after stating- the facts as above, delivered the opinion.

The elbow, as an article of manufacture, is corrugated longitudinally; the function of the corrugation being- to afford expansibility to the pipe under pressure of changing cold and heat in its contents; and is crimped on its inner side, the function of the crimp being merely to *151take up the metal in the formation of the elbow. That the elbow, as well as the pipe itself, should be thus corrugated — that is to say. that the corrugation should extend around the elbow — is, in view of the function of such corrugation, a desirability so obvious that the mere conception of it cannot be said to constitute invention. Indeed it appears in a number of previous elbows, notably in the Austin & Obdyke elbow, patent No. 113,614, and the Ritchie elbow, patent No. 342,465 — the only difference between these elbows and the Dieckmann being in the method of taking up the metal for the purpose of forming the elbow. Whatever, therefore, there is of invention, if invention there be in the Dieckmann patent, is not in the conception of an elbow thus corrugated, but in the process employed to bring about corrugation in connection with the crimping; and it was to the difficulty of discovering such process that the delay, if there was any delay, is to be attributed. This disposes of claims 3 and 4, relating to the elbow as a new article of manufacture.

The process in the Dieckmann patent is described as follows:

“By my process a plain elbow is first formed, preferably by rolling a single piece of sheet inetal into a tube, then taking up the surplus metal upon one side into overlapping crimps” (the elbow being given the desired form).

The end of the elbow is then placed over a die and other dies are reciprocated to strike the elbow and give it the cross-sectional configuration of the first die; and by a forward movement of the elbow upon the die, this configuration is successively impressed upon every portion of the elbow, the result being a smooth, true elbow, with regular faces or corrugations running through the length of the elbow.

The process, it will he thus observed, is first to put in the crimps, whereby the tube or pipe is conformed to elbow shape, and then to corrugate it.

Whether this be a patentable process or not, we need not now determine. The burden of infringement is upon complainant, and that burden has not been met; for according to the evidence offered in Court, the corrugating was done first; and this is supported by the appearance of appellee’s elbows brought to our attention at the hearing, which show that the crimps in the basins of the corrugations had not been subjected to any greater pressure than the crimps on their summits. Indeed, their whole appearance shows that whatever pressure was applied for the purpose of turning over the crimps after they had been formed, was applied almost uniformly on summit side and basin of the corrugations.

The decree appealed from is affirmed.