CHALMERS SPENCE PAT. NON-OONDUCTOB CO. PIERCB. 163 �sections so as to be e;isily removed.' What is contemplated is just this, an open jacket, supported by suitable studs, or struts. That is one form in which the invention is to be carried into effect, and which it is necessary to describe in order to make his patent valid, but he is not conflned so as not to be able to use any other form which is not substantially different from that.nor ishe confined to any method of attaching the struts other than the one that is shown in the patent; that is not made an essential part of the invention at all. The object is to keep it off of the boiler, and that is to be accomplished by the use of struts adapted to that purpose. But the patentee is not confined to any particular mode of attachment on the jacket; so that the question to be considered cornes down to this, which has been repeatedly said during the progress of the argument: Whether the alleged infringing device is substan- tially different from the one embraced in the patent, and that must be dieter- mined with reference to the f unetion to be performed, or the mode in which that function is effectnated. What is the difference? Here you have a jacket with quite a large number of perforations in it. I do not profess to be a skilled mechanic, but it does seem to me to be obvions that all these struts are not necessary to furnish a support to the jacket. �" This [indicating] is supported without anything like the number of struts that are in this model [indicating.] Why are so many put in this model [indicating] '? It seems to me that it is obvioiisly to make available an advan- tage which would be derivable from the perforations of this material ; or, in other words, to make available whatever would be the resuit obtained from the meshes or the perforations by the punching of more holes than are actu- ally requiied to furnish a support to this jacket. Then you have the per- forated, or meshed jacket ; which is supported by struts. As I have already remarked, the form or mode of attaching these struts to the jacket is not made an essential part of the patent. There must be struts, but they are to be appropriately attached. Jfow, instead of being riveted or screwed on, they are punched out of the material itself — instead of taking a separate piece of material and riveting it on, the strut is made by a punch in the material of the jacket, so that you have the same function and precisely the same mode of operation. You have the jacket resting upon the boiler and supported by it in precisely the same way and by the use of precisely the same means. What difference is there in the mode of operation ? ihere is no earthly dif- ference except as to the manner in which the struts are made. There is no other difference about it. The patentee has not limited himself to any par- ticular mode of making these struts. They are to be applied with reference to the function to be performed; that is, that they shall support the jacket upon the boiler. That is what is doue here, and that is all that is done, in so far as the mode of operation is concerned. As we have already said, you have the perforations or the meshes, and these lioles, which operate precisely in the same way, so that guided by our own eyes we have no doubt that there is no fundamental difference between these devices, and we therefore grant the injunction." �Nothing material has been developed since the foregping views were «xpressed. An elaborate and able argument has been presented ��� �
