Opinion of the Court. the rubber is in the centre of the portion which is to be subjected to the wear of the piston-rod. One of the features of the Gately packing consists in locating the rubber between the part of the packing which is to be exposed to wear and the walls of the box: and the elastic portion is located where it will not be subjected to wear. Moreover, neither of the Keirby patents shows layers of canvas cut bias and so arranged in the packing strips that the ends of the threads are the parts submitted to wear: and neither of them shows layers of canvas cut bias, located so that the ends of their threads will wear upon the piston-rod, and secured to one another and the rub-. ber core by vulcanization; but on the contrary, as the Keirby packings wear they are continually presenting to the pistonrod surfaces having new characteristics. The Wise packing is similar to the packing of the Keirby patents, except that outside of the canvas or other fabric an exterior metallic armor is provided, which takes the wear of the piston-rod. All that is above said in relation to the packing of the Keirby patents is true of the Wise packing, and in addition, it was intended in the Wise packing that the metallic exterior should be the wearing portion and should make the joint between the packing and the piston-rod. None of these packings show anything which bears upon the Gately invention, except that they show piston-rod packings, but not having the construction or the characteristics found in the Gately invention. As before remarked, the McBurney patent describes only that part of Gately's invention which forms the wearing surface of the Gately packing. The McLean packing was made up of two parts, one consisting of vulcanized rubber and the other of cork. Of course the front and back portions of this packing could not be united by vulcanization, and the two parts were secured together by a metal strip, which was wound around both the cork and the rubber. In using this packing, the metal strips were first subjected to wear, and, when they were worn through, the cork took the wear; and when this occurred the rubber backing and the cork wearing portion were no longer secured the one to the other, but became separate and independent pieces Opinion of the Court. in the stuffing-box. The character of the wearing surface altered, until such time as the two parts were left free in the box. When the packing was removed from the box, it would come out in two pieces, the rubber back being one piece and the cork front the other piece. This packing does not show such a wearing portion as the Gately patent shows, and is not a homogeneous article, made one by the vulcanization of the parts together, but is a compound article made up of two pieces so tied or secured together that, after a slight amount of wear, the parts cease to perform the purposes for which they were originally intended. The Gately packing is made at the beginning and sold as one homogeneous strip, and exists as such until it is rendered useless by extreme wear, and taken from the stuffing-box; and even at that time it is still a unit, and not two separate pieces disconnected from each other. The Tuck patent of 1852 describes canvas coated with rubber, unvulcanized, which canvas is to be rolled upon itself and used in the stuffing-box in connection with rigid wearing surfaces, the object of the canvas being to force such surfaces into contact with the piston-rod. This patent does not show a single feature of the Gately invention. The Tuck patent of 1854 shows nine forms of packing, none of which are vulcanized. All of the forms consist practically of a rubber core and canvas rolled around such core. In some cases the core is located centrally and in some at one side of the roll; but in all the canvas is rolled upon itself or upon the core, and, when the packing is in use and is subjected to wear, the character of the surface presented to the moving pistonrod is continually changing, it being part of the time a rubber surface and part of the time a canvas surface. The Tuck patent of 1855 shows five different forms of packing, which are, in substance, copies of five examples shown in the Tuck English patent of 1854. There is no vulcanization referred to in this patent of 1855, and the wearing surface is composed of canvas cut on the bias, and rolled around the elastic or rubber portion, which itself is saturated with rubber. The rubber core is not insisted upon as a necessity; but the patent says that it is used at times for the purpose of giving greater elasticity to the packing. Opinion of the Court. All three of the Tuck patents show packing which was different in principle from the Gately packing, in that the wearing portion was of such a character that it was continually changing in its conditions during the wear of the packing, and did not, like the Gately packing, present continuously to the piston-rod a surface having the same characteristics. In the Gately packing, the wearing portion of it is not formed by rolling canvas either upon itself or upon a rubber core, but is formed of layers of canvas secured to themselves and to the rubber backing by vulcanization. In fact, the Gately packing could not be made if it were impossible to vulcanize rubber, whereas all of the Tuck packings are capable of being made independently of vulcanization, their structure being such that canvas is used as a binding or cementing means in connection with any adhesive compound to keep the packing together and to form the strips. In the Gately packing the parts are kept together and in place solely by reason of the fact