absent from the Westland patent, for the specification sets out that gas tubes may extend up into the oil from the bottom, and that small closed vials of compressed gas may be dropped into the oil at the top. The defendant does not undertake to prove that his patent is not an infringement, by any evidence further than his state- ment in his afiBdavit that on consultation and advice with eminent experts and counsel in patent matters, he believes that his improved safety lamp is not an infringement upon anyrights properly clairaed by the Westland patent. We are of the opinion that he is guilty of an infringement for the reasons given. �The validity of the Westland patent is not questioned by the defend- ant. Capital to the extent of $20,000 bas been invested in the man- ufacture of these lamps and a successful business established. Large and numerous sales have taken place without dispute. Exclusive possession is shown for some time, though not for a long period. Under these circumstances an injunction is seldom refused. Curtis, Lavr of Patents, § 413; Orr v. Littlcficld, 1 W. & M. 13; Potter v. Muller, 2 Fish. 465. �The statement of the defendant in his affidavit that the only lamps he bas made were for experimental use, should not, in view of other undisputed testimony, affect the granting of an injunction. It ap- pears that these lamps were exhibited at the fair of the Massachu- setts Charitable Mechanics' Association, held in the fall of 1881, and that circulars were distributed to the public setting off their advan- ��� �
