to the specification had been publicly sold in Victoria prior to the patent, and that the hood was of such composition and construction that any person con- versant with the subject, and applying the common knowledge at the time of the sale, could have reproduced it
Held, that the patent was invalid on the ground that, where a patent is obtained for a process of manufacture, and there has been a prior public sale of the product of that manufacture, if the product is such that any person conversant with the subject and applying the common knowledge at the time of the sale, could have brought about the same result, the patent is invali-
Quare, per Higgins J., whether prior user of a subsequently patented article by others than the patentee, even without proof of actual or potential knowledge by the public of the process by which the article is to be repro- duced, would not invalidate the patent.
Decision of Full Court, Welsbach Light Co. of Australasia Ltd. v. Lascelles, (1906) V.L.R., 677; 28 A.L.T., 155, reversed.
APPEAL from the Supreme Court of Victoria.
The Welsbach Light Company of Australasia Ltd. brought an action against Robert Lascelles for infringement of their patent No. 11,247, Victoria, dated 31st March 1894. The specification of the patent was substantially as follows :-
'AN IMPROVED HOOD FOR INCANDESCENT GAS BURNERS. This invention relates to incandescent gas burners of the kind described in the specification No. 4472 of 1886.
Burners as herein described consist of a network hood of metallic oxide heated to incandescence by the flame of a Bunsen burner over which the hood is suspended. It has been found that the incandescent oxide of the metal thorium, when in a pure state, gives comparatively little light, but that when it has added to it a very small proportion, generally not exceeding one or two per cent. of the oxides of certain others of the rare metals, namely, uranium, cerium or prazeodymium, it has a very high illuminating power. In order to produce a hood of this kind according to this invention, nitrate of thorium in the purest possible condition is dissolved in water to which is added one to two per cent. of solution of nitrate of one of the other metals above mentioned, preferably uranium. A network hood of vegetable textile material is soaked in the solution, dried, and then subjected to heat over a Bunsen burner, whereby the vegetable fibres are burned away