“ It may be doubted whether one who discovers or invents a product be knows to be new will ever find it impossible to describe some aspect of its novelty.
The product claims here involved cannot be validated by reference to the specification. Assuming that in a proper case a claim may be upheld by reference to the descriptive part of the specification in order to give definite content to elements stated in the claim in broad or functional terms, [14] the specification of the Pacz patent does not attempt in any way to describe the filament, except by mention of its coarsegrained quality. ”

“ Although in some instances a claim may validly describe a new product with some reference to the method of production, [16] a patentee who does not distinguish his product from what is old except by reference, express or constructive, to the process by which he produced it, cannot secure a monopoly on the product by whatever means produced. ”

“ That section requires that an applicant for a patent file a written description of his discovery or invention 'in such full, clear, concise, and exact terms as to enable any person skilled in the art or science to which it appertains * * * to make, construct, compound, and use the same; * * * and he shall particularly point out and distinctly claim the part, improvement, or combination which he claims as his invention or discovery.' We may assume that Pacz has sufficiently informed those skilled in the art how to make and use his filament. ”

“ In incandescent lamps, the tungsten filament, through which the electric current passes, grows more luminous than the carbon filament of the early days of the art. There were faults of 'offsetting' and 'sagging,' however, affecting the efficiency of the first tungsten filaments. 'Offsetting' occurs when, during heating in the use of the lamp, the filament forms crystals which extend their boundaries across the entire diameter of the filament, substantially perpendicular to its axis. The crystals in the filament thus come to have an appearance, somewhat analogous to the joints in a bamboo rod. ”

“ Apart from the statement with respect to their function, nothing said about their size distinguishes the earliest filaments, and nothing whatever is said which is descriptive of their contour (termed by the District Court a 'very important element') , not even that they are irregular. ”