Reporter's Statement of the Case 116 C. Cls. will have an intermediate boiling point depending upon the relative quantities present. Methyl bromide boils at a temperature of 40° F. These boiling points are given at atmospheric pressure and these substances when enclosed in hermetically sealed containers will remain in a liquid state although the temperature external to the containers may be above the boiling points. When the containers or ampules are broken, the released liquid upon contact with the air quickly absorbs the heat in the air surrounding it, resulting in the liquid's volatilizing rapidly into gas. Thus, at an ordinary room temperature of 72° F. hydrocyanic acid would evaporate rather rapidly while methyl bromide with a boiling point of 40° F. would volatilize into methyl bromide gas almost instantaneously. 6. In the use of insecticides it is necessary (a) to provide a sufficient concentration of the fumigant per cubic foot of the space utilized to produce a lethal dose for the insects and their eggs, and (b) a sufficient time interval for the fumigant to suitably penetrate the clothing or other material containing the insects and eggs, and for absorption of the fumigant by the insects and eggs. Both quantity of fumigant and time of exposure are thus involved. An ideal condition would be represented by a hermetically sealed or impervious enclosure in which clothing or other materials could be placed, together with the speedy release or volatilization of the fumigant used so that a lethal concentration could be attained in the receptacle as soon as possible, thereby reducing the total duration of the fumigation process. In numerous instances it is impracticable or impossible to use an airtight receptacle for fumigation purposes. Such a situation would be exemplified by the fumigation of a room, closet, or a partially pervious container, in all of which leakage would occur. It is conventional procedure to provide an excess amount of fumigant for such contingency. This may be done either by the release of an extra quantity of fumigant at the beginning of the fumigation process or by releasing additional fumigant at intervals during the fumigation process. It is immaterial which method is used as long as sufficient fumigant is volatilized to maintain a lethal dose for the necessary period of exposure. 685 Reporter's Statement of the Case THE PATENT IN SUIT 7. The introductory statement of the specification describes the invention in the following phraseology: This invention relates to means for distributing gaseous or volatile substances, particularly such as are of a poisonous nature, intended for use as fumigants, insecticides, germicides, etc., commonly containing hydrocyaníc acid gas or other cyanogen compounds in gaseous or liquid form. The invention aims to provide a safe and inexpensive package of convenient size for ordinary domestic use, and which may be transported and sold without special precautions against accident. Fig. 1 of the patent, which shows the preferred embodiment selected for the purpose of illustration, is reproduced herewith. As disclosed and described in the specification, this consists of an elongated sealed glass tube or ampule 11 containing a fumigant in liquid form. This ampule is provided at its middle with a reduced or constricted portion 12 that may be readily fractured to permit the escape of the fluid contents. The specification describes the enclosed fumigant liquid as preferably a gaseous combine containing hydrocyanic acid and cyanogen chloride, or the like, absorbed in a liquid or mixture of liquids. In this connection, the specification states: * * the invention is not restricted to these particular gases and materials, as it is evident that the principal applies to packaging any gas emitting substances or gas that can be handled only with difficulty or danger. The glass ampule is surrounded with a diffusing and vaporizing medium 14 stated to be of absorbent cotton or other material permeable to gas and interposing a substantial re 116 C. Cls. Reporter's Statement of the Case sistance to the free flowing away of the liquid contents when the container is broken open. The patentee defines the term "diffusing element" as follows: The term "diffusing element" as herein employed is intended to embrace any medium that is adapted and arranged to receive and act upon the contents as it issues from the container and prepare it for liberation of the gas gradually or assist in the gradual liberation of the gas. The specification suggests that this material may be wrapped with a few layers of gauze bandage or other suitable material for holding it in close contact with the tube. This, in turn, is covered with a varnished or treated fabric or glazed paper or other moistureproof material 16, stated to be "tightly wrapped around the outside." The ends of the wrapper or covering are held by eyelets 17 which have perforated centers which permit the gas to escape from within the package. The manner of use and the purpose and intent of the invention are described in the following phraseology: Assuming the tube to be filled with a suitable fumigant in solution, the neck 12 of the tube is fractured by a smart blow, and the liquid seeps out into the diffusing absorbent material, where it volatilizes in due course, the gas or vapor finding its way out through the ends of the package or wherever the perforated eyelets 17 or equivalent means are located. The length of time required for the gas to find its way out is sufficient to permit the user to leave the vicinity in advance of the escape of the fumes. 