Reprint of John Platt's paper on machinery for preparing and spinning cotton, published in the journal Engineering in September 1867. It traces the development of mechanical spinning from Lewis Paul and Arkwright through Hargreaves' jenny and Crompton's mule to Roberts' self-acting mule. It also covers preparation machinery such as openers, scutchers, carding engines, drawing frames and roving frames. Half the pages are engineering plates of the machines.