The ‘self-acting’ mule, an improvement of the mule jenny, automated the return of the carriage, previously pushed back by hand, using a system of levers and finely adjusted counterweights. The loom winds the yarn onto a spindle, stretching it and creating its principal torsion. The loom then assembles several of these strands, twisting them again to produce yarn of the desired thickness. This scale model was made by the machine makers Dobson & Barlow in the textile-manufacturing town of Bolton near Manchester. It was acquired by the Conservatoire in 1863.