8. The diffusing medium surrounding the ampule will slow down the evolution of gas when the ampule is broken because of the following action: The fibers of the cotton or other diffusing medium form numerous small interstices through which the fumigant fluid first has to permeate or seep, thus contributing a time interval before the fumes escape. (See last phrase in claim 4, next finding.) After the diffusing medium has become saturated with the fumigant fluid, it will act as a wick, thereby controlling the rate of evolution of the gas. When a liquid evaporates it tends to absorb heat from the surround 685 Reporter's Statement of the Case ing medium or atmosphere. The heat-insulating property of the diffusing medium therefore also contributes to a slow rate of gas evolution. The outer cover is varnished or rendered moistureproof and thus forms a liquid-proof or gas-proof covering which also restricts the evolution of gas by holding the liquid contents of the broken ampule within the absorbent layer and allowing it to evaporate only from the relatively small areas of the apertures at the ends of the package. 9. The single claim in suit is claim 4, as follows: 4. A fumigant gas liberating device consisting of a container having a breakable portion, a body of liquid of a character to give off fumigant gas within said container, and a covering surrounding said container comprising a diffusing medium permeable to gas and arranged to receive said liquid when said breakable portion is broken, said covering interposing a substantial resistance to the free flowing away of said liquid when said breakable portion is broken and providing a path for restricted flow of the fumigant gas to the outer air so that after breaking of said breakable portion a substantial length of time intervenes before the escape of the fumigant gas from the device. 10. The meaning of the words "a substantial length of time" included in the closing phraseology of the above-quoted claim in the previous finding, is not indefinite when interpreted by the specification of the patent in suit. This phrase means to those skilled in the art a sufficient length of time to escape from exposure to a dangerous fumigant gas. To an operator using hydrocyanic acid to fumigate an average size room, 12 ft. by 15 ft. by 82 ft., this would mean a safety period of approximately two minutes in which to leave the room after a fumigating ampule had been broken, the twominute period giving a margin of safety to allow for such contingencies as falling over a chair, etc. If the device disclosed in the patent in suit were utilized and the gas was liberated gradually enough to prevent a concentration of gas dangerous to human life in this size room in less than two minutes (volatilization of four-tenths of an ounce of hydrocyanic acid), it would take approximately sixty minutes at this same rate of egress for the com Reporter's Statement of the Case 116 C. Cls. plete escape of the total amount of fumigant (121⁄2 ounces of hydrocyanic acid) necessary for the fumigation of a room this size. 11. From the date of issuance of the patent in suit until September 20, 1948, when hearings were begun in this case, neither plaintiff nor its assignor, Harry W. Houghton, ever manufactured, used or sold any devices made in accordance with the teachings of the patent notwithstanding the fact that the plaintiff company is engaged in the fumigation business. It does not appear that any licenses were ever granted under the patent in suit. THE ALLEGED INFRINGING STRUCTURE 12. During the six-year period prior to March 15, 1945, the date of filing of the petition in the present suit, the Government, without the license or consent of the plaintiff, had manufactured for it and used within the United States fumigant gas-liberating devices for the fumigation of the clothing of military and other personnel. Such fumigation was to exterminate body lice or "cooties" and their unhatched eggs, and such other vermin as might be present. The method employed was, in brief, to have the individual remove all clothing, which was then enclosed in a fumigation bag into which an ampule containing a fumigant material was placed. The ampule was then broken, releasing the fumigant gas. After a 45-minute exposure at ordinary temperatures the clothing was removed from the bag, shaken out, and donned by the individual. The bag was then immediately reused by another infected person. Time was of the essence in this operation as a relatively large number of individuals were usually involved in this process. 13. The delousing bag used by defendant was made of synthetic rubber and was approximately 2 feet wide by 5 feet long. Such a bag is in evidence as defendant's physical exhibit 10. After the clothing had been placed in this bag, the top was folded over three times to make a reasonably gastight closure and tied by means of tapes attached to the bag. A pocket, both ends of which were open, was located inside the bag and on one side thereof. The fumigant cartridge or ampule was placed within this pocket and the bag |