Opinion of the Court. where large and continuous supplies are obtained by unintermitted pumping, for days and weeks at a time, experience has shown that the quantity of water has gradually but perceptibly improved, as in the case of the wells at Belleville, heretofore mentioned, where an amount of water is emptied largely exceeding the rainfall upon the entire territory not shut out from the valley by outcropping rocks upon three sides and open to salt water upon the fourth, and no practical diminution of the height of the water is observed. "One peculiar characteristic of a driven well, as distinguished from the bored artesian well, is that the driven well is for use in soil where no rock is to be penetrated, and where the pressure of the atmosphere is free to act upon the surface of the water in the earth surrounding it; while the artesian well is usually, if not always, bored into a rock stratum, and is supplied with water through fissures in the rock instead of through the earth itself surrounding the entrance or opening to the well." In describing the mode of constructing a driven well under the patent, the same witness states that the pipes in general use, which are driven into the ground, have openings for the admission of water into them near the lower end, usually extending up around the sides of the pipe from fifteen inches, sometimes, up to several feet. These holes are about threeeighths of an inch square, over which upon raised rings is placed a screen of perforated brass, having openings of a size giving from one hundred and fifty to three hundred to the square inch. When the pump is first applied to such a pipe, a small amount of mud or sand is at first usually brought up, coming from a greater or less distance from the outside of the tube, but not leaving an open space around the perforations, as these are not large enough to admit of but the smaller particles near the tube. It leaves interstices between the coarser particles in it, and through which the water flows, and which are constantly filled with water. The swell on the point of a driven well tube, shown in the drawing and marked a, is made larger in diameter than the tube itself, or the coupling to the tube, for the reason, as stated, that there is a certain elasticity in the soil, which, Opinion of the Court. after driving a certain sized instrument into it, causes the hole to contract after the point passes, and it was thus found necessary to make the point somewhat larger than even the couplings of the pipe, for the purpose of partially relieving the pipe and couplings from the great friction resulting from their passage through the hole thus contracted. After reaching a waterbearing stratum of the earth, the earth at once settles around the point and tube, even more rapidly and effectually than it does above the water stratum, and the hole made by driving an instrument into a water-bearing stratum and withdrawing it will remain intact but a very short time, unless that stratum is composed of gravel and similar substances, thus leaving the entrance to the pipe in close contact with the earth and effectually protecting the entrance from the admission of air or free water standing between the pipe and the earth surrounding it. The effect, therefore, of this feature of the tube is more effectually to make air-tight the point or lower part of the tube. The scientific theory stated by the expert witness on behalf of the complainants, as an explanation of the principle according to which the patented process operates in furnishing a supply of water by means of a driven well, is not contradicted or qualified by any opposing testimony, and, so far as we can know, is not inconsistent with accepted scientific knowledge. The general introduction and use of driven wells since the date of the patent, both in this country and abroad, strongly corroborates the supposition that their construction and operation is based upon the application of some natural force not previously known or used. It appears from the evidence in this cause, that the process of making driven wells was subjected to experimental tests by the best authorities in England, and found so successful that it was used to great advantage in the supply of water to British troops in the Abyssinian expedition under General Napier, in 1867. In view of these premises, Judge Benedict, in Andrews v. Carman, 13 Blatchford, 307, 311, construed the patent in suit according to the following extracts from his opinion in that case: "The difference between the new process under consideration and the old is, that the pressure of the atmosphere, Opinion of the Court. which, in the ordinary well, operates at the sides and bottom of the well pit to maintain an equally distributed atmospheric pressure upon the water, whereby the flow of water into the well is made dependent upon the force of gravity, in the new process is removed from within the well pit, and ceases there to operate against the inward flow of water, so that the pressure of the atmosphere operates with its full power to force the water in the earth from the earth into the well pit, and without any opposition caused by meeting, in its flow, the pressure of the atmosphere at the sides or bottom of the pit. This process involves a new idea, which was put to practical use when the method was devised of fitting tightly in the earth, by the act of driving without removing the earth upwards, a tube, open at both ends, but otherwise air-tight, and extending down to a water-bearing stratum, to which is attached a pump, a vacuum in the well pit, and at the same time in the waterbearing stratum of the earth, being