Findings of Fact 117 C. Cls. fully follows as he manipulates the gate, sometimes toward the open position and other times toward the closed position, but never in a completely open or closed position. THE PRIOR ART 32. The following patents were available to those skilled in the art prior to September 21, 1929, the filing date of the MacLaren patent, the first filing date of the two patents in suit: British patent to Smart and Tucker No. 152,190, complete accepted October 14, 1920 (defendant's exhibit 1); French patent to Montchàtre No. 565,735, délivré November 10, 1923, and translation thereof (defendant's exhibits 2 and 2a, respectively); British patent to Massolle, et al., No. 157,744, complete accepted March 30, 1922 (defendant's exhibit 3); United States patent to Nakken No. 1,928,760, issued October 3, 1933, on an application filed May 21, 1929 (defendant's exhibit 4); United States patent to Winther No. 1,700,393, issued January 29, 1929 (defendant's exhibit 5); United States patent to Case No. 1,625,409, issued April 19, 1927 (defendant's exhibit 6); United States patent to Langmuir No. 1,273,627, issued July 23, 1918 (defendant's exhibit 7). The above enumerated patents are made a part of this finding by reference. 33. British patent to Massolle 157,744 (defendant's exhibit 3) relates to improvements in circuits for electric amplifiers of the type in which the grid-cathode path of a succeeding tube is connected in series with the anode-cathode path of a preceding tube and has for its object the provision of means for adjusting the average potential at the grid. The specification refers to a prior patent of Massolle's, No. 157,733 (defendant's exhibit 25-A) which discloses such a circuit. Massolle in the present specification states with respect to his prior patent that such a type of circuit will demand a large normal current in the amplifier tube, which is generally undesirable." This is the same problem which is present in the similar circuit of Mae Laren, i. e., the grid-cathode path of MacLaren's amplifier tube being connected in series with the anode-cathode path of the preceding tube, which problem Aceves attempted to deal with in the Aceves patent here in issue. 653 Findings of Fact Massolle in the present specification suggests applying an auxiliary potential at the grid of the amplifying tube through the use of an auxiliary resistance so that the potential of the grid may be controlled with respect to its cathode. Four different circuits are shown in which the grid potential is thus controlled. In the circuits shown in Figs. 1, 2 and 3, the input is connected to the first tube in the conventional manner, i. e., the input being fed to the grid and cathode of the first tube, and these circuits are not material to the present issue. The circuit shown in Fig. 4 of Massolle is reproduced herewith. The input device indicated at Z is broadly termed "a controlling device Z" which Massolle states may consist of a photoelectric cell. The output device indicated in this figure by R is a telephone receiver or other indicator. Massolle's complete description of Fig. 4 is as follows: Another auxiliary arrangement, which makes it possible to feed all the tubes and also the controlling member Z from a single anode battery B, is shown in Figure 4, in which the path of the current is clearly indicated. With two tubes this arrangement works just as well, as with separate batteries for each anode circuit, provided that the useful resistance R (i. e., a telephone receiver or other indicator) be connected up, as shown in the drawing, so that it does not lie in the anode circuit of the tube I. If it were connected up at X, that is to say, in series with the tubes I and II, which are connected Findings of Fact 117 C. Cls. up in parallel to one another, then the tension between a and k2 would no longer be constant but would fall with the increase of current in the tube II. The amount of amplification in the positive region of the valve is equal to the ratio, of the grid current variations, to the simultaneous anode current variations, and this ratio may advantageously be determined by a suitable selection of tubes. Furthermore, the alterations in the distribution of potential over the anode cathode path and the grid cathode path are greatest when these paths have substantially equal resistances. It is, therefore, preferable to adapt the grid-cathode output of the succeeding tube to the anode-cathode output of the preceding tube. Under these conditions the succeeding tube is constructed for greater anode power than the preceding tube and the anode-cathode outputs of the tubes will then stand in a ratio corresponding to the intensification figure. Increased anode power is obtained by connecting the tubes I and II in parallel as illustrated in Figure 4 of the drawings. 34. In the circuit shown in Fig. 4, the input circuit is not connected in the conventional manner but is connected to the plate and grid of the first tube. In this circuit as disclosed, the first tube is degenerative and will operate as a cathode follower and will tend to compensate whenever the grid of the second tube becomes positive and draws current. The two bias batteries by means of which the regulatory potential may be applied to the grids, are shown in this circuit at h, h ̧. These batteries are connected to the respective grids by means of resistors W1 W2. 35. An inter partes test was conducted by defendant's expert Stodola during the trial of this case, in which this circuit was tested. Voltage gain of the system shown in Fig. 4 of Massolle was tested both with the cathode follower circuit as disclosed therein and with the conventional type of grid connection. Voltage gain was greater with the conventional type than with the cathode follower type connection. As a cathode follower gives a power gain and not a voltage gain this would be an expected result. The circuit of Fig. 4 operates In phase therewith. 653 Findings of Fact as a cathode follower or compensating tube feeding into an amplifying tube, through a direct connection between the cathode of the compensating tube and the grid of the amplifier. 36. The United States patent to Nakken (defendant's exhibit 4) relates to amplification by means of electronic tubes. For convenience, the circuit diagram of Nakken is reproduced herewith. The system disclosed in this patent contemplates the use of three tubes. The input to the first tube consists of a photoelectric cell which the Nakken specification indicates is primarily for the purpose of producing pulsating or alternating energy impulses and is not a photometer." The photoelectric cell is connected to the first tube of the Nakken amplifier system in the conventional manner, i. e., to the grid and cathode thereof. The Nakken disclosure shows the cathode of each preceding tube directly connected with the grid of the succeeding tube, so that with the exception of Photoelectric cells are and have been for a long time a conventional input device for talking motion pictures. They are actuated by a small beam of light projected through a sound track on a film as it passes an opening, thereby giving rise to a pulsating output of the photoelectric cell in accordance with the sound track, which output is fed into the initial tube of an electronic amplification system. Findings of Fact 117 C. Cls. the first tube the grids of the other tubes will operate in the positive region of grid potential. The last tube in the Nakken system operates as a conventional amplifier, having its output circuit connected to a loud speaker or equivalent device. Two high impedances, each consisting primarily of inductance and having relatively low ohmic resistance, provide a return path for the direct current component back to the battery and reject the fluctuating currents of the signal. These impedances, which are connected respectively between the grids and cathodes of the second and third tubes, function to limit the normal anode currents of the second and third tubes. The polarities of the battery for the photoelectric cell are such that, under normal operating conditions, the grid of the first tube has a negative bias with respect to its cathode, which is the normal operating situation for a high impedance source such as a photoelectric cell. The output of the first tube is applied to the grid of the second tube. The grid of the second tube operates in the positive region and will, under certain circuit conditions, tend to introduce distortion in the system. The output of the second tube is taken between its cathode and plate and this is applied to the grid-cathode space of the third or amplifier tube. This second tube and its associate circuits form a cathode follower system in which the output is in phase with the input, and while there will be no compensation for any distortion introduced into the system at the input of the second tube, the second tube will act to compensate for any distortion due to the operation of the grid of the third tube in the positive region. In other words, while the system will not compensate for distortion introduced into the system in front of the second tube, the second tube will prevent further distortion and compensate for positive current flow in the grid of the third tube. 37. In a comparative inter partes test of the MacLaren, the Aceves, and the Nakken circuits made by defendant's expert, and in which a record player was used as a source of input, there was a noticeable reduction in distortion and noticeable increase in volume between Aceves as compared to MacLaren. There was no appreciable change in either distortion or volume as between the Nakken circuit and the |