Page:Federal Reporter, 1st Series, Volume 4.djvu/453

 OLABEE t). JOHNSON. 439 �Evidence bas been given at tbis hearing tô show that at the time of Jenkins' invention it was well known that both soft rubber and vulcanite became soft about the temperature of steam beat. And from tbis fact it bas been argued that inasmucb as the pacliings in question were intended to be used at the temperature of steam beat, the employment of vulcanite instead of soft rubber, as the skeleton of the pàck- ing, was simply the use of a known equivalent in place of the soft rubber wbicb forms the skeleton of the Jenkins packing. But sucb a conclusion by no means f ollows from the fact proved, wben it also appears that a packing, the skeleton of wbicb is vulcanite instead of soft rubber, wben used at the temperature of steam beat, displays properties not possessed by a packing, the skeleton of wbicb is soft rubber. �The testimony clearly shows that at the temperature at wbicb these packings were intended to be used, the Johnson packing does not lose its tougbuess or close grain; does not llake or crumble, as the Jenkins packing does ; resists press- ure and the action of steam in a manner that the Jenkins packing does not ; is more durable and far more efficient tban the Jenkins packing. Tbis difference in the action of the two packings, wben used at the temperature for wbicb tbey are intended, shows that the employment of the vulcanite in place of the soft rubber, is not the substitution of one substance for another witbout change of results, but tbat, on the con- trary, a different product is obtained. Sucb a state of faets leavea no room to contend that the Johnson packing is ob- tained by simply employing a known equivalent in place of the soft rubber wbicb forms the skeleton of the Jenkins pack- ing. �Tbe evidence also contains expressions of an opinion enter- tained by some persons of experience that ail the sulphur in excess of about 2 pef cent., used in the vulcanization of rubber, is simply mechanically mixed with and not chemic- ally combined with the gum. And, from the evidence, it bas been argued that vulcanite is soft rubber, or, as it is expressed, vulcanite is soft rubber pJîM mecbanical sulphur; and conse- quently the Johnson oompound does not differ in substance ����