The first prominent patent in the American office, upon balls or rollers, is dated June 18, 1861, No. 32,604. There are some three hundred drawings of roller and ball-bearing patents on file at the United States office; this, however, does not represent the entire number issued. All of the more recent patents are substantially modifications of former patterns, such as No. 29,570, 1860; 37,765, 1863; 58,739, 1866; 63,609, 1867; 82,665, 1868; 113,867, 1871; 202,271, 1878, and Peter’s, November 20, 1877, No. 197,289. One of the most useful variations and the one best adapted to the cycle art, is the lateral adjusting bearing of this style. [Illustration: Rear-wheel bearing.] Below find selected figure and claim from a prominent patent over which there has been much contention. +J. H. HUGHES, BEARING FOR WHEELS, NO. 227,632, PATENTED MAY 18, 1880.+ [Illustration: Hughes’s Patent.] “What I claim, and wish protected by Letters Patent is,— “In bearings for bicycles, tricycles, or carriages, the combination of hardened conical or curved surfaces, hardened spherical balls, and the means, substantially as shown and described, of adjusting or setting up the parts, for the purposes set forth. “+Joseph Henry Hughes.+” Other forms, such as the disk pattern with an annular groove upon its face, have their special uses. As to friction, ball-bearings may be said to reduce this to nothing, since in mathematical calculations, rolling friction on hard surfaces is usually neglected, as compared with sliding friction. In actual practice this would not quite hold good, since oil and dirt will make a difference. The balls, in the ordinary bearings in the market, roll upon conical, spherical, or cylindrical surfaces. In either of the last two cases the radius of curvature of the box is so much greater than that of the ball that the effect is the same as upon the cone, and in all cases where a bearing is well constructed the action is the same as that of a ball rolling upon a flat surface. True, some friction results from the contact of the balls with each other, but as there is no force driving them together, it is very slight. [Illustration: Annular, ball-bearing.]