E. H. Risley, for appellant.

Geo. T. Spencer, for appellee.

Mr. Justice WHITE delivered the opinion of the court.

The sole question in this case is whether the appliance to which the plaintiff in errot claims the rights of a patentee under the grant of letters patent No. 134,978, bearing date January 21, 1873, issued to his assignor, involves invention, or is simply a manifestation of mechanical skill.

There is no doubt that in this, as in all similar cases, the letters patent are prima facie evidence that the device was patentable. Sitll, we are always required, with this presumption in mind, to examine the question of invention vel non upon its merits in each particular case. In the present instance the letters patent state the device to be an improvement in gratings for sewer inlets, and describe it as follows: [156 U.S. 342, 343] My improvement consists in the employment of a device to elevate the grating above the opening which it covers a short distance, so that it will not become obstructed by small sticks, straws, leaves, and other small rubbish not large enough to clog the sewer or drain with which it may be connected, and at the same time will stop all matter large enough to do injury in said drain.

My improvement may be attached to any form of grating, round, or square, and consists of a cast-iron ring made to fit the collar which surrounds the opening to hold the grate in place, marked a in the drawing, in which I set the cast or wrought-iron pins, marked b in the drawing, to which the grating is firmly attached, and by means of which the grating may be elevated one to two inches, more or less, as may be desirable. These pins may be of wrought iron fitted to holes drilled in the grate and ring; or the grate, ring, and pins for elevating the grate may be cast all in one piece; or wroughtiron pins may be cast into the ring and grate when they are cast.

The whole grating and ring may be taken out as desired, as easily as if they were not furnished with the supporting ring; and my improvement may be used with a wood or iron collar, as may be desired.

By thus elevating the grate a space is left, through which leaves, straws, small sticks will pass freely, and the grate will be kept clear for the passage of water.

I claim:

The grating for sewer openings herein described, consisting of the ring, a, supporting pins, b. and elevate grating, substantially as specified.

It thus appears that the whole subject-matter which is covered consists of a grate elevated above the top of the catch basin of a sewer, and resting on a ring or support placed below the top of the basin by means of pins which thus lift up the grating, between which pins are left spaces allowing the water to pass through, under the grating, the result of so elevating the grate being, it is claimed, to keep the openings on the grating proper, and the openings below free from the [156 U.S. 342, 344] debris which would otherwise accumulate thereon or against the same. There is no pretense that the claim covers a grate of any particular style of manufacture or any particular shape. In fact, it is expressly stated that the grate may be made either round or square, and that the pins may be of wrought iron, fitted to holes drilled in the grate or ring, or the grate, rings, and pins for elevating the grate may be cast all in one piece, or wrought-iron pins may be cast into the ring and grate when they are cast. Viewed separately, the elements of this device certainly involve no invention. A grate over a sewer is one of the simplest of mechanical devices. The mere use of a ring of iron on which to rest such a grating is obviously nothing more than a mechanical arrangement, which involves no element of invention; and the same is the case with the use of pins or legs for the purpose of holding up a sewer grate. And it is equally clear that the leaving of open sp