94 F. 1006 | U.S. Circuit Court for the District of Southern New York | 1899
The Welsbach incandescent mantle is a light hood or frame, which is suspended over the flame oí a Bunsen burner so as to become heated by it to incandescence,' causing it to
That “the object o£ our improvement is to render these mantles, after ignition, sufficiently hard and resistapt to allow of packing and handling without fear of breakage in the transport. * * * , Difficulty has been found heretofore in the transport of these mantles without breakage, and various methods have been proposed. This difficulty our invention is designed to overcome by dipping the mantles, after they have been given their proper shape, into a liquid which will thoroughly penetrate the pores of the material, and will afterwards set to such a degree of hardness as to protect the material from dan- - ger of breakage in packing or handling, and which can afterward be removed without mechanical injury to the mantles, or without leaving any objectionable residue. * * * We have found that a very satisfactory method of carrying out our invention consists in dipping the cone into a hot solution of volatile hydrocarbon--such as benzine — mixed with paraffine wax or paraffine alone. By these means the mantle is covered with a thin coating of wax, which becomes sufficiently hard on cooling to allow of packing and handling without fear of breakage. The paraffine is capable of burning away without any residue except carbon, which will always be burned completely away by the flame of the Bunsen burner. * * * Other materials may bo employed as long as they set hard at ordinary temperatures, and burn away without mechanical destruction to the mantle, and without leaving any residue, which would injure the light-giving properties of the mantle. The materials referred to as being capable of use in lieu of paraffine may be any solid hydrocarbon of a high boiling point, and many resins and gums soluble in spirit, such as alcohol, etc. Shellac will serve the same purpose, but not quite as advantageously.”
The claim is:
“(1) The herein-described improvement in strengthening incandescent mantles, consisting in coating the completed mantle with paraffine or other suitable material, substantially as set forth.”
The patent now in suit came before this court in the case of Welsbach Light Co. v. Sunlight Incandescent Gas Lamp Co., and at finál
The next question is, what new evidence, not presented at final hearing, is now before (he court? Besides an English patent to Paget, the application for which is subsequent in date to the Dawsons'" application for their English patent, two patents to Welsbach have been introduced. The first is a French patent, No. 172,0(54, deposited November 4, 1885, to which a certificate of addition was deposited April 22, 188(5, and published during the third three months of 1880. Tin1 part of said certificate of addition relied on reads as follows:
“To protect the tissue, and in particular to prevent it from being injured by the jet of gas. one can introduce into il some stronger threads, as is shown in figure 7. likewise, in order to strengthen the parts of the finished mantle which are exposed to the first contact with the flame when it is in use, they are covered, by means of a small brush, with a certain quantity of the same solution in a rather concentrated state, or, rattier, one plunges them into the solution which, when one heals them anew to incandescence, is also converted to earthy substance. In order to make the finished mantle adhere very firmly to the platinum wire forming a. support, the parts in contact with the metallic wire are treated in the same manner. For this purpose one can employ the same solution of salt, or. in preference, a solution of about equal parts of nitrate of magnesium and nitrate of aluminium, to which one can add phosphoric acid. One can also, for this purpose, employ nitrate! of beryllium. The mantles can be plunged into the said solutions either before or after the combustion of the fibrous structure.”
“In order to protect the fabric, and prevent its rupture when it is exposed ,to a strong current of gas, stronger threads can be added to the fabric before it is converted into ashes. Also the fabric can be painted with, or dipped into, a concentrated solution of the salts, so as to provide a fresh layer of the metallic salts, which become fully oxidized soon after the fabric has become incandescent. In order to strengthen the connection of the cone of earths to the platinum wire, those parts of the fabric which are next the wire are more fully impregnated with the solution, or with a solution of about equal parts of nitrates of magnesium and aluminium.”
Exactly what this process of Welsbach’s was may be made clearer by quotation from the patents which were before Judge Townsend. The German patent to Welsbach, issued April 15, 1887 (No. 39,612), says: “To protect the tissue, mainly to prevent a bursting of the same by the emanating gases of the flame, stronger threads may be inserted before incineration. For the same purpose, to strengthen the parts of the finished mantle exposed to the first attack of the gases, said parts are covered with a rather concentrated solution of the salts mentioned by means of a little brush, or covered with a new coating by immersing them. Thereafter, through an incandescence of the whole tissue for a second of time, the earths are again set free. To attach the finished earth mantle very firmly to the supporting platinum wire, so that the mantle can withstand any vibration, the parts of the mantle in contact with the platinum wire are treated in the same manner. For this purpose the same solution is used, or, preferably, a solution of about equal parts of nitrates of magnesium and aluminium with an addition of phosphoric acid. Nitrate of beryllium can be used in the same way for the fixation. The mantles may be covered with the above solutions either before or after the incineration. In producing the ‘Zirconia mantles,’ the mantle is gradually lifted when its upper part is fully incandescent.”
In the other G-erman patent, issued to Mm December IT, 1887 (No. 41,945), Welsbach, by an amendment suggested October 20, 1886, added the following:
' “As an incinerated mantle is very delicate, and quite readily destroyed, although knit mantles can even be touched by hand and deformed by gentle pressure, without being destroyed, but will return to their original shape after the pressure is removed, yet such an incandescent mantle cannot stand any longer transportation, especially when exposed to uneven and violent shocks. If, however, such an incinerated mantle is coated with a substance which is not brittle, and can be burned with perfect ease, and which will permit of the single particles being displaced only within their limit of elasticity, the incandescent body, even in its incinerated condition, will stand without danger any trans portation. To produce this coating, the ready incinerated mantle is dipped for a moment into a very dilute solution of caoutchouc, or into collodion, or some like substance, and is then slowly dried. At the first moment .of the subsequent incandescence of the mantle, this coating is completely destroyed by the flame, and the mantle is left behind in its original shape.”
For this no claim is made in No. 41,945. These two patents last quoted from, it will be noted, are subsequent to Eawsons' invention as disclosed in the English patent of.September 1, 1886.
It is quite apparent that the process set forth in the two new patents is not the same as that described in those last quoted from, which were before Judge Townsend; and it seems entirely clear that it involves a different invention from that covered by the patent in suit. What Welsbach disclosed in those earlier patents was a subsidiary treatment, which lay closely within the lines of his original invention,,
Defendant has introduced four affidavits to show prior use at the laboratory of one Charles M. Lungren. Lungren himself, however, in an answering affidavit, fixes the date (by reference to the formation of the Lungren Incandescent Gas Light Company) too late to affect the validity of the patent. Accepting the conclusion in the Sunlight Case that the patentees are entitled to a liberal application of the doctrine of equivalents, it is unnecessary to discuss the question of infringement. The solution of the defendant in tills case is substantially the same as in the Sunlight Case (collodion and castor oil), with a slight admixture of water. Preliminary injunction may issue.