This is a warping mill from circa 1880. The “warp” or lengthwise threads are wound off many bobbins onto the large drum, which has a measured circumference. Each turn of the drum is measured by a gauge and when the correct length of yarn has been wound onto it, the bell is activated to tell the “warper” that the correct length of thread is on the mill. The warps at Masson Mills are about 900 yards long and can contain many hundreds of individual threads, (the finer the thread, the more per warp).
When the warp reaches the length required it is “beamed off”. By reversing the direction of the mill, the threads are wound onto a beam, ready to be installed at the back of the loom, providing the warp threads for weaving.