The invention of this machine is attributed to John Thorpe, of Rhode Island, in 1828, and so popular did it become by reason of decreased power necessary to drive it, incidental to the omission of the flyers, and good quality of yarn produced, that, between 1860 and 1865, it nearly replaced all other machines in America for spinning cotton. The speed of the ring frame, as well as its output, appeared unbounded; but at high speeds, under unbalanced loads, the spindles were found to vibrate in their bearings, and the quality of yarn, in consequence, degenerated, the spindle bearings became worn, and the limit seemed to be reached at five thousand revolutions per minute. A careful examination of the ring frame revealed no vulnerable part of its general structure that could be improved so as to readily secure increased speed and steadiness of the spindles when unevenly loaded; but with admirable foresight, developing intellects set to improve the spindles themselves, and, in 1871, Jacob H. Sawyer introduced and patented a spindle and bearing, which was one of the most important improvements in the ring frame. He chambered the bobbin, and by carrying the bolster T well up inside supported the former near its load centre. [Illustration: EARLY SPINNING JENNY.] The evolution of the spindle was not yet complete. The Sawyer type, at more than seven thousand revolutions, would vibrate, and of the many attempts to cure the defect none succeeded fully until the very simple change made by Mr. Rabbeth in 1878. He gave the spindle a small amount of play by making the bolster loose in its supporting case, and placed a packing between the two. A. H. Sherman improved upon the Rabbeth structure by making the bolster and step in one piece and omitting the packing, the cushioning being dependent upon the lubricating oil. [Illustration: GINNING COTTON. THE OLD WAY, PRIOR TO 1800.] [Illustration: GINNING COTTON. THE NEW WAY.] The acme of development in this small but most important part of the ring frame was now reached; and in its approved form it embodies the sleeve whirl extending into the bobbin, the loose, yet adjustable bolster, tapering spindle, removable step, and lubricating reservoir. Such spindles are capable of unlimited speeds,—twenty thousand revolutions per minute have been given,—and under absurdly unbalanced loads they run steadily and with less expenditure of power than the older forms at their slower speeds.