Tesla Split-Phase Motor Patent Decision

Judge Kohlsaat on Saturday of last week handed down a d in a case involving the Tesla split-phase motor patent brought before the U. S. Circuit Court for the Northern District of Illinois, which decision upholds the Tesla patent and grants an injunction against the use of the split-phase principle in a wattmeter made by the defendants in the action. The opinion cites the opinions of Judges Archbold, Hazel, Townsend and Lacombe sustaining the patent, and the opinion of the Court of Appeals reversing the Lacombe decision, which latter ruling was followed by Judge Colt in another case. All of the above cases have been reported in these columns.

Judge Kohlsaat says that the decision of Judge Lacombe was reversed largely upon the ground that it did not appear from the record that Tesla's invention was not anticipated or described in a paper read by the late Prof. Ferraris before the Royal Acadmy of Sciences, of Turin, Italy, on March 18, 1888, and published, in part, in an electrical journal issued at Milan on April 22, 1888. He holds, however, that in the later cases-those decided by Judges Archbold and Hazel — the records, together with certain original proofs offered in the present case, establish that Tesla's invention in suit antedated the Ferraris article, was original with Tesla, and that his patents are valid.