that the rubber has been subjected to vulcanization, thus making the packing a homogeneous whole, and not a strip rolled up upon itself and thus kept together. Therefore, none of the patents introduced by the defendants show the Gately invention. It is true that McBurney shows a part of the combination or article patented by Gately, and McLean shows a rubber backing; but the invention of Gately was new and patentable: As to the other evidence and exhibits put in by the defendants, none of them show a rubber backing of pure gum and a front wearing portion united by vulcanization to the back portion, so as to produce a homogeneous article; but they all show something which Gately dispensed with, that is, an elastic core and a wrapping of fibrous or textile material around such core. Where the packing has a covering of textile material wrapped around the elastic portion of the packing, the wearing surface presented to the piston-rod cannot continuously, as in the Gately packing, be identically the same surface in character, nor can such feature exist, unless Gately's or McBurney's wearing portion and the elastic backing are united as a homogeneous whole by the process of vulcanization. Within the requirements of Atlantic Works v. Brady, 107 Opinion of the Court. U. S. 192, 200, we think that Gately made a substantial discovery or invention, which added to our knowledge and made a step in advance in the useful arts; that within the case of Hollister v. Benedict Manufacturing Co., 113 U. S. 59, 73, what Gately did was not merely the work of a skilled mechanic, who applied only his common knowledge and experience, and perceived the reason of the failure of McBurney's packing, and supplied what was obviously wanting; and that the present case involves not simply "the display of the expected skill of the calling," involving "only the exercise of the ordinary faculties of reasoning upon the materials supplied by a special knowledge, and the facility of manipulation which results from its habitual and intelligent practice," but shows the creative work of the inventive faculty. The defendants made two forms of packing, one of them identically the packing of the Gately patent; in the other, a little over one-half of the packing was constructed identically in accordance with the Gately invention, and a little less than one-half was so constructed, except that the canvas was not cut on the bias. This feature made the packing relatively stiffer and injured it; and, even as it was made, like surfaces, or surfaces of the same character, were presented to the pistonrod throughout the entire wear of the packing in the box. It is remarked by Judge Nixon in his opinion, as a fact not to be overlooked and having much weight, that the Gately packing went at once into such an extensive public use, as almost to supersede all packings made under other methods; and that that fact was pregnant evidence of its novelty, value and usefulness. Smith v. Goodyear Dental Vulcanite Co., 93 U. S. 486, 495, 496; Loom Co. v. Higgins, 105 U. S. 580, 591. It may also be added, that the evidence shows that the Gately packing was put upon the market at a price from 15 to 20 per cent higher than the old packings, although it cost 10 per cent less to produce it. The decree of the Circuit Court is Affirmed. The CHIEF JUSTICE and MR. JUSTICE GRAY did not hear the argument and took no part in the decision of this case. Statement of the Case. GAGE v. BANI. APPEAL FROM THE CIRCUIT COURT OF THE UNITED STATES FOR THE NORTHERN DISTRICT OF ILLINOIS. No. 20. Submitted January 29, 1891.- Decided October 26, 1891. Where a tax deed in Illinois is relied on as evidence of paramount title, it is indispensable that it be supported by a valid judgment for the taxes, and a proper precept authorizing the sale. It is well settled in that State that a tax title is purely technical, and depends upon a strict compliance with the statute; and that the giving of the particular notice required by the statute is an indispensable condition precedent to the right to make a deed to the purchaser or his assignee. The owner of land in Illinois, sold for the non-payment of taxes, or of special assessments, is entitled to be informed in the statutory notice whether the sale was for the non-payment of a tax, or of such an assessment; and a notice which informs him that the sale was made "for taxes and special assessments, authorized by the laws of the State of Illinois" is a defective notice. The right of an occupant of land in Illinois, sold for the non-payment of taxes or special assessments, to personal notice of the fact of sale, before the time of redemption expires, is expressly given by the Constitution of Illinois, and is fundamental: and upon a direct issue whether such notice was given, the owner testifying that he did not receive notice, the evidence should be clear and convincing that it was given as required by law, before the tax title can be held to be paramount. THE Court stated the case as follows: The appellee Bani, claiming to be the owner in fee, and being in the actual possession, of lots 12 and 13 in block 2 of Lewis Heintz's subdivision of twenty-four acres in the town of Lake, Cook County, Illinois, brought this suit, December 6, 1883, for a decree setting aside and declaring void three several tax deeds, covering those lots, and which were held by the defendant Asahel Gage. It was alleged in the bill that the plaintiff derived title by warranty deed from Peter Caldwell and wife, of date May 15, 1882, the consideration being $3000; that his purchase was without notice of any adverse claim or title; that from the |