Special Findings of Fact 123 C. Cls. nance of the Marconi aircraft apparatus on aircraft. There is no documentary evidence available to show the exact number printed, but it was customary for the Marconi Company in printing books of this type to order 500 copies. The Marconi Company was shipping its aircraft sets to various parts of the world, and the parts list or packing schedule for each set to be shipped included a copy of this handbook. Prior to 1926 the witness Van de Velde, who was part author in the preparation of the handbook and who is now Deputy Managing Director of the Marconi International Marine Communication Company, visited the shipping room where an order of 100 sets for Japan was being packed, and personally saw handbooks included in one or two of the shipping boxes. Van de Velde also personally sent copies of the Marconi handbook to affiliates and agents of the Marconi Company located in various countries. 47. A copy of the Marconi handbook was sent to Robinson, head of the Wireless Experimental Department of the Royal Air Force at Farnborough, sometime in 1922. Robinson, after reading the book, instructed his librarian to circularize it to all of the technical assistants of the department, after which he was ordered to place it in the RAF library at Farnborough, which library was open to all members of the British Armed Services. 48. Amalgamated Wireless Company (Australasia) Ltd. of Sydney, Australia, was, from 1913 onwards, the principal wireless and radio company in Australasia, which includes Australia, New Zealand and Mandated Territories. This company maintained a technical library of books on radio and related subjects. This library consisted of a couple of bookcases and some open shelves along the wall of their testing room. A copy of the Marconi handbook was sent by the Marconi Company in London to the Amalgamated Wireless Company in Sydney in August 1921; its receipt was acknowledged by that company in September 1921, and it was placed in the library of that company in that year. An inventory of the library made June 30, 1923, showed its presence on the shelves on that date. 591 Special Findings of Fact The copy of the Marconi handbook which was in the library of the Amalgamated Wireless is in evidence as defendant's Exhibit 22 and is identical with defendant's Exhibit 15. 49.. Amalgamated Wireless operated what was known as the Marconi School of Wireless. This school was established several years prior to 1921 as a commercial venture, irrespective of whether its students were employees or potential employees or whether they were outsiders buying instruction. The object of the school was to sell instruction, and there was no obligation in obtaining jobs for the students. The technical library was available to these students. Any respectable member of the public making himself known was permitted to use the library. 50. Prior to 1926 members of the Wireless Institute of Australia, a group of radio amateurs similar in nature to the American amateurs popularly known as "hams,” held periodic meetings in the schoolroom of Amalgamated Wireless (located one floor above the testing room) and the members could bring their radio apparatus to these meetings and use the testing room for calibration of their apparatus. The library was also available to this group. 51. In 1922 the witness Gilmore, not in any way connected with Amalgamated Wireless, was constructing a radio receiving set and personally consulted the Marconi handbook (defendant's Exhibit 22), using it to obtain information to assist him in the construction of his set. 52. The Marconi handbook was available prior to 1926 to any persons skilled or interested in the radio art, and is a printed publication within the meaning and intent of the patent statutes. 53. The Marconi handbook (defendant's Exhibits 15 and 22) is an instruction pamphlet, the purpose of which was to enable those skilled in the art to install Marconi radio sets on airplanes, to test them, maintain them in operation, and, in general, to acquaint those engaged in installation and servicing of the radio sets with some of the problems involved. Section III of this pamphlet deals with the subject of magneto interference, its cause and effect, and the remedies to be applied in order to prevent such interference. 229048-53-42 Special Findings of Fact 123 C. Cls. 54. After a discussion of various types of engines and methods of shielding by means of copper gauze, the Marconi handbook, under the heading "Engine Screening. The Final Cure," states on pages 19 and 20 as follows: In these cases the following system is advised as an absolutely safe and sure method of overcoming the trouble. The principle employed is to screen completely the ignition system of the engine. This, in the first place, necessitates rewiring the engine with special copper braided ignition wire. A suitable type of cable should be employed which consists of more heavily insulated wire than that normally used. The maximum voltage which is liable to occur is about 14,000 volts, and a considerable margin of safety should, of course, be allowed. Having in mind the possibility of trouble arising from time to time, the Marconi Company has taken up this