necessarily created by the operation of a pump attached to a pipe so driven. * * * * * "The novelty of the process under consideration does not lie in a mechanical device for sinking the shaft or raising the water to the surface, but in the method whereby water, by the use of artificial power, is made to move with increased rapidity from the earth into the shaft, whence it results, that a tube but a few inches in diameter, driven down tightly to a waterbearing stratum of the earth, affords an abundant supply of water to a pump attached thereto, and constitutes a practical and productive well. Such an invention is without the field of mechanical contrivance. It consists in the new application of a power of nature, by which new application a new and useful result is attained. There is no new product, but an old product water-is obtained from the earth in a new and advantageous manner. * * * * * "In the specification we find stated more clearly the distinguishing feature of the process, wherein it differs from any process before adopted for procuring a supply of water from the earth; for the specification says that an instrument is to Opinion of the Court. be driven into the ground until it reaches water, having the earth tightly packed around it. It is by means of this packing of the earth tightly around the tube that the force developed by the creating of the vacuum in the well pit is brought to bear directly upon the water lying in the water-bearing stratum, to force it into the well pit; and this driven tube forms the well pit of the new invention, for, as stated, it is to be a tube made airtight throughout its length, except at its lower end, where are to be perforations for the admission of water, and through and from which the water may be drawn by a pump. The specification also mentions the vacuum, and points out where it is to be created, for a vacuum must of necessity be formed in the well pit and in the water-bearing stratum, by operating a pump attached to such a tube, so driven into the earth. * * * * * "I therefore understand this patent to be a patent for a process, and that the element of novelty in this process consists in the driving of a tube tightly into the earth, without removing the earth upwards, to serve as a well pit, and attaching thereto a pump, which process puts to practical use the new principle of forcing the water in the water-bearing strata of the earth from the earth into a well pit, by the use of artificial power applied to create a vacuum, in the manner described." Assuming this construction of the patent to be correct, it is, however, now contended on behalf of the appellant that the reissue is void because the invention described in it is not contained in the original patent. It is to be observed that the scientific theory and principle, the application of which is supposed to constitute the invention of Colonel Green, are not set forth either in the original or reissued patents. This feature was commented upon by Mr. Justice Blatchford in Andrews v. Cross, 19 Blatchford, 294, 305, as follows: "It may be that the inventor did not know what the scientific principle was, or that, knowing it, he omitted, from accident or design, to set it forth. That does not vitiate the patent. He sets forth the process or mode of operation which ends in the result, and the means for working out the process or mode of operation. The principle referred Opinion of the Court. to is only the why and the wherefore. That is not required to be set forth. Under § 26 of the act of July 8, 1870, 16 Stat. 201, under which this reissue was granted, the specification contains a description of the invention and of the manner and process of making, constructing, compounding, and using it,' in such terms as to enable any person skilled in the art to which it appertains to make, construct, compound, and use it; and, even regarding the case as one of a machine, the specification explains the principle of the machine, within the meaning of that section, although the scientific or physical. principle on which the process acts when the pump is used with the air-tight tube, is not explained. An inventor may be ignorant of the scientific principle, or he may think he knows it and yet be uncertain, or he may be confident as to what it is, and others may think differently. All this is immaterial, if by the specification the thing to be done is so set forth that it can be reproduced." The particulars relied on to establish the proposition that the reissued patent describes a different invention from that contained in the original are as follows: 1st. It is said that it is essential to the success of the process that the end of the tube should form an air-tight connection with the surrounding earth; that the tube itself should be air-tight, and attached to a pump with an air-tight connection; which elements are set out in the reissued patent, and are not contained in the original. Upon this point, speaking of the original patent, Judge Shiras, in the Circuit Court for the Southern District of Iowa, in Andrews v. Hovey, 5 McCrary, at page 195, said: "He describes a driving-rod, having a swell thereon, which is to be driven into the ground and then withdrawn, and a tube of a diameter somewhat smaller than the diameter of the swell of the drill-rod is to be inserted in the hole thus made. In no part of the description is it said, either expressly or by fair implication, that the tube, when inserted, must fit so closely into the opening made by the rod that no air can pass down on the outside of the tube to the water, nor is it stated that the pump must be attached by an air-tight connection to the |