In 1894 the Supreme Court held two patents to be for the same invention in Miller vs. Eagle Mfg. Co., 151 U. S., 186, 66 O. G., 845; and after reviewing numerous decisions laid down the following broad rules relating to this class of cases:

"The result of the foregoing and other authorities is that no patent can issue for an invention actually covered by a former patent, especially to the same patentee, although the terms of the claims may differ; that the second patent, although containing a broader claim, more generical in its character than the specific claims contained in the prior patent, is also void; but that where the second patent covers matter described in the prior patent, essentially distinct and separable from the invention covered thereby, and claims made thereunder, its validity may be sustained.

"In the last class of cases it must distinctly appear that the invention covered by the later patent was a separate invention, distinctly different and independent from that covered by the first patent; in other words, it must be something substantially different from that comprehended in the first patent. It must consist in something more than a mere distinction of the breadth and scope of the claims of each patent. If the case comes within the first or second of the above classes, the second patent is absolutely void."

As will be later noted, the foregoing rules were much broader than required by the case under consideration.

However, the rule is clear and definite, not ambiguous or subject to two interpretations. The court definitely stated that no patent can issue for an invention, actually covered by a former patent, especially to the same patentee, although the terms of the claims may differ; that the second patent, although containing a broader claim, more generical in its character than the specific claims contained in the prior patent, is also void. It must con

sist in something more than a mere distinction in the breadth and scope of the claims of each patent.

The cases to be discussed may be divided into the following classes: (1) Where the patents contain claims that cover the same invention, but are not in the same form, as process or method and apparatus or article claims. (2) Where the claims are in the same form, but differ in scope. (3) Where the claims in one patent are combination claims and the claims in the other patent are drawn to an essential element of that combination.

Mosler Safe & Lock Co. vs. Mosler, 127 U. S., 354, is an example of the first class of cases. In this case the applicant obtained a patent for an article and later, on a co-pending application, obtained a patent for a method of making the article. The Supreme Court held the article claims in the first patent and the method claimed in the second patent to be for the same invention, and said:

"After a patent is granted for an article described as made by causing it to pass through a certain method of operation to produce it, the inventor can not afterwards, on an independent application, secure a patent for the method or process of producing the identical article covered by the previous patent, which article was described in that patent as produced by the method or process sought to be covered by taking out the second patent."

A similar view was taken by the C. C. A. 2d circuit, in General Electric Co. vs P. R. Mallory Co. and vs Save Electric Corp. 298 F. R. 597, wherein the court stated that double patenting might exist where there was but a single process and the only possible result thereof was the single product but did not apply in the case under consideration where there were several processes disclosed.

In Aurora Mantle and Lamp Co. vs. Kaufman, 243 F. R. 911, C. C. A. 7th circuit, the process and product were

originally claimed in a single application and after a requirement of division, applicant divided and filed a second application for the process which resulting patent was held valid as it was clear that the product might be made in other ways than the one disclosed.

In in re Zenk C. A. D. C., F. R. 267, 327, the prior patent was directed to the product and the later, granted on a divisional application, was directed to the process which was declared to be valid.

Process and product patents were under consideration in General Bakelite Co. vs. General Insulate Co., D. C. E. D. N. Y., 276 F. R. 166 and there the court held that the respective dates of filing were not material in patents where the product and process were claimed separately in the respective patents.

In Dayton Fan Motor Co. vs. Westinghouse Electric & Mfg. Co., 118 Fed. Rep., 562, C. C. A.. two applications were filed the same day-one for a method and the other for the apparatus. Later an application was filed for a special means for carrying out the method disclosed in the method application. The court held that the last filed application which was first to issue, did not invalidate the later issued patents, and that the method and apparatus patents were not for the same invention and both were valid. It is noted that as applicant had filed two applications each disclosing a different means for carrying out the method that the method disclosed could result from more than one form of apparatus. Therefore the first patent did not disclose the only means by which the method could be carried out. In other words, the first patent did not grant him a monopoly on the method.

In Century Electric Co. vs. Westinghouse Electric & Mfg. Co., 191 Fed., 350, C. C. A., 8th Circuit, applicant filed an application for an apparatus and process. He later divided out the process and filed a second application therefor in accordance with old Rule 41. The process application was the first to issue. The court held that as applicant had divided out the process claims as required by Rule 41, it was clear that at the time the

contracts were made the process and apparatus were believed to be separate inventions. However, it was not clear to the court that the process and apparatus were inseparable. The court thought that an apparatus not the mechanical equivalent of the one patented might carry out the process, in which event the monopoly of the process would not be extended beyond seventeen years, for on the expiration of the term of the process patent anybody would have the right to carry out the process by an apparatus that was not the mechanical equivalent of the one patented.

The case of Ex parte Edison, 220 O. G., 1373, was somewhat similar to the Century Electric case, with this distinction, that whereas Edison divided out in accordance with old Rule 41, as it existed before Steinmetz vs. Allen, the divisional application was not filed until more than a year after Steinmetz vs. Allen had modified Rule 41. Furthermore, while old Rule 41, which required division between process and apparatus claims, was in force at the time of filing of the divisional application in the Century Electric case, the divisional application carved out of the parent Edison application was not filed until more than a year after Rule 41 had been changed. The Commissioner held that in view of the fact that the process and apparatus were so closely related that it was difficult to tell in which the invention. lay, the applications should have been prosecuted and issued concurrently or as nearly so as possible. In view of the long delay in filing and the dilatory prosecution of the divisional case, it was held that to grant a patent on the divisional case would extend the monopoly covered by the parent case long since issued. In other words, it would amount to granting a second patent for the same invention.

In H. Ward Leonard vs. Maxwell Motor Sales Co. . D. C. S. D. N. Y., 288 F. R. 62, method and apparatus patents were involved and the court could not conceive of a possible infringement of one without infringement of the other, nevertheless the second patent was held

valid, one reason being that the applicant was forced to divide his first application.

The second class of cases to be considered is the one wherein the claims are in the same form but differ in scope. The leading decision covering this class of cases is Miller vs. Eagle, supra. This class of cases had caused the Patent Office considerable trouble before the Miller vs. Eagle decision. In Ex parte Holt, 29 O. G., 171, an application was filed in January, 1880, and later another application was filed and called a decision. The later went to issue first. The Commissioner held that there was no line of division between the two cases and said:

"It is true that the patent is issued upon an application long subsequent to that of the case containing the broadest claims, but I consider the relative dates of the applications of no importance, since a patent has issued upon one of them and the subject-matter is indivisible."

This would seem to be in accordance with the rule later enunciated by the Supreme Court in Miller vs. Eagle, but, as will be noted later, the courts have not followed the practice indicated in Ex parte Holt. In Ex parte Ransom, 39 O. G., 119, the Commissioner said:

"A patent should not issue upon an application which is not properly a division of the subjectmatter of a patent to the same party, even though the application upon which the patent was granted was concurrent."

Ex parte Mullen and Mullen, 50 O. G., 837, does not strictly come within the scope of this paper, but the Commissioner in deciding this case laid down the following rules to govern the various classes of cases coming under the head of double patenting: (1) Cases where the various claims differ among themselves only as they constitute different statements of one and the same