subject of ignition screening in order that when cases do occur there may be some efficient remedy for the trouble. The problem consists of three main parts. There is, in the first place, the employment of the proper type of screened ignition wire; in the second place, there is the screening of the sparking plugs themselves; and in the third place, there is the constructing of a shield or screen round the magnetos. Probably the most difficult problem is that of the screened sparking plug. In cooperation with the Robinhood Engineering Works however, a very effective screened aero plug of the wellknown K. L. G. type has been evolved. The procuring of the proper type of cable is, of course, quite a straightforward proposition, and the only remaining problem is that of screening the magneto itself. This is a problem which is best solved either by the engine designers or by some method improvised to meet each individual case. It is obviously impossible to standardise where many types of fittings and types of magnetos exist. The details of the screened spark plug are shown in an illustration in the handbook and consist of a conical metal shield extending between the exterior braided shielding of the spark plug lead and the external shell which screws into the engine block. Electrical continuity is established between the braided shielding and the engine block at each spark plug. This spark plug is basically similar to that shown in the British patent to Guinness, which is illustrated in finding 40. 591 Special Findings of Fact The text of the Marconi handbook then continues as follows: If, however, cases arise where it is impossible owing to restricted space to construct a metal case surrounding the magneto or the distributor, an effective method will be to link the base of the magneto with each of the incoming ignition wires by a fairly broad strip (say, an inch in width) of copper gauze, connecting the braiding of each lead with the framework of the engine immediately at the base of the magneto. These bonding strips should be kept as short as possible and their function will consist of providing a low resistance return path for the oscillations set up in the ignition system. If magneto covers are not used the fitting of these bonding strips is absolutely essential, and should be very thoroughly carried out. As has already been pointed out, it is insufficient to screen only the ignition leads themselves. All wires connected to the magnetos are of equal importance. 55. On page 14 of the handbook, which is included under the subject "Magneto Interference," there occurs a diagrammatic illustration of an engine having ignition screening or shielding. For convenience, this figure (Fig. 2) is reproduced herewith. MAGNETO LEADS CARRIED IN TUBE OR OTHER METALLIC SHEATH SPARKING CYLINDER MAGNETO Fig. 2.-Ignition Screening. This figure, when interpreted by the entire context of the book and particularly by the quoted portions in the above finding, discloses to those skilled in the art a completely Special Findings of Fact 123 C. Cls. shielded ignition system with the spark plug leads, magneto, and spark plugs completely enclosed in metallic shielding or covers. In the figure the metallic sheath which encloses the spark plug leads is shown connected by flanges to the respective engine cylinders and to the magneto cover. This structure provides a continuity of circuit from the grounded base of each spark plug in each engine cylinder back to the metallic cover or housing of the magneto which is mounted on a conventional grounded magneto pad located at the righthand end of the engine. Such disclosure provides a return path for the ignition current through the shielding from the spark plug to the magneto. This is further emphasized by the quoted portion of the handbook in the previous finding relating to an alternative form of incomplete shielding to be used in cases in which it is impossible to construct a metal case surrounding the magneto or distributor, and suggesting the use of bonding strips in lieu thereof, the purpose of which is stated to provide a "low resistance return path for the oscillations set up in the ignition system." 56. The British patent to Lefroy (defendant's Exhibit 38) is for an ignition system for internal-combustion engines said to be particularly suitable for use with aircraft and submarine engines. A stated object is a system more reliable than the customary magneto apparatus and which will cause less interference to radio receiving apparatus than magneto apparatus when used on aircraft. The system suggested by Lefroy involves an alternator which has a condenser connected across its terminals, the condenser being tuned to the frequency of the alternator, which frequency is preferably widely different from the frequency of the radio signals it may be desired to receive in the vicinity of the engine. A rotary distributor, driven at suitable engine speed, selectively connects the condenser in proper sequence to the electrodes of the spark plug in each cylinder, at which time the condenser discharges across the electrodes of the plug. The specification explaining Figure 1 states as follows with respect to the method of connecting the spark plugs to the |